Proposed High-performance Liquid Chromatography Method Research Articles

Development and Validation of New Analytical Methods for the Simultaneous Estimation of Selected Combinations of Drugs in Pharmaceutical Formulations

This paper proposes a high-performance liquid chromatography (HPLC) method for the simultaneous estimation of nortriptyline and gabapentin. The analytical conditions of the method were selected based on the chemical nature of the two compounds, and the method was validated through various studies including system suitability, specificity, linearity, LOD/LOQ, and recovery studies. The proposed method uses a Zorbax C18 column, a phosphate buffer with an acidic pH, and acetonitrile as the organic constituent of the mobile phase. The system suitability test evaluated the suitability of the chromatographic system for the analysis of the drug combination, and the specificity of the method was evaluated by assessing interference from excipients in the pharmaceutical dosage form prepared as a placebo solution. The linearity of the method was evaluated through linear regression analysis of the standard curve, and the LOD and LOQ values were determined by serial dilutions of nortriptyline and gabapentin stock solutions. The recovery studies were conducted to evaluate the degree of accuracy of the proposed method through known amounts of standard nortriptyline and gabapentin added to preanalyzed samples. Overall, the proposed HPLC method offers a reliable and accurate means for the simultaneous estimation of nortriptyline and gabapentin.

Development and Validation of RP-HPLC Method for Determination of Febuxostat in Bulk and Pharmaceutical Dosage Formulations

A new accurate, specific, precise, high performance liquid chromatographic (HPLC) method has been developed and validated for the determination of Febuxostat in bulk and in its pharmaceutical dosage forms of tablet. Acetonitrile: Methanol (70:30) was used as the mobile phase at a flow rate of 1.0ml/min using a Symmetry C18 column Finepack SIL C18T-5 (250x4.6mm, 5m). The effluent was spectroscopically monitored at 314nm. The intraday and inter-day precisions showed coefficients of variation ranged from 0.62% to 2.78% at different levels of concentrations. The calibration curve was linear with a correlation coefficient of 0.9947. The averages of the absolute and relative recoveries were found to be 98.67% to 98.96%. The proposed HPLC method was successfully applied to quantify the amount of Febuxostat in bulk and dosage forms in quality control.

Method Development of an Analytical Procedure for the Determination of Clofarabine in Pharmaceutical Formulations

A novel, simple and economic high performance liquid chromatography (HPLC) method has been developed for the estimation of Clofarabine in bulk and tablet dosage form with greater precision and accuracy.The method was validated as per ICH guidelines. Validation studies demonstrated that the proposed HPLC method is simple, specific, rapid, reliable and reproducible. Hence the proposed method can be applied for the routine quality control analysis of Clofarabine in bulk and tablet dosage forms. All the components of the system are controlled using SCL-10Avp System Controller. Data acquisition was done using LC Solutions software.

Application of High Performance Liquid Chromatography Method for Triadimenol Analysis in Water Sample

Triadimenol is the most important triazole fungicide used for prevention and treatment of plant fungal disease. A simple high performance liquid chromatography (HPLC) method for triadimenol analysis in water sample is reported in this study. The optimized HPLC system using C18 column was achieved using mobile phase composition containing acetonitrile-water (70:30, v/v), a flow rate of 1.0 mL/min, UV detection at 220 nm, and analysis time within 2.5 min. The calibration graph was linear in the range 5 to 50 mg/L with r2 of 0.9997. The limit of detection (LOD) and limit of quantification (LOQ) obtained were 1.23 and 4.12 mg/L, respectively. Combination of solid phase extraction (SPE) and the optimized HPLC method has been successfully applied for the determination of triadimenol in water sample with a recovery of 94.24 % (RSD = 5.38%, n = 4). The proposed HPLC method provides short analysis time, high reproducibility and high sensitivity.

