Subramania Nainar Meyyanathan

A validated RP-HPLC method for simultaneous estimation of nebivolol and hydrochlorothiazide in tablets

A simple, selective, rapid, precise and economical reverse phase high pressure liquid chromatographic method has been developed for the simultaneous estimation of nebivolol and hydrochlorthiazide from pharmaceutical formulation. Phenomenex Gemini C18 (25 cm×4.6 mm i.d., 5 μ) column with a mobile phase consisting of acetonitrile: 50mM ammonium acetate (adjusted to pH 3.5 using orthophosphoric acid) (70:30 v/v) at a flow rate of 1.0 ml/min was used. Detection was carried out at 254 nm. Probenecid was used as an internal standard. The retention times of probenecid, nebivolol and hydrochlorthiazide were 13.05, 3.32 and 4.25 min, respectively. The developed method was validated in terms of accuracy, precision, linearity, limit of detection, limit of quantitation and solution stability. The proposed method can be used for the estimation of these drugs in combined dosage forms.

Bioavailability Studies on Developed Prochlorperazine Maleate Sustained Release Tablets by HPLC

A sensitive and reproducible high performance liquid chromatography (HPLC) method has been developed and validated for the quantification of prochlorperazine sus- tained release tablets in human plasma, after solid phase extraction (SPE). Best chromatographic resolution was achieved on a reverse-phase Phenomenex C 18 column us- ing the mobile phase consisted of a mixture of 20 mM disodium hydrogen ortho phosphate–acetonitrile (95:5) in an isocratic elution with a total run time of 12 min. Linear plot was obtained in the concentration range of 15–300 ng/ml ( r 2 = 0.99). Lower limit of quantification (LLOQ) was found to be 15 ng/ml. Average recovery of the analyte was found to range from 98.25 to 99.13% in plasma at the concentrations of 45, 150 and 270 ng/ml. The intra and inter-day relative standard deviations of low quality con- trol (LQC), medium quality control (MQC) and high qual- ity control (HQC) of prochlorperazine were found to be 2.63, 3.25, 2.83 and 3.57, 5.88 and 3.78 respectively. The present method was successfully applied in the pharma- cokinetic study of prochlorperazine in human plasma.

Formulation and evaluation of dextromethorphan hydrobromide sustained release tablets.

Sustained release (SR) matrix tablets of dextromethorphan hydrobromide were prepared by wet granulation using hydroxypropyl methyl cellulose (HPMC-K-100 CR) as the hydrophilic rate controlling polymer. The effect of the concentration of the polymer and different fillers on the in vitro drug release rate was studied. The studies indicated that the drug release can be modulated by varying the concentration of the polymer and the fillers. A complete cross-over bioavailability study of the optimized formulation of the developed sustained tablets and marketed immediate release tablets was performed on six healthy male volunteers. The extent of absorption of drug from the SR tablets was significantly higher than that for the marketed dextromethorphan hydrobromide tablet because of lower elimination rate and longer half-life.

HPTLC determination of lupeol in Grewia tiliaefolia

Among the complex mixture of biologically active compounds in the bark of Grewia tiliaefolia, a plant used in folklore, lupeol, a constituent of the bark, has been used as an analytical marker indicative of the quality of the plant. A sensitive and reliable quantitative high-performance thin-layer chromatographic method has been developed for the determination of lupeol from Grewia tiliaefolia. Chloroform extracts of bark from five different sources were used for HPTLC on silica gel with benzene-ethyl acetate, 95 + 5, as mobile phase. Under these conditions the RF of lupeol was 0.40. The calibration plot was linear in the range 0.5 to 1.5 (μg lupeol and the correlation coefficient, 0.999, was indicative of good linear dependence of peak area on concentration. The mean assay of lupeol was 2.902 ± 0.243 mg g- bark. The method enables reliable quantification of lupeol and good resolution and separation of lupeol from other constituents of Grewia tiliaefolia. To ascertain the purity of the peak from the test sample its in-situ reflectance spectrum was compared with that from standard lupeol; clear superimposibility indicated the purity of the peaks. Recovery values from 98.00 to 99.78% showed the reliability and reproducibility of the method were excellent. The HPTLC method proposed for quantitative monitoring of lupeol in Grewia tiliaefolia is rapid, simple, and accurate and can be used for routine quality testing.

Synthesis, antimalarial and antibacterial activities of 3-amino acid- and aryl amine-substituted 2-methyl-3H-quinalzolin-4-ones

A new series of 2-methyl-3H-quinazolinones substituted at the third position with amino acids (2–5) and aryl amine (6, 7) was designed, synthesized, and analyzed by infrared, NMR, and mass spectral analysis. Further, the compounds were screened for their in vivo antimalarial activity using the rodent malaria parasite Plasmodium yoelii (N-67) with the Swiss mice model. The compounds were also tested for their antibacterial activity.

