Biomedical subjects

D Sreenivas Rao

Publications and source records attributed to D Sreenivas Rao.

9 recordsLinked to original sources

PubMed2006

Chiral separation of Frovatriptan isomers by HPLC using amylose based chiral stationary phase.

A stereospecific HPLC method for separation of Frovatriptan enantiomers in bulk drug and pharmaceutical formulations was developed and validated on a normal-phase amylose derivertized chiral column. The effects of the organic modifiers namely 2-propanol, ethanol and diethyl amine (DEA) in the mobile phase were optimized to obtain the best enantiomeric separation. Calibration curves were linear over the range of 200-6150 ng/mL, with a regression coefficient (R(2)) of 0.9998. The limit of detection (LOD) and limit of quantification (LOQ) were 65 ng/mL and 200 ng/mL, respectively. The method was accurate and precise and suitable for the intended purpose. Analysis results were compared with the results obtained by using a validated chiral CE method and found to be in very good agreement. This method can be successfully applied to the enantiomeric purity analysis of Frovatriptan in pharmaceutical bulk drug samples and formulations.

Amylose↗

PubMed2006

A validated chiral CE method for Frovatriptan, using cyclodextrin as chiral selector.

A cyclodextrin modified capillary zone electrophoretic method has been developed for the evaluation of chiral purity of Frovatriptan using sulfobutyl ether beta cyclodextrin (SB-beta-CD) as the chiral selector. The method is highly specific, accurate and reproducible. The method was optimized with a systematic method development approach by optimizing the pH of electrolyte, attempting the separation in different classes of chiral selectors and modifying parameters such as cyclodextrin concentration and the organic modifier type and concentration. The optimized method was validated for specificity, precision, linearity, accuracy and stability in solution using Imidazole as the internal standard. The limit of detection (LOD) and limit of quantification (LOQ) were 1.0 microg/mL and 5.0 microg/mL respectively for each isomer. The method was applied for estimating the chiral purity of various batches of Frovatriptan.

Carbazoles↗

PubMed2004

Isolation, synthesis and characterization of impurities in celecoxib, a COX-2 inhibitor.

During the impurity profile of Celecoxib, four polar impurities (impurity I, II, III and IV) and one non-polar impurity (impurity V) with respect to Celecoxib were detected by HPLC. LC-MS has been employed in this impurity profile study. The three polar impurities (I, II and III) were found to be process related while impurities (IV and V) turned out to be isomers. The impurities III, IV and V were isolated with the help of preparative HPLC. The structure of impurities III, IV (ortho-isomer) and V (regio-isomer) were confirmed as [5-(4-methylphenyl)-3-trifluoromethyl-1H-pyrazole], 4-[5-(2'-methyl phenyl)-3-(trifluoromethyl)-1H-pyrazol-1-yl] benzenesulfonamide, and 4-[4-(4'-methylphenyl)-3-(trifluoromethyl)-1H-pyrazol-1-yl]-benzenesulfonamide, respectively. The structures of impurities I, II, III and IV were confirmed by synthesis and structural characterization using spectral data. However, the impurity V was not synthesized.

Celecoxib↗

PubMed2003

A validated LC method for imatinib mesylate.

An isocratic reversed-phase liquid chromatography method with UV detection has been developed for the purity evaluation of imatinib mesylate in bulk drug. The method is selective and is capable of detecting all process intermediates and other related compounds, which may be present at trace levels in the drug substance. The method was validated on a Symmetry Shield RP18 analytical column (150 x 4.6 mm, 5 microm), mobile phase consisting of 30 mM sodium octane sulphonic acid in 10 mM aqueous KH2PO4 (pH 2.5 with H3PO4): MeOH in the ratio of 42:58 v/v. The flow rate was set at 1.0 ml/min and the column was maintained at room temperature. The injection volume was set to 10 microl and the detector was set at a wavelength of 237 nm. The method was validated in terms of system precision, method precision, linearity, accuracy, limit of detection and limit of quantification.

Benzamides↗

PubMed2002

Determination of pioglitazone hydrochloride in bulk and pharmaceutical formulations by HPLC and MEKC methods.

High Performance Liquid Chromatographic (HPLC) and Micellar Electrokinetic Chromatographic (MEKC) methods have been developed for the determination of pioglitazone, a new englycemic antidiabetic agent. Pioglitazone and its unsaturated impurity were separated by MEKC in less than 7 min using a 43 cm x 50 microm i.d. uncoated fused-silica capillary with extended light path for better sensitivity (25 kV at 30 degrees C) and a background electrolyte (BGE) consisting of 20% acetonitrile (v/v) in 20 mM sodium borate buffer pH 9.3 containing 50 mM sodium dodecyl sulphate (SDS). The influence of various parameters on the separation such as pH of the buffer, SDS concentration, buffer concentration, organic modifiers, temperature and voltage were investigated. The MEKC method was compared with HPLC method using a 5 microm symmetry C18 column (250 x 4.6 mm i.d.) eluted with a mobile phase consisting of a mixture of 50% (v/v) acetonitrile and 10 mM potassium dihydrogen phosphate buffer, adjusting the pH to 6.0 with 0.1 M KOH. The HPLC method is capable of detecting all process related compounds, which may be present at trace levels in finished products. Both methods were fully validated and a comparison was made. The results confirm that the methods are highly suitable for its intended purpose.

