Stability-indicating capillary electrophoresis method for the simultaneous determination of metformin hydrochloride,saxagliptin hydrochloride,and dapagliflozin in pharmaceutical tablets

A capillary electrophoretic method coupled to a diode array detector (CE-DAD) was developed and validated for the simultaneous determination of metformin hydrochloride (MET), the dipeptidyl peptidase-4 (DPP-4) inhibitor saxagliptin hydrochloride (SAX), and the sodium glucose co-transporter (SGLT 2) inhibitor dapagliflozin (DAP). The proposed method was used for the determination of these drugs in binary antidiabetic combinations namely, SAX/MET, combination I, DAP/MET, combination II, and SAX/DAP, combination III. CE separation was performed on a fused silica capillary with background electrolyte consisting of 30?mM phosphate buffer (pH 6.0) with a high voltage of 30?kV, a pressure of 20 mbar, and an injection time of 40?s. The compounds were detected at 203?nm for SAX/DAP and 250?nm for MET. The method was linear in the concentration range of 10–200?µ?g/mL (SAX), 1.25–50?µ?g/mL (DAP), and 7.5–1000?µ?g/mL (MET). Full validation of the proposed method was performed as per the ICH guidelines. The obtained errors and deviation values did not exceed 2% assessing good accuracy and precision, respectively. The stability-indicating potential of the proposed method was proved under different stress-degradation conditions. The proposed method was successfully applied to the analysis of the three binary combinations in their tablets.     

Stability‐indicating HPTLC method for quantitative estimation of silybin in bulk drug and pharmaceutical dosage form

In the present study a novel stability‐indicating high‐performance thin‐layer chromatography (HPTLC) method for quantitative determination of silybin in bulk drug and nanoemulsion formulation has been developed and validated on silica using solvent chloroform–acetone–formic acid (9 : 2 : 1 v/v/v) (R_f of silybin 0.46 ± 0.05) in the absorbance mode at 296 nm. The method showed a good linear relationship (r² ± 0.999) in the concentration range 25–1500 ng per spot. It was found to be linear, accurate, precise, specific, robust and stability‐indicating and can be applied for quality control and standardization of several multi‐component hepatoprotective formulations as well as for stability testing of different dosage forms. The method proposed was also used to investigate the kinetics of acidic and alkaline degradation processes by quantification of drug at different temperature to calculate the activation energy and half‐life for silymarin degradation. Copyright © 2009 John Wiley & Sons, Ltd     

Stability-indicating liquid chromatography method development and validation for impurity profiling of montelukast sodium in bulk drug and tablet dosage form

Montelukast sodium (MLS) is a leukotriene receptor antagonist drug used in the treatment of asthma, bronchospasm, allergic rhinitis and urticaria. A reversed-phase high performance liquid chromatography method was developed to separate, identify and quantitative determination of MLS and its eight known organic impurities in tablet dosage form using a C₁₈ column and mobile phases consisting of a gradient mixture of pH 2.5 phosphate buffer and acetonitrile. The stability-indicating character of the developed method was proven using stress testing (1 m HCl at 80°C/30 min, 1 m NaOH at 80°C/30 min, H₂O at 80°C/30 min, 3% H₂O₂ at 25°C/1 min, dry heat at 105°C/10 h and UV–vis light/4 days) and was validated for specificity, quantitation limit, linearity, precision, accuracy and robustness. For MLS and its eight known impurities, the quantitation limits, linearity and recoveries were 0.015–0.03 μg/ml, correlation coefficient > 0.997 (R² > 0.995) and 85.5–107.0%, respectively. The developed chromatographic method is suitable for impurity profiling and also for assay determination of MLS in bulk drugs and pharmaceutical formulations. The mass values (m/z) of newly formed degradation products (DP1 and DP2) of montelukast sodium were identified using liquid chromatography–mass spectrometry.     

