Controlled release behavior and characterization of ropinirole hydrochloride using multi-layer formulation

In this paper, we report cost-effective and simply achievable extended release formulations of ropinirole hydrochloride (RP) by forming coating layers with well-known polymers. The upper and bottom coating layers were composed of one of gel-forming polymers such as PEG, PVP, and HPMC, respectively, designed to control drug release profile. The core tablet is prepared by wet granulation method with RP and HPMC (150 K). The multi-layer tablet showed much slower release behavior than that of commercially available once-diary formulation (REQUIP PD^®, 4 mg, GSK) in the pH 1.2 conditions regardless of coated polymers, and zero order release profiles of RP were observed in the pH 6.8 dissolution conditions, which is nearly identical to dissolution profile of REQUIP PD^®. These results indicate that the formation of multi-layer tablet is one of promising strategies for extended release formulation of RP, in addition, better bioavailability is expected due to minimized dissolution profiles of RP in low pH.