Stability Indicating TLC Method for Quantification of Brexpiprazole in Bulk and Its Pharmaceutical Dosage Form and Determination of Content Uniformity.

A sensitive, selective and precise high performance thin layer chromatographic method has been developed and validated for the quantification of Brexpiprazole in bulk drug and in pharmaceutical dosage form. The method employed HPTLC aluminum plates (pre-coated with silica gel 60 F254) as stationary phase while n-butanol was used as mobile phase. The Rf value of Brexpiprazole was observed to be 0.38. The densitometric analysis was carried out in absorbance mode at 215 nm. The linear regression analysis data for the calibration plots showed a good linear relationship for Brexpiprazole over a concentration range of 200-1,600 ng band-1. The limit of detection and limit of quantification for Brexpiprazole was found to be 66 and 200 ng band-1. To find out the possible degradation pathway, forced degradation studies were performed. The stock solutions of Brexpiprazole (1,000 µg mL-1) were subjected to acid and alkali hydrolysis, chemical oxidation, dry heat degradation and photo degradation. The drug was found to be susceptible to acid and alkali hydrolysis, chemical oxidation, photo degradation and dry heat. The degraded product peaks were well resolved from the pure drug peak with significant difference in their Rf values. Stressed samples were analyzed using developed HPTLC method. The proposed method was validated with respect to linearity, accuracy, precision and robustness. The method was successfully applied to the estimation of Brexpiprazole in marketed formulation and determination of content uniformity of tablet formulation. Statistical analysis showed that the method is repeatable, selective, and precise.

Stability Indicating Liquid Chromatographic Method for Simultaneous Determination of Aspirin and Omeprazole.

BACKGROUND: Aspirin combination is prescribed for its thrombolytic activity where gastric ulceration is the major side effect of aspirin which can be prevented by combining it with proton pump inhibitor omeprazole. Present study describes development of analytical method for the estimation of aspirin and omeprazole in combination. OBJECTIVE: The aim of the present study was to develop and validate chromatographic method for simultaneous analysis of aspirin and omeprazole. METHODS: Isocratic, reversed phase stability indicating liquid chromatographic method was developed for the simultaneous determination of Aspirin and Omeprazole in combination. The separation was achieved on a Thermo Scientific Hypersil ODS (250 x 4.6 mm, 5 µm) column, kept at ambient temperature, using acetonitrile: methanol: 0.05 M phosphate buffer (40:5:55; pH 4 adjusted with 0.1% tri ethyl amine) as a mobile phase at a flow rate of 1 mL/min and UV detection was performed at 225 nm. RESULTS: The retention time was found to be 3.9 min for aspirin and 5.3 min for omeprazole. The method was observed to be linear in the range of 2 - 80 µg/mL for aspirin and 1 - 40 µg/mL for omeprazole, respectively. The proposed method was validated as per ICH guidelines Q2 (R1). The developed RP- HPLC method was successfully applied for the simultaneous estimation of aspirin and omeprazole in the presence of degradation products of both the drugs. CONCLUSION: The present study describes liquid chromatographic method for the estimation of aspirin and omeprzole in combination. The method can be used for the analysis of stability samples and routine quality control samples.

Stability-indicating liquid chromatographic method for the quantification of the new antipsychotic agent asenapine in bulk and in pharmaceutical formulation.

A simple, specific and stability-indicating reversed phase high performance liquid chromatographic method was developed for the quantitative determination of asenapine in tablet dosage form. A SunFire C(18), 5 µm column having 250×4.6 mm i.d. in isocratic mode, with mobile phase containing 0.02 M potassium dihydrogen phosphate: acetonitrile (95:05, v/v, pH 3.5 adjusted with 1% o-phosphoric acid) was used. The flow rate was 1.0 mL min(-1) and effluents were monitored at 232 nm. The retention time of asenapine was 5.51 min. The linearity for asenapine was in the range of 0.1-20 µg/ml. The recoveries obtained for asenapine were 98.31-101.51%. Asenapine stock solutions were subjected to acid and alkali hydrolysis, chemical oxidation, sunlight and dry heat degradation. The degraded product peaks were well resolved from the pure drug peak with significant difference in their retention time values. Stressed samples were assayed using developed LC method. The proposed method was validated with respect to linearity, accuracy, precision and robustness. The method was successfully applied to the estimation of asenapine in tablet dosage form.

Stability indicating LC-method for estimation of paracetamol and lornoxicam in combined dosage form.

