Potassium Dihydrogen Phosphate Buffer pH Research Articles

Deduction of the operable design space of RP-HPLC technique for the simultaneous estimation of metformin, pioglitazone, and glimepiride

A reversed-phase RP-HPLC method was developed for the simultaneous determination of metformin hydrochloride (MET), pioglitazone (PIO), and glimepiride (GLM) in their combined dosage forms and spiked human plasma. Quality risk management principles for determining the critical method parameters (CMPs) and fractional factorial design were made to screen CMPs and subsequently, the Box–Behnken design was employed. The analytical Quality by Design (AQbD) paradigm was used to establish the method operable design region (MODR) for the developed method depended on understanding the quality target product profile (QTPP), analytical target profile (ATP), and risk assessment for different factors that affect the method performance to develop an accurate, precise, cost-effective, and environmentally benign method. The separation was carried out using a mobile phase composed of methanol: 0.05 M potassium dihydrogen phosphate buffer pH 3.7 with 0.05% TEA (78:22, v/v). The flow rate was 1.2 mL/min. DAD detector was set at 227 nm. Linagliptin (LIN) was used as an internal standard. The proposed method was validated according to The International Council for Harmonization of Technical Requirements for Pharmaceuticals for Human Use (ICH). The assay results obtained by using the developed method were statistically compared to those obtained by the reported HPLC method, and a satisfying agreement was observed.

REVERSE PHASE HIGH PERFORMANCE LIQUID CHROMATOGRAPHY (RP-HPLC) METHOD DEVELOPMENT AND VALIDATION OF SAXAGLIPTIN FROM HUMAN URINE

Reversed phase high performance liquid chromatography (RP-HPLC) method for the quantitative determination of saxagliptin (SXG) in human urine was developed and validated to support clinical studies. Chromatographic separation was achieved on an Inertsil® column (250 mm x 4.6 mm, 5 µm). Isocratic elution using a mobile phase of potassium dihydrogen phosphate buffer pH (3) - acetonitrile (80:20, V/V) at a flow rate of 1 mL min-1 with UV detection at 212.1 nm was performed. The retention time of saxagliptin was 6.4 min. The method was validated according to United State Food and Drug Administration (USFDA) (May-2001) guidelines. The developed bioanalytical method was found to be selective, accurate, precise, and having good extraction efficiency. The developed method was satisfactorily applied to the routine quality control analysis of the saxagliptin.

Box-Behnken assisted development and validation of high-performance liquid chromatography method for the simultaneous determination of doxorubicin and vorinostat in polymeric nanoparticles.

While histone deacetylase inhibitors, such as vorinostat, demonstrate a significant effect against hematological cancers, their application for solid tumor treatment is limited. However, there is strong evidence that combinatorial administration of vorinostat and genotoxic agents (e.g., doxorubicin) enhances the antitumoral action of both drugs against tumors. We developed a high-performance liquid chromatography method for the simultaneous determination of doxorubicin and vorinostat in polymeric nanoparticles designed to provide the parenteral administration of both drugs and increase their safety profile. We performed separation on Nucleodur C-18 Gravity column with a mixture of 10mM potassium dihydrogen phosphate buffer pH 3.9:ACN (90:10 v/v) as mobile phase at 240nm. The method was linear within the concentration range of 4.2-52.0μg/ml for both drugs with limits of detection and quantification of 3.5 and 10.7μg/ml for doxorubicin and 2.5 and 7.7μg/ml for vorinostat, respectively. The method was precise and accurate over the concentration range of analysis. Drug loading was 5.4% for doxorubicin and 0.8% for vorinostat. Degradation of doxorubicin after irradiation was less than 5%, while the amount of vorinostat decreased at 88% under the same conditions. Thus, the validated method could be adopted for routine simultaneous analysis of doxorubicin and vorinostat in polymeric nanoparticles.

