RP-HPLC Method for the Determination of Losartan Potassium and Ramipril in Combined Dosage Form

A simple, specific and accurate reverse phase liquid chromatographic method was developed for the simultaneous determination of losartan potassium and ramipril in table dosage forms. A hypersil ODS C18, 4.6×250 mm, 5 μm column in isocratic mode, with mobile phase acetonitrile:methanol:10 mM tetra butyl ammonium hydrogen sulphate in water in the ratio of 30:30:40% v/v/v was used. The flow rate was 1.0 ml/min and effluent was monitored at 210 nm. The retention times of losartan potassium and ramipril were 4.7 and 3.3 min, respectively. The linearity range for losartan potassium and ramipril were in the range of 0.04-100 μg/ml and 0.2-300 μg/ml, respectively. The proposed method was also validated and successfully applied to the estimation of losartan potassium and ramipril in combined tablet formulations.     

Rapid and sensitive liquid chromatographic method for determination of Paclitaxel from parenteral formulation and nanoparticles

A simple and fast reversed phase liquid chromatographic method was developed for estimation of paclitaxel in commercially available parenteral formulation and nanoparticles. Separations were carried out using mobile phase consisting of acetonitrile and 20 mM potassium dihydrogen phosphate (45:55, v/v) on Lichrocart^® C₁₈ analytical column at a flow rate of 1 ml/min and detection wavelength of 230 nm. The developed method exhibited linearity over an analytical range of 50-2000 ng/ml with regression equation, mean peak area= 137.58 concentration (ng/ml)+1765.94, (R₂ =0.9999). The method demonstrated selectivity with no interfering peaks eluting near the vicinity of drug peak. The method was found to be sensitive with detection and quantification limits of 7.57 ng/ml and 22.94 ng/ml. The method has shown consistent and good recoveries from parenteral formulation (100.06±0.86%) and nanoparticles (100.43±0.91%). The method was successfully employed for the analysis of in vitro release study samples of nanoparticle formulation. The method was also applied for determination of paclitaxel content in various pharmaceutical formulations.     

RP-HPLC Estimation of Ramipril and Telmisartan in Tablets

A rapid high performance liquid chromatographic method has been developed and validated for the estimation of ramipril and telmisartan simultaneously in combined dosage form. A Genesis C18 column having dimensions of 4.6×250 mm and particle size of 5 μm in isocratic mode, with mobile phase containing a mixture of 0.01 M potassium dihydrogen phosphate buffer (adjusted to pH 3.4 using orthophosphoric acid): methanol:acetonitrile (15:15:70 v/v/v) was used. The mobile phase was pumped at a flow rate of 1.0 ml/min and the eluents were monitored at 210 nm. The selected chromatographic conditions were found to effectively separate ramipril (R_t: 3.68 min) and telmisartan (R_t: 4.98 min) having a resolution of 3.84. The method was validated in terms of linearity, accuracy, precision, specificity, limit of detection and limit of quantitation. Linearity for ramipril and telmisartan were found in the range of 3.5-6.5 μg/ml and 28.0-52.0 μg/ml, respectively. The percentage recoveries for ramipril and telmisartan ranged from 99.09-101.64% and 99.45-100.99%, respectively. The limit of detection and the limit of quantitation for ramipril was found to be 0.5 μg/ml and 1.5 μg/ml respectively and for telmisartan was found to be 1.5 μg/ml and 3.0 μg/ml, respectively. The method was found to be robust and can be successfully used to determine the drug content of marketed formulations.     

RP-HPLC Estimation of Risperidone in Tablet Dosage Forms

A simple, specific, accurate, and precise reverse phase liquid chromatographic method was developed and validated for the estimation of risperidone in tablet dosage forms. A Phenomenex Gemini C-18, 5 μm column having 250×4.6 mm i.d. in isocratic mode, with mobile phase containing methanol: acetonitrile: 50 mM potassium dihydrogen orthophosphate (80:10:10 v/v) was used. The flow rate was 1.3 ml/min and effluents were monitored at 234 nm. Clozapine was used as an internal standard. The retention time of risperidone and clozapine were 2.5 min and 3.3 min, respectively. The method was validated for linearity, accuracy, precision, specificity, limit of quantification, limit of detection, robustness and stability. The limit of detection and limit of quantification for estimation of risperidone was found to be 500 ng/ml and 990 ng/ml, respectively. Recovery of risperidone was found to be in the range of 99.02-101.68%. Proposed method was successfully applied for the quantitative determination of risperidone in tablet formulations.     

