Optimization and formulations for design of “Lag Phase” in the multilayer drug delivery system of amlodipine besylate and atorvastatin calcium

Multilayer biodegradable polymer drug delivery, time dependent release has many exceptional advantages in controlled drug delivery system. The inception of layer by layer constructed tablet-in-capsule facilitated release of drug in accordance of stimuli response carrier system. Atorvastatin calcium and Amlodipine besylate were chosen a model drug because of its poor absorption in gastrointestinal tract. Three layer multiple unit consist of 10mg Amlodipine besylate blend, lag phase and 20 mg Atorvastatin calcium blend that was compressed into tablet plug and snuggly fitted into the impermeable hard gelatin capsule body and closed by soluble cap of capsule shell. Both the layers of drugs act as a immediate release tablet at the time of delivery were compared and evaluated with market formulation of caduet tablets with strength of 10g Amlodipine Besylate and 20mg Atorvastatin calcium. 3 full factorial design was used to study the effect of two variables. The proportions of hydrophillic polymers like chitosan and sodium starch glycolate had the most significant effect on the release of drug. A zero order of polynomial equation was fitted to data and resulting equation is used to predict the response in optimal region.