Stability indicating HPTLC determination of clopidogrel bisulphate as bulk drug and in pharmaceutical dosage form

A sensitive, selective, precise and stability indicating high-performance thin layer chromatographic method of analysis of clopidogrel bisulphate both as a bulk drug and in formulations was developed and validated in pharmaceutical dosage form. The method employed TLC aluminium plates precoated with silica gel 60F-254 as the stationary phase. The solvent system consisted of carbon tetrachloride-chloroform-acetone (6:4:0.15, v/v/v). This system was found to give compact spots for clopidogrel bisulphate (R_f value of 0.30±0.01). Clopidogrel bisulphate was subjected to acid and alkali hydrolysis, oxidation, photodegradation and dry heat treatment. Also the degraded products were well separated from the pure drug. Densitometric analysis of clopidogrel bisulphate was carried out in the absorbance mode at 230 nm. The linear regression data for the calibration plots showed good linear relationship with r²=0.999±0.001 in the concentration range of 200-1000 ng. The mean value of correlation coefficient, slope and intercept were 0.999±0.001, 0.093±0.011 and 8.83±0.99, respectively. The method was validated for precision, accuracy, ruggedness and recovery. The limits of detection and quantitation were 40 and 120 ng per spot, respectively. The drug undergoes degradation under acidic and basic conditions, oxidation and dry heat treatment. All the peaks of degraded product were resolved from the standard drug with significantly different R_f values. This indicates that the drug is susceptible to acid-base hydrolysis, oxidation and dry heat degradation. Statistical analysis proves that the method is reproducible and selective for the estimation of the said drug. As the method could effectively separate the drug from its degradation products, it can be employed as a stability indicating one.     

Stability indicating high-performance thin-layer chromatographic determination of nelfinavir mesylate as bulk drug and in pharmaceutical dosage form

A sensitive, selective, precise and stability indicating high-performance thin-layer chromatographic method of analysis of nelfinavir mesylate both as a bulk drug and in formulations was developed and validated. The method employed TLC aluminium plates precoated with silica gel 60F-254 as the stationary phase. The solvent system consisted of toluene-methanol-acetone (7:1.5:1.5, v/v/v). This system was found to give compact spots for nelfinavir mesylate (R_f value of 0.45±0.02). Nelfinavir mesylate was subjected to acid and alkali hydrolysis, oxidation, dry heat treatment and photodegradation. Also the peaks of degraded products were well resolved from the pure drug with significantly different R_f values. Densitometric analysis of nelfinavir mesylate was carried out in the absorbance mode at 250 nm. The linear regression analysis data for the calibration plots showed good linear relationship with r²=0.999±0.002 in the concentration range of 1000-6000 ng per spot. The mean value of correlation coefficient, slope and intercept were 0.999±0.002, 0.014±0.001 and 21.73±1.26, respectively. The method was validated for precision, robustness and recovery. The limits of detection and quantitation were 60 and 140 ng per spot, respectively. Statistical analysis proves that the method is repeatable and selective for the estimation of the said drug. As the method could effectively separate the drug from its degradation products, it can be employed as a stability indicating one.     

Development and validation of rapid HPLC method for determination of doxofylline in bulk drug and pharmaceutical dosage forms

A simple, selective, rapid, and economical reversed phase high performance liquid chromatography(RP-HPLC) method for the determination of doxofylline in the commercial dosage form has been developed and validated. The separation and quantification were achieved on an HiQ Sil C 18 W column using a mobile phase of acetonitrile: buffer (50: 50), pH 3, at a flow rate of 1 mL/min with detection of analyte at 272 nm. The separation was achieved within 3.1 ± 0.3 min for doxofylline sample. The method showed good linearity in the range of 10–80 μg/mL. The intra and inter day RSD ranged from 0.37–0.53%. The recovery (mean ± S.D.) of low, middle and high concentrations were 100.04 ± 0.80, 100.01 ± 0.20, 100.07 ± 0.30 respectively. Limit of detection and limit of quantification were 0.03 and 0.1 μg/mL, respectively.     

Development and validation of analytical method for estimation of bilastine in bulk and pharmaceutical (tablet) dosage form

BackgroundThe present work describe a simple, linear, precise, robust, accurate and selective HPLC method for estimation of Bilastine in bulk and tablet dosage form. Bilastine is a second generation antihistamine medication. Generally it is used for treatment of allergic rhinoconjunctivitis and urticaria (hives). Methanol: Acetonitrile: Phosphoric Acid Buffer pH 2.1 in proportion of (21:33:46) was used as mobile phase with flow rate 1.0 ​ml/min. The column used for the method development is 250 ​× ​4.6 mm ​× ​5 ​μm dimension.ResultIn the range of 5–25 ​μg/ml the linearity of Bilastine shows a correlation coefficient of 0.9981.ConclusionThe method was validated as per ICH guidelines for linearity, precision, accuracy, robustness.     

