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 840 g/mL for NEB and 1060 g/mL for HCTZ. LC analysis was performed on a Phenomenex Gemini C18 column (250 4.6 mm id, 5 m particle size) in the isocratic mode with 0.05 M potassium dihydrogen phosphateacetonitrilemethanol (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 114 g/mL for NEB and 0.328 g/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.

Simultaneous Determination of Alprazolam and Fluoxetine Hydrochloride in Tablet Formulations by High-Performance Column Liquid Chromatography and High-Performance Thin-Layer Chromatography

This paper describes validated HPLC and HPTLC methods for simultaneous determination of alprazolam (ALP) and fluoxetine hydrochloride (FXT) in pure powder and formulation. The HPLC separation was achieved on a Nucleosil C8 column (150 mm length, 4.6 mm id, 5 m particle size) using acetonitrilephosphate buffer pH 5.5 (45 + 55, v/v) as the mobile phase at a flow rate of 1.0 mL/min at ambient temperature. The HPTLC separation was achieved on an aluminum-backed layer of silica gel 60F254 using acetonetolueneammonia (6.0 + 3.5 + 0.5, v/v/v) as the mobile phase. Quantification in the HPLC method was achieved with UV detection at 230 nm over the concentration range 414 g/mL for both drugs, with mean recovery of 99.95 0.38 and 99.85 0.56 for ALP and FXT, respectively. Quantification in the HPTLC method was achieved with UV detection at 230 nm over the concentration range of 4001400 ng/spot for both drugs, with mean recovery of 99.32 0.45 and 99.78 0.81 for ALP and FXT, respectively. These methods are simple, precise, and sensitive, and they are applicable for the simultaneous determination of ALP and FXT in pure powder and formulations.

Simultaneous Estimation of Acetylsalicylic Acid and Clopidogrel Bisulfate in Pure Powder and Tablet Formulations by High-Performance Column Liquid Chromatography and High-Performance Thin-Layer Chromatography

This paper describes validated high-performance column liquid chromatographic (HPLC) and high-performance thin-layer chromatographic (HPTLC) methods for simultaneous estimation of acetylsalicylic acid (ASA) and clopidogrel bisulfate (CLP) in pure powder and formulations. The HPLC separation was achieved on a Nucleosil C8 column (150 mm length 4.6 mm id, 5m particle size) using acetonitrilephosphate buffer, pH 3.0 (55 + 45, v/v) mobile phase at a flow rate of 1.0 mL/min at ambient temperature. The HPTLC separation was achieved on an aluminum-backed layer of silica gel 60F254 using ethyl acetatemethanoltolueneglacial acetic acid (5.0 + 1.0 + 4.0 + 0.1, v/v/v/v) mobile phase. Quantitation was achieved with UV detection at 235 nm over the concentration range 424 g/mL for both drugs, with mean recoveries of 99.98 0.28 and 100.16 0.66 for ASA and CLP, respectively, using the HPLC method. Quantitation was achieved with UV detection at 235 nm over the concentration range of 4001400 ng/spot for both drugs, with mean recoveries of 99.93 0.55 and 100.21 0.83 for ASA and CLP, respectively, using the HPTLC method. These methods are simple, precise, and sensitive, and they are applicable for the simultaneous determination of ASA and CLP in pure powder and formulations.

Development and Validation of an HPTLC Method for Determination of Olanzapine in Formulations

A new, simple, and rapid HPTLC method was developed and validated for quantitative determination of olanzapine on silica gel 60F254 layers using methanolethyl acetate (8.0 + 2.0, v/v) as the mobile phase. Olanzapine was quantified by densitometric analysis at 285 nm. The method was found to give compact bands for the drug (Rf = 0.35 0.02). The linear regression analysis data for the calibration plots showed a good linear relationship with r2 = 0.9997 in the concentration range of 100600 ng/band. The method was validated for precision, recovery, repeatability, and robustness as per the International Conference on Harmonization guidelines. The LOD was found to be 23.90 ng/band, and the LOQ was 91.04 ng/band. Statistical analysis of the data showed that the method is precise, accurate, reproducible, and selective for the analysis of olanzapine. The method was successfully used for the determination of equilibrium solubility and quantification of olanzapine as a bulk drug, in a commercially available preparation, and in in-house developed mucoadhesive microemulsion formulations and solution.

