Mobile Phase Composition Of Acetonitrile Research Articles

A Selective and Accurate LC-MS/MS Method for Simultaneous Quantification of Valsartan and Hydrochlorothiazide in Human Plasma

The fixed dose combination of valsartan (VAL) and hydrochlorothiazide (HCTZ) is the most commonly prescribed medicine for the effective treatment of hypertension. In this study, a simple sensitive and accurate liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed for the simultaneous quantitation of VAL and HCTZ in human plasma by using irbesartan (IRB) and hydroflumethiazide (HFMZ) as their specific internal standards (ISs). HLB cartridge-based solid-phase extraction was used for the extraction of analytes and ISs. The chromatographic separation was achieved on Lichrocart RP Select (125 × 4 mm), 5 nm with the mobile phase composition of acetonitrile: 10 mM ammonium acetate buffer: 95:05, v/v, at flow rate of 0.5 mL/min. The turbo ion electrospray ionization in negative mode was used as ion source for the sample ionization. The precursor to product ion transitions were 434.10 > 179.10 (VAL), 295.70 > 204.90 (HCTZ), 427.10 > 192.90 (IRB), and 329.90 > 302.40 (HFMZ) for detection and quantification of analytes and their ISs. The retention times of VAL and HCTZ were 1.90 min and 2.30 min, respectively. The range for the calibration curves of VAL and HCTZ were 50.2–6018.6 ng/mL and 1.25–507.63 ng/mL, respectively, with good linearity having correlation coefficient values of ≥0.995 for both VAL and HCTZ. All validation parameter results (selectivity, precision and accuracy, matrix effects and stabilities) were within the acceptable range as per USFDA guideline for bioanalytical method validation. The intra-day and inter-day accuracy data for VAL were within the range of 105.68–114.22% and 98.41–108.16%, respectively, whereas for HCTZ they were 87.01–101.18% and 95.16–99.37%, respectively. The ion suppression effects produced for VAL and ion enhancement effects produced for HCTZ were insignificant according to the proposed sample cleanup procedure. The developed LC-MS/MS method was successfully applied to bioequivalence study on healthy volunteers.

Extraction Method for Determining Florpyrauxifen-benzyl Herbicide in Soil

Florpyrauxifen-benzyl is the new active ingredient authorized by Brazilian legislation, which acts as herbicide and may be used to control weeds in rice cultivation, but studies on toxicity to humans and the environment are still under review. Due to recent insertion in the world pesticide market, there are still few studies related to the extraction and detection methodologies of this compound. Therefore, this study aimed to optimize and validate solid-liquid extraction with low temperature purification (SLE-LTP) for determining florpyrauxifen-benzyl in soil using highperformance liquid chromatography coupled to a diode array detection (HPLC-DAD). The results showed that the best conditions were achieved using Poroshell column, a temperature of 30 °C, mobile phase composition of acetonitrile:water (85:15 v/v) acidified with formic acid 0.1% (v/v), a flow rate of 0.3 mL min-1, and 243 nm as the wavelength. The best extracting phase was acetonitrile acidified with formic acid 0.1% (v/v) which achieved a recovery rate ca. 100% and relative standard deviation (RSD) less than 3.9%. The methodology was precise, accurate, linear and selective, with a limit of quantification of 20 μg kg-1. The stability study of this compound in soil showed that approximately 17.5 days is the half-life of florpyrauxifen-benzyl in soil.

Application of Box-Behnken experimental design and response surface methodology for selecting the optimum RP-HPLC conditions for the simultaneous determination of methocarbamol, indomethacin and betamethasone in their pharmaceutical dosage form

