Rapid High-Performance Liquid Chromatography Method for Levodopa Quantitation at Low UV Wavelength: Application of Pharmacokinetics Study in Rat Following Intranasal Delivery.

Abstract

Levodopa is widely administered orally in clinical treatment of Parkinson's disease; however, due to levodopa various oral absorption and low bioavailability, intranasal delivery seems to be a suitable alternative route of administration. Pluronic F-127 is a thermosensitive polymer, which can form gel at nasal cavity temperature and increase drug residence time. In this study, a rapid High Performance Liquid Chromatography (HPLC) method was validated in presence of internal standard to determine pharmacokinetic parameters following levodopa administration to rats in three different intravenous solution, intranasal solution and intranasal thermosensitive gel groups. A precised (96.7%) and accurate (95.0%) HPLC method was validated at low UltraViolet (UV) wavelength of 208nm that showed limit of detection and limit of quantitation of 59 and 177ng/mL, respectively. Specificity results showed no interference for levodopa with endogenous serum materials, and serum extraction efficacy was 93%. Pharmacokinetic parameters including bioavailability of 75 and 85% with mean residence time of 78 and 94min were estimated for intranasal solution and thermosensitive gel using the validated HPLC method, which indicated that levodopa nasal gel may be a good alternative with appropriate pharmacokinetic outcome. Therefore, the validated levodopa HPLC analysis method at low UV wavelength was efficiently applied in pharmacokinetic study.