RP-HPLC.

Hypertension (HT) is a very common disorder, particularly for past middle age. It is not a disease in itself, but is an important risk factor for cardiovascular mortality and morbidity. For improved treatment of hypertension, Telmisartan and Benidipine HCl is the newer combination in market, this combination was developed to improve medication for Stage II hypertension. The aim of this review is to focus on comprehensive update of different analytical methods used for estimation of anti-hypertensive drugs like Telmisartan and Benidipine HCl for the treatment of hypertension. This review delivers a detail description on different analytical methods like UV and RP-HPLC for Telmisartan and Benidipine HCl individually and combination with other drugs. For this review, data searches were conducted by scientific papers in the literature as well as in official compendium. All reported methods are found to be simple, accurate, economic, precise and reproducible in nature.

The stability of drug product or a drug substance is a critical parameter which may affect purity, potency and safety. The stability indicating method is that employed for the analysis of stability samples in pharmaceutical industry. Forced degradation studies show the chemical behavior of the molecule which in turn helps in the development of formulation and package. Forced degradation is a degradation of new drug substance and drug product at conditions more severe than accelerated condition. Thus, this review discuss the current trends in performance of stability indicating method to force degradation by providing strategy for conducting studies on degradation mechanism Stability testing by reversed-phase high-performance liquid chromatographic (RP-HPLC) method has been performed of cilinidipine and olmesartan. All the drugs were separated. The retention time of cilinidipine and olmesartan was founded respectively. Ranges of 50 -300μg/ml for cilinidipine and 25 – 150 μg/ml for Olmesartan. Keyword: Olmesartan, Cilnidipine, RP-HPLC.

The estimation of Piperaquinen tetraphosphate and Dihydroartemisinin was done by RP-HPLC. The Phosphate buffer was pH 4.6 and the mobile phase was optimized which consists of MEOH: Phosphate buffer mixed in the ratio of 70:30 % v/ v. A Symmetry C18 (4.6 x 150mm, 5mm, Make X   Terra) column used as stationary phase. The detection was carried out using UV detector at 273 nm. The solutions were chromatographed at a constant flow rate of 1.0 ml/min. the linearity range of Piperaquinen tetraphosphate  and Di hydro artemisinin were found to be from 25-125 mg/ml. Linear regression coefficient was not more than 0.999.The values of % RSD are less than 2% indicating accuracy and precision of the method. The percentage recovery varies from 97-102% of Piperaquinen tetraphosphate and Di hydro artemisinin LOD and LOQ was found to be within limit. The proposed method is precise, simple and accurate to determine the amount of Piperaquinen tetraphosphate and Di hydro artemisinin in formulation. High percentage of recovery shows that the method is free from the interference of excipients used in the formulation. So the method can be useful in the routine quality control of these drugs.

(6-(3,4-diaminophenyl)-5-methyl-4,5-dihydropyridazine-3(2H)-one(GTI-A) and p-anisaldehyde (GTI-B)have been highlighted a (GTI's) potential genotoxic impurities (PGIs) of Pimobendan. A sensitive RP-HPLC method was developed and validated for the determination of (6-(3,4-diaminophenyl)-5-methyl-4,5-dihydropyridazine-3(2H)-one and p-anisaldehyde in pimobendan using Zodiac C18 (125 X 4.6mm 5µ) column, with UV Detector. The calibration curves showed good linearity over the concentration range of 0.5μg/mL to 1.5μg/mL with respect to the sample. The correlation coefficient was 0.999. Excellent recoveries of 102 % were obtained at the level of 0.5μg/mL.

A simple, precise and stability-indicating HPLC method was developed and validated for the simultaneous estimation of anti-retroviral drugs Lopinavir and Ritonavir. The separation was achieved on AgilentC8, 150mm* 4.6 ,5µ  column with isocratic flow. The mobile phase at a flow rate of 1.5ml consisted of 0.05M Potassium Dihydrogen Orthophosphate buffer and Acetonitrile: MeOH in the ratio of (80:20).The ratio of buffer: organic is (45:55).The UV detection was carried  out at 210nm. The method was successfully validated in accordance to ICH guidelines. This method was then used to study the stability aspects of both the drugs when subjected to acidic, alkaline, thermal and photo degradation condition.

