Simultaneous determination of withanolide a and bacoside a in spansules by high-performance thin-layer chromatography

The objective of this work was to develop and validate a simple, rapid, precise, and accurate high performance thin layer chromatography method for simultaneous determination of withanolide A and bacoside A in combined dosage form. The stationary phase used was silica gel G60F(254). The mobile phase used was mixture of ethyl acetate: methanol: toluene: water (4:1:1:0.5 v/v/v/v). The detection of spots was carried out at 320 nm using absorbance reflectance mode. The method was validated in terms of linearity, accuracy, precision and specificity. The calibration curve was found to be linear between 200 to 800 ng/spot for withanolide A and 50 to 350 ng/spot for bacoside A. The limit of detection and limit of quantification for the withanolide A were found to be 3.05 and 10.06 ng/spot, respectively and for bacoside A 8.3 and 27.39 ng/spot, respectively. The proposed method can be successfully used to determine the drug content of marketed formulation.     

Development and Validation of a HPTLC Method for the Estimation of Sumatriptan in Tablet Dosage Forms

A simple, precise, accurate and rapid high performance thin layer chromatographic method has been developed and validated for the estimation of sumatriptan in tablet dosage forms. The stationary phase used was precoated silica gel 60F254. The mobile phase used was a mixture of methanol:water:glacial acetic acid (4.0:8.0:0.1, v/v/v). The detection of spots was carried out at 230 nm. The method was validated in terms of linearity, accuracy, precision and specificity. The calibration curve was found to be linear between 200 to 800 ng/spot. The limit of detection and the limit of quantification for the sumatriptan were found to be 63.87 and 193.54 ng/spot, respectively. The proposed method can be successfully used to determine the drug content of marketed formulation.     

Stability-indicating Simultaneous HPTLC Method for Olanzapine and Fluoxetine in Combined Tablet Dosage Form

A rapid, selective and stability-indicating high performance thin layer chromatographic method was developed and validated for the simultaneous estimation of olanzapine and fluoxetine in combined tablet dosage form. Olanzapine and fluoxetine were chromatographed on silica gel 60 F₂₅₄ TLC plate using methanol:toluene (4:2 v/v) as the mobile phase and spectrodensitometric scanning-integration was performed at a wavelength of 233 nm using a Camag TLC Scanner III. This system was found to give compact spots for both olanzapine (R_f value of 0.63±0.01) and fluoxetine (R_f value of 0.31±0.01). The polynomial regression data for the calibration plots showed good linear relationship with r²=0.9995 in the concentration range of 100-800 ng/spot for olanzapine and 1000-8000 ng/spot for fluoxetine with r²=0.9991. The method was validated in terms of linearity, accuracy, precision, recovery and specificity. The limit of detection and the limit of quantification for the olanzapine were found to be 30 and 100 ng/spot, respectively and for fluoxetine 300 and 1000 ng/spot, respectively. Olanzapine and fluoxetine were degraded under acidic, basic and oxidation degradation conditions which showed all the peaks of degraded product were well resolved from the active pharmaceutical ingredient. Both drugs were not further degraded after thermal and photochemical degradation. The method was found to be reproducible and selective for the simultaneous estimation of olanzapine and fluoxetine. As the method could effectively separate the drugs from their degradation products, it can be employed as a stability-indicating method.     

Simultaneous HPTLC Determination of Rabeprazole and Itopride Hydrochloride From Their Combined Dosage Form

A simple, precise, sensitive, rapid and reproducible HPTLC method for the simultaneous estimation of the rabeprazole and itopride hydrochloride in tablets was developed and validated. This method involves separation of the components by TLC on precoated silica gel G60F254 plate with solvent system of n-butanol, toluene and ammonia (8.5:0.5:1 v/v/v) and detection was carried out densitometrically using a UV detector at 288 nm in absorbance mode. This system was found to give compact spots for rabeprazole (Rf value of 0.23 0.02) and for itopride hydrochloride (Rf value of 0.75±0.02). Linearity was found to be in the range of 40-200 ng/spot and 300-1500 ng/spot for rabeprazole and itopride hydrochloride. The limit of detection and limit of quantification for rabeprazole were 10 and 20 ng/spot and for itopride hydrochloride were 50 and 100 ng/spot, respectively. The method was found to be beneficial for the routine analysis of combined dosage form.     