Simultaneous Determination of Amoxicillin, Lansoprazole, and Levofloxacin in Pharmaceuticals by HPLC with UV–Vis Detector

In this study, a specific and rapid high-performance liquid chromatography (HPLC) method has been developed and validated for the simultaneous determination of amoxicillin, lansoprazole, and levofloxacin in pharmaceuticals. Paracetamol was used as internal standard (IS) in the measurements. UV–Vis absorption spectra of the analytes and the IS were taken for the determination of suitable absorption wavelength of UV–Vis detector (diode array detector, DAD) in the HPLC instrument. A reverse-phase C18 column was used in the separation and determination of amoxicillin, lansoprazole, and levofloxacin together with the IS. The pharmaceutical analytes were quantified by the UV–Vis diode array detector in the HPLC using MeOH-0.01 M CH3COONH4 (70:30) as the mobile phase. The linear calibration curves of them were measured in the ranges of 15–40 mg/L, 2.5–15.0 mg/L, and 7.5–20.0 mg/L for amoxicillin, lansoprazole, and levofloxacin, respectively. Excellent calibration correlations (R2: 0.9942, 0.9997, and 0.9974) were obtained. The percentage recoveries of the amoxicillin, lansoprazole, and levofloxacin in commercial pharmaceuticals were obtained as 105.5%, 98.57%, and 102.5%, respectively. The results showed that amoxicillin, lansoprazole, and levofloxacin together with paracetamol IS could be separated and determined simultaneously with low LOD and LOQ values using the proposed HPLC method.

Development and Validation of HPLC assay of Lycopene in Different Matrices

Lycopene is the red pigment richly found in many red -colored fruits and vegetables such as tomatoes, papaya, pink grapefruit, pink guava, and watermelon. It is an antioxidant that has various beneficent effects and protects against oxidative damage to lipids, protein, and DNA. It is a potent quencher of oxygen and most effective against cancer, cardiovascular diseases, osteoporosis, hypertension, male infertility, and neurodegenerative disease. Lycopene is synthesized by plants and microorganisms but not animals and humans. The main objective of this study is to develop and validate an HPLC assay method for the determination of lycopene in tomato, watermelon, and human blood. A simple assay method is an economical assay method, suitable for the determination of lycopene from plant and biological sources. A new accurate, specific, precise, high performance liquid chromatographic (HPLC) method has been developed and validated for the determination of lycopene in tomatoes, watermelon and blood sample according to the International Conference on Harmonization (ICH) guidelines. Acetonitrile, Methanol, Water (65%, 20%, and 15%) was used as the mobile phase at a flow rate of 0.7ml/min. using a symmetry C18 column. The effluent was spectrophotometrically monitored at 484nm. The calibration curve was linear with a correlation coefficient of 0.9994. The average recovery was found to be 102.0%. The proposed HPLC method was successfully applied to quantify the amount of lycopene in different matrices.

Stability-indicating RP-HPLC assay for simultaneous determination of chlorpheniramine maleate and prednisolone in veterinary injection

The present work described a simple, rapid, sensitive, accurate, and precise method for simultaneous determination of chlorpheniramine maleate (CHRM) and prednisolone acetate (PRED) in injection samples by high-performance liquid chromatography (HPLC) coupled with UV–Vis detection. Chromatographic separation was accomplished, employing isocratic mode and a mobile phase comprised of acetonitrile and a phosphate buffer (50:50, v/v, 30 °C), adjusted to pH 3.0. The flow rate used was 1.0 mL/min on a Thermo Hypersil ODS C18 column (5 μm, 4.6 × 250 mm), and the injection volume of sample was 20 μL. Analysis of CHRM and PRED was performed at a wavelength of 254 nm. The runtime for analysis was 12.5 min, and the retention times of CHRM and PRED were found to be 2.81 and 5.07 min, respectively. The calibration graph showed linearity over the concentration range 10–70 μg/mL for CHRM and 20–140 μg/mL for PRED with a coefficient of determination (R2) ≥0.9986. Repeatability and reproducibility (expressed as % RSD) were lower than 1.72 and 1.47%, respectively. The proposed HPLC method was demonstrated to be simple and rapid for the determination of CHRM and PRED in injection formulation, providing recoveries between 101.6–102.3%, whereas complete separation of degradation products, from analyte under investigation, provided the specificity of the proposed HPLC method.

