The objective of the present study was to develop a programmable novel ‘tablet-in-capsule’ drug delivery device using a swellable hydrophilic polymer Hydroxypropylmethylcellulose K 15 (HPMC K 15) as a plug material for chronotherapeutic delivery of a model drug propranolol hydrochloride. The hard gelatin capsule body was made water insoluble by formaldehyde and heat treatment. The erodible HPMC K 15 tablet plugs were prepared by direct compression. Powder plug batches were also formulated by manually filling the capsule with the drug-polymer blend and the drug and slightly compressed to form a compact plug. The influence of formulation blend of powder plug and tablet plug were studied for the release pattern of propranolol hydrochloride. The batch PP2 (Powder Plug) with 130 mg HPMC K 15, 90 mg dicalcium phosphate (DCP) satisfied the criteria of lag time i.e. less than 10% drug release within 4 h. At the end of 8 h, the batch PP2 showed percentage drug release up to 56.99%. Tablet plugs showed a lag time of only 2 h. The drug release from the tablet plug batches after the lag time was in an extended fashion. It was shown that increasing the concentration of lactose resulted in faster erosion of the plug and thus shorter lag time. Batch TP3 (Tablet Plug) with HPMC K 15: lactose in the 1:1 ratio (200 mg) showed complete drug release within 8 h due to faster erosion of the plug material. In conclusion tablet-in-capsule propranolol hydrochloride delivery system can be suggested as an appropriate device for chronotherapeutic delivery of drug.
Keywords: HPMC K 15, Propranolol hydrochloride, lag time, chronotherapeutic delivery.