Estimation of Atorvastatin Calcium and Fenofibrate in Tablets by Derivative Spectrophotometry and Liquid Chromatography

Two simple and accurate methods to determine atorvastatin calcium (ATO) and fenofibrate (FEN) in combined dosage forms were developed using second-derivative spectrophotometry and reversed-phase liquid chromatography (LC). ATO and FEN in combined preparations (tablets) were quantitated using the second-derivative responses at 245.64 nm for ATO and 289.56 nm for FEN in spectra of their solution in methanol. The calibration curves were linear [correlation coefficient (r) = 0.9992 for ATO and 0.9995 for FEN] in the concentration range of 315 g/mL for ATO and FEN. In the LC method, analysis was performed on a Hypersil ODS-C18 column (250 mm 4.6 mm id, 5 m particle size) in the isocratic mode using the mobile phase methanol-water (90 + 10, v/v), adjusted to pH 5.5 with orthophosphoric acid, at a flow rate of 1 mL/min. Measurement was made at a wavelength of 246.72 nm. Both drugs were well resolved on the stationary phase, and the retention times were 1.95 min for ATO and 5.50 min for FEN. The calibration curves were linear (r = 0.9985 for ATO and 0.9976 for FEN) in the concentration range of 315 g/mL for ATO and FEN. 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 ATO and FEN in combined tablet formulations.

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 metformin 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 μg/mL for PIO and 4–12 μg/mL for MET. In the LC method, analysis was performed on a Hypersil ODS-C18 column with 5 μm 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 μg/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.

Paliperidone microemulsion for nose-to-brain targeted drug delivery system: pharmacodynamic and pharmacokinetic evaluation

OBJECTIVE

The objective of present study was to develop and evaluate paliperidone (PALI) loaded microemulsion (PALI-ME) for intranasal delivery in the treatment of schizophrenia.

MATERIAL AND METHODS

The PALI-ME was formulated by the spontaneous microemulsification method and characterized for physicochemical parameters. Pharmacodynamic assessments (apomorphine-induced compulsive behavior and spontaneous motor activity) were performed using mice. All formulations were tagged with (99m)Tc (technetium). Pharmacokinetic evaluation of PALI in the brain was investigated using Swiss albino rats. Brain scintigraphy imaging was performed in rabbits.

RESULTS AND DISCUSSION

PALI-ME was found stable with average droplet size of 20.01 ± 1.28 nm. In pharmacodynamic studies, significant (p < 0.05) deference in parameters estimated, were found between the treated and control groups. (99m)Tc-tagged PALI solution (PALI-SOL)/PALI-ME/PALI muco-adhesive ME (PALI-MME) was found to be stable and suitable for in vivo studies. Brain-to-blood ratio at all sampling points up to 8 h following intranasal administration of PALI-MME compared to intravenous PALI-ME was found to be 6-8 times higher signifying greater extent of distribution of the PALI in brain. Rabbit brain scintigraphy demonstrated higher intranasal uptake of the PALI into the brain.

CONCLUSION

This investigation demonstrates a prompt and larger extent of transport of PALI into the brain through intranasal PALI-MME, which may prove beneficial for treatment of schizophrenia.

Evaluation of brain targeting efficiency of intranasal microemulsion containing olanzapine: pharmacodynamic and pharmacokinetic consideration

The objective of this study was to develop and evaluate olanzapine (OZP) -loaded microemulsions (OZPME) for intranasal delivery in the treatment of schizophrenia. The OZPME was formulated by the spontaneous microemulsification method and characterized for physicochemical parameters. Pharmacodynamic assessments (apomorphine - induced compulsive behavior and spontaneous locomotor activity) were performed using mice. All formulations were radiolabeled with technetium-99 ((99m)Tc), and biodistribution of drug in the brain was investigated using Swiss albino rats. Brain scintigraphy imaging in rabbits was performed to determine the uptake of the OZP into the brain. OZPME were found clear and stable with average globule size of 23.87 ± 1.07 nm. In pharmacodynamic assessments, significant (p < 0.05) difference in parameters estimated were found between the treated and control groups. (99m)Tc-labeled OZP solution (OZPS)/OZPME/OZP mucoadhesive microemulsion (OZPMME) were found to be stable and suitable for in vivo studies. Brain/blood ratio at all sampling points up to 8 h following intranasal administration of OZPMME compared to intravenous OZPME was found to be five to six times higher signifying larger extent of distribution of the OZP in brain. Drug targeting efficiency and direct drug transport were found to be highest for intranasal OZPMME, compared to intravenous OZPME. Furthermore, rabbit brain scintigraphy also demonstrated higher intranasal uptake of the OZP into the brain. This investigation demonstrates a prompt and larger extent of transport of OZP into the brain through intranasal OZPMME, which may prove beneficial for treatment of schizophrenia.