Development and validation of reversed phase HPLC method for determination of apremilast in bulk and pharmaceutical dosage form

The present study describes a novel Reversed Phase High-Performance LC method for the determination and estimation of Apremilast (APR) in bulk and pharmaceutical formulation. The chromatographic separation was carried out on Agilent 1120LC Compact system with Binary gradient system connected to UV- Absorbance Detector. Acetonitrile: (30mM) Potassium dihydrogen phosphate buffer pH adjusted to 3.0 with o-phosphoric acid (60:40 v/v), and flow rate 1.0ml/min with an injection volume of 20 μL was selected as it gave sharp symmetric peak for APL with minimal tailing and with desired elution graph.The separation was carried out at a room temperature and the eluents were observed by UV - Vis detector set at 236 nm. The retention time of APR obtained was at 4.46 minutes. The calibration curve for APR was linear (r2= 0.995) over thetested concentration range of 10 - 60 μg/ ml with LOD and LOQ of 0.93 μg/ml and 2.82μg/ml respectively. A recovery of APR in tablet formulation was observed in the range of 98.40 -100.00 %. Thus the proposed method for APR was found to be feasible for the estimation of APR in bulk as well as pharmaceutical dosage form.

Stability Indicating RP-HPLC Method For Determination Of Ketoconazole In Bulk Drug And In Tablet Dosage Form

A simple, precise, accurate and sensitive isocratic stability indicating RP-HPLC method has been developed and validated for determination of Ketoconazole in bulk drug and pharmaceutical dosage form. Isocratic RP-HPLC separation was achieved on Agilent C8 (150 mm ?4.6 mm, 5 µm particle size) with the mobile phase 0.3 % Triaethylamine in 20 mM potassium dihydrogen phosphate buffer pH adjusted to 4.0: Acetonitrile (68:32 % v/v) at a flow rate 1.0 ml/min. The retention time of Ketoconazole was 8.97 ± 0.50 min. The method was validated for specificity, linearity, precision, accuracy and robustness. The linear regression analysis data of calibration curve showed good linearity in concentration range 10-60 ?g/ml. The Intraday and Interday precision were 0.59-1.11 % and 0.26-1.73 % RSD respectively. The accuracy was found to be 98.11-99.26 %. The drug was subjected to the stress conditions like hydrolysis, oxidation, photolysis and dry heat. The proposed method is found to be specific with respect to degradation product formed after Acidic hydrolysis, Oxidation, Thermal and Photolytic degradation. The Ketoconazole was found to be stable under neutral hydrolytic, thermal and photolytic stress conditions. Acidic, thermal, photolytic stress conditions showed degradation. The proposed chromatographic method can be used for estimation of drug during stress testing & formal stability studies.

Evolution and effectiveness of HPLC Technique for rapid estimation of an Antiallergenic agent Bilastine

A new, simple, accurate, and specific RP-HPLC stability method for determining bilastine was developed and validated. The proposed method was administered using C18 BDS Hypersil thermo column (4.6 × 250mm i.d), 5 µm particle size with a combination of potassium dihydrogen phosphate buffer pH 6.0: acetonitrile: methanol (50:25:25) as the mobile phase at a wavelength of 220nm. The retention time was 3.9 min for bilastine. The calibration plot was linear over the concentration range of 14.4–33.6µg/ml bilastine with LOD and LOQ of 0.04 and 0.11µg/ml, respectively. The technique was validated for linearity, sensitivity, accuracy, precision, and robustness. Percent recoveries were observed to be nearly 100%. The validated method was used for determining bilastine in Pharmabilast(R) tablets. The technique could be appropriate for routine evaluation at laboratories.