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

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

Simultaneous determination of valsartan and hydrochlorothiazide in tablets by first-derivative ultraviolet spectrophotometry and LC

First-derivative ultraviolet spectrophotometry and high-performance liquid chromatography (HPLC) were used to determine valsartan and hydrochlorothiazide simultaneously in combined pharmaceutical dosage forms. The derivative procedure was based on the linear relationship between the drug concentration and the first derivative amplitudes at 270.6 and 335 nm for valsartan and hydrochlorothiazide, respectively. The calibration graphs were linear in the range of 12.0–36.1 μg ml⁻¹ for valsartan and 4.0–12.1 μg ml⁻¹ for hydrochlorothiazide. Furthermore, a high- performance liquid chromatographic procedure with ultraviolet detection at 225 nm was developed for a comparison method. For the HPLC procedure, a reversed phase column with a mobile phase of 0.02 M phosphate buffer (pH 3.2)-acetonitrile (55: 45; v/v), was used to separate for valsartan and hydrochlorothiazide. The plot of peak area ratio of each drug to the internal standard versus the respective concentrations of valsartan and hydrochlorothiazide were found to be linear in the range of 0.06–1.8 and 0.07–0.5 μg ml⁻¹, respectively. The proposed methods were successfully applied to the determination of these drugs in laboratory-prepared mixtures and commercial tablets.     

Development and Validation of a HPTLC Method for Simultaneous Estimation of L-Glutamic Acid and γ-Aminobutyric Acid in Mice Brain

A new robust, simple and economic high performance thin layer chromatographic method was developed for simultaneous estimation of L-glutamic acid and γ-amino butyric acid in brain homogenate. The high performance thin layer chromatographic separation of these amino acid was achieved using n-butanol:glacial acetic acid:water (22:3:5 v/v/v) as mobile phase and ninhydrin as a derivatising agent. Quantitation of the method was achieved by densitometric method at 550 nm over the concentration range of 10-100 ng/spot. This method showed good separation of amino acids in the brain homogenate with R_f value of L-glutamic acid and γ-amino butyric acid as 21.67±0.58 and 33.67±0.58, respectively. The limit of detection and limit of quantification for L-glutamic acid was found to be 10 and 20 ng and for γ-amino butyric acid it was 4 and 10 ng, respectively. The method was also validated in terms of accuracy, precision and repeatability. The developed method was found to be precise and accurate with good reproducibility and shows promising applicability for studying pathological status of disease and therapeutic significance of drug treatment.     

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

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

Development and validation of a high-performance thin layer chromatography method for the determination of cholesterol concentration

An accurate, sensitive, precise, reliable, and quick method for the determination of cholesterol content by high-performance thin layer chromatography is developed. In this method, aluminum-backed precoated silica gel 60 F₂₅₄ plates were used as the stationary phase and the samples were sprayed with the help of CAMAG sample applicator Linomat 5. The chromatogram was developed with the mobile phase consisting of chloroform:methanol (9.5:0.5, v/v). The samples were detected using CAMAG Scanner 4 and evaluated using the method developed on winCATS software. Densitometric analysis of cholesterol was performed in absorbance mode at 200 nm. In this solvent system, cholesterol gave a compact spot with an R_f value of 0.63 ± 0.03. The linear regression analysis of data for the calibration curve showed good linearity over a concentration range of 2–7 μg/spot with a regression value of 0.99933 and standard deviation of 1.44%. The limit of detection and limit of quantification were found to be 100 ng/spot and 500 ng/spot, respectively. Using the developed method, the concentration of cholesterol in the saponified and unsaponified egg yolk sample was determined. This method was found to be reproducible and can even be used for samples containing complex matrices.     

Simultaneous estimation of andrographolide and wedelolactone in herbal formulations

Andrographolide and wedelolactone are active components of Andrographis paniculata and Eclipta alba, respectively. The extracts of these plants are used in many traditional hepatoprotective formulations. An attempt has been made to develop an accurate, precise and specific HPTLC method to quantify simultaneously both these chemical markers of diversified chemical structures in different dosage forms like tablet and syrup. Precoated silica 60F(254) plates with toluene:acetone:formic acid (9:6:1) as mobile phase and detection wavelength of 254 nm were used. The method was validated in terms of linearity, accuracy, precision and specificity. The calibration curve was found to be linear between 200 to 400 ng/spot for andrographolide and 100 to 200 ng/spot for wedelolactone. The limit of detection and the limit of quantification for andrographolide were 26.16 and 79.28 ng/spot, respectively and for wedelolactone 5.06 and 15.32 ng/spot, respectively.     