Chromatography, High Pressure Liquid↗

PubMed2002

Determination of celecoxib, a COX-2 inhibitor, in pharmaceutical dosage forms by MEKC.

A micellar electrokinetic chromatographic (MEKC) method was developed for the quantification of celecoxib, a COX-2 inhibitor in pharmaceutical dosage forms within the total analysis time of 7 min. The method has been validated and proven to be rugged. The quantification was carried out at 35 degrees C and 25 kV, using a 25 mM borate buffer (pH 9.3), 25 mM sodium dodecyl sulphate with an extended light path capillary (48.5 cm x 50 micro I.D., 40 cm to detector). Calibration curves were constructed for celecoxib (0.2-0.6 mg/ml) by the internal standard method with 2-nitro aniline as an internal standard (coefficient of correlation greater than 0.999). The intermediate precision (between day precision) of migration times and peak area ratios of celecoxib to internal standard were 1.44 and 1.58% R.S.D., demonstrates good reproducibility of the method. The method was applied to a commercial celecoxib formulation (Revibra, 100 mg) and the percentage recoveries were ranged from 93.0 to 98.4%.

Aniline Compounds↗

PubMed2001

LC separation of ortho and meta isomers of celecoxib in bulk and formulations using a chiral column.

A normal phase, isocratic LC method was developed for the separation of positional isomers of celecoxib (I) using a chiral column, Chiralpak-AD. The method is useful for the quantification of ortho (II) and meta (III) forms in bulk drugs and formulation samples of celecoxib. The method has been completely validated and proven to be rugged. The limit of detection (LOD) and limit of quantitation (LOQ) of ortho and meta forms were found to be 38 ng and 116 ng respectively. The active pharmaceutical ingredient was extracted from its finished dosage form (capsule) using ethanol. The percentage recoveries of ortho isomer was found to be 99.8--102.7 and 97.8--103.2 and the percentage recoveries of meta isomer was found to be 99.3--102.6 and 99.7--104 in spiked bulk and formulation samples of celecoxib respectively.

Anti-Inflammatory Agents, Non-Steroidal↗

PubMed2001

LC determination and purity evaluation of nefazodone HCl in bulk drug and pharmaceutical formulations.

A simple, selective and reproducible reversed-phase liquid chromatography (LC) method has been developed for the quantitative determination of nefazodone hydrochloride (I) in the presence of its related impurities, namely 5-ethyl-4-(2-phenoxyethyl)-2H-1,2,4-triazol-3-(4H)one (II), 1-(3-chlorophenyl)-4-(3-chloropropyl) piperazine hydrochloride (III) and 1,1(1)-trimethylene-bis[4-(3-chlorophenyl) piperazine] hydrochloride (IV). The separation was achieved using an Inertsil ODS-3V (250 x 4.6 mm(2)) column and a mobile phase comprising 0.05 M KH(2)PO(4) (pH 3.0), acetonitrile and methanol in the ratio 50:40:10 (v/v/v). The method has been completely validated and proven to be rugged. The limit of detection and limit of quantification for impurities II, III and IV were found to be 50, 79 and 91 ng/ml, and 152, 240 and 280 ng/ml, respectively. The intra- and inter-day assay precision of the method was within 1.2% relative standard deviations. The developed method was applied to the pharmaceutical dosage form (Tablet, Serzone-R) and the percentage recoveries ranged from 99.1 to 100.7. The percentage recovery of impurities ranged from 96.2 to 108.9. The stability studies were performed for nefazodone solution placed on laboratory bench and in the refrigerator for 60 days. The method was proved to be stability indicating in solution.

Antidepressive Agents, Second-Generation↗

PubMed2001

LC determination of rofecoxib in bulk and pharmaceutical formulations.

An isocratic reversed phase-liquid chromatographic (RP-LC) method has been developed for the determination and purity evaluation of rofecoxib in bulk and pharmaceutical dosage forms using photodiode array detection set at 225 nm. The method is simple, rapid and selective. The method is capable of detecting all process intermediates and other related compounds, which may be present at trace levels in finished products. Hence the method is very useful for process monitoring during the production of rofecoxib. Chlorophenyl methyl sulphone has been used as internal standard for the quantitative determination of rofecoxib. The method is linear in the range of 125-500 microg. The precision for inter- and intra-day assay variation of rofecoxib is below 1.6% relative standard deviation (R.S.D.). The accuracy determined as relative mean error (R.M.E.) for the intra-day assay is within +/-2.0%. The drug was extracted from tablets (Vioxx) using acetonitrile. The percentage recoveries from dosage forms were ranged from 98.2 to 102.6.

Chemistry, Pharmaceutical↗