Simultaneous Determination of Curcumin and Quinine Co-Encapsulated in Nanoemulsion by Stability-Indicating LC Method

Background: In this paper, an isocratic reverse phase liquid chromatography method was developed and validated for the determination of curcumin and quinine in nanoformulation using a photodiode array detector. Methods: The optimum chromatographic condition with adequate resolution for curcumin (3.8 minutes, 426 nm) and quinine (8.9 minutes, 232 nm) was achieved when the separation was carried out using a Waters RP-18 (4.6 mm x 300 mm) column employing acetonitrile, methanol and aqueous 0.01 % triethylamine (pH adjusted to 3.0 with phosphoric acid) (45: 35: 20, v/v/v) as the mobile phase, and flow rate of 1.0 mL min(-1). The specificity and stability-indicating capability of the method was verified subjecting reference substance and the formulation to hydrolytic, oxidative, photolytic, and thermal stress conditions. Results: The results obtained from degradation studies demonstrated that the antimalarial nanoformulation proposed was more stable, when compared with the solutions of these drugs in the associated and individual forms. The influence of mobile phase composition, pH, and flow rate on resolution was investigated. The method was validated with respect to linearity, limits of detection and quantitation, precision, and accuracy. The response was linear over a range of 12.0 to 18.0 mu g mL(-1)(r = 0.999), for both drugs. The limits of detection and quantitation were found to be 1.2 and 3.6 mu g mL(-1), for curcumin, and 0.6 and 1.8 mu g mL(-1), for quinine. Conclusion: Further, the proposed method was found to be reproducible and convenient for stability-indicating analysis of curcumin and quinine-loaded nanoemultion.