A Novel and Rapid RP-HPLC Quantitative Method for the estimation of Canagliflozin in Human Plasma

A simple, precise and accurate method was developed for the quantitative estimation of Canagliflozin in human plasma using Dapagliflozin as internal standard by Reverse Phase-High Performance Liquid Chromatographic technique. Chromatographic conditions were of stationary phase Phenomenex Luna C18 (2) (150 x 4.6 mm, 5m), Mobile phase 0.01 N Potassium dihydrogen Phosphate buffer pH (3.5±0.05) : acetonitrile in the ratio of 45:55 and flow rate at 1.0 ml/min, detection wave length was UV 222 nm, column oven temperature was maintained at 30ᵒC, and sample injection volume of 10 µL. Retention time of Canagliflozin was found to be about 8.7 min. Coefficient of Variation for Canagliflozin peak was 3.15 %, % recovery was 94.58 %. The linearity of method was studied from 0.06 µg/ml to 2.4 µg/ml (R2 = 0.999). The Signal to Noise ratio of lower limit of quantification (0.06 µg/ml) was found to be 50. The proposed bio-analytical method was validated by following ICH guidelines.

Validated stability-indicating RP-HPLC method for simultaneous estimation of cilnidipine and chlorthalidone in tablet dosage form

A novel, simple, specific, accurate & precise stability-indicating Gradient reverse-phase high-performance liquid chromatography (RP-HPLC) method was developed for simultaneous estimation of Cilnidipine & Chlorthalidone in tablet dosage form, validated as per ICH guideline. The separation was achieved on Inertsil ODS column (250 mm x 4.6 mm, 5 μm) in a gradient mode. The mobile phase consisted of Methanol, 0.025 M Potassium dihydrogen phosphate Buffer pH 5.5 adjusted by 10% v/v Ortho Phosphoric Acid (50:50 v/v) (Solution A) and Acetonitrile, 0.025 M Potassium dihydrogen phosphate Buffer pH 5.5 adjusted by 10%v/v Ortho Phosphoric Acid (75:25 v/v) (Solution B), gradient programming for 20 min at 1 ml/min rate of flow and response was detected at 225 nm. The retention time was found to be 3.580 min and 12.606 mins for Chlorthalidone and Cilnidipine, respectively. The method is validated according to ICH guideline, which includes linearity, specificity, accuracy, precision and robustness. Linearity was obtained over the concentration range of 10-60 μg/ml for Cilnidipine and 6.25-37.5 μg/ml for Chlorthalidone, had a regression coefficient (r2) almost 0.9966. The % Recovery was found to be 99.63-100.59 % and 100.24-100.51 % for Cilnidipine and Chlorthalidone, respectively. The method was found to be specific enough to separate all degradation products from the active compound. Drug samples were exposed to various stress conditions like photolysis, oxidation, heat conditions, and hydrolysis (acidic and alkaline), there was no interference of any degradants and excipient in the determination of drugs so that methods can be successfully applied for routine QC analysis.

Stability indicating validated RP-HPLC method for Simultaneous estimation of Elbasvir and Grazopravir in Bulk and Pharmaceutical Dosage form

Elbasvir a NS5A inhibitor is used in combination of Grazoprevir (NS3/4A protease inhibitor) for the treatment of chronic Hepatitis C, an infectious liver disease caused by infection with Hepatitis C Virus (HCV) under the trade name Zepatiar®. A stability indicating reverse phase HPLC method was developed and validated for the determination of Elbasvir and Grazoprevir in tablet dosage form. A waters Alliance HPLC with Zorbax eclipse XDB C18 (250 x 4.6 mm) 3.5μ columnwas used for chromatographic separation. A mobile phase consisting of potassium dihydrogen phosphate buffer pH adjusted to 4.0: acetonitrile (40: 60v/v) with a flow rate of 1.0 mL/min was used, the UV detection was carried out at 260 nm. The established method was linear, accurate and precise over the range of 12.5 to 75 μg/mL with a regression equation of Y=20782X+2849.4 and correlation coefficient of 0.9995for elbasvir and linear over the range of 25–150 μg/mL with a regression equation of Y=14897X+20611 and correlation coefficient of 0.9992for Grazoprevir. The validated method demonstrated high sensitivity, accuracy, precision, selectivity and robustness. The method demonstrated high selectivity in presence of degradants produced during the stress conditions when Elbasvir and Grazoprevir were subjected to acid, alkali, oxidation, thermal and photolytic degradation.