Microemulsion-based drug delivery system for transnasal delivery of Carbamazepine: preliminary brain-targeting study

This study reports the development and evaluation of Carbamazepine (CMP)-loaded microemulsions (CMPME) for intranasal delivery in the treatment of epilepsy. The CMPME was prepared by the spontaneous emulsification method and characterized for physicochemical parameters. All formulations were radiolabeled with (99m)Tc (technetium) and biodistribution of CMP in the brain was investigated using Swiss albino rats. Brain scintigraphy imaging in rats was also performed to determine the uptake of the CMP into the brain. CMPME were found crystal clear and stable with average globule size of 34.11 ± 1.41 nm. (99m)Tc-labeled CMP solution (CMPS)/CMPME/CMP mucoadhesive microemulsion (CMPMME) were found to be stable and suitable for in vivo studies. Brain/blood ratio at all sampling points up to 8 h following intranasal administration of CMPMME compared to intravenous CMPME was found to be 2- to 3-fold higher signifying larger extent of distribution of the CMP in brain. Drug targeting efficiency and direct drug transport were found to be highest for CMPMME post-intranasal administration compared to intravenous CMP. Rat brain scintigraphy also demonstrated higher intranasal uptake of the CMP into the brain. This investigation demonstrates a prompt and larger extent of transport of CMP into the brain through intranasal CMPMME, which may prove beneficial for treatment of epilepsy.

Simultaneous Estimation of Amlodipine Besylate and Indapamide in a Pharmaceutical Formulation by a High Performance Liquid Chromatographic (RP-HPLC) Method

An isocratic reversed-phase liquid chromatograpic assay method was developed for the quantitative determination of amlodipine besylate (AML) and indapamide (IND) in combined dosage form. A Brownlee C-18, 5 μm column with a mobile phase containing 0.02 M potassium dihydrogen phosphate-methanol (30+70, v/v) total pH-adjusted to 3 using o-phosphoric acid was used. The flow rate was 1.0 mL min(-1) and effluents were monitored at 242 nm. The retention times of amlodipine besylate and indapamide were 5.9 min and 3.6 min, respectively. The proposed method was validated with respect to linearity, accuracy, precision, and robustness. The method was successfully applied to the estimation of amlodipine besylate and indapamide in combined tablet dosage forms.

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 C₁₈, 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.

Development and Validation of HPTLC Method for Estimation of Carbamazepine in Formulations and Its In Vitro Release Study

A new, simple, and rapid high-performance thin-layer chromatographic method was developed and validated for quantitative determination of Carbamazepine. Carbamazepine was chromatographed on silica gel 60 F254 TLC plate using ethyl acetate-toluene-methanol (5.0 + 4.0 + 1.0 v/v/v) as mobile phase. Carbamazepine was quantified by densitometric analysis at 285 nm. The method was found to give compact spots for the drug (Rf=0.47 ± 0.01). The linear regression analysis data for the calibration plots showed good linear relationship with r2=.9995 in the concentration range 100–600 ng/spot. The method was validated for precision, recovery, repeatability, and robustness as per the International Conference on Harmonization guidelines. The minimum detectable amount was found to be 16.7 ng/spot, whereas the limit of quantitation was found to be 50.44 ng/spot. Statistical analysis of the data showed that the method is precise, accurate, reproducible, and selective for the analysis of Carbamazepine. The method was successfully employed for the estimation of equilibrium solubility, quantification of Carbamazepine as a bulk drug, in commercially available preparation, and in-house developed mucoadhesive microemulsion formulations and solution.

Development and validation of an ultra performance liquid chromatography method for venlafaxine hydrochloride in bulk and capsule dosage form

A simple, specific, accurate, and precise ultra performance liquid chromatographic method was developed and validated for the estimation of venlafaxine hydrochloride in tablet dosage forms. A acquity TM BEH column having C18, 100×2.1 mm i.d. in isocratic mode, with mobile phase containing dipotassium hydrogen phosphate: Acetonitrile (30:70 v/v; pH 7.00 with dilute o-phosphoric acid) was used. The flow rate was 0.75 ml/min and effluents were monitored at 227 nm. The retention time of venlafaxine hydrochloride was 0.548 min. The method was validated for specificity, linearity, accuracy, precision, limit of quantification, limit of detection, robustness and solution stability. Limit of detection and limit of quantification for estimation of venlafaxine hydrochloride were found to be 6.11 μg/ml and 20.33 μg/ml, respectively. Recoveries of venlafaxine hydrochloride in tablet formulations were found to be in the range of 99.3-99.5%. Proposed method was successfully applied for the quantitative determination of venlafaxine hydrochloride in tablet dosage forms.

