HPLC determination and steady-state bioavailability study of levodropropizine sustained-release tablets in dogs

Abstract

A simple HPLC method using UV detection was developed and validated for the determination of levodropropizine (LDP) in dog plasma. The sample was prepared for injection using a liquid-liquid extraction method with 1-phenypiperazine as the internal standard. The mobile phase was methanol-diethylamine solution (0.05 M) (20:80, v/v, pH adjusted to 3.0 with H3PO4) with a detection wavelength of 240 nm. The limit of quantitation (LOQ) of LDP in a biological matrix was determined to be 25.25 ng/mL. The calibration curve was linear across the concentration range of 25.25 to 2020 ng/mL. The intra-day and inter-day precision values (CV %) were within 7% and accuracy (R.E. %) was within 6% of the nominal values for medium (252.5 ng/mL) and high (2020 ng/mL) LDP concentrations. For the LDP concentration at the LOQ, the intra-day and inter-day precision and accuracy were within 20% and 10%, respectively. The average absolute recovery for LDP was 70.28%. This method was successfully used to analyze plasma samples in a steady-state bioavailability study of a newly developed sustained-release LDP tablets (SR) using immediate-release tablets (IR) as the reference. The relative bioavailability of the SR was determined to be 106.3 +/- 12.8% (n=6). The Cmax of the SR was significantly lower (P<0.05), and the tmax was significantly longer than that of the IR (P<0.05). The results of ANOVA and two one-sided tests indicated that the SR exhibited acceptable sustained release properties and was bioequivalent to the IR.

Simultaneous Determination of Levodropropizine, Methylparaben, and Propylparaben in Oral Co-Formulated Syrup by Rp-HPLC Method

“…LDP is an official drug, it was assayed in British pharmacopeia by potentiometric titration (2) , Literature surveys revealed several HPLC methods for the determination of Levodropropizine in pharmaceutical products using UV-VIS spectrophotometric detector (3)(4)(5)(6) and in biological fluids; using HPLC with UV-VIS spectrophotometric detector (7) , fluorescence detector (8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18) , tandem mass spectrometric detector (19)(20)(21)(22) , and GC-MS detector (23)(24)(25) . HPLC and TLC methods were reported for the separation of related substance in LDP (26) .…”