Method Development and Validation for Simultaneous Estimation of Glimepiride and Simvastatin by using Reversed Phase High-performance Liquid Chromatography

An analytical method was developed using reverse phase high performance liquid chromatograph (RP-HPLC) system and a C-18 reverse-phase column (Nucleodur C18, 250mm × 4.6mm i.d.,5μ) for simultaneous estimation of simvastatin and glimepiride. Acetonitrile and potassium dihydrogen phosphate buffer pH 4 (75:25, v/v) were used as mobile phase. The flow rate was 1 mL min−1 and the chromatogram of both drugs was detected at wavelength of 232 nm. Method was validated as per ICH Q2 (R1) guidelines. The retention times of glimepiride and simvastatin was found to be 4.726 min and 9.829 min, respectively. Both drugs have shown linearity over the concentration range 2–10μg/mL with r2 of 0.997 for GLM and 0.998 for SIM. The mean percentage recovery of both the drugs was found within 98–102% at all the levels which indicated that the method was accurate. The percentage relative standard deviation was found less than 2% which indicated that method was satisfactorily precised. The LOD and LOQ were found to be 0.24 and 0.73 for simvastatin and 0.32 and 0.96 for glimepiride. The method was found to be robust as there was no significant change in response with variation in pH, flow rate and mobile phase composition. It was concluded that the developed method has passed all the validation tests and can be successfully applied to estimate the presence of both the drugs in bulk as well as in pharmaceutical formulations.

Development and Validation of HPLC method for simultaneous estimation of Rifampicin and Ofloxacin using experimental design

ABSTRACTA accurate, precise and robust isocratic HPLC method has been developed and validated for simultaneous determination of Rifampicin and Ofloxacin. The chromatographic separation was carried out on Kinetex C18, 100 A Phenomenex column with a mixture of 0.03M Potassium dihydrogen phosphate buffer pH 3.0: Acetonitrile (55:45) as mobile phase at 230 nm. The retention times were 2.91 and 4.87 min for Ofloxacin and Rifampicin, respectively. Calibration plots were linear over the concentration range 1–5 and 2–10 µg/ml for Rifampicin and Ofloxacin, respectively. The method was validated for linearity, sensitivity accuracy, precision, and robustness. Percent recoveries were found to be close to 100% with low variability. Fractional factorial design with four factors was chosen for robustness testing. The volume of acetonitrile and flow rate showed significant effect on retention factor of both the drugs and asymmetry factor of ofloxacin. The method may be adopted for routine analysis at industry.

DEVELOPMENT AND VALIDATION OF RP-HPLC METHOD FOR THE DETERMINATION OF ALVIMOPAN IN RAT PLASMA

Objective: The present investigation demonstrates a simple, sensitive and accurate high pressure liquid chromatographic (HPLC) method for the determination of alvimopan (AMP) in rat plasma.Methods: The chromatographic separation was achieved within 10 min by using acetonitrile: potassium dihydrogen phosphate buffer pH 3.0 adjusted with orthophosphoric acid (50:50) as mobile phase on Altima Grace Smart C-18 column (5μ; 250 × 4.6 mm) at a flow rate of 1.0 ml/min with injection volume 50 µl. The drug was extracted from plasma by liquid-liquid extraction using a mixture of methanol: acetonitrile (50:50) as a solvent. The retention times of drug and internal standard were found to be 5.17 and 6.74 min, respectively. This method was validated as per the United States Food and Drug Administration (US-FDA) guidelines.Results: The results of the validation parameters were found to be within the acceptance limits. The method was linear in the concentration range from 5-1000 ng/ml (r2= 0.9998), and the extraction recovery was found to be 78.71±3.86% for AMP. The lower limit of quantification was found to be 5ng/ml, and the stability of recovered samples at different conditions was found to be more than 95%.Conclusion: The developed method possess good selectivity, specificity, there was no interference found in the plasma blanks at retention times of AMP and Internal Standard (IS). We found a good correlation between the peak area and concentration of the drug under prescribed conditions. Furthermore, the method can also be used to estimate the pharmacokinetic parameters of AMP.Keywords: Alvimopan, Liquid-liquid extraction, Method development, Matrix effect, Plasma, Recovery, Stability, Validation