Stability Indicating RP-HPLC Estimation of Atorvastatin Calcium and Amlodipine Besylate in Pharmaceutical Formulations

A simple, specific, accurate and stability indicating reversed phase high performance liquid chromatographic method was developed for the simultaneous determination of atorvastatin calcium and amlodipine besylate 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 0.02 M potassium dihydrogen phosphate:acetonitrile:methanol (30:10:60, v/v/v) adjusted to pH 4 using ortho phosphoric acid was used. The flow rate was 1.0 ml/min and effluents were monitored at 240 nm. The retention times of atorvastatin calcium and amlodipine besylate were 11.6 min and 4.5 min, respectively. The calibration curves were linear in the concentration range of 0.08-20 μg/ml for atorvastatin calcium and 0.1-20 μg/ml for amlodipine besylate. Atorvastatin calcium and amlodipine besylate stock solutions were subjected to acid and alkali hydrolysis, chemical oxidation and dry heat degradation. The degraded product peaks were well resolved from the pure drug peak with significant difference in their retention time values. The proposed method was validated and successfully applied to the estimation of atorvastatin calcium and amlodipine besylate in combined tablet dosage forms.

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 mum column having 250x4.6 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.

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 × 4.6 mm id, 5μm 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 1–25 μg/ml with range of recovery 99.8–101.3 % 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,

Development and validation of an HPTLC method for determination of olanzapine in formulations

A new, simple, and rapid HPTLC method was developed and validated for quantitative determination of olanzapine on silica gel 60F254 layers using methanol-ethyl acetate (8.0 + 2.0, v/v) as the mobile phase. Olanzapine was quantified by densitometric analysis at 285 nm. The method was found to give compact bands for the drug (Rf = 0.35 +/- 0.02). The linear regression analysis data for the calibration plots showed a good linear relationship with r2 = 0.9997 in the concentration range of 100-600 ng/band. The method was validated for precision, recovery, repeatability, and robustness as per the International Conference on Harmonization guidelines. The LOD was found to be 23.90 ng/band, and the LOQ was 91.04 ng/band. Statistical analysis of the data showed that the method is precise, accurate, reproducible, and selective for the analysis of olanzapine. The method was successfully used for the determination of equilibrium solubility and quantification of olanzapine as a bulk drug, in a commercially available preparation, and in in-house developed mucoadhesive microemulsion formulations and solution.

Simultaneous determination of alprazolam and fluoxetine hydrochloride in tablet formulations by high-performance column liquid chromatography and high-performance thin-layer chromatography

This paper describes validated HPLC and HPTLC methods for simultaneous determination of alprazolam (ALP) and fluoxetine hydrochloride (FXT) in pure powder and formulation. The HPLC separation was achieved on a Nucleosil C8 column (150 mm length, 4.6 mm id, 5 microm particle size) using acetonitrile-phosphate buffer pH 5.5 (45 + 55, v/v) as the mobile phase at a flow rate of 1.0 mL/min at ambient temperature. The HPTLC separation was achieved on an aluminum-backed layer of silica gel 60F254 using acetone-toluene-ammonia (6.0 + 3.5 + 0.5, v/v/v) as the mobile phase. Quantification in the HPLC method was achieved with UV detection at 230 nm over the concentration range 4-14 microg/mL for both drugs, with mean recovery of 99.95 +/- 0.38 and 99.85 +/- 0.56% for ALP and FXT, respectively. Quantification in the HPTLC method was achieved with UV detection at 230 nm over the concentration range of 400-1400 ng/spot for both drugs, with mean recovery of 99.32 +/- 0.45 and 99.78 +/- 0.81% for ALP and FXT, respectively. These methods are simple, precise, and sensitive, and they are applicable for the simultaneous determination of ALP and FXT in pure powder and formulations.

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.

Stability Indicating RP-HPLC Estimation of Nebivolol Hydrochloride in Pharmaceutical Formulations

A simple, specific, accurate and stability indicating reversed phase liquid chromatographic method was developed for the determination of nebivolol hydrochloride in tablet dosage forms. A phenomenex Gemini C-18, 5 μm column having 250×4.6 mm i.d., with mobile phase containing methanol: acetonitrile: 0.02 M potassium dihydrogen phosphate (60:30:10, v/v/v; pH 4.0) was used. The retention time of nebivolol hydrochloride was 2.6 min. The linearity for nebivolol hydrochloride was in the range of 0.2-10 μg/ml. The recovery was found to be in the range of 98.68-100.86%. The detection limit and quantification limit were found to be 0.06 μg/ml and 0.2 μg/ml, respectively. Nebivolol stock solutions were subjected to acid, alkali and neutral hydrolysis, chemical oxidation and dry heat degradation. The degraded product peaks were well resolved from the pure drug peak with significant difference in their retention time values. The proposed method was validated and successfully applied to the estimation of nebivolol hydrochloride in tablet formulations.

