Objectives: The present study focused on application of a simple, sensitive, rapid, accurate and precise, dual wavelength spectrophotometric method for the quantification of amlodipine besylate and celecoxib in combined dosage form using methanol as a solvent. Materials and Methods: Based on overlain spectra, for quantification of both drugs by proposed dual wavelength spectrophotometric method, the wavelengths selected for the analysis are 280 nm (λ1), 290 nm (λ2), 340 nm (λ3) and 360 nm (λ4). For the quantification of amlodipine besylate absorbance difference measurements was carried out at 340 nm and 360 nm where celecoxib shows same absorbance value. In case of celecoxib absorbance difference measurement carried out at 280 nm and 290 nm where amlodipine besylate showed the same absorbance value at both the wavelengths. The proposed was validated in accordance with guidelines of ICH. Results: The method shown linearity in the concentration range 20-100 μg/ml and 5-25 μg/ml for celecoxib and amlodipine besylate respectively, with good correlation coefficient (r2>0.998). The percentage recovery at different concentration levels were found to be 98.33 to 99.75 % for amlodipine besylate and 98.58 to 99.303 % for celecoxib, indicating the accuracy of the method. Conclusion: The results of analysis were statistically validated and demonstrated to be free from interferences through recovery studies. For the quantification of both the drugs in the commercial available tablets the method was successfully applied.
Introduction: Polar anti-hypertensive drugs like benidepine and metoprolol often suffer from peak fronting and peak tailing effects in RP-HPLC. SCX chromatography which is alternative and complimentary to this RP-HPLC also has the capability to separate benidepine and metoprolol. Considering these aspects, SCX method was developed with performing stability indicating studies for the simultaneous quantification of benidepine (BEN) and metoprolol (MET) in bulk and tablet formulation. Methods: This investigation was performed on the Phenomenex Luna SCX column (100 × 2.1 mm, ID, particle size 5 μm) where both BEN and MET were eluted with ammonium formate (15mM) buffer: MeOH in ratio of 75:25 v/v for 12 min with isocratic elution at the flow rate of 1.2 ml/min; performed at 28°C and monitored at 226 nm wavelength. Results: The average retention time of BEN and MET were 1.290 and 3.520 min, respectively. The validation studies revealed good linearity over different concentration ranging between 7.5-250 μg/ml for BEN and 15.5-250 μg/ml for MET with R2 values were 0.999 recorded for both drugs. Average drug recoveries of BEN and MET were ranging between 99.36±0.83% and 100.51±1.03%, respectively. The acid (0.1N HCl; 50°C), dry heat (50°C) and alkali (0.1N NaOH; 50°C) have not made any significant changes in both BEN and MET but peroxide (3% H2O2; 28°C) have degraded the BEN but MET was unaffected. Conclusion: The present SCX method represented the shortest run time for the investigation of benidipine and metoprolol where the results of linearity, accuracy, precision, robustness and specificity were under the obligation of ICH guidelines.
