A liquid chromatographic method for the simultaneous determination of amlodipine, valsartan and hydrochlorothiazide in tablets

A simple, rapid, sensitive, specific, accurate, precise and fast high performance liquid chromatographic method for the determination of antihypertensive drugs amlodipine, valsartan and hydrochlorothiazide singly or in combination was developed and validated. Separation of the analytes was achieved on a Hypersil C-18 (250 mm × 4.6 mm, 5 μm) column using a mobile phase consisting of acetonitrile-KH2PO4 pH 3.0- water (75:6:19 % v/v/v) delivered at 1 ml/min, UV detection at 229 nm and 40 oC column temperature. The precision of the method was demonstrated through repeatability (coefficient of variation = 0.298-0.724) as well as intermediate precision (coefficient of variation = 0.435-1.412). The detector response was linear over the 25-150 % range with R2 ≥ 0.99 for each of the three analytes. The limit of detection for hydrochlorothiazide, valsartan and amlodipine were 10.72, 21.20 and 14.45 ng, while the limits of quantification were 35.76, 71.23 and 48.16 ng, respectively. The method showed satisfactory robustness and accuracy with a recovery of 99.7-100.6 %. The method was applied in the assay of 6 commercial products containing drugs under study. The results obtained revealed quality problems among the samples analyzed.Keywords: HPLC, amlodipine, valsartan, hydrochlorothiazide, antihypertensive

Phytochemical and anthelmintic study of the root bark of Teclea trichocarpa, Engl. (Rutaceae)

The root bark of Teclea trichocarpa exhibited anthelmintic activity against egg hatching and larval development of sheep nematodes (Strongyloides). Three compounds, namely lupeol, melicopicine and 6-methoxytecleanthine were isolated from the dichloromethane-methanol (50:50) extract of the plant. Melicopicine and 6-methoxytecleanthine exhibited mild anthelmintic activity. The present study lends scientific credence to the traditional use of Teclea trichocarpa in the treatment of human helminth infections.Keywords:  Teclea trichocarpa, phytochemical, anthelminti

Antimicrobial activity of extracts and phytosterols from the root bark of Lonchocarpus eriocalyx

The root bark of Lonchocarpus eriocalyx was dried, powdered and extracted using chloroform, methanol and hot water. The extracts exhibited antibacterial activity against Pseudomonas aeruginosa, Escherichia coli and Staphylococcus aureus and antifungal activity against Saccharomyces cerevisiae. The decoction (100mg/ml) was more active than the chloroform and methanol extracts against the four microorganisms. Chromatographic fractionation of the chloroform extract using normal phase silica yielded the phytosterols lupeol and lupenone. At 100 mg/ml, the compounds were active against all the four microorganisms, with lupeol being more active than lupenone. This is the first report of the isolation of lupenone from Lonchocarpus eriocalyx.Keywords:  Lonchocarpus eriocalyx, lupeol, lupenone, antimicrobial activit

A stability indicating liquid chromatography method for the assay of rufinamide bulk material and tablets

A simple, rapid, isocratic stability indicating reverse phase liquid chromatography method was developed for the assay of rufinamide bulk drug and tablets. The method achieved adequate resolution of rufinamide, related substances A and B as well as laboratory generated degradation products. The method uses a Phenomenex® Hyperclone BDS C-18 column (250 × 4.6 mm, 5 μ) maintained at 35 °C and a mobile phase composed of methanol-0.1 M octane sulfonic acid-0.1 M KH2PO4, pH 6.5-water (30:10:5:55, % v/v/v/v) delivered at a flow rate of 1.0 ml/min. The eluents were monitored by means of ultraviolet detection at 210 nm. During validation, the method satisfied the International Conference on Harmonization acceptance criteria for linearity sensitivity, precision, accuracy, and robustness. The developed method may be applied in the routine analysis of rufinamide bulk material and tablets as well as stability studies.Keywords: Rufinamide, stability indicating method, related compoun