Simultaneous determination of cetirizine and pseudoephedrine combined in tablet dosage form by high performance liquid chromatography

This study develops and validates an efficient, sensitive and simple method for the simultaneous determination of cetirizine dihydrochloride and pseudoephedrine combined in tablet dosage form by high performance liquid chromatography [HPLC] with an ultraviolet [UV] detector.The validation of this method was carried out according to ICH and USP guidelines. In this study, the mobile phase used was acetonitrile: water [530:470 [v/v]] with 200mg sodium heptane sulfonic acid and the pH value was adjusted to 2.5 with sulfuric acid. The limit of detection and quantification for cetirizinedihydrochloride were 0.805 and 2.685 microg/mL, respectively, and the limit of detection and quantification for pseudoephedrine were 17.976 and 59.921 microg/mL, respectively. The linearity was studied in the concentration range of 12.2 and 36.5 microg/mL forcetirizinedihydrochloride and 295.91 and 861.73 microg/mL for pseudoephedrine. The recovered amounts of cetirizinedihydrochloride and pseudoephedrine were 98.2% -102.9% and 99.5%- 102.4%, respectively.

Determination of metformin in human plasma using normal phase high performance liquid chromatography

A simple, selective, sensitive, accurate, and precise normal phase HPLC method coupled with UV detection has been developed and validated for the determination of metformin in human plasma. After protein precipitation with acetonitrile, Metformin was extracted with dichioromethane. The mobile phase consisted of acetonitrile and phosphate buffer [0.05M] [60:40% v/v] pH 7.0, the stationary phase was a normal phase silica column [250X4.6 mm ID, 5pm particle size]. Detection was carried out using a UV detector set at 235nm. The method was linear over the concentration range 0.016-2.709 micro g/ml [y = 0.7898X +0.0048] and gave a limit of quantitation of 16 ng/ml. Analytical recovery, measured over three days, averaged 94.88%. The interday precision ranged 4.1 to 11.8 CV [%] for four quality control samples including LLOQ, low, medium, and high. Metformin was found to be stable in plasma and in working standard solutions during sample collection, storage, and processing as well as in five freeze thaw cycles. The described HPLC method was successfully employed for the analysis of authentic samples collected from three bioequivalence studies involving 32 volunteers each. The average concentration - time profiles were plotted from the three bioequivalence studies which involved three doses of 500 mg/tablet, 850 mg/tablet and 1000mg/tablet under fasting conditions. Slow GI absorption and linear pharmacokinetics characterized the disposition of metformin