Simultaneous estimation of acetylsalicylic acid and clopidogrel bisulfate in pure powder and tablet formulations by high-performance column liquid chromatography and high-performance thin-layer chromatography

This paper describes validated high-performance column liquid chromatographic (HPLC) and high-performance thin-layer chromatographic (HPTLC) methods for simultaneous estimation of acetylsalicylic acid (ASA) and clopidogrel bisulfate (CLP) in pure powder and formulations. The HPLC separation was achieved on a Nucleosil C8 column (150 mm length x 4.6 mm id, 5 microm particle size) using acetonitrile-phosphate buffer, pH 3.0 (55 + 45, v/v) mobile phase at a flow rate of 1.0 mL/min at ambient temperature. The HPTLC separation was achieved on an aluminum-backed layer of silica gel 60F254 using ethyl acetate-methanol-toluene-glacial acetic acid (5.0 + 1.0 + 4.0 + 0.1, v/v/v/v) mobile phase. Quantitation was achieved with UV detection at 235 nm over the concentration range 4-24 microg/mL for both drugs, with mean recoveries of 99.98 +/- 0.28 and 100.16 +/- 0.66% for ASA and CLP, respectively, using the HPLC method. Quantitation was achieved with UV detection at 235 nm over the concentration range of 400-1400 ng/spot for both drugs, with mean recoveries of 99.93 +/- 0.55 and 100.21 +/- 0.83% for ASA and CLP, respectively, using the HPTLC method. These methods are simple, precise, and sensitive, and they are applicable for the simultaneous determination of ASA and CLP in pure powder and formulations.

RP-HPLC Estimation of Venlafaxine Hydrochloride in Tablet Dosage Forms

A simple, specific, accurate, and precise reverse phase high performance liquid chromatographic method was developed and validated for the estimation of venlafaxine hydrochloride in tablet dosage forms. A Phenomenex Gemini C-18, 5 mum column having 250 x 4.6 mm i.d. in isocratic mode, with mobile phase containing methanol: 0.05 M potassium dihydrogen orthophosphate (70:30, v/v; pH 6.2) was used. The flow rate was 1.0 ml/min and effluents were monitored at 226 nm. Carbamazepine was used as an internal standard. The retention time of venlafaxine hydrochloride and carbamazepine were 3.7 min and 5.3 min, respectively. The method was validated for specificity, linearity, accuracy, precision, limit of quantification, limit of detection, robustness and solution stability. Limit of detection and limit of quantification for estimation of venlafaxine hydrochloride were found to be 100 ng/ml and 300 ng/ml, respectively. Recoveries of venlafaxine hydrochloride in tablet formulations were found to be in the range of 99.02-101.68%. Proposed method was successfully applied for the quantitative determination of venlafaxine hydrochloride in tablet dosage forms.

Estimation of atorvastatin calcium and fenofibrate in tablets by derivative spectrophotometry and liquid chromatography

Two simple and accurate methods to determine atorvastatin calcium (ATO) and fenofibrate (FEN) in combined dosage forms were developed using second-derivative spectrophotometry and reversed-phase liquid chromatography (LC). ATO and FEN in combined preparations (tablets) were quantitated using the second-derivative responses at 245.64 nm for ATO and 289.56 nm for FEN in spectra of their solution in methanol. The calibration curves were linear [correlation coefficient (r) = 0.9992 for ATO and 0.9995 for FEN] in the concentration range of 3-15 microg/mL for ATO and FEN. In the LC method, analysis was performed on a Hypersil ODS-C18 column (250 mm x 4.6 mm id, 5 microm particle size) in the isocratic mode using the mobile phase methanol-water (90 + 10, v/v), adjusted to pH 5.5 with orthophosphoric acid, at a flow rate of 1 mL/min. Measurement was made at a wavelength of 246.72 nm. Both drugs were well resolved on the stationary phase, and the retention times were 1.95 min for ATO and 5.50 min for FEN. The calibration curves were linear (r = 0.9985 for ATO and 0.9976 for FEN) in the concentration range of 3-15 microg/mL for ATO and FEN. 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 ATO and FEN in combined tablet formulations.

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.