A precise, accurate and sensitive liquid chromatographic method is presented for the simultaneous analysis of moxifloxacin, levofloxacin, ciprofloxacin and dexamethasone in reference drugs, ophthalmic dosage form and in physiological fluids. Separation was achieved on a C1(8)analytical column with acetonitrile-phosphate buffer (35:65 v/v) as mobile phase which was pumped isocratically at a flow rate of 1.0 mL min-1 and monitored at 254 nm wavelength. The calibration curve was linear in range of 40-10 000 ng mL-1. Test results in pharmaceutical and physiological samples showed excellent drug recovery (96.5-102.3 %) with good precision (0.81-2.3 % RSD). Test results were linear to sample concentration and correlation coefficient was more than 0.9990. The small value of quantification and detection levels showed the method to be sensitive enough for use in clinical and industrial investigations of all the mentioned drugs.

A novel reverse phase, isocratic HPLC method is described to separate five anti-diabetic drugs i.e., glimepiride, metformin, sitagliptin, rosiglitazone and pioglitazone. Nucleosil C18 analytical column was used as stationary phase, while mobile phase consisted of acetonitrile:phosphate buffer: methanol (40/40/20, v/v) pH 2.0. Effluent was monitored at a flow rate 1 mL/min and detected at wavelength of 240 nm. This research produced excellent chromatography over a wide concentration range of 25-10000 ng/mL. Sepprated and well resolved quantifiable peaks were obtained and test results were linear in this range. Correlation coefficient of more than 0.9990 was witnessed as well as Low %RSD values i.e., maximum 2.0% documented excellent precision of the method. Good recoveries from pharmaecutical (99-101%), urine and plasma samples (>96%) in a range of concentrtion granted very good linearity, accuracy and precision. The projected method has satisfactory applications in quality control of these molecules as well as quantification of these molecules in urine and plasma samples.