An isocratic RP-HPLC method has been developed for the separation and determination of methocarbamol (MTL), indomethacin (IND), and betamethasone (BET) in combined dosage form using an Inertsil ODS-3v C18 (250 × 4.6 mm, 5 μm) column with UV- detection at 235 nm. Experimental design using Box-Behnken design (BBD) was applied to study the response surface during method optimization and to achieve a good separation with a minimum number of experimental runs. The three independent parameters were pH of buffer, % of acetonitrile and flow rate of the mobile phase while the peak resolution of IND from MTL and the peak resolution of BET from IND (R2) were taken as responses to obtain mathematical models. The composite desirability was employed to optimize a set of responses overall (peak resolutions). The predicted optimum assay conditions include a mobile phase composition of acetonitrile and phosphate buffer (pH 5.95) in a ratio of 79:21, v/v, pumped at a flow rate of 1.4 mL min−1. With this ideal condition, the optimized method was able to achieve baseline separation of the three drugs with good resolution and a total run time of less than 7 min. The linearity of MTL, IND, and BET was determined in the concentration ranges of 5–600 µg mL− 1, 5–300 µg mL− 1, and 5–300 µg mL− 1 and the regression coefficients were 0.9994, 0.9998, and 0.9998, respectively. The average percent recoveries for the accuracy were determined to be 100.41 ± 0.60%, 100.86 ± 0.86%, and 100.99 ± 0.65% for MTL, IND, and BET, respectively. The R.S.D.% of the intra-day precision was found to be less than 1%, while the R.S.D.% of the inter-day precision was found to be less than 2%. The RP-HPLC method was fully validated with regard to linearity, accuracy, precision, specificity, and robustness as per ICH recommendations. The proposed method has various applications in quality control and routine analysis of the investigated drugs in their pharmaceutical dosage forms and laboratory-prepared mixtures with the goal of reducing laboratory waste, analysis time, and effort.

Chiral Separation of Econazole by High Performance Liquid Chromatography Method using Cyclodextrin as Chiral Column

The chiral separation of econazole, an antifungal drug with one chiral center has been successfully carried out using the high-performance liquid chromatography (HPLC) method. Enantioresolution of econazole (Rs = 2.29) was achieved using cyclodextrin-based chiral column (Astec Cyclobond, 25 cm × 4.6 mm × 5 μm), mobile phase composition of acetonitrile : water (0.2% HCOOH) (20:80, v/v), and UV detection of 220 nm.The optimized HPLC method has been applied for the quantitative determination of econazole in the pharmaceutical (liquid) sample withpercentage recovery of 100.75 % (RSD = 0,95%; n = 3). The effect of several HPLC parameters on the chiral separation of econazole was also evaluated and the method was successfully validated in terms of linearity, accuracy, precision, and selectivity. The present HPLC method was simple, short analysis time, and high resolution.

Implementation of Quality by Design Approach for Optimization of RP-HPLC Method for Quantification of Abiraterone Acetate in Solid Dispersion in Forced Degradation Studies

Background: Abiraterone acetate is a derivative of steroidal progesterone, used as a first-line therapy for metastatic castration of prostate cancer. Objective: The present study encompasses the design of an experiment approach for developing a simple, reliable, and rapid RP-HPLC method for the estimation of abiraterone acetate. Method: The chromatographic separation was efficiently conducted on a Hypersil Gold C18 (50 x 4.6 mm, 5 µm) HPLC column, using the mobile phase composition of acetonitrile: dibasic potassium phosphate (0.01 mM) in the ratio of 80:20 (%v/v) at pH 6.5 with an isocratic elution mode. Furthermore, the different force degradation study including hydrolysis, oxidation, thermal, and photolytic was performed for abiraterone acetate. Result: The dynamic linearity was established in the concentration range of 0.5-10 µg/mL with r2 of 0.9998. Furthermore, the limit of detection and the limit of quantitation were 0.0978 µg/mL and 0.3260 µg/mL. The degradation of abiraterone acetate was shown in both acidic (54.16 ± 0.247 after 24 hrs) and basic conditions (35.06 ± 0.458 after 24 hrs). Furthermore, the developed method was successfully employed to quantify abiraterone acetate in bulk powder and the solid dispersion did not show any change in the retention time. Conclusion: The developed method was validated according to the ICH Q2 (R1) specification, which was found to be sensitive, accurate, precise, robust, linear, and selective compared to the reported chromatographic method.