The Developed RP- HPLC method allows rapid and precise determinations of Cefixime  and Paracetamol. The scope of the present work is to expand and optimization of the chromatographic conditions and to develop RP-HPLC method. A series of mobile phases and columns were tried, among the various mobile phases, Buffer: Acetonitrile (65:35A) (PH-3.5) as an ideal mobile phase, since it gave a good resolution and peak shapes with perfect optimization. The flow rate was optimized at 1 ml/min. The Linearity and correlation coefficient of Cefixime and Paracetamol was found to be 0.999, and 0.999 respectively. Precision was performed and % RSD for Cefixime and Paracetamol were found to be 1.17% and 1.32% respectively. Three concentrations 50%, 100%, 150%, were injected in a triplicate manner and amount recovered and % Recovery was found to be 100%. Limit of detection was calculated by standard deviation method Cefixime and Paracetamol and LOD for Cefixime and Paracetamol were found to be 0.03and 0.02 respectively. Limit of Quantification was calculated by standard deviation method Cefixime and Paracetamol and LOQ for Cefixime and Paracetamol were found to be 0.08 and 0.06 respectively. Small deliberate changes in method like flow rate, mobile phase ratio, and temperature are made but there were no recognized change in the result and are within range as per ICH Guide lines. The average % Assay was calculated and found to be 100.46% and 99.84% for Cefixime and Paracetamol respectively. Hence, the chromatographic method developed for Cefixime and paracetamol is said to be rapid, simple, specific, sensitive, precise, accurate and reliable that can be effectively applied for routine analysis in research institutions, quality control department in Industries, approved testing laboratories, Bio-pharmaceutics and Bio-equivalence studies and in clinical pharmacokinetic studies.

An accurate, precise and reproducible RP-HPLC method for the simultaneous determination of Lamivudine and Raltegravir in the bulk API dosage form has been developed and validated. Chromatographic separation was carried out on Agilent C18 (100×4.6mm, 3.5u particle size) column using mobile phase composed of phosphate buffer (PH3.0): acetonitrile (ACN) in ratio 60:40 at a flow rate of 0.8ml/min. The analyte was monitored using DAD detector at 231nm. The retention times were found to be 1.12 and 4.08 for Lamivudine and Raltegravir respectively. The linearity for each were found in the range 10-60µg/ml and their regression values are 0.998 and 0.999 respectively. The developed method was validated as per ICH guidelines.

A simple, accurate and sensitive RP-HPLC method was developed and validated for the determination of candesartan cilexetil and hydrochlorothiazide in tablet dosage form. The separation of the two drugs was achieved on a Reprospher 100 –C l 8 column (250 x 4.6 mm, 5 µm particle size) with UV detection at 260 nm. The mobile phase consists of two solution, solution (1) orthophosphoric acid (pH 2.2) and the solution (2) which is acetonitrile and purified water in the ratio 55: 45 v/v, respectively. The method was validated in terms of linearity, accuracy, precision, specificity, limit of detection, limit of quantitation and robustness. Linearity was observed in the concentration range 10-70µg/ml for hydrochlorothiazide and 12.8 -89.6µg/ml for candesartan cilexetil. The limit of quantitation was found to be 8.58 and 4.6 µg/ml for hydrochlorothiazide and candesartan cilexetil, respectively whereas the limit of detection, was found to be 2.8 and 1.5 µg /ml for hydrochlorothiazide and candesartan cilexetil, respectively. The % recovery range of candesartan cilexetil was 97.84-101.62% and 100.9-101.53% for hydrochlorothiazide. Variation in HPLC conditions (flow rate, column temperature, mobile phase composition, and wavelength) were used to evaluate the robustness of the method. The method proved to be robust and still produces good results.

A simple, precise, rapid and specific reversed phase high performance liquid chromatographic method for determination of S (-) Metoprolol Succinate was developed and validated. The chromatographic separation was achieved on Inertsil ODS column (125×4.6mm, 5µ), using a mixture of 20mM potassium dihydrogen phosphate (pH adjusted to 3.5 with ortho-phosphoric acid) and acetonitrile as mobile phase in the ratio of 80:20 at flow rate of 1.5 mL/min. The detection was performed at 220 nm. The calibration curve was linear in the range of 30 - 90 µg/mL (r2 = 0.99999). Major impurities and degradation products were well separated from S(-) Metoprolol Succinate. Thus this assay method can be considered as stability-indicating.

Simple, accurate and stability-indicating reversed phase high performance liquid chromatographic method was developed and validated for the determination of Eperisone HCl using a Phenomenex Luna C18 (250 x 4.6 mm)  5μm column and a mobile phase of buffer and methanol in the proportion of (30:70) pH 3.0 adjusted with o-phosphoric acid. The retention time of Eperisone HCl were found to be 9.050min respectively. Linearity was established for Eperisone HCl in the range of 50.25 to 150.75µg/ml, respectively. The percentage recovery of Eperisone HCl was found to be in the range of 98.96-99.68% respectively. The selected drug were subjected to acid, alkali and neutral hydrolysis, oxidation, dry heat, photolytic and UV degradation and the degradation studies revealed, Eperisone HCl is well resolved from the pure form with significant differences in their retention time values. This method can be successfully employed for the quantitative analysis of Eperisone HCl in pure and formulation.