SIMPLE LIQUID CHROMATOGRAPHY METHOD WITH UV DETECTION FOR DETERMINATION OF BROMAZEPAM IN SOLID PHARMACEUTICAL DOSAGE FORMS

Abstract

Bromazepam is a psychoactive drug belonging to class of benzodiazepines with well-known hypnotic and sedative effects. It acts on the central neural system as an inhibitor of the neurotransmitter gamma aminobutyric acid. It is frequently prescribed for treatment of severe anxiety, to reduce tension, agitation and depression. Dissolution testing (the process by which a solid solute enters in to a solution) is a requirement for all solid oral dosage forms and is used in all phases of research and development for product release and stability testing. Tablet dissolution test is a standardized method for measuring the rate of drug release from a dosage form and it simulates the percentage of active substance that can be absorbed into the blood circulation. The direct determination of Bromazepam in pharmaceutical dosage forms using HPLC with UV detector to carry out dissolution test, have not yet been described. Development of HPLC method with UV detection for direct determination of in-vitro dissolution test of Bromazepam tablets, which can be used in the same time as method for determination of assay of Bromazepam in Bromazepam tablets, can make analytical procedure easier and quicker. A simple, selective, linear, precise and accurate RP-HPLC method has been developed and validated for assay and in-vitro dissolution test of Bromazepam tablets. The method was validated according to the guidelines set by the International Conference of Harmonization for validation of analytical procedures. The chromatographic separation was carried out using reversed phase HPLC LiChrospher RP Select B column (125 x 4.0 mm i.d.; 5μm) at temperature of 50oC. Mobile phase was consisting of the mixture of methanol, acetonitrile and potassium dihydrogen phosphate buffer (pH 7.0, adjusted with 0.5M Potassium hydroxide), with the ratio of 45:5:50 (v/v/v) and flow rate of 1.0 ml/min. The detection was carried out at 239 nm. System suitability tests were performed through evaluation of different parameters (retention time, tailing factor, retention factor and selectivity) on freshly prepared standard solution of bromazepam. The retention time of bromazepam in 0,1M HCl was 3.5 min. High percentage of recovery shows that the method is free from the interferences from excipients in test samples. Linearity of response was calculated as a ratio of peak areas of bromazepam vs. concentration in 0,1M HCl and spiked tablets in the concentration range of 0.0018 – 0.016 mgmL-1. The response was linear over the concentration range of 0.0018 – 0.016 mgmL-1 and coefficient of correlation was greater than 0.99. Good linearity shows that the proposed method may be useful for quickly and routinely determination of the percentage of dissolved bromazepam from bromazepam tablets and it can be a method of choice for assay determination in the same time.