Development and Evaluation of Press Coated Tablets forChronopharmaceutical Drug Delivery using Gellable andPermeable Polymers

The role of chronotherapeutics in hypertension management is based on the recognition that blood pressure does not remain constant throughout the day. Instead, it tends to be higher in the early morning hours and lower in the evening hours. The main objective of the present studies reported here was to investigate whether compression coating could be used to produce tablets providing maximum in-vitro drug release 6 to 8 hours after an evening dose taken at approximately 10:00 pm. The basic idea behind the dosage form development is to investigate effect of coating design on lag time and drug release from directly compressed time-controlled release tablet. The aim of the present study was to design time controlled tablet of Diltiazem hydrochloride, as Chronopharmaceutical drug delivery system by compression coating. Formulation design involves coating polymer blend ratio (100:0, 75:25, 50:50, 25:75, 0:100 w/w) of Klucel HF, Klucel HXF and Eudragit RSPO which were exploited for their pulsatile drug release ability. The effect of different weight ratio of combination of permeable polymers and gellable polymer, different particle size of gellable polymer in outer shell polymers blend were studied on the drug release behavior of the time controlled tablet formulation. Coating materials blend were evaluated for micromeritic properties like flow properties, compressibility index, Hausner’s ratio and also evaluated the tablet for hardness, thickness, friability, weight variation, water uptake studies. The obtained results showed the capability of the system in delaying drug release for a programmable period of time to attain drug release 6 to 8 hours after an evening dose taken at approximately 10:00 pm according to a time-dependent approach.