Concurrent Determination of Daclatasvir and Sofosbuvir in Pure Binary Mixture and Their Combined Film Coated Tablets by a Simple Stability Indicating RP-HPLC Method

A trouble-free, simple, specific and highly sensitive stability indicating phase HPLC method was developed for concurrent assessment of Daclatasvir and Sofosbuvir in pure and in their combined tablet formulation. An effectual separation was accomplished by using XDB Phenyl (250 x 4.6mm, 5µ,100 A0) column, mobile phase composition of Acetonitrile: buffer(0.1%v/v Trifluoroaceticacid in water) (50:50 v/v) and isocratic elution at a flow rate of 1ml/min and detection wavelength of 275nm. The extreme stress conditions like hydrolysis with acid and base, peroxide oxidation, thermal decomposition were used as per ICH specifications to assess the stability of the analytes in bulk and dosage forms. The retention times of Daclatasvir and Sofosbuvir were found at 2.8 and 3.7min respectively. The proposed method has linear response in the concentration ranges from 12 to 36µg/ml and 80 to 240 µg/ml for Daclatasvir and Sofosbuvir respectively. The detection and quantification limits calculated as 2.5μg/ml and 7.8μg/ml for DCL, 5.2μg/ml and 15.8μg/ml SOF respectively. All the method validation parameters were met the acceptance limits of Q2 specifications of ICH procedures. The degradation products produced by forced degradation studies were have good resolution from Daclatasir and Sofosbuvir peaks, which represents the methods stability. The proposed RP-HPLC method was highly sensitive, precise, stability indicating and economical. That’s why the method has the capacity to employ in the pharmaceutical manufacturing of Daclatasvir and Sofosbuvir and routine analysis in quality control department.

Development and Validation of Reverse‐Phase High‐Performance Liquid Chromatography Method for Estimation of Itraconazole through Hydroxypropyl Methylcellulose Acetate Succinate based Polymeric Films using Quality by Design principles

AbstractThe present work encompasses the application of quality by design principles through the design of experiments for analytical method development using reverse‐phase high‐performance liquid chromatography for estimation of itraconazole as pure drug and from polymeric amorphous dispersion films. A three‐factor three‐level Box Behnken design was used for multivariate analysis of the critical method parameters namely mobile phase composition, flow rate, and pH with a target of achieving a faster retention time of less than 4 min. The optimized method conditions were mobile phase composition of acetonitrile:water in 70:30 ratio, a flow rate of 1 mL/min, and pH of water at pH 7.0. With these method conditions, a retention time of 3.7 min was achieved, and the method was successfully validated to establish linearity in the concentration range of 29.5–129.5 μg/mL with a correlation coefficient of 1.0. The limits of detection and quantification were 0.3 μg/mL and 1.0 μg/mL, respectively. Forced degradation study revealed the ability of the method to detect degradation to oxidation and acidic conditions. This method was used for estimation of drug assay and dissolution from polymeric solid dispersion films prepared at different drug loading concentrations with hydroxypropyl methyl cellulose acetate succinate for accessing formulation variables like polymer type and concentration for improved drug dissolution of Itraconazole.

Bioanalytical Method Development and Validation of Empagliflozin by LC–MS/MS Method and Quantitative Estimation of Drug Concentration in Human Plasma

Objective: The objective of this work is to develop rapid, selective, and sensitive liquid chromatography tandem–mass spectrometry (LC–MS/MS) method for the quantitative estimation of empagliflozin. Sample and standard solutions were prepared using methanol. Methodology: The chromatographic separation was achieved with X Bridge C18 column (75 mm × 4.6 mm, 3.5 μ) using a mobile phase composition of acetonitrile and 10 mM ammonium bicarbonate (70:30 V/V) at a flow rate of 0.8 mL/min with a run time of 2.40 min. The method showed good linearity in the range of 2–1000 ng/mL with correlation coefficient (r) of >0.9998. Results: The % CV of peak area ratio (analyte area/ISTD area) and % CV of retention times for analyte and ISTD were within the acceptance criteria. There was no significant carry over observed during this experiment. All the investigated human plasma lots were found to be free of significant interferences at the retention time of drug and ISTD. The intra- and inter-day precision values for empagliflozin comply with the acceptance criteria. The battery of stability studies, namely, bench-top, freeze-thaw, and long-term stability was performed. All the stability studies showing the % C.V. of area responses for the replicate injections should be within 15%. Conclusion: The developed method was very simple, precise, reliable, sensitive, and robustness. The retention time takes less time consumption and high sensitivity, the method applicable for routine analysis and bioanalysis.

