REQUIP XL, prolonged release formulation of ropinirole hydrochloride (RH) in market, could release ropinirole constantly and showed satisfactory therapeutic effect and good compliance. REQUIP XL was composed of more than 10 kinds of excipients and prepared by Geomatrix technology, which was complex and laborious. The purpose of this study was to obtain a dosage form of RH with similar in vitro release profile and bioequivalence in vivo compared to REQUIP XL. Osmotic pump tablet combined with fast release phase was selected as the delivery system of RH and similar release curves were obtained in different media. The tablets were also administered to beagle dogs and the pharmacokinetic parameters were calculated using a non-compartmental model. Cmax, tmax, mean residence time (MRT), and area under the curve from 0 to 24 h (AUC0-24) were 3.97 ± 0.53 ng/mL, 3.58 ± 0.49 h, 8.29 ± 0.93 h, and 35.20 ± 8.11 ng/mL ċ h for ropinirole osmotic pump tablets (ROPT) and 4.15 ± 1.07 ng/mL, 2.92 ± 0.49 h, 7.84 ± 1.09 h, and 34.34 ± 10.06 ng/mL ċ h for REQUIP XL. The log-transformed mean Cmax and AUC0-24 of ROPT were about 92.15% and 102.49% relative to that of REQUIP XL, respectively. The 90% confidence intervals of Cmax and AUC0-24 for ROPT were 75.69-115.31% and 88.89-122.30%, respectively. So it could be concluded that ROPT was uniform with REQUIP XL both in vitro and in beagles and the release profiles of Geomatrix technology may be obtained by osmotic pump combined with fast release technology.
Keywords: Bioequivalent; REQUIP XL; in vitro release; osmotic pump tablet; ropinirole.