Spectrophotometric and HPLC Methods for Simultaneous Estimation of Amlodipine Besilate, Losartan Potassium and Hydrochlorothiazide in Tablets

Two UV-spectrophotometric and one reverse phase high performance liquid chromatography methods have been developed for the simultaneous estimation of amlodipine besilate, losartan potassium and hydrochlorothiazide in tablet dosage form. The first UV spectrophotometric method was a determination using the simultaneous equation method at 236.5, 254 and 271 nm over the concentration range 5-25, 10-50 and 5-25 μg/ml for amlodipine besilate, losartan potassium and hydrochlorothiazide, respectively. The second UV method was a determination using the area under curve method at 231.5-241.5, 249-259 and 266-276 nm over the concentration range of 5-25, 5-25 and 10-50 μg/ml for amlodipine besilate, hydrochlorothiazide and losartan potassium, respectively. In reverse phase high performance liquid chromatography analysis is carried out using 0.025 M phosphate buffer (pH 3.7):acetonitrile (57:43 v/v) as the mobile phase and Kromasil C18 (4.6 mm i.d×250 mm) column as stationery phase with detection wavelength of 232 nm linearity was obtained in the concentration range of 2-14, 20-140 and 5-40 μg/ml for amlodipine besilate, losartan potassium and hydrochlorothiazide, respectively. Both UV-spectrophotometric and reverse phase high performance liquid chromatography methods were statistically validated and can be used for analysis of combined dose tablet formulation containing amlodipine besilate, losartan potassium and hydrochlorothiazide.     

Ion-Pairing Reverse-Phase High Performance Liquid Chromatography Method for Simultaneous Estimation of Atenolol and Indapamide in Bulk and Combined Dosage Form

A sensitive, accurate, precise and validated ion-pairing reverse-phase liquid chromatographic method for the quantitative determination of atenolol and indapamide in bulk and tablet dosage form was developed. The proposed ion-pairing reverse-phase high performance liquid chromatography method utilises C₁₈ column with 5 μm, 150×4.6 mm i.d. column and mobile phase consisting of 0.1% w/v solution of octane sulphonic acid, sodium salt and methanol (55:45 v/v), (pH 2.8) and ultraviolet detection at 235 nm. A linearity range of 1-250 μg/ml and 1-25 μg/ml for atenolol and indapamide, respectively, was obtained. The mean recoveries are 100.48 and 99.82% for atenolol and indapamide, respectively. The method was validated as per International Conference on Harmonization guidelines.     

Evaluation of impurities level of perindopril tert-butylamine in tablets

Perindopril tert-butylamine is a new member of angiotensin-converting enzyme inhibitors group used in the treatment of hypertension and heart failure. In this paper, the evaluation of reversed-phase high-performance liquid chromatographic method (RP-HPLC) for the determination of impurities level of perindopril tert-butylamine in tablets was done. The chromatograms were recorded using a Hewlett Packard 1100 chromatographic system with DAD detector. Separations were performed on a YMC-Pack C8 column (250 mm × 4.6 mm; 5 μm particle size) at 50 °C column temperature. Mobile phase was a mixture of acetonitrile–potassium phosphate buffer (0.05 M) (37:63, v/v) (pH 2.5). pH of the mobile phase was adjusted with ortophosphoric acid. Mixture of acetonitrile–water (40:60, v/v) was used as a solvent. Injection volume was 50 μl, flow rate 1.7 ml min⁻¹ and UV-detection was performed at 215 nm. The developed method subjected to method validation and parameters in terms of selectivity, linearity, precision, accuracy, limit of detection, limit of quantitation and robustness were defined. The validated method is suitable for the simultaneous determination of perindopril tert-butylamine as well as its impurities in pharmaceuticals.     

New Stability-Indicating RP-HPLC Method for Determination of Diclofenac Potassium and Metaxalone from their Combined Dosage Form

A simple, precise and accurate isocratic RP-HPLC stability-indicating assay method has been developed to determine diclofenac potassium and metaxalone in their combined dosage forms. Isocratic separation was achieved on a Hibar-C₁₈, Lichrosphere-100^® (250 mm × 4.6 mm i.d., particle size 5 μm) column at room temperature in isocratic mode, the mobile phase consists of methanol: water (80:20, v/v) at a flow rate of 1.0 ml/min, the injection volume was 20 μl and UV detection was carried out at 280nm. The drug was subjected to acid and alkali hydrolysis, oxidation, photolysis and heat as stress conditions. The method was validated for specificity, linearity, precision, accuracy, robustness and system suitability. The method was linear in the drug concentration range of 2.5–30 μg/ml and 20–240 μg/ml for diclofenac potassium and metaxalone, respectively. The precision (RSD) of six samples was 0.83 and 0.93% for repeatability, and the intermediate precision (RSD) among six-sample preparation was 1.63 and 0.49% for diclofenac potassium and metaxalone, respectively. The mean recoveries were between 100.99–102.58% and 99.97–100.01% for diclofenac potassium and metaxalone, respectively. The proposed method can be used successfully for routine analysis of the drug in bulk and combined pharmaceutical dosage forms.     

