A rapid HPLC method for determination of zolpidem and its degradation product in tablets using a monolithic column.
A simple, accurate reverse phase high-performance liquid chromatographic method, utilizing a monolithic silica column, for determination of zolpidem hemitartrate and its degradation product in tablet dosage form was developed. Analysis was achieved on the monolithic, C18 (100 mm, 3.9 mm) column, in isocratic mode with acetonitrile-NaH2PO4 (pH 7.0; 0.01 M; 35:65, v/v) as mobile phase and a flow rate of 2.5 mL/min at room temperature with UV detection at 245 nm. Diazepam was applied as an internal standard. The retention time of zolpidem and its degradation product was 2.14 and 1.89, respectively. Calibration curve was linear in the range of 0.12-5 µg/mL and the recovery values were found to be 97-101%. The limit of quantitation was determined 0.12 μg/mL. The relative standard deviation values of intraday and interday studies were calculated as 0.13-1.1% and 0.54-1.3%, respectively.
Rapid Determination of Sildenafil Citrate in Pharmaceutical Preparations Using Monolithic Silica HPLC Column
Abstract A simple, rapid, and sensitive high performance liquid chromatography (HPLC) method has been developed and validated for the determination of sildenafil citrate in pharmaceutical preparations. The method was developed utilizing a 100 × 4.6 mm I.D. monolithic silica column and an isocratic elution of 60:40, v/v acetonitrile/water. The elution of the analyte was monitored at 292 nm with a flow rate of 2.0 mL/min. All analyses were conducted at ambient temperature. Linearity was observed in the concentration range from 50–3000 ng/mL, with a correlation coefficient (R 2) greater than 0.999. The limit of detection was 25 ng/mL. Parameters of validation prove the precision of the method and its applicability for the determination of sildenafil citrate in pharmaceutical tablet formulations. The method is fast (less than 1 min) and is suitable for high throughput analysis of the drug.
Catalytic removal of tert-butyldimethylsilyl (TBS) ether by PVP-I
Abstract A mild, efficient and rapid protocol the deprotection of alcoholic TBDMS ethers using PVP-1 as catalyst in methanol, the procedure of deprotection of various TBDMS ethers were found to be very convenient, easy work-up, high yielding.