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Publisher: Springer-Verlag   (Total: 2335 journals)

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Showing 1 - 200 of 2335 Journals sorted alphabetically
3D Research     Hybrid Journal   (Followers: 19, SJR: 0.214, h-index: 10)
4OR: A Quarterly J. of Operations Research     Hybrid Journal   (Followers: 9, SJR: 1.073, h-index: 25)
AAPS J.     Hybrid Journal   (Followers: 16, SJR: 1.192, h-index: 74)
AAPS PharmSciTech     Hybrid Journal   (Followers: 6, SJR: 0.718, h-index: 54)
Abdominal Imaging     Hybrid Journal   (Followers: 16, SJR: 0.723, h-index: 60)
Abhandlungen aus dem Mathematischen Seminar der Universitat Hamburg     Hybrid Journal   (Followers: 2, SJR: 0.447, h-index: 12)
Academic Psychiatry     Full-text available via subscription   (Followers: 22, SJR: 0.492, h-index: 32)
Academic Questions     Hybrid Journal   (Followers: 7, SJR: 0.135, h-index: 6)
Accreditation and Quality Assurance: J. for Quality, Comparability and Reliability in Chemical Measurement     Hybrid Journal   (Followers: 25, SJR: 0.378, h-index: 30)
Acoustical Physics     Hybrid Journal   (Followers: 10, SJR: 0.355, h-index: 20)
Acta Analytica     Hybrid Journal   (Followers: 7, SJR: 0.387, h-index: 6)
Acta Applicandae Mathematicae     Hybrid Journal   (Followers: 1, SJR: 0.624, h-index: 34)
Acta Biotheoretica     Hybrid Journal   (Followers: 5, SJR: 0.419, h-index: 25)
Acta Diabetologica     Hybrid Journal   (Followers: 14, SJR: 1.318, h-index: 46)
Acta Endoscopica     Hybrid Journal   (Followers: 1, SJR: 0.113, h-index: 8)
acta ethologica     Hybrid Journal   (Followers: 4, SJR: 0.465, h-index: 23)
Acta Geochimica     Hybrid Journal   (Followers: 3)
Acta Geodaetica et Geophysica     Hybrid Journal   (Followers: 1, SJR: 0.294, h-index: 13)
Acta Geotechnica     Hybrid Journal   (Followers: 6, SJR: 1.818, h-index: 22)
Acta Informatica     Hybrid Journal   (Followers: 5, SJR: 0.524, h-index: 32)
Acta Mathematica     Hybrid Journal   (Followers: 9, SJR: 8.021, h-index: 47)
Acta Mathematica Hungarica     Hybrid Journal   (Followers: 2, SJR: 0.53, h-index: 29)
Acta Mathematica Sinica, English Series     Hybrid Journal   (Followers: 5, SJR: 0.406, h-index: 30)
Acta Mathematica Vietnamica     Hybrid Journal   (SJR: 0.451, h-index: 5)
Acta Mathematicae Applicatae Sinica, English Series     Hybrid Journal   (SJR: 0.22, h-index: 20)
Acta Mechanica     Hybrid Journal   (Followers: 18, SJR: 0.898, h-index: 52)
Acta Mechanica Sinica     Hybrid Journal   (Followers: 4, SJR: 0.426, h-index: 29)
Acta Metallurgica Sinica (English Letters)     Hybrid Journal   (Followers: 5, SJR: 0.525, h-index: 18)
Acta Meteorologica Sinica     Hybrid Journal   (Followers: 3, SJR: 0.524, h-index: 14)
Acta Neurochirurgica     Hybrid Journal   (Followers: 7, SJR: 0.833, h-index: 73)
Acta Neurologica Belgica     Hybrid Journal   (SJR: 0.348, h-index: 27)
Acta Neuropathologica     Hybrid Journal   (Followers: 3, SJR: 6.61, h-index: 117)
Acta Oceanologica Sinica     Hybrid Journal   (Followers: 3, SJR: 0.295, h-index: 17)
Acta Parasitologica     Hybrid Journal   (Followers: 9, SJR: 0.581, h-index: 28)
Acta Physiologiae Plantarum     Hybrid Journal   (Followers: 2, SJR: 0.551, h-index: 39)
Acta Politica     Hybrid Journal   (Followers: 13, SJR: 0.658, h-index: 20)
adhäsion KLEBEN & DICHTEN     Hybrid Journal   (Followers: 5, SJR: 0.103, h-index: 4)
ADHD Attention Deficit and Hyperactivity Disorders     Hybrid Journal   (Followers: 20, SJR: 0.871, h-index: 15)
Adhesion Adhesives & Sealants     Hybrid Journal   (Followers: 7)
Administration and Policy in Mental Health and Mental Health Services Research     Partially Free   (Followers: 15, SJR: 0.795, h-index: 40)
Adsorption     Hybrid Journal   (Followers: 4, SJR: 0.774, h-index: 52)
Advances in Applied Clifford Algebras     Hybrid Journal   (Followers: 3, SJR: 0.319, h-index: 15)
Advances in Atmospheric Sciences     Hybrid Journal   (Followers: 34, SJR: 0.959, h-index: 44)
Advances in Computational Mathematics     Hybrid Journal   (Followers: 15, SJR: 1.255, h-index: 44)
Advances in Contraception     Hybrid Journal   (Followers: 2)
Advances in Data Analysis and Classification     Hybrid Journal   (Followers: 48, SJR: 1.113, h-index: 14)
Advances in Gerontology     Partially Free   (Followers: 7, SJR: 0.141, h-index: 3)
Advances in Health Sciences Education     Hybrid Journal   (Followers: 23, SJR: 1.397, h-index: 42)
Advances in Manufacturing     Hybrid Journal   (Followers: 3, SJR: 0.2, h-index: 4)
Advances in Polymer Science     Hybrid Journal   (Followers: 40, SJR: 0.637, h-index: 89)
Advances in Therapy     Hybrid Journal   (Followers: 6, SJR: 0.79, h-index: 44)
Aegean Review of the Law of the Sea and Maritime Law     Hybrid Journal   (Followers: 7)
Aequationes Mathematicae     Hybrid Journal   (Followers: 2, SJR: 0.882, h-index: 23)
Aerobiologia     Hybrid Journal   (Followers: 1, SJR: 0.511, h-index: 36)
Aesthetic Plastic Surgery     Hybrid Journal   (Followers: 8, SJR: 0.821, h-index: 49)
African Archaeological Review     Hybrid Journal   (Followers: 14, SJR: 0.612, h-index: 24)
Afrika Matematika     Hybrid Journal   (Followers: 1, SJR: 0.248, h-index: 6)
AGE     Hybrid Journal   (Followers: 7, SJR: 1.358, h-index: 33)
Ageing Intl.     Hybrid Journal   (Followers: 6, SJR: 0.337, h-index: 10)
Aggiornamenti CIO     Hybrid Journal   (Followers: 1)
Aging Clinical and Experimental Research     Hybrid Journal   (Followers: 3, SJR: 0.529, h-index: 55)
Agricultural Research     Hybrid Journal   (Followers: 3)
Agriculture and Human Values     Hybrid Journal   (Followers: 12, SJR: 1.197, h-index: 49)
Agroforestry Systems     Hybrid Journal   (Followers: 20, SJR: 0.64, h-index: 56)
Agronomy for Sustainable Development     Hybrid Journal   (Followers: 10, SJR: 1.732, h-index: 59)
AI & Society     Hybrid Journal   (Followers: 7, SJR: 0.171, h-index: 19)
AIDS and Behavior     Hybrid Journal   (Followers: 13, SJR: 2.006, h-index: 71)
Air Quality, Atmosphere & Health     Hybrid Journal   (Followers: 2, SJR: 0.706, h-index: 19)
Akupunktur & Aurikulomedizin     Full-text available via subscription   (Followers: 1)