ENANTIOMETRIC SEPARATION OF SITAGLIPTIN IN A FIXED DOSE COMBINATION FORMULA OF SITAGLIPTIN AND METFORMIN BY A CHIRAL LIQUID CHROMATOGRAPHIC METHOD

Objective: Sitagliptin phosphate and metformin hydrochloride tablet is an FDA approved combination product for the treatment of diabetes mellitus type 2. There are no reported evidence for estimation of undesired (S)-sitagliptin in a combination product. The objective of this study was to develop a high sensitive liquid chromatography method for the determination of (S)-enantiomer of sitagliptin phosphate in a fixed dose combination formula of metformin and sitagliptin.
 Methods: The proposed novel high-performance liquid chromatography (HPLC) method uses programmed gradient elution of a mixture of ethanol-diethylamine(DEA) 100:0.1 (v/v) as mobile phase-A and a mixture of methanol-water 60:40 (v/v) as mobile phase-B. The chromatographic conditions were designed to nullify the metformin interference and in which sitagliptin enantiomers elute first and followed by metformin. A satisfactory resolution (≥2.5) between (S)-sitagliptin and active form (R)-sitagliptin was achieved with gradient elution on Chiralpak IA column (5μm, 4 × 250 mm) at a flow rate of 0.5 ml/min and the detector wavelength set at 265 nm. The injection volume set as 10 µl. The developed method has been validated as per the International Conference on Harmonisation (ICH) guidelines.
 Results: The proposed HPLC method for determination of (S)-sitagliptin, showed good linearity in the concentration range of 0.5 µg/ml to 13.6 µg/ml and capable to quantify accurately up to the lowest level (LOQ) of 0.017%. The validated method was successfully applied to quantify the (S)-sitagliptin for different marketed formulations of sitagliptin with metformin and sitagliptin alone, and the corresponding recovery values were found to be in the range of 95.1% to 98.4%.
 Conclusion: The proposed validated HPLC method was found to be suitable for the quantitative determination of (S)-sitagliptin in the formulations of sitagliptin with metformin and sitagliptin alone.

Analysis of PK11195 concentrations in rodent whole blood and tissue samples by rapid and reproducible chromatographic method to support target-occupancy PET studies

In Positron Emission Tomography (PET) research, it is important to assess not only pharmacokinetics of a radiotracer in vivo, but also of the drugs used in blocking/displacement PET studies. Typically, pharmacokinetic/pharmacodynamic (PK/PD) analyses of drugs used in rodent PET studies are based on population average pharmacokinetic profiles of the drugs due to limited blood volume withdrawal while simultaneously maintaining physiological homeostasis. This likely results in bias of PET data quantification, including unknown bias of target occupancy (TO) measurements. This study aimed to develop a High Performance Liquid Chromatography (HPLC) method for PK/PD quantification of drugs used in preclinical rodent PET research, specifically the translocator 18 kDa protein (TSPO) selective drug, PK11195, that used sub-millilitre blood volumes. The lowest detection limit for the proposed HPLC method ranged between 7.5 and 10 ng/mL depending on the method used to calculate the limit of detection, and the measured average relative standard deviation for intermediate precision was equal to 17.2%. Most importantly, we were able to demonstrate a significant difference between calculated PK11195 concentrations at 0.5, 1, 2, 3, 5, 15 and 30 min post-administration and individually measured whole blood levels (significance level range from p < 0.05 to p < 0.001; one-way ANOVA, Dunnet's post hoc test, p < 0.05). The HPLC method developed here uses sub-millilitre sample volumes to reproducibly assess PK/PD of PK11195 in rodent blood. This study highlights the importance of individually measured PK/PD drug concentrations when quantifying the TO from blocking/displacement rodent PET experiments.