Development and Validation of a Reversed-Phase High-performance Liquid Chromatography Method for Determination of Desmopressin in Chitosan Nanoparticles

A simple isocratic reversed-phase high performance liquid chromatographic method was developed for determination of released desmopressin from chitosan nanoparticles in the in vitro media. The chromatographic separation was achieved with acetonitrile/water (25:75, v/v), in which water contained 0.1% v/v trifluoroacetic acid with pH=2.5 as mobile phase, a Chromolith^® Performance RP-18e column (150×4.6 mm; 5 μm) kept at 40° and ultraviolet detection at 220 nm. The compound was eluted isocritically at a constant flow rate of 1.6 ml/min. The method was validated according to the International Conference on Harmonisation guidelines. The validation characteristics included accuracy, precision, linearity rang, selectivity, limit of detection, limit of quantitation and robustness. The calibration curve was linear (r>0.9999) over the concentration rang 0.5-100 μg/ml. The limit of detection and limit of quantitation in the release media were 0.05 and 0.5 μg/ml, respectively. The proposed method had an accuracy of and intra- and inter-day precision <4.2. Furthermore, to evaluate the performance of the proposed method, it was used in the analysis of desmopressin level in real samples containing chitosan nanoparticles in the in vitro media.     

A validated capillary electrophoresis method for simultaneous determination of ezetimibe and atorvastatin in pharmaceutical formulations

A simple, precise, and sensitive capillary electrophoresis technique coupled with a diode array detector has been developed for the separation and simultaneous determination of ezetimibe and atorvastatin in pharmaceutical formulations. Separation of both ezetimibe and atorvastatin was achieved utilizing fused silica capillary (58 cm × 75 μm ID) and background electrolyte solution that consisted of phosphate buffer (2.5 mM, pH 6.7): methanol (70:30 v/v). The proposed method was validated by testing its specificity, linearity, precision, accuracy, recovery, and detection limit/quantitation limit values. The method was linear over the range 2.5–50 μg/ml for ezetimibe (r = 0.9992) and 1–100 μg/ml for atorvastatin (r = 0.9999). Within-day and between-day RSD for ezetimibe and atorvastatin were ⩽5.6% and ⩽2.9%, respectively. The detection limit was 0.07 μg/ml for ezetimibe and 0.06 μg/ml for atorvastatin. The validated method was successfully employed for the determination of ezetimibe and atorvastatin in tablets with no interfering peaks from common pharmaceutical excipients. The percentage recoveries of the two drugs from their tablets were 99.80 ± 1.76 and 100.19 ± 1.83, respectively.     

Development and Validation of Reversed-Phase High Performance Liquid Chromatographic Method for Hydroxychloroquine Sulphate

In the present work new, simple reversed-phase high performance liquid chromatographic method was developed and validated for the determination of hydroxychloroquine sulphate in blood plasma. Chloroquine sulphate was used as an internal standard. The chromatographic separation was achieved with octadecyl silane Hypersil C₁₈ column (250×6 mm, 5 μm) using water and organic (acetonitrile:methanol: 50:50, v/v) mobile phase in 75:25 v/v ratio, with sodium 1-pentanesulfonate and phosphoric acid. This organic phase was maintained at pH 3.0 by orthophosphoric acid. The flow rate of 2.0 ml/min^. with detection at 343 nm was used in the analysis. The calibration curve of standard hydroxychloroquine sulphate was linear in range 0.1-20.0 μg/ml. The method was validated with respected to linearity, range, precision, accuracy, specificity and robustness studies according to ICH guidelines. The method was found to be accurate and robust to analyze the hydroxychloroquine sulphate in plasma samples.     