Analysis of Canagliflozin in Rat Plasma After Oral Administration by Liquid Chromatographic as (Pharmacokinetic Study)

The research work aims to develop a bioanalytical method using liquid chromatography and validated for the determination of canagliflozin by using an internal standard. Department of Pharmaceutical Chemistry, Smt. Kishoritai Bhoyar College of Pharmacy, New Kamptee, Nagpur (MS). Isocratic chromatography separation was achieved on an LC system with PDA detector on an ACE C18 (150mm× 4.6mm × 5µm) column using a mobile phase composition of acetonitrile: ammonium acetate buffer in the ration of 50:50 v/v (pH 4.5), orthophosphoric acid is used to adjust pH of mobile phase and the flow rate at 1.0ml/ min. and estimation was carried out at 291 nm. The retention time of a drug was 4.633 minutes. The method was validated for several parameters (specificity, linearity, precision, and accuracy) and also successfully applied for the pharmacokinetic in female rats. Calibration plot was linear (r2 > 0.9973) over the concentration range of 5-30 µg/ml for canagliflozin. The high recovery and low relative standard deviation (%RSD) confirm the suitability of the method. The result of Limit of Detection (LOD) and Limit of Quantitation (LOQ) were found to be 0.1099 μg/ml and 0.3331 μg/ml, respectively. The new RP-HPLC method can be conveniently adapted for examining canagliflozin concentration in rat plasma after oral administration.

Development of Fast and Simple LC-ESI-MS/MS Technique for the Quantification of Regorafenib; Application to Pharmacokinetics in Healthy Rabbits

Background: A simple quantification technique by liquid chromatography electrospray ionization- tandem mass spectrometry (LC-ESI-MS/MS) is required for regorafenib in biological matrices with bioavailability studies in healthy rabbits, when compared with reported techniques. Objective: The main aim of the research work was to develop a validated LC-ESI-MS/MS technique for the quantification of regorafenib and application to bioavailability studies in healthy rabbits. Methods: Chromatographic separation was achieved with hypersil-C18 analytical column (50mm×4.6 mm, 4μm) and mobile phase composition of acetonitrile and 5mM ammonium acetate in the proportion of 70:30. The mobile phase was infused into the column with high pressure to get a 0.7 ml/min flow rate. The total retention time of the analyte is promising when compared with the existed methods for regorafenib. Quantitation was processed by monitoring transitions of m/z -483.0/262.0 and 450.0/260.0 for regorafenib and internal standard respectively in multiple reaction monitoring. Results: The linearity equation and correlation coefficient (R2) findings were y =0.9948x+2.6624 and 0.998 respectively. The intra and inter-day precision of the developed technique was found between 1.00 – 8.50% for the QC-samples (2, 4, 240 and 480ng/ml). From bioavailability study, the drug was shown Tmax of 3.688 ± 0.754; average AUC0→α and AUC0→t were 6476.81 ± 259.59 and 6213.845 ± 257.892 respectively and Cmax was found to be 676.91 ± 22.045 in healthy rabbits. Conclusion: The developed technique was validated and successfully applied in the pharmacokinetic study of the drug (40 mg tablet) administered through the oral route in healthy rabbits.

A simple and sensitive HILIC-based UHPLC-MS/MS method for quantifying of rivaroxaban in dried blood spots: Application in comparison with the plasma sample method

Rivaroxaban, indicated for the treatment of atrial fibrillation, deep vein thrombosis, pulmonary embolism, and coronary or peripheral artery disease, is one of the most frequently used direct oral anticoagulants. Therapeutic drug monitoring [TDM] is essential to minimize bleeding and thrombosis during personalized rivaroxaban treatment. An efficient and reliable analytical technique is required to quatify the rivaroxaban during its therapeutic indication. Dried blood spots (DBSs) sampling is a convenient bioanalytical method with minimal invasive blood drawing, long-term stability, and low shipment and storage costs. Therfore, DBS sampling technique is growing rapidly for TDM of drugs in medical care. This study developed an ultra high performance liquid chromatography–tandem mass spectrometry method of quantitating rivaroxaban in DBSs samples using the isotopic labeled analog (rivaroxaban-d4) as an internal standard (IS). Rivaroxaban and IS were separated on an Acquity HILIC column and eluted with a mobile-phase composition of acetonitrile and 20 mM ammonium acetate in the ratio of 95:5 at a flow rate of 0.3 mL/min. The precursor-to-product ion transitions of 436.03 ˃ 144.9 for rivaroxaban and 440.04 ˃ 144.9 for IS were used to quantify in multiple reaction monitoring mode. The method was accurate and precise in the 2.06–1000 ng/mL calibration range without hematocrit and blood spot volume effects. Rivaroxaban was stable in DBSs samples under different anticipated storage and temperature conditions. We observed good correlation between the plasma concentration and the DBSs concentration, indicating that the proposed DBSs method is suitable for monitoring the rivaroxaban concentration using a simple and convenient sample collection procedure.

