Research Article
Prakash Bhagav, Pandurang Desh
Abstract
A new simple, sensitive and selective UV- spectrophotometric method was developed and validated for the estimation of brimonidine tartrate (BRT) in bulk and in formulations. The method was also applied for the determination of drug solubility, apparent partition coefficient and pKa. BRT was estimated at 248 nm in phosphate buffer (pH 7.4). The linearity range was found to be 3-18 μg/ml with a regression equation of Absorbance = 0.0630 ÃÂ (concentration in μg/ml) + 0.0050. The LOD and LOQ were found to be 0.15 μg/ml and 0.45 μg/ml respectively. The method was found to be accurate (mean percentage accuracy of 99.92) and precise with % RSD less than 1.97 (for intra-day) and less than 1.36 (for inter-day). The developed method was successfully employed for the determination of BRT in pharmaceutical dosage forms (ophthalmic solutions, ocuserts and gels). Forced degradation studies with acid, alkali and temperature based stress conditions showed that the method is stability indicating. The determined preformulation parameters (solubility, apparent partition coefficient and pKa) were found to be similar to the earlier reported results.