RP-HPLC

A simple, rapid and specific RP-HPLC method has been developed and validated for determination of Carvedilol in bulk and tablet formulations. Chromatographic separation was performed by Phenomenex Luna C-18 (250 x 4.6mm, 5μm particle size) column with a mobile phase consisting of a mixture of phosphate buffer, acetonitrile and methanol in the ratio (30:45:25 v/v/v), pH adjusted to 4.8 with ortophosphoric acid. The mobile phase was was filtered through a 0.45μ cellulose nitrate filter, sonicated for 15 min and delivered at a flow rate of 1ml/min. Detection was performed at a wave length of 241 nm at ambient temperature. Linearity was obtained in a concentration range of 30 to130 µg/ml with a correlation coefficient (r2) of 0.999. The limit of detection and limit of quantification were 1.08 and 3.24 μg/ml, respectively. No interference of excipients in determining tablet formulation; identical results were obtained like that of the standard sample.  The proposed RP-HPLC method is simple, accurate, precise, rapid and economical to be employed for routine analysis of carvedilol in pharmaceutical dosage forms. 

  A simple, specific, accurate and precise reverse phase high performance liquid chromatographic method was developed for simultaneous estimation of diazepam and propranolol hydrochloride in pharmaceutical tablet formulation. The separation was achieved on Phenomenex C18 column (250 mm i.d., 4.6 mm, 5 µm particle size) using methanol: acetonitrile: water (50 : 25 : 25, v/v/v, pH adjusted to 2.8 ± 0.05 with ortho- phosphoric acid) as the mobile phase at a flow rate of 1.0 ml min-1. The quantification was achieved with PDA detector at 235 nm. The injection volume was 20 µl. The retention times of diazepam and propranolol hydrochloride were 5.38 ± 0.29 min and 3.80 ± 0.15 min, respectively. The method was validated for linearity, precision, specificity, robustness and recovery according to the ICH guidelines. The linearity was obtained in the concentration range of 0.1-5.0 µg/ml for both drugs with mean recovery of 100.3 ± 0.47 and 100.2 ± 0.78 % for diazepam and propranolol hydrochloride, respectively. The limit of detection and quantification for diazepam were 0.015 and 0.050 µg/ml, respectively and for propranolol hydrochloride were 0.014 and 0.045 µg/ml, respectively. The method was found to be simple and highly sensitive and can be useful in the routine quality control of diazepam and propranolol hydrochloride in bulk manufacturing and pharmaceutical dosage forms.   Key words: Diazepam, propranolol hydrochloride, RP-HPLC, validation, simultaneous, tablet