simultaneous equation method

A simple, rapid, precise and highly selective spectrophotometric method was developed for simultaneous estimation of Norfloxacin and metronidazole in tablet dosage form. This method involves the measurement of absorbances of Norfloxacin and Metronidazole at the wavelength of 272nm (λmax of Norfloxacin) and 334nm (λmax Metronidazole) .0.1 N NaOH was used as solvent. Linearity was observed in the concentration range of 1-10 µg/ml for Norfloxacin and 1- 19µg/ml for Metronidazole. The accuracy of the method was confirmed by recovery studies of tablet dosage forms and was found to be 101 and 102% for Norfloxacin and metronidazole respectively. The method showed good reproducibility and recovery with % RSD less than 2. The LOD of Norfloxacin and metronidazole and LOQ of Norfloxacin and metronidazole   was found to be 0.3μg/ml and 1.16μg/ml and 0.79μg/ml and 2.4μg/ml respectively. The developed method was free from interferences due to excipients present in tablets .Thus the proposed method was found to be rapid, specific, precise, accurate and cost effective quality control tool for the routine analysis of Norfloxacin and metronidazole in bulk and combined dosage form.

The manuscript describes validated simultaneous equation method for the simultaneous estimation of Amlodipine Besylate and Indapamide in combined dosage form. Simultaneous equation method was based on the estimation of both the drugs at two wavelengths i.e. absorption maxima of both drugs. An absorption maxima of Amlodipine besylate was 240 nm and absorption maxima of Indapamide was 215 nm in methanol. The linearity was obtained over the concentration range of 10 – 30 µg/mL for amlodipine besylate and 2 – 10 µg/mL for Indapamide with mean recovery of 99.45 ± 0.84 % and 99.46 ± 0.33 % for Amlodipine Besylate and Indapamide, respectively. These methods were found to be simple, sensitive, accurate, precise and economical and applicable for the simultaneous determination of Amlodipine Besylate and Indapamide in combined dosage form.

A rapid, simple, sensitive, accurate, and precise UV spectrophotometric method has been developed for the simultaneous estimation of anti-retroviral agents lamivudine, didanosine and efavirenz in pharmaceutical dosage form. The absorption maxima of the drugs were found to be 271, 250 and 247 nm for lamivudine, didanosine and efavirenz respectively. Lamivudine, didanosine and efavirenz obeyed Beer’s law in the concentration range of 10-100 µg/ml, 10-100 µg/ml and 10-70 µg/ml respectively. The percentage recovery was within the range of 98% - 101%, indicating that insignificant interference from the other ingredients in the formulation. The above method was validated in terms of linearity, accuracy, precision, Limit of Detection (LOD), Limit of Quantification (LOQ) etc. in accordance with ICH guide lines. The developed method was free from interferences due to excipients present in tablets. The method was rapid, simple and suitable for routine quality control analysis.