Analytical Quality by Design (AQbD) Approach Based HPTLC Method for Quantification of Fisetin with Superior Recovery in Formulations

Background: A stability indicating high-performance thin layer chromatography (HPTLC) method was developed for the evaluation of fisetin (FIS) in active pharmaceutical ingredient (API) and marketed capsule formulation in accordance with the ICH guidelines. Methods: The mobile phase combination toluene: ethyl acetate: formic acid: methanol (3: 5.5: 1: 0.5 v/v/v/v) was optimized with the aid of AQbD approach. The absorbance mode at 254 nm was chosen for densitometric analysis as it gives a compact spot of FIS at R-f value of 0.74. Results: The R-2 value obtained from the linear regression equation of calibration plots made by taking the spot in the concentration range of 100-1400 ng/spot was found to be 0.9993. The observed LOD and LOQ value was found to be 29.8 ng/spot and 98.5 ng/spot, respectively. The exposure of FIS to various stress conditions revealed the fact that the drug is stable in photochemical and dry heat stress conditions without any degradation. The drug-exposed to acidic, alkaline and oxidative stress was found to be degraded into different degradation products with the highest degradation was found in alkaline stress. All degradation products were observed to be fairly separated from well-resolved parent peak of FIS. Conclusion: The developed HPTLC method have shown well-resolved peaks and also shown good recovery in the compound FIS as well as FIS formulation.