Formulation and in vitro evaluation of bi-layer tablet of cyclobenzaprine hydrochloride ER and diclofenac potassium IR – A novel fixed dose combination

Abstract

The aim of this study was to prepare bi-layer tablet of Diclofenac Potassium (DP) and Cyclobenzaprine Hydrochloride (CBH) for the effective treatment of severe pain due to inflammation and muscle spasm. DP and CBH were formulated as immediate and extended release layer respectively. DP was formulated as immediate release layer (IR) using excipients like microcrystalline cellulose and maize starch in different drug to excipient ratio keeping other excipients as constant. DP granules was prepared by wet granulation method using purified water and mixed with extragranular excipients. CBH was formulated as extended release (ER) layer using hydrophilic matrix (hydroxypropylmethylcellulose [HPMC K100MCR]). The effect of concentration of hydrophilic matrix (HPMC K100MCR) on CBH release was studied. The dissolution study of extended release layer showed that an increasing amount of HPMC results in reduced CBH release. The rationale for formulation of bi-layer tablet of these two drugs in combination was (1) to reduce the manufacturing cost and time (2) to reduce the dosing frequency and thereby improve the patient compliance.