A simple, specific and stability indicating reversed phase high performance liquid chromatographic method was developed for the simultaneous determination of paracetamol and lornoxicam in tablet dosage form. A Brownlee C-18, 5 µm column having 250×4.6 mm i.d. in isocratic mode, with mobile phase containing 0.05 M potassium dihydrogen phosphate:methanol (40:60, v/v) was used. The flow rate was 1.0 ml/min and effluents were monitored at 266 nm. The retention times of paracetamol and lornoxicam were 2.7 min and 5.1 min, respectively. The linearity for paracetamol and lornoxicam were in the range of 5-200 µg/ml and 0.08-20 µg/ml, respectively. Paracetamol and lornoxicam stock solutions were subjected to acid and alkali hydrolysis, chemical oxidation and dry heat degradation. The proposed method was validated and successfully applied to the estimation of paracetamol and lornoxicam in combined tablet dosage form.

Development and validation of a stability-indicating RP-HPLC method for duloxetine hydrochloride in its bulk and tablet dosage form.

The objective of the present work was to develop a stability-indicating RP-HPLC method for duloxetine hydrochloride (DUL) in the presence of its degradation products generated from forced decomposition studies. The drug substance was found to be susceptible to stress conditions of acid hydrolysis. The drug was found to be stable to dry heat, photodegradation, oxidation and basic condition attempted. Successful separation of the drug from the degradation products formed under acidic stress conditions was achieved on a Hypersil C-18 column (250 mm à 4.6 mm id, 5Îm particle size) using acetonitrile: 0.01 M potassium dihydrogen phosphate buffer (pH 5.4 adjusted with orthophosphoric acid) (50:50, v/v) as the mobile phase at a flow rate of 1.0 ml/min. Quantification was achieved with photodiode array detection at 229 nm over the concentration range 1â25 Îg/ml with range of recovery 99.8â101.3 % for DUL by the RP-HPLC method. Statistical analysis proved the method to be repeatable, specific, and accurate for estimation of DUL. It can be used as a stability-indicating method due to its effective separation of the drug from its degradation products.

Determination of nebivolol hydrochloride and hydrochlorothiazide in tablets by first-order derivative spectrophotometry and liquid chromatography.

Two simple and accurate methods for analysis of nebivolol hydrochloride (NEB) and hydrochlorothiazide (HCTZ) in their combined dosage forms were developed using first-order derivative spectrophotometry and reversed-phase liquid chromatography (LC). NEB and HCTZ in their combined dosage forms (tablets) were quantified using first-derivative responses at 294.6 and 334.6 nm in the spectra of their solutions in methanol. The calibration curves were linear in the concentration range of 8-40 microg/mL for NEB and 10-60 microg/mL for HCTZ. LC analysis was performed on a Phenomenex Gemini C18 column (250 x 4.6 mm id, 5 microm particle size) in the isocratic mode with 0.05 M potassium dihydrogen phosphate-acetonitrile-methanol (30 + 20 + 50, v/v/v; pH 4) mobile phase at a flow rate of 1 mL/min. Detection was made at 220 nm. Both of the drugs and the internal standard (ezetimibe) were well resolved with retention times of 5.1 min for NEB, 2.9 min for HCTZ, and 8.2 min for ezetimibe. The calibration curves were linear in the concentration range of 1-14 microg/mL for NEB and 0.3-28 microg/mL for HCTZ. Both methods were validated and found to be accurate, precise, and specific, and results were compared statistically. Developed methods were successfully applied for the estimation of NEB and HCTZ in their combined dosage forms.

Estimation of pioglitazone hydrochloride and metformin hydrochloride in tablets by derivative spectrophotometry and liquid chromatographic methods.

Two simple and accurate methods of analysis to determine pioglitazone hydrochloride (PIO) and mefformin hydrochloride (MET) in combined dosage forms were developed using second-derivative spectrophotometry and reversed-phase liquid chromatography (LC). PIO and MET in combined preparations (tablets) were quantified using the second-derivative responses at 227.55 nm for PIO and 257.25 nm for MET in spectra of their solutions in a mixture of methanol and acetonitrile (30 + 70). The calibration curves were linear [correlation coefficient (r) = 0.9984 for PIO and 0.9986 for MET] in the concentration range of 8-40 microg/mL for PIO and 4-12 microg/mL for MET. In the LC method, analysis was performed on a Hypersil ODS-C18 column with 5 microm particle size using the mobile phase acetonitrile-water-acetic acid (75 + 25 + 0.3), adjusted to pH 5.5 with liquor ammonia, at a flow rate of 0.5 mL/min. Measurement was made at a wavelength of 230 nm. Both the drugs were well resolved on the stationary phase, and the retention times were 8.5 min for PIO and 16.0 min for MET. The calibration curves were linear (r = 0.9933 for PIO and 0.9958 for MET) in the concentration range of 4-20 microg/mL for PIO and MET. Both methods were validated, and the results were compared statistically. They were found to be accurate, precise, and specific. The methods were successfully applied to the estimation of PIO and MET in combined tablet formulations.