Algebra and Logic     Hybrid Journal   (Followers: 2, SJR: 0.566, h-index: 18)
Algebra Universalis     Hybrid Journal   (Followers: 2, SJR: 0.388, h-index: 22)
Algebras and Representation Theory     Hybrid Journal   (SJR: 0.868, h-index: 20)
Algorithmica     Hybrid Journal   (Followers: 7, SJR: 0.898, h-index: 56)
Allergo J.     Full-text available via subscription   (Followers: 1, SJR: 0.183, h-index: 20)
Allergo J. Intl.     Hybrid Journal   (Followers: 2)
Alpine Botany     Hybrid Journal   (Followers: 3, SJR: 0.729, h-index: 20)
ALTEX : Alternatives to Animal Experimentation     Open Access   (Followers: 3, SJR: 1.392, h-index: 32)
AMBIO     Hybrid Journal   (Followers: 14, SJR: 1.094, h-index: 87)
American J. of Cardiovascular Drugs     Hybrid Journal   (Followers: 10, SJR: 0.864, h-index: 39)
American J. of Community Psychology     Hybrid Journal   (Followers: 24, SJR: 1.237, h-index: 83)
American J. of Criminal Justice     Hybrid Journal   (Followers: 5, SJR: 0.634, h-index: 13)
American J. of Cultural Sociology     Hybrid Journal   (Followers: 11, SJR: 0.283, h-index: 3)
American J. of Dance Therapy     Hybrid Journal   (Followers: 4, SJR: 0.175, h-index: 13)
American J. of Potato Research     Hybrid Journal   (Followers: 2, SJR: 0.558, h-index: 35)
American J. of Psychoanalysis     Hybrid Journal   (Followers: 20, SJR: 0.293, h-index: 13)
American Sociologist     Hybrid Journal   (Followers: 10, SJR: 0.18, h-index: 13)
Amino Acids     Hybrid Journal   (Followers: 8, SJR: 1.362, h-index: 83)
AMS Review     Partially Free   (Followers: 4)
Analog Integrated Circuits and Signal Processing     Hybrid Journal   (Followers: 5, SJR: 0.21, h-index: 37)
Analysis and Mathematical Physics     Hybrid Journal   (Followers: 4, SJR: 0.665, h-index: 7)
Analysis in Theory and Applications     Hybrid Journal  
Analysis of Verbal Behavior     Hybrid Journal   (Followers: 4)
Analytical and Bioanalytical Chemistry     Hybrid Journal   (Followers: 32, SJR: 1.096, h-index: 123)
Anatomical Science Intl.     Hybrid Journal   (Followers: 2, SJR: 0.301, h-index: 26)
Angewandte Schmerztherapie und Palliativmedizin     Hybrid Journal  
Angiogenesis     Hybrid Journal   (Followers: 3, SJR: 2.212, h-index: 69)
Animal Cognition     Hybrid Journal   (Followers: 13, SJR: 1.122, h-index: 55)
Annales françaises de médecine d'urgence     Hybrid Journal   (Followers: 1, SJR: 0.156, h-index: 4)
Annales Henri Poincaré     Hybrid Journal   (Followers: 3, SJR: 1.377, h-index: 32)
Annales mathématiques du Québec     Hybrid Journal   (Followers: 4)
Annali dell'Universita di Ferrara     Hybrid Journal   (SJR: 0.504, h-index: 14)
Annali di Matematica Pura ed Applicata     Hybrid Journal   (Followers: 1, SJR: 1.167, h-index: 26)
Annals of Behavioral Medicine     Hybrid Journal   (Followers: 10, SJR: 2.112, h-index: 98)
Annals of Biomedical Engineering     Hybrid Journal   (Followers: 18, SJR: 1.182, h-index: 94)
Annals of Combinatorics     Hybrid Journal   (Followers: 3, SJR: 0.849, h-index: 15)
Annals of Data Science     Hybrid Journal   (Followers: 8)
Annals of Dyslexia     Hybrid Journal   (Followers: 9, SJR: 0.857, h-index: 40)
Annals of Finance     Hybrid Journal   (Followers: 26, SJR: 0.686, h-index: 14)
Annals of Forest Science     Hybrid Journal   (Followers: 4, SJR: 0.929, h-index: 57)
Annals of Global Analysis and Geometry     Hybrid Journal   (Followers: 1, SJR: 1.136, h-index: 23)
Annals of Hematology     Hybrid Journal   (Followers: 13, SJR: 1.117, h-index: 62)
Annals of Mathematics and Artificial Intelligence     Hybrid Journal   (Followers: 6, SJR: 0.593, h-index: 42)
Annals of Microbiology     Hybrid Journal   (Followers: 9, SJR: 0.402, h-index: 26)
Annals of Nuclear Medicine     Hybrid Journal   (Followers: 5, SJR: 0.68, h-index: 45)
Annals of Operations Research     Hybrid Journal   (Followers: 8, SJR: 1.186, h-index: 78)
Annals of Regional Science     Hybrid Journal   (Followers: 7, SJR: 0.405, h-index: 42)
Annals of Software Engineering     Hybrid Journal   (Followers: 12)
Annals of Solid and Structural Mechanics     Hybrid Journal   (Followers: 9, SJR: 0.553, h-index: 8)
Annals of Surgical Oncology     Hybrid Journal   (Followers: 11, SJR: 1.902, h-index: 127)
Annals of Telecommunications     Hybrid Journal   (Followers: 7, SJR: 0.315, h-index: 25)
Annals of the Institute of Statistical Mathematics     Hybrid Journal   (Followers: 1, SJR: 0.931, h-index: 31)
Antonie van Leeuwenhoek     Hybrid Journal   (Followers: 5, SJR: 0.992, h-index: 87)
Apidologie     Hybrid Journal   (Followers: 4, SJR: 1.14, h-index: 57)
APOPTOSIS     Hybrid Journal   (Followers: 7, SJR: 1.554, h-index: 87)
Applicable Algebra in Engineering, Communication and Computing     Hybrid Journal   (Followers: 2, SJR: 0.354, h-index: 27)
Applications of Mathematics     Hybrid Journal   (Followers: 1, SJR: 0.274, h-index: 20)
Applied Biochemistry and Biotechnology     Hybrid Journal   (Followers: 45, SJR: 0.575, h-index: 80)
Applied Biochemistry and Microbiology     Hybrid Journal   (Followers: 17, SJR: 0.267, h-index: 26)
Applied Categorical Structures     Hybrid Journal   (Followers: 2, SJR: 0.361, h-index: 21)
Applied Composite Materials     Hybrid Journal   (Followers: 45, SJR: 0.705, h-index: 35)
Applied Entomology and Zoology     Partially Free   (Followers: 2, SJR: 0.554, h-index: 34)
Applied Geomatics     Hybrid Journal   (Followers: 3, SJR: 0.323, h-index: 9)
Applied Geophysics     Hybrid Journal   (Followers: 7, SJR: 0.541, h-index: 13)
Applied Intelligence     Hybrid Journal   (Followers: 13, SJR: 0.777, h-index: 43)
Applied Magnetic Resonance     Hybrid Journal   (Followers: 3, SJR: 0.358, h-index: 34)
Applied Mathematics & Optimization     Hybrid Journal   (Followers: 4, SJR: 0.955, h-index: 33)
Applied Mathematics - A J. of Chinese Universities     Hybrid Journal   (SJR: 0.275, h-index: 8)
Applied Mathematics and Mechanics     Hybrid Journal   (Followers: 4, SJR: 0.37, h-index: 26)
Applied Microbiology and Biotechnology     Hybrid Journal   (Followers: 61, SJR: 1.262, h-index: 161)
Applied Physics A     Hybrid Journal   (Followers: 8, SJR: 0.535, h-index: 121)