Enantioseparation of N-acetyl-dl-cysteine as o-phtaldialdehyde derivatives obtained with various primary aliphatic amine additives on polysaccharide-based chiral stationary phases

A sensitive and rapid high-performance liquid chromatography (HPLC) method was developed to enantioseparation of N-acetyl-dl-cysteine after precolumn derivatization using o-phthaldialdehyde and primary aliphatic amines. Seven polysaccharide-based chiral columns were tested in a reversed phase mode. Under the optimal chromatographic conditions, N-acetyl-dl-cysteine derivatives were completely enantioseparated on Chiralcel OZ-3R column with the resolution more than 2.5. The impact of various primary aliphatic amine additives as co-reagents (ethyl-, 1-propyl-, 1-butyl-, 1-pentylamine, (R)-sec-butylamine, tert-butylamine, isobutylamine, cyclopropyl-, cyclobutyl-, cyclopentyl and cyclohexylamine) used in precolumn derivatization step on the retention behavior (retention factor, selectivity and column efficiency) of N-acetyl-dl-cysteine derivatives was investigated. The effect of chromatographic conditions including acetonitrile content in the mobile phase, mobile phase pH, salt concentration in the mobile phase and column temperature on the retention and selectivity was investigated. The developed method was properly validated in terms of linearity, sensitivity (limit of detection and limit of quantification), accuracy, precision, intermediate precision and selectivity according to International Council for Harmonisation (ICH) of Technical Requirements for Pharmaceuticals for Human Use guidelines using internal normalization procedure. Proposed HPLC method was successfully applied to the determination of optical purity in commercially available N-acetyl-L-cysteine samples.

A comparative study of different chromatographic techniques for determination of toxic impurities of some commonly used anesthetics

2,6-Dimethylaniline (DMA) and o-toluidine (TOL) are considered as toxic impurities and carcinogenic metabolites as well as hydrolytic products upon degradation process for lidocaine (LD) and prilocaine (PR), respectively. The presence of such impurities above the permutable limits can adversely affect health and cause severe complications. Three different separation techniques, namely, high-performance liquid chromatography (HPLC), capillary zone electrophoresis (CZE), and thin-layer chromatography (TLC), were applied for the selective determination of the toxic compounds DMA and TOL and their intact drugs, LD and PR, respectively. The proposed HPLC method was carried out on Inertsil ODS 3 column (50 mm × 4.6 mm, 5 μm), utilizing a green mobile phase consisting of ethanol and 34 mM disodium hydrogen phosphate (20:80, v/v; pH = 6 adjusted using o-phosphoric acid). The flow rate was 1 mL min−1 with UV detection at 220 nm. The CZE separation was performed using 50 mM monobasic sodium phosphate (pH = 2.5), and voltage programming started with 22 kV for the first 6.7 min down to 18 kV from 6.9 min till 10 min. The suggested TLC method was achieved on TLC plates pre-coated with silica gel 60 F245 using a developing solvent containing toluene—chloroform—ethanol—triethylamine (5:5:1:0.1, by volume). These methods were validated with respect to linearity range, accuracy, precision, limit of detection, limit of quantification and robustness and were successfully applied for the determination of the two drugs in pure form and in pharmaceutical dosage form. A comparative study was held between the three chromatographic methods to evaluate the selectivity of the separation and the sensitivity, accuracy, and precision of the quantification.

FPSE-HPLC-DAD method for the quantification of anticancer drugs in human whole blood, plasma, and urine

The present work describes a fast, sensitive and selective procedure for the analyses of aromatase inhibitors including anastrozole, letrozole and exemestane used in the treatment of metastatic breast cancer by high performance liquid chromatography (HPLC) in human whole blood, plasma, and urine samples succeeding an extraction by innovative fabric phase sorptive extraction (FPSE). These drugs were successfully determined using a Luna C18 column at 25 °C using acetonitrile and phosphate buffer. The analytical method was validated, using weighted-matrix matched standard calibration curves. The intra- and inter-day accuracy values (precision and trueness) fulfill the criteria of International Guidelines on Bioanalytical Methods Validation. The analytical performances were further tested on real human biological samples. To the best of our knowledge, this is the first FPSE procedure applied to human whole blood, plasma, and urine samples for the concurrent analysis of aromatase inhibitors possessing a wide range of polarity index values and could be easily adopted as a rapid and green analytical protocol for clinical and pharmaceutical applications. The proposed HPLC method is very innovative since in the literature there are only methods dealing with a single antitumoral drug, and no process has been described so far for these three antitumoral drugs together directly from the whole blood.

