Quality by Design-based RP-HPLC Method for Estimation of Curcumin in Rat Plasma and Fecal Microbiota Extract-based...

Curcumin (CRM) is known to possess various therapeutic properties, such as anti-inflammatory and antidiabetic properties, and is, therefore, considered to be an effective therapeutic.

A sensitive method for the estimation of CRM in plasma, as well as fecal matter-based solid self-nano emulsifying drug delivery system (S-SNEDDS), has been reported for the first time.

A bioanalytical method was optimized using Box-Behnken Design having 13 runs and 3 responses. The optimized method was developed using methanol and water (70:30 v/v) with a flow rate of 1 mL/min. Quercetin was used as an internal standard. A specificity test was also performed for the developed CRM solid self-nano emulsifying drug delivery system.

The retention time of CRM was found to be 14.18 minutes. The developed method was validated and found to be linear in the range of 50-250 ng/mL with an R² of 0.999. Accuracy studies indicated that CRM had a percentage recovery of less than 105% and more than 95%, respectively. Precision studies were carried out for inter, intraday, and inter-analyst precision, and the %RSD was found to be less than 2%. The limit of detection (LOD) and limit of quantification (LOQ) were found to be 3.37 ng/mL and 10.23 ng/mL, respectively. Stability studies for shortterm, long term and freeze-thaw cycles showed a %RSD of less than 2%, indicating the stability of CRM in the plasma matrix. Moreover, the blank fecal microbiota extract slurry did not show any peak at the retention time of CRM in a CRM-loaded solid nanoemulsifying drug delivery system containing fecal microbiota extract indicating its specificity.

Hence, the developed method can have clinical implications as it helps estimate CRM in blood samples and also provides a simple and sensitive method for the estimation of plant-based flavonoids along with fecal microbiota extract formulations.