Determination of lacosamide in human plasma by LC–MS/MS and its application to a human pharmacokinetic study

AbstractA highly sensitive, specific, and rapid liquid chromatography–tandem mass spectrometry method for determination of lacosamide in human plasma has been developed using lacosamide d6 as an internal standard with 50 µL of human plasma. Protein precipitation technique was used to extract the analyte from human plasma. The chromatographic separation was achieved on ZODIAC C18, 4.6 × 100 mm, 5 µm column using an isocratic mobile phase composition of acetonitrile and 0.1% formic acid buffer (80:20, v/v) at a flow rate of 0.9 mL/min. A detailed method validation was performed as per the recent US FDA guidelines and the calibration curve obtained was linear (r2 = 998) over the concentration range 0.075–25.461 µg/mL. API‐4500 liquid chromatography with tandem mass spectrometry was operated with multiple reaction monitoring mode during the entire analysis. The proposed method was successfully applied to a pharmacokinetic study in healthy, adult human volunteers after oral administration of lacosamide 200 mg film‐coated tablet under fed conditions.

Development and validation of a novel UPLC-MS/MS method for quantification of delafloxacin in plasma and aqueous humour for pharmacokinetic analyses

Acute bacterial skin and skin structure infections are one of the most frequent infectious disease requiring hospitalization for treatment. Delafloxacin is a clinically approved fluoroquinolone antibiotic for the treatment of ABSSSIs. In spite of being marketed since 2017, there is no published analytical method for quantification of delafloxacin in biological samples. Herein, a selective and sensitive UPLC-MS/MS method was developed and validated for quantitative analysis of delafloxacin in rat plasma and rabbit aqueous humour samples. The liquid liquid extraction (using ethyl acetate) was used for analyte extraction form rat plasma, whereas protein precipitation (acetonitrile) was used for aqueous humour samples preparations. An Acquity UPLC BEH C18 column was used for chromatographic separation of delafloxacin and internal standard (rivaroxaban). The mobile phase composition of acetonitrile (containing 0.1% formic acid) and 10 mM ammonium acetate in ratio of 60:40 were used for sample elution at 300 µL/min flow rate. The electrospray ionization operated in positive mode was used for sample ionization and detection of analyte and internal standard were performed by multiple reaction monitoring (MRM) mode. The MRM transitions were set to 441.14 > 379.09 and 436.89 > 144.87 for delafloxacin and internal standard, respectively. The method was validated as per USFDA guideline for bioanalytical method and all the evaluated parameters were within the acceptable ranges. The developed method in plasma was successfully used to analyze samples in pharmacokinetic study of newly developed stearic acid-chitosan solid lipid nanoparticles formulation of delafloxacin in rat.

Development and Validation of UPLC-MS/MS Method for the Determination of Aripiprazole in Rat Plasma Using Liquid-Liquid Extraction: Pharmacokinetic and Bioequivalence Application

A selective, simple, sensitive and rapid ultra-performance liquid chromatographic tandem mass spectrometric (UPLC-MS/MS) method for the detection of aripiprazole in rat plasma has been developed and validated using aripiprazole-D8 as internal standard (IS). A simple single step sample preparation process was accomplished by liquid-liquid extraction (LLE). The post-treatment samples were chromato-graphed and analyzed on a UPLC bridged ethyl hybrid (BEH) C-18 column using mobile phase composition of acetonitrile: 0.1% formic acid in water::70:30 (v/v). Aripiprazole was analyzed by MS detector in positive electrospray ionization mode (ESI). Multiple reactions monitoring (MRM) was employed to observed the transition for aripiprazole (m/z 448.35→285.09) and aripiprazole-D8 (m/z 456.2→293.2). The developed method was validated and found linear in the working range of 2-1025 ng/mL with correlation coefficient, r2 = 0.99951 and quantification limit of 2.02 ng/mL. All validation parameters were in accordance with the ICH guidelines and met the acceptance criteria. The method was found to be accurate (recovery, 97.07 to 103.64%, precise (% CV, 2.68 to 7.70%), rapid (run time 4 min) and specific. The validated method was successfully used for the determination of plasma concentration of aripiprazole after single oral administration in rats and hence could be useful for in vivo pharmacokinetic study and bioequivalence testing of aripiprazole formulations.

