Original Articles: 2012 Vol: 4 Issue: 6
Design and development of chronopharmaceutical drug delivery of simvastatin
The aim of the present investigation is to develop a pulsatile drug delivery system basedon an insoluble capsule body filled with simvastatin microspheres and sealed with HPMCK4M plug. Simvastatin is a water insoluble drug and its absorption is dissolution rate limited. Hence simvastatin microspheres were prepared by quasi emulsion solvent diffusion method of the spherical crystallization technique. Optimized microsphere formulations were selected by percentage drugcontent, invitrostudies. The plugs of varying thickness and hardness were prepared by direct compression which was then placed in the capsule opening. The drug delivery system was designed to deliver the drug at such a time when it was needed (nocturnal time). Dissolution studies of pulsatile capsule device in media with different pH (1.2, 7.4 and6.8) showed that drug release in colon could be modulated by optimizing the concentration of polymers in the plug and also the position of plug. The study showed that, lag time prior to drug release was highly affected by the plug position. The dissolution data revealed that the plug position and the composition of plug were very important to achieve a optimum formulation.The drug release from all the pulsing caps followed Zero order kinetics andmechanisam of drug release was governed by peppas - korsmeyermodel.Drug –polymer interaction studies indicated no interaction or complexation in between the drug and the polymer.