Simultaneous Estimation of Aloe Emodin and Emodin from Rheum emodi,Cassia alata and Aloes by HPTLC

A simple, precise, specific, accurate high performance thin layer chromatography method was developed for simultaneous estimation of aloe emodin and emodin from medicinal plants like Rheum emodi (Rhubarb), Barbados aloes (dried juice of Aloe barbadensis leaf) and Cassia alata (Candle bush). Thin layer chromatographic aluminum plates pre-coated with silica gel 60 F₂₅₄ was used as the stationary phase for chromatographic separation of the drugs. Toluene:ethyl acetate:formic acid (10:2:1 v/v/v) was selected as mobile phase and analysis was carried out in absorbance mode at iso-absorptive wavelength of 263 nm. This method shows good resolution for both drugs with retention factor 0.37±0.03 and 0.55±0.03 for aloe emodin and emodin, respectively. The regression analysis data indicated good linear relationship for the calibration plots for aloe emodin and emodin in the range of 300 - 800 ng/spot and 150 - 400 ng/spot and regression coefficient was 0.9993 and 0.9994, respectively. Validation of the method was performed according to International Conference on Harmonisation guidelines for following parameters: Accuracy, precision, limit of detection, linearity, limit of quantification, robustness and specificity. In conclusion, the developed method was found to be rapid, simple, reliable and specific for the identification and quantitation of these anthraquinones in medicinal plants and marketed formulations.     

Central composite design expert-supported development and validation of HPTLC method: Relevance in quantitative evaluation of protopine in Fumaria indica

The current study was executed for method development, validation and to estimate the concentration of protopine in methanolic extract of Fumaria indica by high-performance thin-layer chromatography (HPTLC). Isolation of bioactive compounds was carried out using the mobile phase, toluene:ethyl acetate:diethyl amine (8:2.5:0.5 v/v/v), and detected at wavelength 290 nm. This method was validated for precision, specificity, linearity, limit of detection (LOD), limit of quantification (LOQ), etc. The calibration range was found to be 500–5000 ng/spot for the bioactive compound. Protopine was separated with an R_f value of 0.22 ± 0.03. The method was validated for linearity (r2 ≥ 0.996 ± 0.082), accuracy 98.75–102.12%), and RSD of precision (0.49–2.07) with a calibration curve range of 500.00–5000.00 ng/spot. The LOD and LOQ were found to be 83.92 ng/spot and 254.30 ng/spot., respectively. The Central Composite design expert was applied for the validation of robustness. Three independent variables such as the volume of toluene in solvent system, chamber saturation time and wavelength were investigated. The results indicated that a slight change in these variables had no significant effect on the peak response. This developed HPTLC method is simple, precise, robust, specific, rapid, and cost effective. It could be used for quality control study and quantification of protopine in the plant extract and different herbal formulations containing the plant species.     

Quantification of the cephalosporin antibiotic cefditoren in human plasma by high-performance liquid chromatography

A simple, sensitive and selective high-performance liquid chromatography (HPLC) method with ultraviolet detection (305 nm) was developed and validated for quantification of cefditoren (CAS 104145-95-1), a broad-spectrum orally administered cephalosporin in human plasma. Following solid-phase extraction using Waters Oasis SPE cartridges, the analyte and internal standard (hydrochlorothiazide, CAS 58-93-5) were separated using an isocratic mobile phase of 0.03 % trifluoro acetic acid buffer / acetonitrile (81/19, v/ v) on reverse phase Waters symmetry C18 column. The lower limit of quantification was 50 ng/mL, with a relative standard deviation of less than 4%. A linear range of 50 to 5000 ng/mL was established. This HPLC method was validated with between-batch and within-batch precision of 0.5 to 3.7 % and 0.5 to 2.5%, respectively. The between-batch and within-batch accuracy was 96.9 to 103.8% and 97.5 to 102.3%, respectively. Stability of cefditoren in plasma was excellent, with no evidence of degradation during sample processing (autosampler) and 30 days storage in a freezer. This validated method is sensitive, simple and repeatable enough to be used in pharmacokinetic studies.     

