A stability-indicating HPLC method was developed and validated for the quantitative determination of fexofenadine in tablet dosage forms. An isocratic seperation was achieved using a Zorbax, Eclipse XBD, C-8 Column having 150 x 4.6 mm i.d., 5 µm particle size column with flow rate of 1.2 ml/min and using UV detector to monitor the eluate at 210 nm. The mobile phase consist of phosphate buffer: acetonitrile: methanol (60:20:20; v/v/v) with pH 3.7 adjusted with o-phosphoric acid. The drug was subjected to oxidation, hydrolysis, photolysis and thermal degradation. Fexofenadine was found to degrate in acidic, basic and oxidation condition. Complete seperation of degraded product was achieved from parent compound. All degradation products in an overall analytical run time of approximately 60 min with the parent compound fexofenadine eluting at approximately 12.1 ±0.9 min. The method was linear over the concentration range of 1-100 µg/ml (r2= 0.9970) with limit of detection and quatification of 0.2 µg/ml and 0.6 µg/ml, respectively. The method has the requisite accuracy, selectivity, sencitivity, precision and robustness to assay fexofenadine in tablets. Degradation products resulting from stress studies did not interfere with the detection of fexofenadine and the assay is thus stability indicating.

A simple, specific, accurate and precise reverse phase high pressure liquid chromatographic method has been developed for the simultaneous determination of nimesulide and tizanidine from tablets. The sample was analyzed using methanol: water in the ratio of 65:35, pH adjusted to 4.15 with orthophosphoric acid on an octadecylsilane C 18 column. The effluent was monitored at 1.4 ml/min flow rate using 307 nm as detecting wavelength. The linear dynamic ranges for nimesulide and tizanidine were 0.2-1.0 µg/ml and 10-50 µg/ml, respectively. Coefficients of correlation obtained for nimesulide and tizanidine were 0.998 and 0.996-respectively. Nimesulide is an antiinflammatory drug. Chemically, sulphonamide. It is approved for used in treatment of nimesulide is N-(4-nitro-2-phenoxyphenyl)methane musculoskeletal disorder, dyemenorrhoea, thrombophlebitis and dental pain, inflammation. Some *For correspondence HPLC 1,2 and spectrophotometric 3,4 methods have been reported in the literature for its estimation. Tizanidine is a

Objective: The combined dose tablet formulation containing aspirin and ticlopidine hydrochloride is used to reduce the formation of harmful blood clots in blood vessels which helps in preventing a heart attack or stroke in people with heart disease. The objective of the present work was to develop an accurate, precise, economical and less time consuming UPLC method and subsequently validate the method as per ICH guidelines, for routine quality control of combined dose tablet formulation containing above mentioned drug. Methods: The present work describes development and validation of ultra performance liquid chromatographic method for simultaneous quantitation of aspirin and ticlopidine hydrochloride in tablets. The chromatographic separation was carried out using Supelcosil LC-18 (3.3 cm × 4.6 mm × 3 µm) column using mixture of Potassium Phosphate buffer (0.01M) and Acetonitrile (20:80 v/v) as mobile phase with a flow rate of 0.6 ml per minute, total run time was 3 minutes. The detection and quantitation of chromatographic peaks was carried out at 230 nm. Results: The retention time for aspirin (ASP) and ticlopidine hydrochloride (TPH) was 0.529 minutes and 1.530 minutes, respectively. The linearity of detector response was observed in the concentration range of 20 – 60 µg/ml and 50-150 µg/ml for ASP and TPH, respectively. The LOD and LOQ for ASP and TPH was found to be 0.399 & 1.209 and 3.385 & 10.260, respectively. The accuracy of the method was found in the range of 99.92 – 100.58 % and 98.91 – 100.52 for ASP and TPH, respectively. The relative standard deviation for intra-day and inter-day precision studies was below 2 % indicating that the method is precise. The robustness of the proposed method was evaluated by varying the chromatographic parameters and the effect of these changes on retention time and tailing factor was studied. The % RSD for retention time and tailing factor was below 2 % indicating that the method is robust. The forced degradation studies were carried out to evaluate the specificity of the method. As the method was able to quantitate ASP and TPH selectively in presence of degradation products, the method was found to be specific. As the results of validation studies were within standard limits, the method was successfully applied for simultaneous estimation of ASP and TPH in marketed tablet formulation. Conclusion: The method has distinct advantages over reported UV and HPLC methods and hence the developed UPLC method can be used for routine quality control of Aspirin and Ticlopidine hydrochloride combined tablet formulation.

A simple, specific, precise, and accurate stability-indicating assay method using high performance thinlayer chromatography (HPTLC) is described for estimation of daclatasvir dihydrochloride (DCV) in bulk drug and in the tablet dosage form. The separations were achieved on prepared TLC plates precoated with silica gel 60 F254. The mobile phase developed and optimized for bringing out the separation involves toluene: methanol in the ratio of (6:4 V/V). The densitometric scanning wavelength selected was 312.0 nm. The compact bands of DCV were obtained at RF value of 0.702±0.032. The method developed was able to separate peaks of all the degradation products formed in ICH prescribed stress conditions with sufficient difference in their RF values. The developed method was validated for linearity and range, specificity, precision, accuracy, and robustness, and the results were found to be within acceptance criteria. The reliability of the method was evaluated when it was applied for the estimation of DCV in pharmaceutical tablet formulation and assay results gave good recovery.