STABILITY INDICATING RP-HPLC ASSAY METHOD FOR ESTIMATION OF DIMETHYL FUMARATE IN BULK AND CAPSULES

Objective: To develop an accurate, simple, precise and specific stability indicating RP-HPLC method for estimation of dimethyl fumarate in bulk and capsules.Methods: An Inertsil ODS (150x4.6 mm, 5µ) column and a mobile phase containing acetonitrile: potassium dihydrogen phosphate buffer pH 6.8 (50:50% v/v) was used for this study. The flow rate was maintained at 1.0 ml/min; column temperature was fixed at 35 °C and UV detection was carried out at 210 nm. The forced degradation studies were performed and method was validated with as per ICH guidelines.Results: The retention time of dimethyl fumarate was found to be 3.3±0.02 min. The value of correlation coefficient between peak area and concentration was found to be 0.9993. The mean percent recovery of dimethyl fumarate in capsules was found in the range of 99.65 to 101.64%. The results of forced degradation studies indicated that the drug was found to be stable in basic, oxidative and thermal conditions while degraded in acidic conditions.Conclusion: It can be conducted from results that the developed HPLC method is simple, accurate, precise and specific. Results of stress testing study revealed that the method is stability indicating. Thus, this method can be used for routine analysis of dimethyl fumarate capsules and check their stability.

Development and validation of an HPLC-UV method for the simultaneous determination of the antipsychotics clozapine, olanzapine and quetiapine, several beta-blockers and their metabolites.

A simple, accurate and selective column-switching high-performance liquid chromatography (HPLC) method was developed and validated for simultaneous quantification of six beta-blockers (metoprolol, timolol, bisoprolol, propranolol, carvedilol and nebivolol), three of their metabolites (α-hydroxy metoprolol, N-desisopropyl propranolol and 4'-hydroxy carvedilol 4-HCAR), three antipsychotics (olanzapine, clozapine and quetiapine) and three of their metabolites (N-desmethyl olanzapine, N-desmethyl clozapine and N-desalkyl quetiapine) in human serum. After pretreatment on a Merck LiChrospher RP-4 ADS column (25 μm), drugs were separated on a Phenomenex Gemini Phenyl Hexyl 110 A column (250 × 4.6 mm, 5 μm) using a gradient mixture of acetonitrile and potassium dihydrogen phosphate buffer pH 3.1 (containing 10% methanol) as a mobile phase at a flow rate of 1 mL/min. The total analysis time was 40 min. For detection of the analytes, four different UV wavelengths were used: 215, 226, 242 and 299 nm. The method was validated according to the guidelines of the Society of Toxicology and Forensic Chemistry in terms of selectivity, linearity, accuracy, precision and stability and successfully applied for the analysis of the 15 described analytes in human serum.

RAPID SEPARATION AND DETERMINATION OF RIZATRIPTAN N-OXIDE IMPURITY IN RIZATRIPTAN BENZOATE IN A BULK DRUG SUBSTANCE BY REVERSE PHASE LIQUID CHROMATOGRAPHY