Development and Validation of HPTLC Method for Estimation of Tenoxicam and its Formulations

A simple, precise, accurate and rapid high performance thin layer chromatographic method has been developed and validated for the estimation of tenoxicam in the microemulsion gels. Tenoxicam was chromatographed on silica gel 60 F₂₅₄ TLC plate, as a stationary phase. The mobile phase was toluene: ethyl acetate: formic acid (6:4:0.3 v/v/v), which gave a dense and compact spot of tenoxicam with a R_f value of 0.38±0.03. The quantification was carried out at 379 nm. The method was validated in terms of linearity, accuracy, precision and specificity. To justify the suitability, accuracy and precision of the proposed method, recovery studies were performed at three concentration levels. Statistical analysis proved that the proposed method is accurate and reproducible with linearity in the range of 100 to 400 ng. The limit of detection and limit of quantification for tenoxicam were 25 and 50 μg/spot, respectively. The proposed method can be employed for the routine analysis of tenoxicam as well as in pharmaceutical formulations.     

Simultaneous quantitative determination of metoprolol, atorvastatin and ramipril in capsules by a validated stability-indicating RP-UPLC method

A simple ultra performance liquid chromatographic (UPLC) method has been developed for the simultaneous estimation of Metoprolol (MT), Atorvastatin (AT) and Ramipril (RM) from capsule dosage form. The method was developed using Zorbax® XDB-C18 (4.6 mm × 50 mm, 1.8 μm) column with a mobile phase consisting of 0.06% ortho phosphoric acid in Milli Q® water having an ion pair reagent, 0.0045 M Sodium lauryl sulphate as buffer, at ratio of buffer: Acetonitrile (50:50 v/v), at 55°C column temperature with a flow rate of 1.0 ml/min. Detection was carried out with ultra-violet detection at 210 nm for RM, MT and AT respectively. The retention times were about 1.3, 2.1 and 2.6 min for MT, AT and RM respectively, the method was validated for linearity, accuracy, precision, specificity, robustness and ruggedness. The % mean recoveries are 101.9, 102.1 and 101.4 for MT, AT and RM respectively. The method was found to be rugged and robust and can be successfully used to determine the three drugs and its combinations.     

Validated High Performance Thin Layer Chromatographic Determination and Content Uniformity Test for Rosiglitazone in Tablets

A simple, rapid, precise and economical high performance thin layer chromatographic method has been developed and validated for determination of rosiglitazone in its tablet dosage form using caffeine as an internal standard. It was performed on silica gel 60 GF₂₅₄ thin layer chromatographic plates as a stationary phase using mobile phase methanol:toluene:chloroform:triethylamine (1:8:0.5:0.5 v/v/v/v) and the detection was carried out in the absorbance mode at 264 nm showing R_f value 0.31 for rosiglitazone and 0.52 for caffeine. The linear regression data curve shows good linear relationship in the concentration range 1.0-7.0 µg/µl. The content uniformity test was carried out as per USP specification of the content uniformity test of 85-115%. The percent drug estimated of rosiglitazone from two different marketed formulations were found to be in the range 99.83-100.21. The recovery of drugs was carried out by standard addition method were found to be 100.21±1.06 and 100.04±0.30 by height and area respectively. The method was validated with the determination of accuracy, precision, specificity, linearity detector response and ruggedness. The proposed method provides a faster and cost effective quality control tool for routine analysis of content uniformity test for rosiglitazone in tablet formulation.     

Determination of combined p-hydroxy benzoic acid preservatives in a liquid pharmaceutical formulation by HPLC

This paper describes a reversed-phase high performance liquid chromatographic (RP-HPLC) assay method for the determination of combined p-hydroxy benzoic acid (ethylparaben (EP), methylparaben (MP) and propylparaben (PP)) preservatives in a liquid pharmaceutical formulation. The chromatographic separation was achieved with potassium phosphate buffer (pH 7.05)-methanol (47.5:52.5, v/v) as mobile phase, a Spherisorb C(18) column (250 mm x 4.6mm) and UV detection at 254 nm. The analysis time was <8 min. The method was validated with respect to linearity, precision, accuracy, selectivity, specificity and ruggedness. The calibration curves showed good linearity over the concentration range of 2-140 microg/ml. The correlation coefficient were >0.9999 in each case. The relative standard deviation (R.S.D.) values for intra- and inter-day precision studies were <1%. The procedure describe here is simple, selective and is suitable for routine quality control analysis and stability tests.     