Determination of organic acids in the root exudates of Cr-hyperaccumulator Leersia hexandra Swartz using high performance liquid chromatography

High performance liquid chromatography (HPLC) was used for the separation and quantification of the low molecular-mass organic acids in the root exudates of Cr-hyperaccumulator Leersia hexandra Swartz. Eight organic acids, oxalic, tartaric, formic, malic, lactic, acetic, maleic and citric acids, were separated on an XSelect HSS T3 column (250 mm×4.6 mm, 5 μm) within 13 min with the mobile phase of 40 mmol/L potassium dihydrogen phosphate-phosphorous acid at pH 2.40, a flow-rate of 1.0 mL/min, a detection wavelength of 205 nm and a column temperature of 25℃. This is a simple and highly sensitive method for the separation of the eight organic acids with well-shaped peaks. The limits of detection (LODs) for the eight acids ranged from 0.12 mg/L to 12.32 mg/L. Under the optimized conditions, tartaric, malic, lactic, maleic and citric acids in the root exudates were detected with high linearities, acceptable recoveries and excellent precisions. The contents of these acids calculated in the root exudates were (130.90±1.44) μg/g (root dry weight (DW)) for tartaric acid, (1031.34±4.38) μg/g (root DW) for malic acid, (65.54±1.01) μg/g (root DW) for lactic acid, (0.96000±0.00367) μg/g (root DW) for maleic acid and (201.50±1.13) μg/g (root DW) for citric acid. The proposed HPLC method is quite suitable for the simultaneous determination of organic acids in the root exudates of Leersia hexandra Swartz, and can be used in other plant root exudates as well.

Определение флавоноидов в цветках с листьями боярышника методом ВЭЖХ со спектрофотометрическим детектированием

Разработана методика качественного и количественного определения витексина, рутина, гиперозида и кверцетина в сырье «цветки с листьями боярышника» методом ВЭЖХ со спектрофотометрическим детектированием. Разделение проводили на колонке Luna C18(2) 4,6 мм  150 мм, 5 мкм в условиях ступенчатого градиента. Калибровочные кривые для 4 флавоноидов в изученных диапазонах удовлетворяют условию линейности (r2 &gt; 0,995). Показатели регенерации анализа в течение 1 дня/недели составляют 95,9 – 104,3 %/95,6 – 102,9 % для витексина, 94,0 – 102,2 %/93,5 – 101,5 % для рутина, 98,0 – 102,2 %/97,5 – 102,9 % для гиперозида, 96,0 – 109,8 %/97,2 – 111,0 % для кверцетина. Коэффициент вариации (RSD, %) в течение суток и между сутками не превышал 3 %. Относительная ошибка (ε, %) единичного определения каждого аналита с доверительной вероятностью 95 % не превышает 3 % для рутина, гиперозида и витексина, 4 % — для кверцетина.

Open-label uncontrolled pilot study on antipsoriatic activity of Rosa hemisphaerica

Background and objective: Rosa hemisphearica (Rosaceae) is highly cultivated worldwide as an ornamental plant and medicinally have an antibacterial and antioxidant effect. This study aimed to investigate clinically and histopathologically the anti-inflammatory activity of Rosa hemisphearica in psoriasis and to correlate the anti-inflammatory activity with the active constituents in the plant by the phytochemical study. Methods: In this open-label uncontrolled pilot study, a topical preparation of R. hemisphearica stem extract was used by 20 patients suffering from psoriasis for three weeks. Three histopathological slides for each patient, one each week for three weeks was done for anti-inflammatory response evaluation. Subsequently, total phenolic content was measured followed by thin layer chromatography (TLC) and high-performance liquid chromatography (HPLC) analysis for the identification of phenolic acid content in the stem. Results: By histopathological examination revealed that both Munro’s and Kogoj’s abscesses were gradually disappeared, the granular layer gradually restored to normal and the inflammatory cells gradually reduced in number prominently polymorph (neutrophils) and eventually histocytes disappeared. Total phenolic contents in R. hemisphearica stem extract were determined as 205.625 µg gallic acid equivalent each gm of the sample extract, TLC, and HPLC results showed the presence of rosmarinic acid in the stem extract. On quantitative HPLC analysis, the percentage of rosmarinic acid in the stem extract was 0.024 with a retention time (Rt) of 3.4 min. The proposed HPLC method was found to be linear, accurate and precise. Conclusion: The organic solvent extract of R. hemisphearica stem showed a significant reduction in an inflammatory cell among psoriatic patients under study. Rosmarinic acid was identified by TLC and HPLC as important phenolic acid constituents.