Applied Physics B: Lasers and Optics     Hybrid Journal   (Followers: 22, SJR: 0.983, h-index: 104)
Applied Psychophysiology and Biofeedback     Hybrid Journal   (Followers: 5, SJR: 0.677, h-index: 47)
Applied Research in Quality of Life     Hybrid Journal   (Followers: 10, SJR: 0.288, h-index: 15)
Applied Solar Energy     Hybrid Journal   (Followers: 16, SJR: 0.251, h-index: 6)
Applied Spatial Analysis and Policy     Hybrid Journal   (Followers: 4, SJR: 0.351, h-index: 9)
Aquaculture Intl.     Hybrid Journal   (Followers: 21, SJR: 0.613, h-index: 40)
Aquarium Sciences and Conservation     Hybrid Journal   (Followers: 1)
Aquatic Ecology     Hybrid Journal   (Followers: 31, SJR: 0.646, h-index: 44)
Aquatic Geochemistry     Hybrid Journal   (Followers: 3, SJR: 0.764, h-index: 39)
Aquatic Sciences     Hybrid Journal   (Followers: 12, SJR: 1.172, h-index: 53)
Arabian J. for Science and Engineering     Hybrid Journal   (Followers: 5, SJR: 0.345, h-index: 20)
Arabian J. of Geosciences     Hybrid Journal   (Followers: 1, SJR: 0.417, h-index: 16)
Archaeological and Anthropological Sciences     Hybrid Journal   (Followers: 21, SJR: 1.056, h-index: 15)
Archaeologies     Hybrid Journal   (Followers: 12, SJR: 0.397, h-index: 13)
Archiv der Mathematik     Hybrid Journal   (SJR: 0.597, h-index: 29)
Archival Science     Hybrid Journal   (Followers: 51, SJR: 0.804, h-index: 22)
Archive for History of Exact Sciences     Hybrid Journal   (Followers: 7, SJR: 0.28, h-index: 15)
Archive for Mathematical Logic     Hybrid Journal   (Followers: 1, SJR: 0.946, h-index: 23)
Archive for Rational Mechanics and Analysis     Hybrid Journal   (SJR: 4.091, h-index: 66)
Archive of Applied Mechanics     Hybrid Journal   (Followers: 4, SJR: 0.865, h-index: 40)
Archives of Computational Methods in Engineering     Hybrid Journal   (Followers: 4, SJR: 2.841, h-index: 40)
Archives of Dermatological Research     Hybrid Journal   (Followers: 6, SJR: 0.9, h-index: 65)
Archives of Environmental Contamination and Toxicology     Hybrid Journal   (Followers: 10, SJR: 0.846, h-index: 84)
Archives of Gynecology and Obstetrics     Hybrid Journal   (Followers: 16, SJR: 0.695, h-index: 47)
Archives of Microbiology     Hybrid Journal   (Followers: 8, SJR: 0.702, h-index: 85)
Archives of Orthopaedic and Trauma Surgery     Hybrid Journal   (Followers: 8, SJR: 1.039, h-index: 56)
Archives of Osteoporosis     Hybrid Journal   (Followers: 2, SJR: 1.092, h-index: 13)
Archives of Sexual Behavior     Hybrid Journal   (Followers: 9, SJR: 1.198, h-index: 74)
Archives of Toxicology     Hybrid Journal   (Followers: 16, SJR: 1.595, h-index: 76)
Archives of Virology     Hybrid Journal   (Followers: 4, SJR: 1.086, h-index: 90)
Archives of Women's Mental Health     Hybrid Journal   (Followers: 13, SJR: 1.264, h-index: 50)
Archivio di Ortopedia e Reumatologia     Hybrid Journal  
Archivum Immunologiae et Therapiae Experimentalis     Hybrid Journal   (Followers: 2, SJR: 1.2, h-index: 42)
ArgoSpine News & J.     Hybrid Journal   (SJR: 0.102, h-index: 3)
Argumentation     Hybrid Journal   (Followers: 4, SJR: 0.295, h-index: 18)
Arid Ecosystems     Hybrid Journal   (Followers: 3)
Arkiv för Matematik     Hybrid Journal   (SJR: 0.948, h-index: 22)
Arnold Mathematical J.     Hybrid Journal   (Followers: 1)
Arthropod-Plant Interactions     Hybrid Journal   (Followers: 2, SJR: 0.797, h-index: 17)
Arthroskopie     Hybrid Journal   (Followers: 1, SJR: 0.145, h-index: 8)
Artificial Intelligence and Law     Hybrid Journal   (Followers: 8, SJR: 0.288, h-index: 25)
Artificial Intelligence Review     Hybrid Journal   (Followers: 15, SJR: 0.948, h-index: 48)
Artificial Life and Robotics     Hybrid Journal   (Followers: 8, SJR: 0.231, h-index: 14)
Asia Europe J.     Hybrid Journal   (Followers: 4, SJR: 0.247, h-index: 9)
Asia Pacific Education Review     Hybrid Journal   (Followers: 9, SJR: 0.371, h-index: 17)
Asia Pacific J. of Management     Hybrid Journal   (Followers: 11, SJR: 1.676, h-index: 50)
Asia-Pacific Education Researcher     Hybrid Journal   (Followers: 11, SJR: 0.353, h-index: 13)
Asia-Pacific Financial Markets     Hybrid Journal   (Followers: 2, SJR: 0.19, h-index: 15)
Asia-Pacific J. of Atmospheric Sciences     Hybrid Journal   (Followers: 20, SJR: 1.006, h-index: 14)
Asian Business & Management     Hybrid Journal   (Followers: 7, SJR: 0.41, h-index: 10)
Asian J. of Business Ethics     Hybrid Journal   (Followers: 7)
Asian J. of Criminology     Hybrid Journal   (Followers: 5, SJR: 0.263, h-index: 8)
AStA Advances in Statistical Analysis     Hybrid Journal   (Followers: 2, SJR: 0.681, h-index: 15)
AStA Wirtschafts- und Sozialstatistisches Archiv     Hybrid Journal   (Followers: 5, SJR: 0.195, h-index: 5)
ästhetische dermatologie & kosmetologie     Full-text available via subscription  
Astronomy and Astrophysics Review     Hybrid Journal   (Followers: 21, SJR: 4.511, h-index: 44)
Astronomy Letters     Hybrid Journal   (Followers: 19, SJR: 0.58, h-index: 30)
Astronomy Reports     Hybrid Journal   (Followers: 12, SJR: 0.473, h-index: 23)
Astrophysical Bulletin     Hybrid Journal   (Followers: 2, SJR: 0.469, h-index: 11)
Astrophysics     Hybrid Journal   (Followers: 22, SJR: 0.243, h-index: 11)

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Journal Cover AAPS PharmSciTech
  [SJR: 0.718]   [H-I: 54]   [6 followers]  Follow
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 1530-9932
   Published by Springer-Verlag Homepage  [2335 journals]
  • Influence of long-term stability conditions on microbicidal nucleoside
           prodrug (WHI-07)-loaded gel-microemulsion
    • Authors: Osmond J. D’Cruz; Fatih M. Uckun