Development and Validation of a Stability-Indicating RP-HPLC Method for the Quantitative Analysis of Anagrelide Hydrochloride

A simple, rapid, and stability-indicating reverse-phase liquid chromatographic assay method was developed for Anagrelide Hydrochloride (ANG) in the presence of its degradation products generated from forced decomposition studies. The HPLC separation was achieved on a C18 Inertsil column (250 mm × 4.6 mm i.d. particle size is 5 μm), using solution A, a mixture of 0.03 M potassium di-hydrogen phosphate pH-adjusted to 3.0 using ortho-phosphoric acid (buffer): methanol: acetonitrile (90:5:5, v/v/v), and solution B, which contains a mixture of buffer: acetonitrile (10:90, v/v). The UV detector was operated at 251 nm while column temperature was maintained at 40°C, and the gradient program had the flow rate of 1.0 mL min⁻¹. The developed method was validated as per ICH guidelines with respect to specificity, linearity, precision, accuracy, robustness, and limit of quantification. The method was found to be simple, specific, precise, accurate, and reproducible. Selectivity was validated by subjecting the stock solution of ANG to acidic, basic, photolysis, oxidative, and thermal degradation. The calibration curve was found to be linear in the concentration range of 0.05–152 μg mL⁻¹ (R² = 0.9991). The peaks of degradation products did not interfere with that of pure ANG. The utility of the developed method was examined by analyzing the tablets containing ANG.     

Development and Validation of HPTLC Method for the Estimation of Rizatriptan Benzoate in Bulk and Tablets

A new, simple high performance thin layer chromatographic method has been proposed for the determination of rizatriptan benzoate in a tablet dosage form. The drug was separated on aluminum plates precoated with silica gel 60 F(254) with dichloromethane-acetone-acetic acid 3:2:0.2(v/v/v) as mobilephase. Quantitative analysis was performed by densitometric scanning at 230 nm. The method was validated for linearity, accuracy, precision and robustness. The calibration plot was linear over the range 200-700 ng/band for rizatriptan benzoate. The method was successfully applied to the analysis of drug in bulk and marketed tablets.     

Simultaneous Determination of Valsartan and Hydrochlorothiazide in Tablets by RP-HPLC

A simple, reproducible and efficient reverse phase high performance liquid chromatographic method was developed for simultaneous determination of valsartan and hydrochlorothiazide in tablets. A column having 200 × 4.6 mm i.d. in isocratic mode with mobile phase containing methanol:acetonitrile:water:isopropylalcohol (22:18:68:2; adjusted to pH 8.0 using triethylamine; v/v) was used. The flow rate was 1.0 ml/min and effluent was monitored at 270 nm. The retention time (min) and linearity range (μg/ml) for valsartan and hydrochlorothiazide were (3.42, 8.43) and (5-150, 78-234), respectively. The developed method was found to be accurate, precise and selective for simultaneous determination of valsartan and hydrochlorothiazide in tablets.     

Development and Validation of a Liquid Chromatographic Method for Estimation of Dicyclomine Hydrochloride,Mefenamic Acid and Paracetamol in Tablets

Liquid chromatographic method was developed for simultaneous quantitative determination of dicyclomine hydrochloride, mefenamic acid and paracetamol in their combined dosage form. The separation was achieved using a C₁₈ column (250×4.6 mm id, 5 μm) using acetonitrile:20 mM potassium dihydrogen phosphate 70:30 (v/v) adjusted to pH 4 using orthophosphoric acid as mobile phase at a flow rate of 1 ml/min and detection at 220 nm. Separation was completed within 12 min. The retention times of dicyclomine hydrochloride, mefenamic acid and paracetamol were 3.8, 9.3 and 2.5 minutes respectively. The proposed method was found to have linearity in concentration range of 10–100 μg/ml for dicyclomine hydrochloride, 0.05-10 μg/ml for mefenamic acid and 0.1−20 μg/ml for paracetamol. The developed method has been statistically validated and was found to be simple, precise, reproducible and accurate. The developed and validated method was successfully used for the quantitative analysis of commercially available dosage form.     

Simultaneous separation and determination of coenzyme Q(10) and its process related impurities by NARP-HPLC and atmospheric pressure chemical ionization-mass spectrometry (APCI-MS)

A non-aqueous reversed phase high performance liquid chromatographic (NARP-HPLC) method for determination of coenzyme Q₁₀ in pharmaceutical preparations has been developed using Kromosil C₈ column with acetonitrile and isopropyl alcohol (84:16, v/v) as a mobile phase. Photodiode array (PDA) detector set at 210 nm was used for monitoring of the eluents. The method is simple, rapid, selective and capable of separating all process impurities at trace level with detection limits <0.1 μg/ml. It has been validated with respect to accuracy, precision, linearity, and limits of detection and quantification. The linearity range was 50–300 μg/ml. The percentage recoveries ranged from 95.10 to 101.02. The method was found to be suitable not only for monitoring the reactions during the process development but also quality assurance of coenzyme Q₁₀. For identification of related substances atmospheric pressure chemical ionisation-mass spectrometry (APCI-MS) was used.