A simple, fast and precise reverse phase high performance liquid chromatographic method is developed for the simultaneous determination of aceclofenac, paracetamol and tizanidine. Chromatographic separation of the three drugs were performed on a hypersil C18column (250 mm x 4.6 mm, 5 µm) as stationary phase with a mobile phase comprising of mix phosphate buffer pH 7.0: acetonitrile (40:60 v/v), at a flow rate of 0.7 mL min-1and UV detection at 230 nm. The proposed method was validated for linearity, accuracy, precision, LOD, LOQ. Linearity, accuracy and precision were found to be acceptable over the ranges of 100-300 µg mL-1for aceclofenac, 500-1500 µg mL-1for paracetamol and 2-6 µg mL-1for tizanidine HCl equivalent to tizanidine. It can be conveniently adopted for routine quality control analysis.

A simple, precise, rapid, accurate and economic reverse phase high performance liquid chromatographic method has been developed for the estimation of prulifloxacin in tablet dosage form. The separation was achieved by using octadecylsilane column (C18) and KH2PO4 buffer: acetonitrile adjusted to pH 7.3 with triethyl amine in proportion of 10:90 v/v as mobile phase, at a flow rate of 1.0 ml/min. The detection was carried out at 278 nm. The retention time of prulifloxacin was found to be 2.4 min. The limit of detection and limit of quantitation were found to be 0.14 μg/ml and 0.42 μg/ml respectively. The accuracy and reliability of the proposed method was ascertained by evaluating various validation parameters like linearity, precision, accuracy and specificity according to ICH guidelines. The proposed method provides an accurate and precise quality control tool for routine analysis of prulifloxacin in tablet dosage form.

A simple, very fast, precise and accurate reverse phase ultra performance liquid chromatographic method was developed for the determination and validation of topotecan hydrochloride in bulk and injection dosage form. A Waters BEH C18, 50×2.1 mm, 1.7 μm particle size column in gradient mode was used with mobile phase comprising of 0.1% v/v orthophosphoric acid in water and acetonitrile. The analytical column was thermostated at 50° and flow rate was set at 0.4 ml per min, with photo diode array detection at 260 nm. The retention time of topotecan was found 1.38 min. The method was validated in terms of linearity, accuracy, precision and specificity. The calibration curve was found linear between 20 to 60 μg/ml. The limit of detection and limit of quantification were found 0.2353 and 0.7131 μg/ml, respectively. Percentage recoveries were obtained in the range of 98.91% and 99.17%. The proposed method is precise, accurate, selective and reproducible. The ultra performance liquid chromatographic assay procedure, which proved superior because of its greater sensitivity and relatively shorter (4 min) run time, should be an important tool for speedy future analysis of topotecan hydrochloride in bulk and its injection dosage form.

Candesartan Cilexetil is an antihypertensive agent currently available in combination with Hydrochlorothiazide. However, it has been proven by research that half dose of Chlorthalidone is equipotent to the dose of Hydrochlorothiazide in similar combination with Candesartan Cilexetil. At present there is no Liquid Chromatographic (LC) method available for the simultaneous estimation of Candesartan Cilexetil and Chlorthalidone in pharmaceutical dosage form. A simple, rapid, reliable and robust reversed phase ultra-performance liquid Chromatography (RP-UPLC) method was developed as per International Conference on Harmonization (ICH) guidelines. The best separation was achieved in less than 5 minutes on a 50 × 2.1 mm, 2.2 µm particle size Dionex C18 column with the gradient mobile phase 5 mM, 6.2 ± 0.5 pH ammonium acetate buffer - acetonitrile at a flow rate of 0.5 mL/min at 215nm. The detector response was linear in the range of 10-200 ppm of these drugs. LOD obtained was 3.04 ppm for Candesartan Cilexetil, 2.82 ppm for Chlorthalidone. Further evaluation of robustness of this method was carried out using Plackett-Burman verification with four factors two levels (high & low) within analytical QbD-principles using statistical software. The outcome of normal probability and overall desirability plots were found acceptable.