Comparative Study of the UV Chemometrics, Ratio Spectra Derivative and HPLC-QbD Methods for the Estimation of Their Simultaneous Estimation in Combined Marketed Formulation

The CARISOMA™ consists of carisoprodol (CAR), paracetamol (PCM) and caffeine (CAF) used for fibromyalgia and osteoarthritis. The study discussed the comparative study of UV chemometrics (method A), ratio spectra derivative (method B) and HPLC-QbD (method C) for simultaneous estimation of the aforementioned drugs in API and marketed tablet formulation. From the listed methods, method A can estimate CAR without derivatization. Analytical figures of merit (FOM) were determined for method A. The CAR has a weak chromophoric group so diazotization was carried out and the derivatized-CAR (D-CAR) was evaluated by IR, mass and NMR; further estimated by method B simultaneously with PCM and CAF. Method C involved the application of quality by design approach for the estimation of aforesaid drugs. The calibration curves of CAR, PCM and CAF found linear in the range of 1–5 µg mL−1, 2–10 µg mL−1 and 0.2–1 µg mL−1 for method A; 1–5 µg mL−1, 2–10 µg mL−1, 0.2–1 µg mL−1 for method B and 10–50 µg mL−1, 20–100 µg mL−1 and 1.85–9.25 µg mL­−1 for method C. Method C involved the use of C18 column and ACN: potassium dihydrogen phosphate buffer (90:10 v/v) as the mobile phase at pH 3. For resolution of drugs, the described methods were successfully applied, validated and compared statistically. Method A was found to be more acceptable due to its accuracy and simplicity.