Stability-indicating method for simultaneous estimation of olmesartan medoxomile, amlodipine besylate and hydrochlorothiazide by RP-HPLC in tablet dosage form

A simple, specific, accurate and precise stability-indicating reversed-phase high-performance liquid chromatographic method was developed for simultaneous estimation of olmesartan medoxomile (OLME), amlodipine besylate (AMLO) and hydrochlorothiazide (HCTZ) in tablet dosage form. The method was developed using an RP C18 base deactivated silica column (250 × 4.6 mm, 5 μm) with a mobile phase consisting of triethylamine (pH 3.0) adjusted with orthophosphoric acid (A) and acetonitrile (B), with a timed gradient program of T/%B: 0/30, 7/70, 8/30, 10/30 with a flow rate of 1.4 mL/min. Ultraviolet detection was used at 236 nm. The retention times for OLME, AMLO and HCTZ were found to be 6.72, 4.28 and 2.30, respectively. The proposed method was validated for precision, accuracy, linearity, range, robustness, ruggedness and force degradation study. The calibration curves of OLME, AMLO and HCTZ were linear over the range of 50-150, 12.5-37.5 and 31-93 μg/mL, respectively. The method was found to be sensitive. The limits of detection of OLME, AMLO and HCTZ were determined 0.19, 0.16 and 0.22 μg/mL and limits of quantification of OLME, AMLO and HCTZ were determined 0.57, 0.49 and 0.66, respectively. Forced degradation study was performed according to International Conference on Harmonization guidelines.     

Development and validation of the HPLC method for the analysis of trimetazidine hydrochloride in bulk drug and pharmaceutical dosage forms

A simple, economic, selective, precise, and accurate high-performance liquid chromatographic (HPLC) method for the analysis of trimetazidine hydrochloride in both bulk drug and pharmaceutical formulations was developed and validated in the present study. The mobile phase consisted of water: methanol: triethylamine (75: 25: 0.1 v/v/v), and pH 3.3 was adjusted with orthophosphoric acid. This system was found to give a sharp peak of trimetazidine hydrochloride at a retention time of 3.375 ± 0.04 min. HPLC analysis of trimetazidine hydrochloride was carried out at a wavelength of 232 nm with a flow rate of 1.0 mL/min. The linear regression analysis data for the calibration curve showed a good linear relationship with a regression coefficient of 0.997 in the concentration range of 5–90 μg/mL. The linear regression equation was y = 35362x − 8964.2. The limit of detection (LOD) and limit of quantification (LOQ) were found to be 3.6 and 10.9 μg/mL, respectively. The developed method was employed with a high degree of precision and accuracy for the analysis of trimetazidine hydrochloride. The developed method was validated for accuracy, precision, robustness, detection, and quantification limits as per the ICH guidelines. The wide linearity range, accuracy, sensitivity, short retention time, and composition of the mobile phase indicated that this method is better for the quantification of trimetazidine hydrochloride. The text was submitted by the authors in English.     

Validated HPTLC method for simultaneous estimation of levofloxacin hemihydrate and ornidazole in pharmaceutical dosage form

A simple, rapid, and accurate high-performance thin-layer chromatography (HPTLC) method is described for the simultaneous determination of levofloxacin hemihydrate and ornidazole in tablet dosage form. The method is based on the HPTLC separation of the two drugs followed by densitometric measurements of their spots at 298 nm. The separation is carried out on Merck TLC aluminium sheets of silica gel 60 F254 using n-butanol-methanol-ammonia (5:1:1.5, v/v/v) as mobile phase. The linearity is found to be in the range of 50-250 and 100-500 ng/spot for levofloxacin hemihydrate and ornidazole, respectively. The method is successively applied to pharmaceutical formulation because no chromatographic interferences from the tablet excipients are found. The suitability of this HPTLC method for the quantitative determination of the compounds is proved by validation in accordance with the requirements laid down by International Conference on Harmonization (ICH) guidelines.     

Simultaneous determination of metformin and glimepride in pharmaceutical dosage form by reverse-phase liquid chromatography

A simple, rapid, and precise reversed-phase liquid chromatographic method has been developed for the simultaneous determination of metformin in combination with glimepride. Under the developed conditions, good separation of the analytes was achieved in short analysis time. Several parameters affecting the separation of the analytes were studied, including pH and the concentration of SDS. The method is validated and shown to be linear in the range of 25 microg/mL to 150 microg/mL for metformin and 0.1 microg/mL to 0.6 microg/mL for glimepride. The method is applied for the analysis of these analytes in commercially available tablets.     