      Abstract: The objective of this study was to evaluate the long-term stability of the antiretroviral spermicide WHI-07 (5-bromo-6-methoxy-5,6-dihydro-3′-azidothymidine-5′-(p-bromophenyl)-methoxyalaninyl phosphate) in a polymer-based microemulsion. The recovery and stability of WHI-07 in gelmicroemulsion was examined by a validated high-performance liquid chromatography (HPLC) method. The stability was examined over a period of 24 weeks at 3 controlled temperatures (4°C, 25°C, and 40°C). The recovery of the prodrug from 0.5% to 2.0% WHI-07-loaded gel-microemulsion was 99.8%. HPLC analysis revealed that a 2% WHI-07-loaded gel-microemulsion stored at room temperature and cold temperatures for 24 weeks retained >90% of the prodrug, whereas those stored at 40°C maintained 90% of initial WHI-07 for at least 10 weeks. The observed stability of WHI-07 in gel-microemulsion is of great importance for its widespread utility in various climatological conditions.
      PubDate: 2017-03-08
      DOI: 10.1208/pt070373
      Issue No: Vol. 7, No. 3 (2017)
  • Evaluation of powder and tableting properties of chitosan
    • Authors: Katharina M. Picker-Freyer; Diana Brink
      Abstract: The aim of this study was to analyze the process of tablet formation and the properties of the resulting tablets for 3 N-deacetylated chitosans, with a degree of deacetylation of 80%, 85%, or 90%. Material properties, such as water content, particle size and morphology, glass transition temperature, and molecular weight were studied. The process of tablet formation was analyzed by 3-D modeling, Heckel analysis, the pressure time function, and energy calculations in combination with elastic recovery dependent on maximum relative density and time. The crushing force and the morphology of the final tablets were analyzed. Chitosans sorb twice as much water as microcrystalline cellulose (MCC), the particle size is comparable to Avicel PH 200, a special type of MCC, the particles look like shells, and the edges are bent. Molecular weight ranges from 80 000 to 210 000 kDa, the glass transition temperature (Tg) was not dependent on molecular weight. The chitosans deform ductilely as MCC; however, plastic deformation with regard to time and also pressure plasticity are higher than for MCC, especially for Chit 85, which has the lowest crystallinity and molecular weight. At high densification, fast elastic decompression is higher. 3-D modeling allowed the most precise analysis. Elastic recovery after tableting is higher than for MCC tablets and continues for some time after tableting. The crushing force of the resulting tablets is high owing to a reversible exceeding of Tg in the amorphous parts of the material. However, the crushing force is lower compared with MCC, since the crystallinity and the Tg of the chitosans are higher than for MCC. In summation, chitosans show plastic deformation during compression combined with high elasticity after tableting. Highly mechanically stable tablets result.
      PubDate: 2017-03-08
      DOI: 10.1208/pt070375
      Issue No: Vol. 7, No. 3 (2017)
  • Design and development of microemulsion drug delivery system of acyclovir
           for improvement of oral bioavailability
    • Authors: Pradip Kumar Ghosh; Rita J. Majithiya; Manish L. Umrethia; Rayasa S. R. Murthy
      Abstract: The main purpose of this work was to develop an oral microemulsion formulation for enhancing the bioavailability of acyclovir. A Labrafac-based microemulsion formulation with Labrasol as surfactant and Plurol Oleique as cosurfactant was developed for oral delivery of acyclovir. Phase behavior and solubilization capacity of the microemulsion system were characterized, and in vivo oral absorption of acyclovir from the microemulsion was investigated in rats. A single isotropic region, which was considered to be a bicontinuous microemulsion, was found in the pseudoternary phase diagrams developed at various Labrasol:Plurol Oleique:Labrafac ratios. With the increase of Labrasol concentration, the microemulsion region area and the amount of water and Labrafac solubilized into the microemulsion system increased; however, the increase of Plurol Oleique percentage produced opposite effects. The microemulsion system was also investigated in terms of other characteristics, such as interfacial tension, viscosity, pH, refractive index, diffusion, and bioavailability. Acyclovir, a poorly soluble drug, displayed high solubility in a microemulsion formulation using Labrafac (10%). Labrasol (32%), Plurol Oleique (8%), and water (50%). The in vitro intraduodenal diffusion and in vivo study revealed an increase of bioavailability (12.78 times) after oral administration of the microemulsion formulation as compared with the commercially available tablets.
      PubDate: 2017-03-08
      DOI: 10.1208/pt070377
      Issue No: Vol. 7, No. 3 (2017)
  • Removal of peroxides in polyethylene glycols by vacuum drying:
           Implications in the stability of biotech and pharmaceutical formulations
    • Authors: Vineet Kumar; Devendra S. Kalonia
      Abstract: The purpose of this study was to investigate the utility of vacuum drying for removing peroxides from polyethylene glycols (PEGs). PEG solutions (PEG 1450 and PEG 20000) containing varying levels of peroxides were prepared by storing under different light and temperature conditions. PEGs containing low and high levels of peroxides were vacuum dried from dilute and concentrated solutions (2.5%, 7.5%, 15%, and 50% wt/vol of PEG 1450 and 2.5%, 7.5%, 15%, and 25% wt/vol of PEG 20000). Ferrous ion oxidation in presence of ferric ion indicator xylenol orange (FOX) colorimetric assay was used to determine the concentration of peroxides. Peroxide content in PEGs increased upon storage. The increase was more pronounced when PEGs were stored at higher temperatures and exposed to light. Vacuum drying at 0.1 mm Hg for 48 hours at 25°C resulted in greater than 90% decrease in the level of peroxides in all cases except when high peroxide containing 25% wt/vol solution of PEG 20000 or 50% wt/vol solution of PEG 1450 were dried. The reduction in the level of peroxides for PEGs dried from high peroxide containing 25% wt/vol solution of PEG 2000 and 50% wt/vol solution of PEG 1450 was found to be 88% and 52%, respectively. Oxidation of methionine in Met-Leu-Phe peptide was significantly reduced when vacuum-dried PEGs were used. Vacuum drying PEG solutions at low pressures is an effective method for the removal of the residual peroxides present in commercially available PEGs.