DEVELOPMENT OF THE METHODOLOGY OF THE CHROMATOGRAPHIC DETERMINATION OF NIFEDIPINE IN MEDICINES

ABSTRACTObjective: The aim was to develop a simple, rapid, less expensive, linear, precise, and accurate reverse phase high performance liquid chromatographymethod for determination of nifedipine in tablets.Methods: The chromatographic analysis of nifedipine was performed using liquid chromatograph Agilent 1290 Infinity II LC System. Selectedconditions were isocratic elution with binary mobile phase consisting of solution methanol and 0.1% trifluoroacetic acid (55:45). Detection wascarried out using spectrophotometric detector at 265 nm. The method was validated as per ICH guidelines.Results: The retention time for nifedipine by proposed high performance liquid chromatography (HPLC) method is observed as 3.5 minutes. Thecorrelation coefficients are 1.0000. The developed chromatographic method was found to be accurate with recovery 99.2-99.8% and was foundwithin the acceptance criteria (i.e. 98.0-102.0%) with acceptable % relative standard deviation of not more than 2% at each level. The assay results ofnifedipine in tablets by developed method are highly reproducible, reliable and are in good agreement with the label claim of the medicines (average99.62 %).Conclusion: Finally, it should be noted that a new simple, rapid, linear, precise, accurate HPLC method was developed and validated for thedetermination of nifedipine in medicines in accordance with the ICH guidelines. These results show the method are accurate, precise, sensitive,economic, and rugged. The proposed HPLC method is rapider (retention time is 3.5 minutes). This method can be useful for the routine analysis ofnifedipine in pharmaceutical dosage form.Keywords: Nifedipine, High-performance liquid chromatography, Validation, Linearity, Accuracy, Range of application.

DEVELOPMENT OF ASSAY METHOD AND FORCED DEGRADATION STUDY OF VALSARTAN AND SACUBITRIL BY RP-HPLC IN TABLET FORMULATION

Objective: A stability-indicating high performance liquid chromatographic (HPLC) method was developed and validated for the estimation of combined tablet formulation of valsartan and sacubitril.Methods: Chromatographic separation was optimized by gradient HPLC on a C18 column [Xterra, 250 x 4.6 mm, 5µ] utilizing a mobile phase consisting acetonitrile, methanol and potassium dihydrogen phosphate, pH 3.8 in the ratio of 30: 50:20 v/v at a flow rate of 1 ml/min with UV detection at 263 nm.Results: The retention time of sacubitril and valsartan was 3.01 min and 4.22 min respectively. Good linearity obtained over the range of 20μg/ml to 160μg/ml for valsartan and sacubitril. The correlation coefficient was found to be 0.999and0.998 for sacubitril and valsartan respectively. The % RSD of precision for sacubitril and valsartan was found to be 0.31 and 0.27 respectively. The % mean recovery was found to be 99.20-99.54% for valsartan and 99.85-100.90% for sacubitril. The results obtained for accuracy, precision, LOD, LOQ and ruggedness were within limits.Conclusion: The proposed HPLC method was found to be simple, specific, precise, accurate, rapid and economical for simultaneous estimation of valsartan and sacubitril in bulk and tablet dosage form. Thus the validated economical method was applied for forced degradation study of valsartan and sacubitril tablet.