Development of a stability indicating HPTLC method for the estimation of olanzapine in pharmaceutical dosage forms

We report herein an accurate, precise, and economical stability indicating high performance thin layer chromatographic (HPTLC) method developed to assess the safety of olanzapine in pharmaceutical formulations. Olanzapine was subjected to forced degradation studies to assess the effect of environmental conditions on its stability. Stress conditions such as hydrolysis under acidic and alkaline environment, degradation and oxidation by heat, light and air were used to study the stability of olanzapine. Mobile phase comprising of toluene: methanol (5:5 v/v) and aluminum plate pre-coated with silica gel 60 F₂₅₄ as a stationary phase were used for the development of chromatogram by HPTLC technique. Densitometric analysis of olanzapine carried out at 297 ​nm gave sharp symmetrical peak with R_f value of 0.50 and a satisfactory baseline resolution for all components. The drug was found to undergo degradation under acidic, alkaline and oxidative conditions. A single distinct peak in acidic and alkaline media while two peaks obtained as a result of oxidative degradation were well resolved along with the parent drug. The degradation products and parent drug showed significantly different R_f values. The developed HPTLC method gave quick and reproducible results for the olanzapine content in the tablets. The mean recoveries were 100.75% which confirms accuracy of the proposed method. The method was further validated for specificity, ruggedness and robustness. Based on the results, it can be suggested that the developed HPTLC method is quite efficient in separating the olanzapine from its degradation products; hence it can be used by pharmaceutical industries and regulatory bodies for the routine analysis of olanzapine in various pharmaceutical dosage forms.     

LC–MS/MS analysis of metformin,saxagliptin and 5‐hydroxy saxagliptin in human plasma and its pharmacokinetic study with a fixed‐dose formulation in healthy Indian subjects

A specific and rapid liquid chromatography–tandem mass spectrometry method is proposed for the simultaneous determination of metformin (MET), saxagliptin (SAXA) and its active metabolite, 5‐hydroxy saxagliptin (5‐OH SAXA) in human plasma. Sample preparation was accomplished from 50 μL plasma sample by solid‐phase extraction using sodium dodecyl sulfate as an ion‐pair reagent. Reversed‐phase chromatographic resolution of analytes was possible within 3.5 min on ACE 5CN (150 × 4.6 mm, 5 μm) column using acetonitrile and10.0 mm ammonium formate buffer, pH 5.0 (80:20, v /v) as the mobile phase. Triple quadrupole mass spectrometric detection was performed using electrospray ionization in the positive ionization mode. The calibration curves showed good linearity (r ² ≥ 0.9992) over the established concentration range with limit of quantification of 1.50, 0.10 and 0.20 ng/mL for MET, SAXA and 5‐OH SAXA respectively. The extraction recoveries obtained from spiked plasma samples were highly consistent for MET (75.12–77.84%), SAXA (85.90–87.84%) and 5‐OH SAXA (80.32–82.69%) across quality controls. The validated method was successfully applied to a bioequivalence study with a fixed‐dose formulation consisting of 5 mg SAXA and 500 mg MET in 18 healthy subjects. The reproducibility of the assay was demonstrated by reanalysis of 87 incurred samples.     

Stability indicating RP-HPLC method for simultaneous estimation of rupatadine fumarate and montelukast sodium in bulk and tablet dosage form

A simple, selective, accurate and sensitive high performance liquid chromatography (HPLC) method was developed and validated for the simultaneous determination of rupatadine fumarate (RPT) and montelukast sodium (MNT). Chromatographic separation achieved isocratically on a Hypersil BDS C₈ (250 mm × 4.6 mm, 5 μm) column utilizing a mobile phase of methanol: acetonitrile: buffer (40: 30: 30), (pH 3 with H₃PO₄) at a flow rate of 1.0 mL/min and column oven temperature 40°C with UV detection at 270 nm. Statistical analysis proves that the method is reproducible and selective for the simultaneous estimation of RPT and MNT. As the method could effectively separate the drugs from their degradation products, it can be employed as stability indicating method. The developed method was validated as per ICH guidelines in terms of accuracy, precision, linearity and specificity.     