      PubDate: 2017-03-08
      DOI: 10.1208/pt070362
      Issue No: Vol. 7, No. 3 (2017)
  • Enhancement of dissolution profile by solid dispersion (kneading)
    • Authors: Aftab Modi; Pralhad Tayade
      Abstract: This article investigates enhancement of the dissolution profile of valdecoxib using solid dispersion with PVP. The article also describes the preparation of fast-dissolving tablets of valdecoxib by using a high amount of superdisintegrants. A phase solubility method was used to evaluate the effect of various water-soluble polymers on aqueous solubility of valdecoxib. Polyvinyl pyrrolidone (PVP K-30) was selected and solid dispersions were prepared by the method of kneading. Dissolution studies, using the USP paddle method were performed for solid dispersions of valdecoxib. Infrared (IR) spectroscopy, differential scanning calorimetry (DSC), and x-ray diffractometry (XRD) were performed to identify the physicochemical interaction between drug and carrier, hence its effect on dissolution. Tablets were formulated containing solid dispersion products and compared with commercial products. IR spectroscopy, XRD, and DSC showed no change in the crystal structure of valdecoxib. Dissolution of valdecoxib improved significantly in solid dispersion products (<85% in 5 minutes). Tablets containing solid dispersion exhibited better dissolution profile than commercial tablets. Thus, the solid dispersion technique can be successfully used for improvement of dissolution of valdecoxib.
      PubDate: 2017-03-08
      DOI: 10.1208/pt070368
      Issue No: Vol. 7, No. 3 (2017)
  • In vitro and in vivo evaluation of single-unit commercial conventional
           tablet and sustained-release capsules compared with multiple-unit
           polystyrene microparticle dosage forms of ibuprofen
    • Authors: Shunmugaperumal Tamilvanan; Biswanath Sa
      Abstract: The major aims of the present study were (1) to select a multiple-unit formulation that matched the in vitro dissolution profile of single-unit sustained-release commercial capsules, (2) to compare the sustaining/controlling efficacy of the selected multiple-unit formulation with that of the single-unit commercial conventional tablet and sustained-release capsules, and (3) to determine whether an in vitro-in vivo correlation exists for single- and multiple-unit formulations. Ibuprofen (20%–60% wt/wt)-loaded multiple-unit polystyrene microparticles were prepared by an emulsion-solvent evaporation method from an aqueous system. The in vitro release profiles obtained in phosphate buffer of pH 6.8 for drug-loaded polystyrene microparticles and for commercial sustained-release capsules (Fenlong-SR, 400 mg) were compared. Since the microparticles with 30% ibuprofen load showed a release profile comparable to that of the Fenlong-SR release profile, the microparticles with this drug load were considered to be the optimized/selected formulation and, therefore, were subjected to stability study and in vivo study in human volunteers. A single-dose oral bioavailability study revealed significant differences in Cmax, Tmax, t1/2a, t1/2e, Ka, Ke, and AUC between the conventional tablet and optimized or Fenlong-SR capsule dosage forms. However, all the parameters, with the exception of Ka along with relative bioavailability (F) and retard quotient (RΔ), obtained from the optimized ibuprofenloaded microparticles were lower than that obtained from the commercial Fenlong-SR formulation. Furthermore, linear relationship obtained between the percentages dissolved and absorbed suggests a means to predict in vivo absorption by measuring in vitro dissolution.
      PubDate: 2017-03-08
      DOI: 10.1208/pt070372
      Issue No: Vol. 7, No. 3 (2017)
  • Cross-linked guar gum microspheres: A viable approach for improved
           delivery of anticancer drugs for the treatment of colorectal cancer
    • Authors: Mohini Chaurasia; Manish K. Chourasia; Nitin K. Jain; Aviral Jain; Vandana Soni; Yashwant Gupta; Sanjay K. Jain
      Abstract: In the present work, guar gum microspheres containing methotrexate (MTX) were prepared and characterized for local release of drug in the colon, which is a prerequisite for the effective treatment of colorectal cancer. Guar gum microspheres were prepared by the emulsification method using glutaraldehyde as a cross-linking agent. Surface morphological characteristics were investigated using scanning electron microscopy. Particle size, shape, and surface morphology were significantly affected by guar gum concentration, glutaral dehyde concentration, emulsifier concentration (Span 80), stirring rate, stirring time, and operating temperature. MTX-loaded microspheres demonstrated high entrapment efficiency (75.7%). The in vitro drug release was investigated using a US Pharmacopeia paddle type (type II) dissolution rate test apparatus in different media (phosphate-buffered saline [PBS], gastrointestinal fluid of different pH, and rat cecal content release medium), which was found to be affected by a change to the guar gum concentration and glutaraldehyde concentration. The drug release in PBS (pH 7.4) and simulated gastric fluids followed a similar pattern and had a similar release rate, while a significant increase in percent cumulative drug release (91.0%) was observed in the medium containing rat cecal content. In in vivo studies, guar gum microspheres delivered most of their drug load (79.0%) to the colon, whereas plain drug suspensions could deliver only 23% of their total dose to the target site. Guar gum microspheres showed adequate potential in achieving local release of drug in in vitro release studies, and this finding was further endorsed with in vivo studies.
      PubDate: 2017-03-08
      DOI: 10.1208/pt070374
      Issue No: Vol. 7, No. 3 (2017)
  • Effect of formulation factors on in vitro transcorneal permeation of
           gatifloxacin from aqueous drops
    • Authors: Mahendra Singh Rathore; Dipak K. Majumdar
      Abstract: The purpose of this research was to optimize the formulation factors for maximum in vitro permeation of gatifloxacin from aqueous drops through excised goat cornea and to evaluate the permeation characteristics of drug from selected marketed eyedrop formulations. Permeation studies were conducted by putting 1 mL of formulation on the cornea (0.67 cm2) fixed between the donor and receptor compartments of an all-glass modified Franz diffusion cell and measuring gatifloxacin concentration in the receptor (containing normal saline under stirring) by spectrophotometry at 291.5 nm, after 120 minutes. Raising the drug concentration of the drops increased the drug permeation but decreased the percent permeation and the in vitro ocular availability. Raising the pH of the formulation from pH 5 to 7.2 increased both the drug permeation and the in vitro ocular availability. Eyedrops containing benzalkonium chloride (BAK; 0.01% wt/vol) and disodium edetate (EDTA; 0.01% wt/vol) showed maximum permeation, followed by Zymar, BAK (0.01% wt/vol), Gatilox, Gatiquin, and Gate (statistically significantP<.05 compared with control). In vitro titration of the formulations with 0.1N NaOH indicated the presence of a buffer in Zymar (pH 6) and Gate (pH 5.8), which may cause irritation and induce lacrimation, resulting in reduced ocular availability in vivo. Thus, formulation with BAK and EDTA, which is unbuffered, has a better likelihood of being absorbed in vivo. The BAK-EDTA formulation significantly (P<.05) increased the permeation of gatifloxacin through paired excised corneas of goat, sheep, and buffalo, compared with the control formulation. The goat cornea showed the greatest increase in permeation, followed by the sheep and buffalo corneas.