Development and validation of enantioselective high performance liquid chromatographic method for Valacyclovir, an antiviral drug in drug substance

A chiral high performance liquid chromatographic method was developed and validated for the enantiomeric resolution of Valacyclovir, L-valine 2-[(2-amino-1,6-dihydro-6-oxo-9h-purin-9-yl) methoxy] ethyl ester, an antiviral agent in bulk drug substance. The enantiomers of Valacyclovir were resolved on a Chiralpak AD (250 mm x 4.6 mm, 10 microm) column using a mobile phase system containing n-hexane: ethanol: diethylamine (30:70:0.1, v/v/v). The resolution between the enantiomers was found not less than four. The presence of diethylamine in the mobile phase has played an important role in enhancing chromatographic efficiency and resolution between the enantiomers. The developed method was extensively validated and proved to be robust. The limit of detection and limit of quantification of (D)-enantiomer were found to be 300 and 900 ng/ml, respectively, for 20 microL injection volume. The calibration curve showed excellent linearity over the concentration range of 900 ng/ml (LOQ) to 6000 ng/ml for (D)-enantiomer. The percentage recovery of (D)-enantiomer was ranged from 97.50 to 102.18 in bulk drug samples of Valacyclovir. Valacyclovir sample solution and mobile phase were found to be stable for at least 48 h. The proposed method was found to be suitable and accurate for the quantitative determination of (D)-enantiomer in bulk drugs substance. It can be also used to test the stability samples of Valacyclovir.     

Quantification of faropenem in human plasma by high-performance liquid chromatography

A simple, sensitive and specific high-performance liquid chromatography (HPLC) method with ultraviolet detection (315 nm) was developed and validated for quantitation of faropenem (CAS 106560-14-9), the newest addition to the group of beta-lactam antimicrobials, in human plasma. Following solid-phase extraction using Waters Oasis SPE cartridges, the analyte and internal standard (hydrochlorothiazide, CAS 58-93-5) were separated using an isocratic mobile phase of 10 mmol/L acetate buffer (pH adjusted to 7.0 with dilute acetic acid) / methanol / triethyl amine (70/30/0.03, v/v/v) on reverse phase Waters symmetry C18 column. The lower limit of quantitation was 200 ng/mL, with a relative standard deviation of less than 2 %. A linear range of 200 to 25000 ng/mL was established. This HPLC method was validated with between-batch and within-batch precision of 1.6 to 2.3 % and 0.4 to 1.6 %, respectively. The between-batch and within-batch bias was -3.1 to 5.3 % and -6.0 to 1.5 %, respectively. Frequently coadministered drugs did not interfere with the described methodology. The stability of faropenem in plasma was excellent, with no evidence of degradation during sample processing (autosampler) and 30 days storage in a freezer. This validated method is sensitive, simple and repeatable enough to be used in pharmacokinetic studies.     

RP-HPLC Estimation of Risperidone in Tablet Dosage Forms

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

HPTLC method for guggulsterone. I. Quantitative determination of E- and Z-guggulsterone in herbal extract and pharmaceutical dosage form

A sensitive, selective, precise and robust high-performance thin-layer chromatographic method of analysis of E and Z stereoisomers of guggulsterone (the hypolipidemic agent in the gum-resin exudates of Commiphora mukul) 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-acetone (9:1, v/v). Densitometric analysis of guggulsterone was carried out in the absorbance mode at 250 nm. This system was found to give compact spots for E- and Z-guggulsterone (Rf value of 0.38 +/- 0.02 and 0.46 +/- 0.02, respectively) following double development of chromatoplates with the same mobile phase. The linear regression analysis data for the calibration plots for E- and Z-guggulsterone showed good linear relationship with r2 = 0.9977 +/- 0.054 and 0.9975 +/- 0.068, respectively, in the concentration range of 100-6000 ng/spot. The mean value of slope and intercept were 0.11 +/- 0.006 and 0.11 +/- 0.005, 14.26 +/- 0.56 and 10.92 +/- 0.76, respectively, for E- and Z-guggulsterone. The method was validated for precision, robustness and recovery. The limit of detection and quantitation were 12, 10 and 24, 20 ng/spot, respectively, for E- and Z-guggulsterone. Statistical analysis proves that the method is repeatable and selective for the estimation of the said drug. Since the proposed mobile phase effectively resolves the E- and Z-isomers of guggulsterone, this HPTLC method can be applied for identification and quantitation of these isomers in herbal extracts and pharmaceutical dosage form.     