Objective: The objective is described to develop and validate a simple, reliable, precise, and specific analytical method for rapid separation and determination of N-oxide impurity in rizatriptan Benzoate active pharmaceutical ingredient bulk drug substances by reverse phase liquid chromatography as per the International Conference on Harmonization (ICH) guidelines.Methods: The methodology utilized as reverse phase liquid chromatography with gradient composition. The mobile phase proportion was compromised mobile A containing 0.25 mm potassium dihydrogen phosphate buffer pH 2.0 and methanol (95:5 v/v) and mobile B containing Acetonitrile. ODS 3V, 250 × 4.6 mm, 5 µm. column. The flow rate is 1.0 ml/minute using an LC system detector at wavelength 280 nm, and the column oven temperature is 40°C. The chromatographic separation performed in reverse phase by the gradient composer over run time was 35 minute. The resolution between N-oxide and rizatriptan was recorded on the chromatogram was more than six. The developed analytical method was validated according to the ICH guidelines.Results: Linearity was found in rizatriptan N-oxide over the concentration range of 450-11000 ng/ml, with the linear regression (Correlation coefficient R = 0.999) and proved to be robust. Limit of detection and limit of quantification of the rizatriptan N-oxide was found 150 and 450 ng/ml. The retention time of rizatriptan and rizatriptan N-oxide was recorded 22.6 and 24.7 minutes, respectively. The percentage recovery of N-oxide has been ranged from 96.0 to 102.0 in the bulk drug material sample. The proposed analytical method has been found suitable, precise, reliable, and accurate for the separation and quantitative determination.Conclusion: A specific, simple, accurate, reliable, and rapid reproducible analytical method has been developed and validated for reverse phase high- performance liquid chromatography to determine N-Oxide impurity in rizatriptan benzoate from bulk drugs material as per ICH guideline.Keywords: Rizatriptan benzoate, N-oxide impurity, High performance liquid chromatography, Reverse phase, ODS column and validation.

Method Development and Its Validation for Simultaneous Estimation of Domperidone and Esomeprazole by RP-HPLC in Combination Tablet Dosage Form

A simple and validated reverse phase high performance liquid chromatography (RP-HPLC) method was developed for simultaneous estimation of Esomeprazole and Domperidone. Different HPLC Chromatographic conditions were used to find out the optimum chromatographic condition for best elution of drugs. Good chromatographic separation was achieved on Develosil ODS HG-5 RP C18 (15cmX4.6mm, 5mm Particle size), analytical column using a mixture of Potassium dihydrogen phosphate buffer pH: acetonitrile in the ratio of 45:55 v/v used as mobile phase at the flow rate of 1 ml/min and detector wavelength at 284nm. The validation of the proposed method was carried out for specificity, linearity and range, accuracy, precision, limit of detection and limit of quantification. Linearity range was found to be 0-140 µg/ml and 0-150 µg/ml with correlation coefficients of 0.995 & 0.994 and retention time of 2.59 and 3.85 min for Domperidone and Esomeprazole respectively. The LOD was found to be 0.341 mg/ml and 2.031 mg/ml and LOQ was found to be 1.023 mg/ml and 6.093 mg/ml respectively. The result shows the developed method is yet another suitable method for assay and stability studies which can help in the analysis of Domperidone & Esomeprazole in different formulations.

Method Development and Its Validation for Simultaneous Estimation of Domperidone and Esomeprazole by RP-HPLC in Combination Tablet Dosage Form

A simple and validated reverse phase high performance liquid chromatography (RP-HPLC) method was developed for simultaneous estimation of Esomeprazole and Domperidone. Different HPLC Chromatographic conditions were used to find out the optimum chromatographic condition for best elution of drugs. Good chromatographic separation was achieved on Develosil ODS HG-5 RP C18 (15cmX4.6mm, 5μm Particle size), analytical column using a mixture of Potassium dihydrogen phosphate buffer pH: acetonitrile in the ratio of 45:55 v/v used as mobile phase at the flow rate of 1 ml/min and detector wavelength at 284nm. The validation of the proposed method was carried out for specificity, linearity and range, accuracy, precision, limit of detection and limit of quantification. Linearity range was found to be 0-140 μgg/ml and 0-150 μgg/ml with correlation coefficients of 0.995 & 0.994 and retention time of 2.59 and 3.85 min for Domperidone and Esomeprazole respectively. The LOD was found to be 0.341 μg/ml and 2.031 μg/ml and LOQ was found to be 1.023 μg/ml and 6.093 μg/ml respectively. The result shows the developed method is yet another suitable method for assay and stability studies which can help in the analysis of Domperidone & Esomeprazole in different formulations.