      PubDate: 2017-03-08
      DOI: 10.1208/pt070357
      Issue No: Vol. 7, No. 3 (2017)
  • Graphical comparison of image analysis and laser diffraction particle size
           analysis data obtained from the measurements of nonspherical particle
    • Authors: Richard N. Kelly; Kimberly J. DiSante; Elliott Stranzl; Jacqueline A. Kazanjian; Paul Bowen; Tatsuyama Matsuyama; Nadine Gabas
      Abstract: The purpose of this paper is to describe results from the use of a set of Excel macros written to facilitate the comparison of image analysis (IA) and laser diffraction (LD) particle size analysis (psa) data. Measurements were made on particle systems of differing morphological characteristics including differing average aspect ratios, particle size distribution widths and modalities. The IA and LD psa data were plotted on the same graph treating both the weighting and the size unit of the LD psa data as unknowns. Congruency of the IA and LD plots was considered to indicate successful experimental determination of the weighting and size unit. The weighting of the resulting LD psa data (so-called volume-weighted) is shown to be better correlated with IA area-weighted data. The size unit of LD psa data is shown to be a function of particle shape. In the case of high aspect ratio particles characterized by approximately rectangular faces the LD psa data is shown to be a function of multiple particle dimensions being related to IA size descriptors through a simple variation of the law of mixtures. The results demonstrate that successful correlations between IA and LD psa data can be realized in the case of non-spherical particle systems even in the case of high aspect ratio particles; however, the inappropriateness of the application of the Equivalent Spherical Volume Diameter and the Random Particle Orientation assumptions to the interpretation of the LD psa results must first be acknowledged. Correlation permits cross validation of IA and LD psa results increasing confidence in the accuracy of the data from each orthogonal technique.
      PubDate: 2017-03-08
      DOI: 10.1208/pt070369
      Issue No: Vol. 7, No. 3 (2017)
  • Effect of formulation factors on in vitro permeation of moxifloxacin from
           aqueous drops through excised goat, sheep, and buffalo corneas
    • Authors: Pravin Kondiba Pawar; Dipak K. Majumdar
      Abstract: The purpose of this investigation was to evaluate the effect of formulation factors on in vitro permeation of moxifloxacin from aqueous drop through freshly excised goat, sheep, and buffalo corneas. Aqueous isotonic ophthalmic solutions of moxifloxacin hydrochloride of different concentrations (pH 7.2) or 0.5% (wt/vol) solutions of different pH or 0.5% solutions (pH 7.2) containing different preservatives were made. Permeation characteristics of drug were evaluated by putting 1 mL formulation on freshly excised cornea (0.50 cm2) fixed between donor and receptor compartments of an all-glass modified Franz diffusion cell and measuring the drug permeated in the receptor (containing 10 mL bicarbonate ringer at 37°C under stirring) by spectrophotometry at 291 nm, after 120 minutes. Statistical analysis was done by one-way analysis of variance (ANOVA) followed by Dunnett’s test. Increase in drug concentration in the formulation resulted in an increase in the quantity permeated but a decrease in percentage permeation. Increase in pH of the solution from 5.5 to 7.2 increased drug permeation, indicating pH-dependent transport. Compared with control formulation, moxifloxacin 0.5% (wt/vol) solution (pH 7.2) containing disodium edetate (EDTA) (0.01% wt/vol) produced significantly (P<.05) higher permeation with all the corneas. Formulation with benzyl alcohol significantly (P<.05) increased permeation with buffalo cornea compared with its control. Presence of benzalkonium chloride (BAK) (0.01% wt/vol) and EDTA (0.01% wt/vol) in the formulation increased permeation to the maximum with all the corneas. The results suggest that moxifloxacin 0.5% ophthalmic solution (pH 7.2) containing BAK (0.01%) and EDTA (0.01%) provides increased in vitro ocular availability through goat, sheep, and buffalo corneas.
      PubDate: 2017-03-08
      DOI: 10.1208/pt070113
      Issue No: Vol. 7, No. 1 (2017)
  • Artemisia arborescens L essential oil-loaded solid lipid nanoparticles for
           potential agricultural application: Preparation and characterization
    • Authors: Francesco Lai; Sylvia A. Wissing; Rainer H. Müller; Anna M. Fadda
      Abstract: The aim of this study was to formulate a new delivery system for ecological pesticides by the incorporation of Artemisia arborescens L essential oil into solid lipid nanoparticles (SLN). Two different SLN formulations were prepared following the high-pressure homogenization technique using Compritol 888 ATO as lipid and Poloxamer 188 or Miranol Ultra C32 as surfactants. The SLN formulation particle size was determined using Photon correlation spectroscopy (PCS) and laser diffraction analysis (LD). The change of particle charge was studied by zeta potential (ZP) measurements, while the melting and recrystallization behavior was studied using differential scanning calorimetry (DSC). In vitro release studies of the essential oil were performed at 35°C. Data showed a high physical stability for both formulations at various storage temperatures during 2 months of investigation. In particular, average diameter of Artemisia arborescens L essential oil-loaded SLN did not vary during storage and increased slightly after spraying the SLN dispersions. In vitro release experiments showed that SLN were able to reduce the rapid evaporation of essential oil if compared with the reference emulsions. Therefore, obtained results showed that the studied SLN formulations are suitable carriers in agriculture.
      PubDate: 2017-03-08
      DOI: 10.1208/pt070102
      Issue No: Vol. 7, No. 1 (2017)
  • Molecular interactions of the inclusion complexes of hinokitiol and
           various cyclodextrins
    • Authors: Rina Suzuki; Yutaka Inoue; Sontaya Limmatvapirat; Isamu Murata; Ikuo Kanamoto
      Abstract: The aim of this study was to prepare inclusion complexes of hinokitiol (HT)/α-cyclodextrin (α-CD) and HT/β-cyclodextrin (β-CD) by cogrinding and to evaluate the differences in their formation. The physical properties of the preparation were evaluated by Job’s plot, phase solubility studies, differential scanning calorimetry, powder X-ray diffraction, solid fluorescence spectra, and infrared absorption spectra. Intermolecular interaction in the solid state was confirmed to be in the ratios HT/α-CD = 1/2 and HT/β-CD = 1/1. Results indicated that the dissolution property of HT was improved by inclusion in the complexes HT/α-CD and HT/β-CD compared with HT crystals. The 1H-1H ROESY NMR spectrum of HT/α-CD showed that part of the seven-membered ring of HT and the isopropyl group of HT was linked to the wider edges of the two α-CDs. In HT/β-CD, the seven-membered ring of HT interacted with the narrower edge of β-CD and the isopropyl group of HT interacted with the wider edges. This structure of inclusion complexes was attributed to the difference in the cavity diameter of the CD and was thought to influence the dissolution properties.