The ICH guidance in practice: stress degradation studies on indinavir sulphate and development of a validated specific stability-indicating HPTLC assay method

A sensitive, selective, precise and stability-indicating high-performance thin layer chromatography (HPTLC) method for analysis of indinavir sulphate 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 carbon tetrachloride/chloroform/methanol/10% v/v ammonia (4:4.5:1.5:0.05, v/v/v/v). Densitometric analysis of indinavir sulphate was carried out in the absorbance mode at 260 nm. This system was found to give compact spots for indinavir sulphate (Rf value of 0.43 +/- 0.02, for six replicates). Indinavir sulphate was subjected to acid and alkali hydrolysis, oxidation, dry and wet heat treatment, and photo degradation. The drug undergoes degradation under acidic and basic conditions, oxidation, dry and wet heat treatment, and photo degradation. Also the degraded products were well resolved from the pure drug with significantly different Rf values. The method was validated for linearity, precision, robustness, limit of detection (LOD), limit of quantitation (LOQ), specificity and accuracy. Linearity was found to be in the range of 100-6000 ng/spot with significantly high value of correlation coefficient r2 = 0.997 +/- 0.64. The linear regression analysis data for the calibration plots showed good linear relationship with r2 = 0.999 +/- 0.002 in the working concentration range of 1000-6000 ng/spot. The LOD and LOQ were 40 and 120 ng/spot, respectively. Statistical analysis proves that the method is repeatable and specific 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. Moreover, the proposed HPTLC method was utilized to investigate the kinetics of acid degradation process. Arrhenius plot was constructed and activation energy was calculated.     

LC determination of praziquantel in human plasma

A simple high-performance liquid chromatographic (HPLC) method for the determination of praziquantel in human plasma was developed and validated. The present method was described by adding drop-wise 0.2 M Zinc sulfate and acetonitrile to plasma sample for deproteinization. This method used a reversed-phase Spherisorb ODS 2 column (5 microm), 250 x 4.6 mm i.d. as a stationary phase with a mobile phase consisting of acetonitrile- methanol-water (36:10:54, v/v/v), a flow rate of 1.5 ml/min and UV detection wavelength of 217 nm. Diazepam was used as internal standard. The standard calibration curve was linear over the concentration range of 100-2000 ng/ml (r=0.999). The equation of a linear regression line was y=8.05E-04+7.25E-04x with slope and intercept values of 0.0007 and 0.0008, respectively. The limit of detection was 12.25 ng/ml and the limit of quantification was set at 100 ng/ml. The intra- and inter-day assay coefficients of variation (CV) were 3.0+/-1.7 and 6.3+/-1.9%, respectively. The percentage of recovery was 102.1+/-5.6. Therefore, the HPLC method described here was simple, rapid and reproducible since it did not require extraction and evaporation processes in sample preparation, which will reduce time-consuming or expensive sample preparation.     

Simultaneous determination of irbesartan and hydrochlorothiazide in human plasma using HPLC coupled with tandem mass spectrometry: Application to bioequivalence studies

A sensitive, specific and selective liquid chromatography/tandem mass spectrometric method has been developed and validated for the simultaneous determination of irbesartan and hydrochlorothiazide in human plasma. Plasma samples were prepared using protein precipitation with acetonitrile, the two analytes and the internal standard losartan were separated on a reverse phase C₁₈ column (50 mm × 4 mm, 3 μm) using water with 2.5% formic acid, methanol and acetonitrile (40:45:15, v/v/v (%)) as a mobile phase (flow rate of 0.70 mL/min). Irbesartan and hydrochlorothiazide were ionized using ESI source in negative ion mode, prior to detection by multiple reaction monitoring (MRM) mode while monitoring at the following transitions: m/z 296 → 269 and m/z 296 → 205 for hydrochlorothiazide, 427 → 175 for irbesartan. Linearity was demonstrated over the concentration range 0.06–6.00 μg/mL for irbesartan and 1.00–112.00 ng/mL for hydrochlorothiazide. The developed and validated method was successfully applied to a bioequivalence study of irbesartan (300 mg) with hydrochlorothiazide (12.5 mg) tablet in healthy volunteers (N = 36).