Development and Validation of Stability-Indicating RP-HPLC Method for the Estimation of Fisetin in Novel Cubosomal Nanoformulation: Application to the Marketed Formulation and Selected Plant Extracts

Abstract

Background: Fisetin (FIS) is a bioactive flavonoid found in various plants, reported for many pharmacological activities, and presently marketed as a nutraceutical. To overcome less water solubility and bioavailability issues, FIS cubosomal nanoformulation has been prepared and characterized. Objective: To estimate FIS in prepared novel cubosomes, an RP-HPLC analytical method development with the most sensitivity, economical, robust, and wide applicability in marketed FIS formulations and plant extracts also. Method: An RP-HPLC method was developed and validated as per ICH Q2R1 guidelines by using C-18 Phenomenex Luna 5µ, 100A0 column, LC-20 AD pump, and Shimadzu LC solution 1.25 software. The combination of acetonitrile and formic acid (0.1%v/v) in the ratio of 25:75 v/v was used as a mobile phase for chromatographic separation using a PDA detector at 360 nm and a flow rate of 1 ml/min. Results: In the range of 0.1 to 16 µg/ml, the developed method was remarkably linear (R2 ˃ 0.999). This method was found to be accurate (recovery 98.24 to 100.65 %), precise, robust (% RSD ˂ 2), and more sensitive than the earlier reported method with LOD and LOQ values of 17.26 and 52.31 ng/ml respectively. The FIS estimation was also performed using the developed method in the marketed FIS formulation Doctor’s Best ® Fisetin, and different plants extracts such as strawberry, grapes, black tea, and green tea. The forced degradation study suggests FIS was unstable in alkaline and oxidative stress conditions. Conclusion: For FIS estimation in cubosomal nanoformulation, a widely applicable, novel, robust, most sensitive, and economical RP-HPLC method was developed and validated, and also applied to marketed formulation and plant extracts.

Development and Validation of UV-Spectrophotometric Method for Estimation of Vinpocetine in Marketed Formulation and Nanoformulation

“…The ethanol injection technique was used to prepare Vinpocetine-loaded niosomes (VLN). Briefly, several ratios of cholesterol, span-60, and Vinpocetine (10mg) were precisely weighed and dissolved in 10ml of ethanol utilizing bath sonication at 60 o C. The transparent organic solution was immediately transferred into the aqueous solution at 60°C while the mixture was vigorously stirred at 500 rpm on a magnetic stirrer (Remi) using a teflon coated bead (24,25). The aqueous solution rapidly changed into milky solution suggested niosomes formation.…”