A novel, precise, rapid and sensitive reverse phase high performance liquid chromatographic method has been developed for the validated estimation of Tadalafil in bulk and tablet dosage form. The separation was achieved on Agilent Eclipse XDB C18 column (150 mm×4.6 mm, 5 µ) using a mobile phase that consists of the buffer (potassium dihydrogen orthophosphate) and acetonitrile in the ration of 50:50 V/V, pH 6 was adjusted with orthophosphoric acid. The flow rate was maintained at 1.2 ml/min and the detection wavelength was 285 nm. The method was validated for linearity, specificity, sensitivity as per ICH guidelines. The retention time was found to be 3.181 for Tadalafil. The calibration curve was linear over the concentration range of 10-150 µg/ml. The % RSD was satisfactory which showed the method found to be reliable. The high percentage recovery confirmed the suitability of the method for estimation of Tadalafil in pharmaceutical dosage form. The developed method could be applicable for routine analysis of Tadalafil in bulk and tablet dosage form.

A RPHPLC chromatographic method was developed and validated for the determination of Quinapril and Hydrochlorothiazide in bulk powder and in pharmaceutical formulations. Quinapril and Hydrochlorothiazide can be separated on Zorbax Eclipse XDB, C18 column (150 x 4.6 mm, 5 mm) at 30 C using Acetonitrile: Phosphate buffer, pH 4.5 was adjusted with o-phosphoric acid in the ratio of 35:65 v/v as a mobile phase at flow rate of 0.9 mL min-1 and detected at 210 nm. The retention time of Quinapril and Hydrochlorthiazide was found to be 2.099 min and 5.537 min respectively. The validation of the proposed method was carried out for specificity, linearity, accuracy, precision, LOD, LOQ and robustness. Calibration was linear over a range of 50-300 g mL-1 and 31.25187.5 g mL-1 with correlation coefficient of 0.999 for Quinapril and Hydrochlorthiazide, respectively. The robustness of the method was evaluated by deliberately altering the chromatographic conditions. The method developed can be applicable for quality control analysis.

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INTRODUCTION:3-(9H-carbazol-4-yloxy)-2-hydroxypropyl [2-(2methoxyphenoxy) ethyl] amine (Figure1) Carvedilol is used to treat heart failure and hypertension (high blood pressure). It is also used after a heart attack that has caused your heart not to pump as well. Mechanism of action Carvedilol is a racemic mixture in which nonselective beta-adrenoreceptor blocking activity is present in the S (-) enantiomer and alpha-adrenergic blocking activity is present in both R (+) and S (-) enantiomers at equal potency. Carvedilol's beta-adrenergic receptor blocking ability decreases the heart rate, myocardial contractility, and myocardial oxygen demand [1][2][3][4]. Carvedilol also decreases systemic vascular resistance via its alpha adrenergic receptor blocking properties. Carvedilol and its metabolite BM-910228 (a less potent beta blocker, but more potent antioxidant) have been shown to restore the inotropic responsiveness to Ca 2+ in OHfree radical-treated myocardium. Carvedilol and its metabolites also prevent OHradical-induced decrease in sarcoplasmic reticulum Ca 2+ -ATPase activity. Therefore, carvedilol and its metabolites may be beneficial in chronic heart failure by preventing free radical damage [4][5][6][7]. The main object of the work is to develop a new method development and validation of forced degradation Studies of carvedilol by using UV spectroscopy [7][8][9][10].

Recent study was conducted to develop and validate analytical methods for estimation of Risedronate sodium in pure and pharmaceutical dosage form using UV Spectroscopy and               RP- HPLC method. The first method (Method A) based on the UV Spectroscopy using 0.1M Hcl as diluent lambda max was found at 261 nm. Linearity existed perceived in the concentration between 10-50 μg/ml (r 2 = 0.999) for the method. The method was validated pertaining to linearity, precision and accuracy studies, LOD and LOQ consistent with ICH guidelines. The second method (Method B), based on determination of Risedronate sodium tablet dosage form by RP-HPLC method.  Chromatography separation was carried out on a C18 (150X4.6 mm x5 µ) SS Column using Methanol: Ammonium formate (85:15) as the mobile phase at a flow rate of   1.0 ml/min. The chromatographic analysis was carried out in the reflectance and absorbance mode at 254 nm and retention time of the drug was found to be 1.11 ml/min for standard and tablet. Linear responses of the drug were in the concentration range of 200-1000 µg/ml. The accuracy of the method was assessed by standard dilution method and found to be 98% to              102% .The results of the analysis were validated statistically prism software. The method established was found to be simple, precise, linear, accurate and sensitive. The developed method can be used for routine quality control analysis of Risedronate sodium in pure and pharmaceutical dosage form.