Method Development and Its Validation for Simultaneous Estimation of Domperidone and Esomeprazole by RP-HPLC in Combination Tablet Dosage Form

A simple and validated reverse phase high performance liquid chromatography (RP-HPLC) method was developed for simultaneous estimation of Esomeprazole and Domperidone. Different HPLC Chromatographic conditions were used to find out the optimum chromatographic condition for best elution of drugs. Good chromatographic separation was achieved on Develosil ODS HG-5 RP C18 (15cmX4.6mm, 5m Particle size), analytical column using a mixture of Potassium dihydrogen phosphate buffer pH: acetonitrile in the ratio of 45:55 v/v used as mobile phase at the flow rate of 1 ml/min and detector wavelength at 284nm. The validation of the proposed method was carried out for specificity, linearity and range, accuracy, precision, limit of detection and limit of quantification. Linearity range was found to be 0-140 μg/ml and 0-150 μg/ml with correlation coefficients of 0.995 and 0.994 and retention time of 2.59 and 3.85 min for Domperidone and Esomeprazole respectively. The LOD was found to be 0.341 g/ml and 2.031 g/ml and LOQ was found to be 1.023 g/ml and 6.093 g/ml respectively. The result shows the developed method is yet another suitable method for assay and stability studies which can help in the analysis of Domperidone and Esomeprazole in different formulations.

Application of Validated Stability-Indicating HPLC Method in Stability Testing of Acetaminophen and Guaiphenesin Tablets

The aim of the work is to develop and validate the simple, fast and precise stability indicating high performance liquid chromatography method for the separation and quantification of acetaminophen and guaiphenesin in pharmaceutical dosage form. The quantification was carried out using Symmetry C18 (4.6x150 mm, 3.5 m) enhanced polar selectivity column and mobile phase comprised of potassium dihydrogen phosphate buffer pH 2.5 and methanol in proportion of ratio 65:35v/v. The flow rate was mL/min and the effluent was monitored at 228 nm. The retention time of acetaminophen and guaiphenesin were 2.6 and 4.6 min respectively. Linearity of acetaminophen and guaiphenesin were in the range of 50 to 90 µg/mL and 30 to 55 µg/mL respectively with correlation coefficients 0.999. The percentage recoveries were 99.80% and 99.85% for acetaminophen and guaiphenesin respectively. There was complete separation of degradation peaks and analyte peaks, which demonstrate the specificity of assay method in the presence of its degradation products; it can be employed as a stability indicating one. Due to simplicity, rapidity and accuracy of the proposed Stability Indicating High Performance Liquid Chromatography method, it is used for analysis of stability samples of Acetaminophen and Guaiphenesin in quality control laboratories.

Validation of RP-HPLC Method for Simultaneous Estimation of Cefixime Trihydrate and Clavulanate Potassium in Tablets

A simple, accurate, precise, rapid and economic HPLC method has been developed and validated for the simultaneous estimation of cefixime trihydrate and clavulanate potassium in tablet dosage forms. The chromatographic separation was achieved on a Hypersil C18 column (4.6 x 250 mm, 5 μm particle size). For HPLC method development, a mobile phase consisting of methanol: 30 mM potassium dihydrogen phosphate buffer pH 3.0 adjusted with orthophosphoric acid (30:70 v/v) was used at flow rate of 1.0 ml/min. The optimum wavelength selected was 278 nm. Under these chromatographic conditions, cefixime trihydrate and clavulanate potassium peaks were well resolved, with retention times of cefixime trihydrate and clavulanate potassium being 5.8266 and 3.2633 min, respectively. The proposed method was found to have excellent linearity in the concentration range 20-100 μg/ml with correlation coefficients r2 = 0.9946 and 0.9926, respectively. The method was validated for linearity, precision, LOD, LOQ and robustness. The proposed method was optimized and validated as per the ICH guidelines.