Validation of HPLC-UV method for simultaneous determination of quercetin and luteolin from chartamus tinctorius L in solid lipid nanoparticles incorporated in floating gel in situ formulation

Abstract

Safflower extract (SE) is known to have various benefits in the drug and food industries. The main ingredients, like quercetin and luteolin, show vigorous antioxidant activites but have low solubility and stability to air, light and heat. Solid lipid nanoparticles (SLNs) are suitable carrier to overcome the stability issues and improve the solubility of SE. In aiming to deliver via oral route, the absorption can be further enhanced through floating rafts system (GFRS). Here, we developed a novel validated RP-HPLC method for determining simultaneous quercetin and luteolin to support formulation development. Effective chromatographic separation was carried out using a reversed-phase column C18 (150 × 4.6 mm, 5 µm) with isocratic method; 0.1% v/v trifluoro acetic acid (TFA) in water and acetonitrile (35 %v/v: 65 %v/v). The method was validated in four different media; methanol, FaSSGF, FeSSGF, and PBS pH 7,4. The results indicate the linearity of the method with a 0.998 correlation coefficient (R). Additionally, all media's LLOQ values ranged between 0.12 µg/mL and 0.31 µg/mL. Notably, the procedure was precise and accurate with the necessary dilution integrity, indicating the methods' validity. Finally, the method was successfully applied to determine quercetin and luteolin in SE, SLNs containing SE, and floating in situ gel containing SLNs of SE. Consequently, the delivery approach developed here could be an appropriate solution for the oral delivery of SE. Based on these findings, additional in vivo investigations on an animal model should be conducted to evaluate the efficacy of this approach.