O smotically controlled oral drug delivery systems utilize osmotic pressure as energy source for the controlled delivery of drugs, independent of pH and hydrodynamic conditions of gastrointestinal tract (GIT). The present study was aimed to develop osmotic controlled extended release formulations of verapamil hydrochloride an angiotensin II receptor antagonist with anti-hypertensive activity. Verapamil hydrochloride matrix tablets were prepared by direct compression process using hydroxypropyl methylcellulose (HPMC) K 15M as polymeric material and mannitol as osmogen at varied concentrations. The matrix tablets were further coated with different compositions of ethylcellulose7cps and polyethylene glycol (PEG)-4000 by pan coating method. Physical parameters such as weight uniformity, drug content, hardness and friability were evaluated for uncoated tablets and were found to be within I. P limits. The coating thickness and percentage of coating applied for various tablets were also evaluated. The optimized coated tablets were further subjected to micro drilling on the upper face to get 0.5 μm orifice diameter. All the tablets were further subjected to dissolution studies by using USP apparatus II with 6.8 pH phosphate buffer as medium. These studies indicated that all the tablets were found to release the drug up to 12 hours, while coated tablets with orifice found to release the drug at zero order rate, which was in good agreement with peppas n > 0.9.
The present paper illustrates about development and validation of a new, simple, precise and accurate RP-HPLC method with enhanced sensitivity for the simultaneous determination of Doxylamine Succinate (DAS) and Pyridoxine Hydrochloride (PDH) in bulk and its dosage forms. The drug showed good absorbance in mobile phase at 263 nm. Under the optimized conditions, linear relationship with good correlation coefficient (0.9994 and 0.9992 for DAS and PDH respectively) was found between the concentration range of 10-50 µg/ml for DAS and 5-25 µg/ml for PDH. The limit of detection for the method was 1.8 and 0.4 µg/ml for DAS and PDH respectively. The limit of quantification for the method was observed to be 4.4 and 4.2 µg/ml for DAS and PDH respectively The precision of the method was satisfactory; the values of relative standard deviations did not exceed 2%. The recovery values were 99.4-99.8% ± 1.61% for DAS and 99.8-100.4% ± 0.12% for PDH. The chromatographic method was developed on AGILENT HPLC with UV detection. The method was optimized by Kromosil-C18, (250 * 4.6mm, 5μ) column by using phosphate buffer (pH _ 5): methanol (40:60) as a mobile phase with 1 ml/min as flow rate. The detection wavelength is 263 nm. The proposed method are successfully applied for the determination of DAS and PDH in bulk and their dosage forms. The method is having higher sensitivity and wider linear range. The proposed method is practical and valuable for its routine application in quality control laboratories for estimation of DAS and PDH.
A stability indicating RP-HPLC method was developed for the simultaneous estimation of the anti hypertensive drugs Hydrochlorothiazide, Amlodipine Besylate and Telemisartan. These drugs were subjected to stress studies under different conditions as per ICH guidelines. The separations were carried out using C 18 reverse phase column (Agilent ODS UG 5 column, 250mm x 4.5mm,5µm) employing Acetonitrile and Acetate buffer (60:40 v/v) as mobile phase and pH adjusted to 5 at flow rate of 1ml/min was used for separation, detected at 333 nm. The drugs were exposed to acidic, alkaline, oxidative, thermal and photolytic conditions and the stressed samples were analyzed by the proposed method. Degradation studies showed that all the three drugs were degraded under oxidative, thermal and photolytic conditions, negligible degradation observed under acidic, alkaline conditions. Analytical validation parameters such as specificity, linearity, accuracy, precision, Ruggedness and Robustness were determined and relative standard deviation of all the parameters were found to be less than 2%. Hence this method was found to be stable indicator that can be used for the routine analysis of these drugs in the bulk and combined tablet dosage form.
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