Rapid Stability Indicating HPLC Method for the Analysis of Leflunomide and Its Related Impurities in Bulk Drug and Formulations.

Leflunomide (LFNM) is a drug that belongs to isoxazole derivatives and has immunosuppressive and anti-inflammatory activities. A literature search confirms that there is no method reported for the simultaneous estimation of LFNM and its related impurities A and B in pharmaceutical dosage forms or in bulk drug. Hence the present work aimed to develop a simple stability indicating RP-HPLC method for the separation and quantification of LFNM and its impurities A and B. Systematic trials of method conditions like mobile phase ratio, pH, flow rate, stationary phase, and detector wavelength were performed for the simultaneous analysis of LFNM and its related impurities A and B. The developed method was validated as per the ICH guidelines including forced degradation studies in different stress conditions. Optimized separation was achieved on a Thermo Scientific Hypersil ODS C18 column (250 mm×4.6 mm; 5 μm id) using mobile phase composition of acetonitrile, methanol, and 0.1 M sodium perchlorate in the ratio of 40:30:30 (v/v), pH 4.6, at a flow rate of 1.0 mL/min in isocratic elution. UV detection was carried out at a wavelength of 246 nm. Well-resolved peaks were observed with high numbers of theoretical plates, lower tailing factor, and reproducible relative retention time and response factor. The method was validated and all the validation parameters were found to be within the acceptance limits. Stability tests were done through exposure of the analyte solution to five different stress conditions, i.e. 1 N HCl, 1 N NaOH, 3% H2O2, thermal degradation of powder, and exposure to UV radiation. The method can successfully separate the degradation products along with both the impurities studied. The % degradation was also found to be less. The method developed for LFNM is simple and precise and can be applied for the separation and quantification of LFNM and its related impurities in bulk drug and pharmaceutical formulations.

Application of chemometric approach for QbD-Enabled development and validation of an RP-HPLC method for estimation of methotrexate

The present work describes Quality by design (QbD)-oriented development of a reverse phase high performance liquid chromatographic (RP-HPLC) method for quantification of methotrexate (MTX). Initially, for performing HPLC studies with UV detector, an appropriate wavelength was selected using a novel technique of Principal Component Analysis (PCA). Risk assessment study was performed, followed by factor screening study using a fractional factorial design (FFD). Subsequently, factor optimization was conducted using a central composite design (CCD), with flow rate and mobile phase ratio as the critical method parameters (CMPs), and tailing factor (TF), theoretical plate count (TPC) and % assay selected as the critical analytical attributes (CAAs). Polynomial modeling was performed to embark upon an optimal solution, followed by numerical and graphical optimization. Chromatographic separation was conducted using the mobile phase composition of acetonitrile (ACN) and ammonium acetate buffer (10 mM, pH 6) in the ratio of 25:75 v/v, flow rate of 0.8 mL/min, column oven temperature of 40 °C, and UV detection at 257 nm. Further, the analytical method was validated as per ICH Q2(R1) guidelines for linearity, accuracy, precision, sensitivity and robustness, ratifying that all the parameters were within the acceptable limits for quantification of MTX.

DEVELOPMENT OF VALIDATED STABILITY INDICATING METHOD BY RP-HPLC FOR SIMULTANEOUS ESTIMATION OF MEROPENEM AND VABORBACTAM IN BULK AND PHARMACEUTICAL FORMULATION

Objective: To develop a simple, rapid, precise and reproducible liquid chromatographic method for the estimation meropenem (MEP) and vaborbactam (VAB) in bulk and pharmaceutical formulation and study of the stability of the drugs in different stressed conditions.
 Methods: The chromatographic separation was achieved on a Kromasil C18 column (250 × 4.6 mm) using a mobile phase composition of acetonitrile and 10 mmol phosphate buffer (pH 3.50) in a ratio 30:70 v/v, pumped at a flow rate of 1.0 ml/min with UV detection set at 260 nm.
 Results: Symmetrical and sharp peaks of MEP and VAB were obtained at retention times of 2.29 and 3.10 min, respectively. The chromatographic method was validated for linearity, limits of detection and quantitation, precision, accuracy, system suitability and robustness. Calibration curves were obtained in the concentration ranges of 25–150 μg/ml for MEP and VAB. Stability tests done through the exposure of the analytes solution for different stress conditions and the obtained results indicate no interference of degradants with HPLC method.
 Conclusion: The proposed method has been found to be selective, precise, linear, accurate, and sensitive. The method can be successfully applied to the assay determination of bulk drugs and combined dosage forms for routine analysis.

