No abstract

Objective: Metformin hydrochloride is a biguanide antihyperglycemic agent which is a generally recommended first-line drug for the treatment of diabetes mellitus (Type II). The purpose of this investigation is to prepare sustained release matrix granules of metformin hydrochloride which are coated to extend the drug release over a longer time period.Methods: Metformin hydrochloride granules were prepared by mixing all the dry powders in a V-cone blender and wetting the powder mix with aqueous solution of hydroxypropyl methyl cellulose K100. The prepared granules (MG1-MG5) were investigated for drug release. The batch of granules which exhibited extended release for up to 4 h was coated in a standard coating pan with blends of Eudragit RS and RL to further enhance release period. These were marked as coated metformin granules (CMG3) and CMG4 which were later filled into empty capsules. The granules were characterized for micromeritic properties, percentage yield, particle size distribution, percentage of drug content, and in vitro release of the drug.Results: All the formulations showed percentage yield in the range of 77.66-82.86% and drug content in the range of 78.23-96.62%. CMG3 showed drug release of 97.02% for 12 h. Fourier-transform infrared spectroscopy and differential scanning calorimetry studies indicated that no possible interaction existed between the drug and the polymers used. Scanning electron microscopy images revealed that the granules were spherical in shape with smooth surface and completely covered with a coating of polymer. Kinetic analysis of drug release confirmed that drug release followed zeroorder kinetics where it is independent of the concentration. Conclusion:From the results, it was analyzed that design of coated granules employing the polymers used in the present work can produce a sustained release of the drug over a period of 12 h.

Objectives: This research was aimed to evaluate a novel approach for preparation of mucoadhesive microspheres which can reside in the gastrointestinal tract for an extended time period. The microspheres contained amoxicillin, an anti-bacterial agent useful for the eradication of Helicobacter pylori. Methods: Ten different formulations were prepared by chemical cross-linking technique using gluteraldehyde as a cross linking agent and chitosan as mucoadhesive polymer. Natural release retardant polymers like guar gum, gum ghatti and xanthan gum were employed. All the microspheres were characterized for morphology, particle size, drug entrapment efficiency, swelling index, bioadhesion to mucosal tissue and in vitro drug dissolution and anti-bacterial activity against E. coli. Results: The FTIR and DSC data indicated that there were no interactions between the drug and polymers used. All the microspheres exhibited good flow properties. The microspheres had a spherical shape with rough surface. The microspheres showed a good mucoadhesivity and also anti-bacterial activity. The release of the drug was prolonged to 12h when incorporated into mucoadhesive microspheres. Conclusion: Data obtained in this study concluded that mucoadhesive microspheres of amoxicillin can be used to effectively clear H. pylori from the gastrointestinal tract due to prolonged residence time resulting from mucoadhesion. In this study drug release was diffusion controlled and followed zero order kinetics.

Poor aqueous solubility and low oral bioavailability of an active pharmaceutical ingredient are the major constraints during the development of new product. Various approaches have been used for enhancement of solubility of poorly aqueous soluble drugs, but success of these approaches depends on physical and chemical nature of the molecules being developed. Co-crystallization of drug substances offers a great opportunity for the development of new drug products with superior physicochemical such as melting point, tabletability, solubility, stability, bioavailability and permeability, while preserving the pharmacological properties of the active pharmaceutical ingredient. Co-crystals are multi component systems in which two components, an active pharmaceutical ingredient and a coformer are present in stoichiometric ratio and bonded together with non-covalent interactions in the crystal lattice. This review article presents a systematic overview of pharmaceutical co-crystals, differences between co-crystals with salts, solvates and hydrates are summarized along with the advantages of co-crystals with examples. The theoretical parameters underlying the selection of coformers and screening of co-crystals have been summarized and different methods of co-crystal formation and evaluation have been explained.