Biomedical subjects

R S Chaudhary

Publications and source records attributed to R S Chaudhary.

5 recordsLinked to original sources

PubMed1999

Simultaneous determination of metronidazole benzoate, methylparaben, and propylparaben by high-performance liquid chromatography.

The simultaneous determination of metronidazole benzoate (MB), methylparaben (MP), and propylparaben (PP) in an oral suspension formulation was developed using high-performance liquid chromatography (HPLC). The method was developed using a Novapak C18 (3.9 x 150 mm, 4 microns) column, methanol-water (50:50, v/v) as the mobile phase and an ultraviolet (UV) detector at 254 nm. The peak area response versus concentration was linear in a concentration range from 40 to 400 micrograms/ml of MB, 0.8 to 8.0 micrograms/ml of MP, and 0.2 to 2.0 micrograms of PP. The correlation coefficients were 0.9997 for MB, 0.9987 for MP, and 0.9983 for PP, with relative standard errors of 1.12%, 1.28%, and 1.67%, respectively.

Anti-Infective Agents↗

PubMed1994

Dissolution test method for rifampicin-isoniazid fixed dose formulations.

A dissolution procedure for a rifampicin-isoniazid combination formulation was evaluated using 0.1 N hydrochloric acid solution and 0.4% (w/v) sodium lauryl sulphate solution as dissolution media. Rifampicin and isoniazid along with degradation components were chromatographed using reversed-phase liquid chromatography on a 10 microns octadecylsilica column using methanol-0.01 M disodium hydrogen phosphate (70:30, v/v; pH 4.6 +/- 0.1) as mobile phase. The detection was carried out at 254 nm. The data obtained indicate that the dissolution medium consisting of 0.4% (w/v) sodium lauryl sulphate solution is suitable for such a combination. The degradation observed in dissolution medium consisting of 0.1 N hydrochloric acid was 10-23%.

Capsules↗

PubMed1993

Determination of diltiazem hydrochloride in human serum by high-performance liquid chromatography.

A simple and sensitive reversed-phase high-performance liquid chromatographic method for the determination of diltiazem in human serum has been developed. The method involves a one-step deproteinization of serum for sample clean-up using acetonitrile. A LiChrosorb RP-8 column (30 cm x 4.1 mm I.D.) was eluted isocratically with acetonitrile-0.01 M dibasic sodium phosphate (40:60, v/v) containing 0.01% triethanolamine. Diltiazem was monitored at 237 nm and 0.1 a.u.f.s. The completion time for assay was less than 15 min, and the lower limit of quantitation was 10 ng/ml for a 100-microliters injection volume. Using this method, the pharmacokinetic parameters were calculated from a serum concentration versus time profile of diltiazem.

Acetonitriles↗

PubMed1993

Reversed-phase high-performance liquid chromatography of ketorolac and its application to bioequivalence studies in human serum.

A reversed-phase high-performance liquid chromatographic assay was used to study the bioequivalence of the anti-inflammatory drug (+/-)-ketorolac in human volunteers. Following deproteinization of human serum with 5% zinc sulphate solution, ketorolac was chromatographed on a 10-microns octadecylsilica column using acetonitrile-water as mobile phase and ultraviolet detection at 313 nm. Under these conditions the method was reproducible with a coefficient of variation of less than 5%. The assay procedure was linear in the range 0.25-1.5 micrograms/ml, with a sensitivity of 0.01 micrograms/ml ketorolac. The recovery of ketorolac from serum ranged from 90 to 95%.

Analgesics↗

PubMed1990

Viral aetiology of acute respiratory infections in children in north India.

Two hundred and thirty children clinically diagnosed as suffering from acute respiratory infection were tested for four major groups of viral aetiological agents, i.e. influenza para-influenza, respiratory syncytial virus (RSV) and adenoviruses using indirect immunofluorescence technique. At least one of the respiratory viruses was identified in 51 (22 per cent) specimens, which included influenza A in 6 (3 per cent), influenza B in 3 (1 per cent), para-influenza type 1 in 3 (1 per cent), para-influenza type 3 in 13 (6 per cent), RSV in 11 (5 per cent) adenovirus in 12 (5 per cent), and dual virus infections in 3 (1 per cent) cases. Maximum number of virus identification was noted in children below 1 year of age, particularly infection with RSV followed by para-influenza and adenoviruses. Value of rapid diagnosis by indirect immunofluorescence technique is stressed.

Child, Preschool↗