Estimation of Lopinavir by RP-HPLC

Simple, sensitive and accurate HPLC method has been developed for the estimation of Lopinavir in pharmaceutical dosage forms. Lopinavir is an antiretroviral drug. Chromatographic separation was conducted on phenomenex lunar (250x4.6mm, 5µ) column at temperature 35°C, using a mobile phase composition of Acetonitrile: Water (70:30). The flow rate was 1ml/min and effluent was monitored at 198nm. The proposed method was validated as per the ICH guidelines. Evaluation of all the validation parameters suggested that the acceptance criteria were met. The proposed method can be used for routine analysis for the estimation of Lopinavir.

NOVEL RP-HPLC METHOD DEVELOPMENT AND VALIDATION FOR ESTIMATION OF TELMISARTAN AND NEBIVOLOL HCL IN PHARMACEUTICAL DOSAGE FORM

Objective: A simple, accurate, precise, robust reverse phase high performance liquid chromatography (RP-HPLC) method was developed for the estimation of telmisartan and nebivolol hydrochloride (HCl) simultaneously in its combined dosage form.Methods: The compounds were well resolved in an isocratic method using the mobile phase composition of acetonitrile: Buffer (potassium dihydrogen orthophosphate pH adjusted 3.1 with orthophosphoric acid) in a ratio of 40:60 v/v at a flow rate of 1.2 ml/min using C18 Shim-pack (150 mm × 4.6 mm, 5 μ) column. The detection was carried out at 280 nm.Results: The retention time of telmisartan and nebivolol HCl was 4.8 min and 6.5 min, respectively. The developed method was validated by evaluating various validation parameters such as linearity, precision, accuracy, robustness, specificity, limit of detection, and limit of quantification according to the international council for harmonization guidelines. The standard calibration curve was obtained in the concentration range of 24–56 μg/ml for telmisartan and 3–7 μg/ml for nebivolol HCl. The overall average % recovery was found out to be 100.35 for telmisartan and 98.84 for nebivolol HCl.Conclusion: Statistical analysis of the data showed that the method is reproducible and selective for the estimation of telmisartan and nebivolol HCl. The proposed method could be used for analysis of telmisartan and nebivolol HCl in their dosage form.

DEVELOPMENT AND VALIDATION OF STABILITY INDICATING METHOD RP-HPLC METHOD OF ACOTIAMIDE

Objective: The objective of present work was to develop and validate simple, precise, accurate and specific stability indicating method for determination of acotiamide in presence of its degradation products.Methods: An isocratic RP-HPLC method has been developed using C-8 Thermo Hypersil BDS Column (250 x 4.6 mm i.d., 5µparticle size) with the mobile phase composition of acetonitrile: 0.1 % triethylamine in 0.2% formic acid (30: 70) at column oven temperature of 40 °C. The flow rate was 1.0 ml min-1 and effluent was detected at 282 nm. The method was validated in terms of linearity, accuracy, precision, LOD (Limit of Detection), LOQ (Limit of Quantification) and robustness as per ICH guidelines.Results: The method was found to be linear in the range of 10-60µg/ml. Limit of detection and limit of quantification was found to 0.36µg/ml and 1.10 µg/ml.% Recovery was found to be in the range of 99.45%-99.75%and precision less than 2%. The developed method was successfully applied for estimation of Acotiamide in marketed tablet formulation and percentage assay was found to be 100.45%. Acotiamide was subjected to stress degradation under acid, base, neutral hydrolysis, oxidation, dry heat, photolysis conditions. Significant degradation was observed in acid and base degradation.Conclusion: The developed RP-HPLC method was simple, rapid, accurate, precise and stability indicating for the estimation of Acotiamide in bulk and tablet dosage form.