Validated HPTLC method of analysis of dexibuprofen in its formulation

A simple, sensitive, precise, and rapid high-performance thin-layer chromatographic (HPTLC) method for analysis of dexibuprofen in pharmaceutical formulation has been developed and validated. The method uses aluminum foil HPTLC plates coated with silica gel 60F254 as stationary phase and hexane—ethyl acetate—glacial acetic acid 7.5:2.5:0.5 (v/v) as mobile phase. Densitometric analysis of dexibuprofen and the internal standard (aceclofenac) was performed in reflectance mode at 217 nm. The system was found to give compact bands for dexibuprofen (RF 0.50). Linear regression analysis of the calibration data revealed a good linear relationship between response and concentration in the range 50–300 ng per band (r2 = 0.9902). The method was validated for precision, accuracy, recovery, and robustness. The method has been successfully applied to analysis of an oral solid dosage formulation.

Determination of deflazacort in human plasma by liquid chromatography-mass spectrometry after liquid-liquid extraction and its application in human pharmacokinetics studies.

Purpose: A sensitive liquid chromatography-mass spectrometric (LC/MS) has been developed and validated for the quantification of deflazacort in human plasma after liquid-liquid extraction (LLE). Materials and Methods: Best chromatographic resolution was achieved on a reverse-phase Phenomenex C18 column with the mobile phase of acetonitrile–water (30:70) and isocratic elution resulted in a total run time of about 3.5 min. The analyte was detected by using an electrospray positive ionization mass spectrometry in the selected ion monitoring (SIM) mode. Linearity was obtained in the concentration range studied (5–150 ng/ml) (r = 0.9974). Results: Lower limit of quantification (LLOQ) was found to be 5 ng/ml in 500μl plasma sample. Average recovery of the analyte was found to range from 86.80 to 88.19% in plasma at the concentrations of 15.0, 60.0 and 120.0 ng/ml. Conclusions: The present method was successfully applied in the pharmacokinetic study of deflazacort in human plasma.

Development and Validation of a HPLC and an UV Spectrophotometric Methods for Determination of Dexibuprofen in Pharmaceutical Preparations.

A high-performance liquid chromatographic (HPLC) and a ultraviolet (UV) methods were developed and validated for the quantitative determination of Dexibuprofen (DI) in pharmaceutical dosage form. HPLC was carried out by reversed phase technique on a RP-18 column with a mobile phase composed of acetonitrile and 0.5% triethylamine (pH 7.5 adjusted with orthophosphoric acid (30 : 70, v/v)). UV method was performed with the λ max at 222.0 nm. Both the methods showed good linearity, reproducibility and precision. No spectral or chromatographic interferences from the tablet excipients were found in UV and HPLC. The method was successfully applied to commercial DEXIFEN tablets. Validation parameters such as linearity, precision, accuracy, and specificity were determined. The proposed method could be applicable for routine analysis of DI and monitoring of the quality of marketed drugs.

Liquid chromatography-mass spectrometric method for simultaneous estimation of apigenin and luteolin from Achillea millefolium Linn

To develop a rapid, specific, accurate and efficient liquid chromatography-mass spectrometry method and validate as per ICH guidelines for the simultaneous estimation of apigenin and luteolin from Achillea millefolium. The chromatographic separation was achieved by using C8 column, 150 x 4.6mm i.d., 5μ Hibar Lichrospher, mobile phase containing 0.1% formic acid: acetonitrile (20:80 v/v). The flow rate was 0.4 ml/min. The retention time of apigenin and luteolin was found to be 8.48 min and 8.01 min respectively. Apigenin and luteolin exhibited linear in the range of 10–50 ng/ml. The method was validated for the parameters like system suitability, specificity, linearity, accuracy, precision, limit of detection and limit of quantification. The proposed method was successfully applied for the simultaneous estimation of both the constituents in Achillea millefolium and established a quantitative method for the simultaneous determination of apigenin and luteolin from Achillea millefolium.

Development of a Forced Degradation Profile of Alosetron by Single Mode Reversed-Phase HPLC, LC-MS, and its Validation

Determination of alosetron in the presence of its degradation products was studied and validated by a novel HPLC method. The separation of the drug and its degradation products was achieved with the Jones Chromatography C18 analytical column (150 mm x 4.6 mm; 3 µm) with a stationary phase in isocratic elution mode. The mobile phase used was 0.01 M ammonium acetate, pH-adjusted to 3.5 with glacial acetic acid and acetonitrile in the ratio of 75:25 (V/V) at a flow rate of 1 ml/min and UV detection was carried out at 217 nm. Further, the drug was subjected to stress studies for acidic, basic, neutral, oxidative, and thermal degradations as per ICH guidelines and the drug was found to be labile in base hydrolysis and oxidation, while stable in acid, neutral, thermal, and photolytic degradation conditions. An MS study has been performed on the major degradation products to predict the degradation pathway of alosetron. The method provided linear responses over the concentration range of 100–1500 ng/ml and regression analysis showed a correlation coefficient value (r2) of 0.994. The LOD and LOQ were found to be 1 ng/ml and 3 ng/ml, respectively. The developed LC method was validated as per ICH guidelines with respect to accuracy, selectivity, precision, linearity, and robustness.