No abstract

Synthesis of series of cross linked polymers of methacrylic acid (PMAs) and acrylic acid ( P U S ) is reported. Polymers of both the types have been investigated f o r physiochemical properties like solubility, density, swelling index and equilibrium swelling. A suitable method was devised for study of bioadhesion. Floating tablets were prepared and coated with some of the synthesized polymers. The tablets were then evaluated for physical properties (including bioadhesion) as well as for drug content and in vitro drug release. The results were compared with those obtained with Carbopol 934P. Some polymers showed better bioadhesion and drug release pattern as compared to Carbopol 934P. * For Correspondance 1. Present address : U.S. Vitamins, Deonar, Bombay -400 088 2. Present address : Ion Exchange (India) Ltd., Ambarnath. a79 Copyright 0 199 1 by Marcel Dekker, Inc. Drug Dev Ind Pharm Downloaded from informahealthcare.com by University of Otago on 12/27/14 For personal use only. Drug Dev Ind Pharm Downloaded from informahealthcare.com by University of Otago on 12/27/14 For personal use only.pH of Suspension : The pH of a 0 . 5 % suspension of polymer in deionised water and in 0.5% carbopol 934 P gel was read. The aqueous supensions gave pH in the range of 4.15 to 4.55. Addition of the polymer to carbopol further reduced pH of suspension to between 3.7 and 3 . 8 .Effect of DH on Eauilibrium Swellins of Polvmers : A 0.1% suspension of the polymer was prepared in deionised water, Drug Dev Ind Pharm Downloaded from informahealthcare.com by University of Otago on 12/27/14For personal use only.

The objective of the present study was to formulate a hydroxypropyl methylcellulose (HPMC) gel drug reservoir system with ethanol-water as a solvent system and limonene as a penetration enhancer for enhancing the transdermal delivery of nicorandil so as to develop and fabricate a membrane-moderated transdermal therapeutic system (TTS). The in vitro permeation of nicorandil was determined across rat abdominal skin from a solvent system consisting of ethanol or various proportions of ethanol and water. The ethanol-water (70:30 v/v) solvent system that provided an optimal transdermal permeation was used in formulating an HPMC gel drug reservoir system with selected concentrations (0% w/w, 4% w/w, 6% w/w, 8% w/w or 10% w/w) of limonene as a penetration enhancer for further enhancement of transdermal permeation of nicorandil. The amount of nicorandil permeated in 24 h was found increased with an increase in the concentration of limonene in the drug reservoir system up to a concentration of 6% w/w, but beyond this concentration there was no further increase in the amount of drug permeated. The flux of nicorandil was 370.9 ± 4.2 µg/cm²·h from the drug reservoir system with 6% w/w of limonene, which is about 2.6 times the required flux to be obtained across rat abdominal skin for producing the desired plasma concentration for the predetermined period in humans. The results of a Fourier Transform Infrared study indicated that limonene enhanced the percutaneous permeation of nicorandil by partially extracting the stratum corneum lipids. It is concluded that the HPMC gel drug reservoir system prepared with a 70:30 v/v ethanol-water solvent system containing 6% w/w of limonene is useful in designing and fabricating a membrane-moderated TTS of nicorandil.

Poly(DL-lactic acid), synthesized in this laboratory from DL-lactic acid, was used to prepare microspheres containing piroxicam, using a solvent evaporation technique. The microspheres obtained were characterized for their surface characteristics (by SEM), surface charge, density, particle size distribution, glass transition temperature, drug incorporation and encapsulation efficiency, IR spectroscopy and in vitro drug release. The suspension of microspheres was evaluated for its syringeability. The effect of channelling agents such as PVP and PEG 6000 on in vitro drug release was studied. The effect of gamma-radiation on poly(DL-lactic acid) and on the in vitro release of piroxicam from the microspheres was also studied.

No abstract