Marker Based Standardization of Quercetin in Marketed Capsules by Novel Zero Order Spectroscopic and Area Under Curve Spectroscopic Methods

Background: Quality control and standardization of phytomedicines play a vital role in herbal drug industries. Marker based quantification and standardization is one of the essential approaches used in quality evaluation of herbal products. The Quercetin is an important flavonoid having variety of therapeutic activities and many formulations are available in the market. Capsule dosage form of Quercetin is largely marketed. The main objective for analytical development of proposed research is to develop and validate marker-based quantification of analytical methods to carry out quality control of Quercetin along with its standardization in marketed Ayurvedic capsule formulation. Materials and Methods: In the proposed analytical research work two novel UV-spectrophotometric methods mainly Area Under Curve (AUC) spectroscopic and zero order spectroscopic methods were developed and also validated for marker-based quantification of Quercetin. The development of both UV-spectrophotometric methods was carried out by using water: methanol (50:50%v/v) as a solvent. In zero order spectroscopic method absorbance of Quercetin was measured at 372nm. The detection of Quercetin was carried out at 372nm. The area covered between 325nm to 402nm was used for calculation. Results: Quercetin exhibits λmax at 372nm obeying Beer’s law at concentration ranges lying between 2-10μg/mL giving r2 values of 0.9997 and 0.9992 respectively using absorbance and area under curve method. The validation parameters for all these methods were found to be well within the acceptance values. Both UV-spectrophotometric methods showed excellent recovery values between 98 to 107%. Both newly developed and validated marker-based quantification methods were successfully applied for estimation of Quercetin in its marketed capsule dosage form. Conclusion: The proposed research work concludes that these two developed UV-Spectrophotometric methods were new, simple, precise, and accurate for marker-based quantification of Quercetin in marketed formulation.