      PubDate: 2017-03-15
      DOI: 10.1208/s12249-017-0748-7
  • Microemulsion-Based Mucoadhesive Buccal Wafers: Wafer Formation, In Vitro
           Release, and Ex Vivo Evaluation
    • Authors: Minh Nguyet Pham; Toi Van Vo; Van-Thanh Tran; Phuong Ha-Lien Tran; Thao Truong-Dinh Tran
      Abstract: Microemulsion has the potentials to enhance dissolution as well as facilitate absorption and permeation of poorly water-soluble drugs through biological membranes. However, its application to govern a controlled release buccal delivery for local treatment has not been discovered. The aim of this study is to develop microemulsion-based mucoadhesive wafers for buccal delivery based on an incorporation of the microemulsion with mucoadhesive agents and mannitol. Ratio of oil to surfactant to water in the microemulsion significantly impacted quality of the wafers. Furthermore, the combination of carbopol and mannitol played a key role in forming the desired buccal wafers. The addition of an extra 50% of water to the formulation was suitable for wafer formation by freeze-drying, which affected the appearance and distribution of carbopol in the wafers. The amount of carbopol was critical for the enhancement of mucoadhesive properties and the sustained drug release patterns. Release study presented a significant improvement of the drug release profile following sustained release for 6 h. Ex vivo mucoadhesive studies provided decisive evidence to the increased retention time of wafers along with the increased carbopol content. The success of this study indicates an encouraging strategy to formulate a controlled drug delivery system by incorporating microemulsions into mucoadhesive wafers.
      PubDate: 2017-03-15
      DOI: 10.1208/s12249-017-0754-9
  • Trans-ungual Delivery of AR-12, a Novel Antifungal Drug
    • Authors: Avadhesh Singh Kushwaha; P. Sharma; H. N. Shivakumar; C. Rappleye; A. Zukiwski; S. Proniuk; S. Narasimha Murthy
      Abstract: AR-12 is a novel small molecule with broad spectrum antifungal activity. Recently, AR-12 was found to be highly active against Trichophyton rubrum, one of the predominantly responsible organisms that cause onychomycosis. The primary objective of this project was to investigate the ability of AR-12 to penetrate into and across the human nail plate followed by improving its trans-ungual permeation using different penetration enhancers. TranScreen-N™, a high throughput screening method was utilized to explore the potential nail penetration enhancers to facilitate the drug delivery through the nail. This screen demonstrated that dexpanthenol and PEG 400 were the most efficient enhancers. The in vitro permeation studies were performed across the human cadaver nail plates for 7 days with three AR-12 (5% w/v) formulations containing 10% w/v dexpanthenol (Formulation A), 10% w/v PEG 400 (Formulation B), and a combination of 10% w/v dexpanthenol + 10% w/v PEG 400 (Formulation C). The in vitro studies concluded that dexpanthenol and PEG 400 were able to deliver a significant amount of AR-12 into and across the nail plate that was found to be more than MIC 50 level of the drug.
      PubDate: 2017-03-13
      DOI: 10.1208/s12249-017-0752-y
  • Influence of Testing Parameters on In Vitro Tramadol Release from
           Poloxamer Thermogels using the Immersion Cell Method
    • Authors: Lorina Bisharat; Diego R. Perinelli; Alberto Berardi; Giulia Bonacucina; Serena Logrippo; Feras W. Darwish Elhajji; Marco Cespi; Giovanni F. Palmieri
      Abstract: ABSTRACT The immersion cell is an in vitro performance test of drug release from semisolids. Several studies made use of immersion cells to investigate drug release from thermosensitive Poloxamer-based gels; however, specifications on the parameter setting are not yet available. Therefore, the aim of this study was to evaluate the influence of testing parameters on tramadol (a model drug) release, release rate, and dissolution efficiency (DE) from Poloxamer gels, using immersion cells. The thermosensitive gelling formulation showed batch-to-batch uniformity of gelling behavior, drug content, and drug release. The use of a membrane in the immersion cell resulted in slower drug release as compared to the absence of a membrane. Moreover, the faster the paddle rotation, the faster the drug release was. Membrane thickness showed a strong and significant linear relationship with corresponding DE values (Pearson’s correlation coefficient, r = −0.9470; p = 0.004). Factors that did not influence drug release include paddle position, i.e., distance between paddle and membrane, as well as membrane mean pore size. This study sets forth the importance of carefully controlling the following parameters including presence/absence of membrane, paddle rotation speed, and membrane thickness during the setup of release experiments from gels using immersion cells.
      PubDate: 2017-03-13
      DOI: 10.1208/s12249-017-0753-x
  • Modeling of the Nanoparticles Absorption Under a Gastrointestinal
           Simulated Ambient Condition
    • Authors: Katherina Fernández; Marlene Roeckel; Edgardo Canales; Javiera Dumont
      Abstract: Proanthocyanidins (PAs) have several bioactivities, but they are unstable in the digestive tract and possess low bioavailability. Nanoencapsulation stabilizes these compounds for oral administration. The intestinal absorption of grape seed and skin extracts, and the poly-lactic acid (PLA) nanoparticles loaded with such extracts was modeled, taking into consideration physicochemical process parameters, evaluating the PAs concentration profile in the human small intestine. Density (ρ), solubility, viscosity (μ), diffusion coefficient (D), and the global mass transfer coefficient (K) for both substrates were estimated, simulating their passing from the intestine into the blood at 37°C. For the seed and skin extracts encapsulated in PLA the physicochemical parameters were: D = 1.81 × 10^−5 and D = 5.72 × 10^−5 cm2/s; K = 3.4 × 10^−3 and K = 2.47 × 10^−4 cm/s, respectively. Lower resistance was offered by the seed extract than by skin extracts (nanoencapsulated), which was explained by differences in structural composition, and average molecular weight of the two kinds of extracts, which should be more favorable to the mass transfer in comparison to the raw extracts. The concentration profile of grape extracts in the small intestine was modeled through a pure convection model, and the encapsulated extract on PLA nanoparticles using a mixed regime model, which described the process of dissolution and absorption of the grape extracts from the intestine to the blood stream. The absorbed fraction predicted by the model was 42.7 and 24.2% for seed and skin extracts, respectively. Those values increased to 100% for both extracts after the simulation with the nanoencapsulated extracts. Consequently, extract encapsulation should produce a significant increase in intestinal absorption.