Quality evaluation of cortex berberidis from different geographical origins by simultaneous high performance liquid chromatography combined with statistical methods

Purpose: To develop an effective method for evaluating the quality of Cortex berberidis from different geographical origins. Methods: A simple, precise and accurate high performance liquid chromatography (HPLC) method was first developed for simultaneous quantification of four active alkaloids (magnoflorine, jatrorrhizine, palmatine, and berberine) in C ortex berberidis obtained from Qinghai, Tibet and Sichuan Provinces of China. Method validation was performed in terms of precision, repeatability, stability, accuracy, and linearity. Besides, partial least squares discriminant analysis (PLS-DA) and one-way analysis of variance (ANOVA) were applied to study the quality variations of Cortex berberidis from various geographical origins. Results: The proposed HPLC method showed good linearity, precision, repeatability, and accuracy. The four alkaloids were detected in all samples of Cortex berberidis . Among them, magnoflorine (36.46 - 87.30 mg/g) consistently showed the highest amounts in all the samples, followed by berberine (16.00 - 37.50 mg/g). The content varied in the range of 0.66 - 4.57 mg/g for palmatine and 1.53 - 16.26 mg/g for jatrorrhizine, respectively. The total content of the four alkaloids ranged from 67.62 to 114.79 mg/g. Moreover, the results obtained by the PLS-DA and ANOVA showed that magnoflorine level and the total content of these four alkaloids in Qinghai and Tibet samples were significantly higher ( p < 0.01) than those in Sichuan samples. Conclusion: Quantification of multi-ingredients by HPLC combined with statistical methods provide an effective approach for achieving origin discrimination and quality evaluation of Cortex berberidis . The quality of Cortex berberidis closely correlates to the geographical origin of the samples, with Cortex berberidis samples from Qinghai and Tibet exhibiting superior qualities to those from Sichuan. Keywords: Tibetan medicine, Cortex berberidis , Origin discrimination, Quality evaluation, Magnoflorine, Palmatine, Berberine, Jatrorrhizine

An effective and sensitive stability-indicating chromatographic approach based on HPLC for silodosin assay

A stability-indicating reversed-phase high-performance liquid chromatography (HPLC) method with a high sensitivity was developed for the determination of silodosin (SIL) in the presence of hydrochlorothiazide (HCT) as an internal standard. Chromatographic separation of SIL and IS were successfully achieved on an Agilent ZORBAX CN column with an isocratic mobile phase composed of a mixture of methanol:acetonitrile:ammonium acetate (pH 4.0; 0.015 M) (40:30:30, v/v/v) at a flow rate of 1.3 mL min−1. The drugs were quantified using a photodiode array detector set at a wavelength of 270 nm. The reversed-phase HPLC method has been validated as per International Conference on Harmonisation (ICH) of Technical Requirements for Registration of Pharmaceuticals for Human Use guidelines to determine SIL in pharmaceutical dosage form. The proposed method showed a good linearity in the concentration range of 4.0–600.0 μM with a lower detection limit of 85.0 nM under optimized conditions. The statistical performance of the fully validated HPLC method was compared to our developed sensitive spectrofluorimetric method, and the performance results of the proposed HPLC method were considerably satisfactory. The validated method was successfully applied to quantify the SIL in capsules, and the corresponding recovery value was found to be 99.5 %. The validated HPLC method may be a promising alternative analytical tool for routine analysis of SIL in pharmaceutical samples.

Development of an analytical protocol for the estimation of maltitol from yoghurt, burfi and flavoured milk

An enzymatic treatment based isolation method was standardized for the hydrolysis of lactose, leading to removal of lactose peak which had same retention time as maltitol from the isolates of yoghurt, burfi, pasteurized and in-bottle sterilized flavoured milk. High performance liquid chromatography (HPLC) method was developed and validated for estimation of maltitol in these products. The developed HPLC method was simple, precise and accurate. Heating (90 °C/10 min, 90 °C/20 min), in-bottle sterilization (121 °C/15 min), heat desiccation, and fermentation resulted in no loss of maltitol during preparation of yoghurt, burfi, pasteurized and in-bottle sterilized flavoured milk. Storage of these products had no effect on the concentration of maltitol. The proposed HPLC method can be successfully used for the routine determination of maltitol in these products.