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Pharmaceutical Perspective (pharmaceutical + perspective)
Selected AbstractsCharacterization of chitin,metal silicates as binding superdisintegrantsJOURNAL OF PHARMACEUTICAL SCIENCES, Issue 12 2009Iyad Rashid Abstract When chitin is used in pharmaceutical formulations, processing of chitin with metal silicates is advantageous, from both an industrial and pharmaceutical perspective, compared to processing using silicon dioxide. Unlike the use of acidic and basic reagents for the industrial preparation of chitin,silica particles, coprecipitation of metal silicates is dependent upon a simple replacement reaction between sodium silicate and metal chlorides. When coprecipitated onto chitin particles, aluminum, magnesium, or calcium silicates result in nonhygroscopic, highly compactable/disintegrable compacts. Disintegration and hardness parameters for coprocessed chitin compacts were investigated and found to be independent of the particle size. Capillary action appears to be the major contributor to both water uptake and the driving force for disintegration of compacts. The good compaction and compression properties shown by the chitin,metal silicates were found to be strongly dependent upon the type of metal silicate coprecipitated onto chitin. In addition, the inherent binding and disintegration abilities of chitin,metal silicates are useful in pharmaceutical applications when poorly compressible and/or highly nonpolar drugs need to be formulated. © 2009 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 98:4887,4901, 2009 [source] Basics and applications of solid-state kinetics: A pharmaceutical perspective,JOURNAL OF PHARMACEUTICAL SCIENCES, Issue 3 2006Ammar Khawam Abstract Most solid-state kinetic principles were derived from those for homogenous phases in the past century. Rate laws describing solid-state degradation are more complex than those in homogenous phases. Solid-state kinetic reactions can be mechanistically classified as nucleation, geometrical contraction, diffusion, and reaction order models. Experimentally, solid-state kinetics is studied either isothermally or nonisothermally. Many mathematical methods have been developed to interpret experimental data for both heating protocols. These methods generally fall into one of two categories: model-fitting and model-free. Controversies have arisen with regard to interpreting solid-state kinetic results, which include variable activation energy, calculation methods, and kinetic compensation effects. Solid-state kinetic studies have appeared in the pharmaceutical literature over many years; some of the more recent ones are discussed in this review. © 2006 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 95:472,498, 2006 [source] ,-arrestins and heterotrimeric G-proteins: collaborators and competitors in signal transductionBRITISH JOURNAL OF PHARMACOLOGY, Issue S1 2008K DeFea G-protein-coupled receptors (GPCRs), also known as seven transmembrane receptors (7-TMRs), are the largest protein receptor superfamily in the body. These receptors and their ligands direct a diverse array of physiological responses, and hence have broad relevance to numerous diseases. As a result, they have generated considerable interest in the pharmaceutical industry as drug targets. Recently, GPCRs have been demonstrated to elicit signals through interaction with the scaffolding proteins, ,-arrestins-1 and 2, independent of heterotrimeric G-protein coupling. This review discusses several known G-protein-independent, ,-arrestin-dependent pathways and their potential physiological and pharmacological significance. The emergence of G-protein-independent signalling changes the way in which GPCR signalling is evaluated, from a cell biological to a pharmaceutical perspective and raises the possibility for the development of pathway specific therapeutics. British Journal of Pharmacology (2008) 153, S298,S309; doi:10.1038/sj.bjp.0707508; published online 26 November 2007 [source] Percutaneous permeation of enantiomers and racemates of chiral drugs and prediction of their flux ratios using thermal data: A pharmaceutical perspectiveCHIRALITY, Issue 5 2003Mohsen I. Afouna Abstract Albeit pharmacological, pharmacokinetic, and toxicological differences between enantiomeric pairs or between the pure enantiomers and racemate of chiral drugs are known to exist for decades, we are just beginning to realize that there are apparent differences between these species with respect to their percutaneous permeation as well. Such differences in permeation are likely to be enhanced when chiral drugs are formulated with chiral excipients, necessitating a careful assessment of the effect of formulation excipients on the permeation as well as the overall therapeutic outcomes. The in vitro transport data from the preclinical investigations, using laboratory animal models and/or in vitro cell culture systems, must be carefully validated in vivo as there are differences between these models and the human skin. Mathematical models such as MTMT that utilize the interdependence of certain physicochemical characteristics and percutaneous permeability have a predictive value in assessing the flux behavior of enantiomers and racemates. Chirality 15:456,465, 2003. © 2003 Wiley-Liss, Inc. [source] | ||||||||||