      PubDate: 2017-03-10
      DOI: 10.1208/s12249-017-0751-z
  • Design of a Time-Controlled Pulsatile Release System for Propranolol Using
           the Dry-Coated Method: In Vitro and In Vivo Evaluation
    • Authors: Kai Chen; Yanyan Wang; Xiumei Gai; Haiying Wang; Yuenan Li; Haoyang Wen; Weisan Pan; Xinggang Yang
      Abstract: The objective of this study was to design a time-controlled pulsatile release (TCPR) system containing propranolol (PNH) as an active pharmaceutical ingredient. Here, the developed dosage forms were coated with hydroxypropyl-methylcellulose (HPMC) and other excipients as barrier layer using dry-coated technology. The influence of HPMC, microcrystalline cellulose (MCC), and lactose in the outer coating and the coating weight on drug release were investigated. Then, a three-factor, five-level central composite design (CCD) and response surface method were used to optimize the formula of the coating. After data processing, the optimal prescription was found to be as follows: HPMC E50(X1) 86.2 mg, MCC(X2) 43.8 mg, and lactose (X3) 21.3 mg in the coating. Moreover, the in vitro tests showed that the optimized formulation of TCPR had a lag time of 4 h followed by a 4-h drug release. Also, determination of the extent of erosion of the TCPR tablets revealed that the lag time is related to the coating erosion speed. The in vivo test in beagle dogs and comparison of the parameters for the TCPR tablets and reference preparations showed significant differences for Tmax (7.83 ± 0.408 and 2 ± 0.00) and Cmax (185.45 ± 28.561 and 587 ± 45.27 ng/ml) but no significant differences in the AUC0-∞ (1757.876 ± 208.832 and 1779.69 ± 229.02 ng h/ml). These results demonstrated that the TCPR tablets successfully prolonged the lag time and controlled the release of propranolol.
      PubDate: 2017-03-09
      DOI: 10.1208/s12249-017-0746-9
  • Formulation and Evaluation of Thermoreversible In Situ Nasal Gels
           Containing Mometasone Furoate for Allergic Rhinitis
    • Authors: Ebru Altuntaş; Gülgün Yener
      Abstract: The purpose of the present work was to develop a mucoadhesive thermoreversible nasal gel with a tailored gelling temperature to provide the prolonged contact between mometasone furoate and the nasal mucosa and in order to prevent drainage of the formulation. For this purpose, in situ gel containing a thermogelling polymer poloxamer 407 (Pluronic® F-127) and a mucoadhesive polymer Carbopol® 974P NF was prepared. In this content, formulations were designed to have gelation temperature below 34°C to obtain gelation at intranasal cavity. Evaluation of the prepared in situ gels was carried out by the determination of sol-gel transition temperature, rheological and mechanical characteristics, mucoadhesion strength, drug content, physicochemical stability, in vitro release profiles, and ex vivo permeation across sheep nasal mucosa of formulations. Consequently, the in situ gel (CP5) which had favorable gelation temperature (30.1 ± 0.24°C), rheological and mechanical characteristics, in vitro release profile (T%100 180 min), and mucoadhesion strength (0.289 ± 0.0069 mJ) was developed. Consequently, the in situ gel system has been concluded as a promising approach in order to improve the therapeutic effects of intranasal mometasone furoate administration.
      PubDate: 2017-03-09
      DOI: 10.1208/s12249-017-0747-8
  • Optimization and Evaluation of Gastroretentive Ranitidine HCl Microspheres
           by Using Factorial Design with Improved Bioavailability and Mucosal
           Integrity in Ulcer Model
    • Authors: Abeer Khattab; Nashwah Zaki
      Abstract: The purpose of our investigation was to develop and optimize the drug entrapment efficiency and bioadhesion properties of mucoadhesive chitosan microspheres containing ranitidine HCl prepared by an ionotropic gelation method as a gastroretentive delivery system; thus, we improved their protective and therapeutic gastric effects in an ulcer model. A 3 × 22 full factorial design was adopted to study the effect of three different factors, i.e., the type of polymer at three levels (chitosan, chitosan/hydroxypropylmethylcellulose, and chitosan/methylcellulose), the type of solvent at two levels (acetic acid and lactic acid), and the type of chitosan at two levels (low molecular weight (LMW) and high molecular weight (HMW)). The studied responses were particle size, swelling index, drug entrapment efficiency, bioadhesion (as determined by wash-off and rinsing tests), and T 80% of drug release. Studies of the in vivo mucoadhesion and in vivo protective and healing effects of the optimized formula against gastric ulcers were carried out using albino rats (with induced gastric ulceration) and were compared to the effects of free ranitidine powder. A pharmacokinetic study in rabbits showed a significant, 2.1-fold increase in theAUC0–24of the ranitidine microspheres compared to free ranitidine after oral administration. The optimized formula showed higher drug entrapment efficiency and mucoadhesion properties and had more protective and healing effects on induced gastric ulcers in rats than ranitidine powder. In conclusion, the prolonged gastrointestinal residence time and the stability of the mucoadhesive microspheres of ranitidine as well as the synergistic healing effect of chitosan could contribute to increasing the potential of its anti-gastric ulcer activity.
      PubDate: 2017-03-07
      DOI: 10.1208/s12249-017-0744-y
  • Self-Stabilizing Ampholytic Starch Excipients for Sustained Release of
           Highly Soluble Drugs: the Case Study of Metformin
    • Authors: Khalil Sakeer; Pompilia Ispas-Szabo; Mircea Alexandru Mateescu
      Abstract: ABSTRACT A new class of starch derivatives carrying cationic and anionic functional groups was developed aiming to provide an alternative for the formulation of highly soluble drugs. The new ampholytic starch derivatives were synthesized in two steps; first the CarboxyMethyl (CM) groups were grafted on starch chains followed by introduction of AminoEthyl (AE) groups. The final product, CarboxyMethyl-AminoEthyl-Starch (CM-AE-St), could be obtained in different degrees of substitution by varying the number of CM and AE groups. It was hypothesized that the simultaneous presence of anionic and cationic groups will generate a stronger self-stabilization of starch matrices and an improved control of drug release. Metformin (biopharmaceutical classification system—BCS, class I) was selected as model drug and monolithic tablets with 50 and 60% loading were prepared by direct compression of the active molecule with various CM-AE-St derivatives. The in vitro drug dissolution tests have shown that higher degrees of substitution for both CM and AE groups favor the ability of ampholytic CM-AE-St to control the drug release in simulated gastric fluid and in simulated intestinal fluid. Tablets based on CM-AE-St derivatives were compared to the commercial Glumetza® (50% loading). The drug release was controlled for 12 h exhibiting a similar Higuchi’s model dissolution profile for the two dosage forms. Structural studies (FT-IR, 1H NMR, SEM, TG, X-ray diffraction) run on CM-AE-St derivatives put in evidence derivatization and self-stabilization phenomena. These new ampholytic starch derivatives offer a simple and convenient alternative to formulate and manufacture highly soluble drugs in a single step process.
      PubDate: 2017-03-07
      DOI: 10.1208/s12249-017-0723-3
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