Development and validation of a reversed-phase ion-pair high-performance liquid chromatographic method for the determination of risedronate in pharmaceutical preparations

A stability indicating, reversed-phase ion-pair high-performance liquid chromatographic method was developed and validated for the determination of risedronate in pharmaceutical dosage forms. The determination was performed on a BDS C₁₈ analytical column (250 mm × 4.6 mm i.d., 5 μm particle size); the mobile phase consisted of 0.005 M tetrabutylammonium hydroxide and 0.005 M pyrophosphate sodium (pH 7.0) mixed with acetonitrile in a ratio (78:22, v/v) and pumped at a flow rate 1.00 mL min⁻¹. The ultraviolet (UV) detector was operated at 262 nm. The retention times of magnesium ascorbyl phosphate, which was used as internal standard and risedronate were 4.94 and 5.95 min, respectively. The calibration graph was ranged from 2.50 to 20.00 μg mL⁻¹, while detection and quantitation limits were found to be 0.48 and 1.61 μg mL⁻¹, respectively. The intra- and inter-day percentage relative standard deviations, %R.S.D., were less than 5.9%, while the relative percentage error, %E_r, was less than 0.4%. The method was applied to the quality control of commercial tablets and content uniformity test and proved to be suitable for rapid and reliable quality control.     

A novel validated LC method for quantitation of lopinavir in bulk drug and pharmaceutical formulation in the presence of its potential impurities and degradation products

A simple isocratic liquid chromatographic method was developed for determination of lopinavir from its related impurities and assay for the first time. This method involves the use of a C(8) (Symmetry Shield RP8, 150 x 4.6 mm, 5 microm) column. The method was validated over the range of limit of quantitation (LOQ) to 120% of impurity specification limit and LOQ to 150% of working concentration for assay. The mobile phase consisted of a mixture of 50 mM of potassium phosphate buffer, acetonitrile and methanol in the ratio of 40:50:10. The flow rate was set at 1.0 mL/min with UV detection monitored at 210 nm. The drug was subjected to stress conditions of hydrolysis, oxidation, photolysis and thermal degradation. The developed method was validated for linearity, range, precision, accuracy and specificity. This method was successfully applied for content determination of lopinavir in pharmaceutical formulations. The method can be conveniently used in a quality control laboratory for routine analysis for assay and related substances as well for the evaluation of stability samples of bulk drugs and pharmaceutical formulations.     

Stability-indicating validated HPLC method for simultaneous determination of oral antidiabetic drugs from thiazolidinedione and sulfonylurea groups in combined dosage forms

For type 2 diabetes treatment, combinations of drugs from the thiazolidinedione and sulfonylurea groups are now available in the same tablet or capsule. Therefore, a stability-indicating and validated HPLC method was developed for simultaneous determination of pioglitazone, rosiglitazone, and glipizide in combined dosage forms. The examined drugs were subjected to different conditions such as acid and base, temperature, and UV light, and degradation of pioglitazone and glipizide was observed under thermal and acidic stress. However, selectivity of the presented method for pioglitazone, rosiglitazone, and glipizide assay against their degradation products was confirmed. It was also demonstrated to be robust, resisting small deliberate changes in pH of the buffer, flow rate, and percentage of acetonitrile in the mobile phase. The presented method utilizes a LiChrospher RP18 column (125 x 4.0 mm), acetonitrile in phosphate buffer at pH 4.3 (40 + 60, v/v) as the mobile phase, and UV detection at 225 nm for pioglitazonel glipizide or 245 nm for rosiglitazone/glipizide. The method was validated with respect to linearity, precision, and accuracy. Finally, the elaborated procedure was applied for the QC of pioglitazone/glipizide and rosiglitazone/glipizide mixtures.     

Development and validation of an HPLC method for mefloquine hydrochloride determination in tablet dosage form

A simple HPLC method for determination of mefloquine hydrochloride in tablets was developed and validated. The separation was carried out on an Xterra RP18 (250 x 4.6 mm id, 5 pm particle size) analytical column. The mobile phase was 0.05 M monobasic potassium phosphate buffer (pH 3.5)-methanol (40 + 60, v/v). The flow rate and wavelength were set to 1 mL/min and 283 nm, respectively. The method was specific for mefloquine hydrochloride in the presence of hydrolytic, oxidative, and photolytic degradation products. It was also linear, precise, accurate, and robust, being suitable for routine QC analyses and stability studies. The developed HPLC method was compared to a previously described spectrophotometric method.