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Biomedical subjects

G W Peng

Publications and source records attributed to G W Peng.

35 records · Page 2Linked to original sources
PubMed1978

Rapid and micro high-pressure liquid chromatographic determination of chloramphenicol in plasma.

A high-pressure liquid chromatographic method was developed for chloramphenicol in plasma. Plasma samples were deproteinized with 2.5 volumes of acetonitrile, and the supernates were chromatographed on a reversed-phase column, using acidified ethanol-water as the mobile phase and UV spectrophotometry for detection. The sensitivity for accurate quantitation of chloramphenicol was about 2.5 microgram/ml in plasma, and concentrations as low as 0.5 microgram/ml could be detected. Only about 8 min is needed for each sample. This method is specific, rapid, and sufficiently sensitive and may be useful for clinical monitoring.

Animals↗
PubMed1978

Rapid and micro high-pressure liquid chromatographic determination of plasma phenytoin levels.

A rapid and simple high-pressure liquid chromatographic microanalytical method was developed for the determination of clinically encountered plasma phenytoin levels. This method is accurate down to about 1 microgram of phenytoin/ml of plasma and requires as little as 10 microliter of sample. Total analysis time is about 10 min. The method involves deproteinizing with acetonitrile followed by monitoring the deproteinized sample at 254 nm. Phenytoin's primary metabolite in humans, 5-(p-hydroxyphenyl)-5-phenylhydantoin, also can be quantitated when present in moderately high clinically encountered concentrations. Plasma profiles of phenytoin and its metabolite were followed with time after an intravenous bolus injection to a rabbit.

Animals↗
PubMed1978

High-performance liquid-chromatographic determination theophylline in plasma.

A high-performance liquid-chromatographic method is reported for monitoring theophylline in plasma. Samples are deproteinized with 2.5 volumes of acetonitrile and the supernates chromatographed on a reversed-phase column. Absorption at 275 nm is monitored. One can accurately measure 1.5 mg of theophylline per liter, in as little as 10 microliter of plasma, and only about 7 min is required per sample. No interference was found in plasma samples from asthmatic patients. This method is particularly useful for routine therapeutic monitoring of both pediatric and adult patients.

Chromatography, High Pressure Liquid↗
PubMed1977

Potential antitumor agents: procarbazine analogs and other methylhydrazine derivatives.

With the objective of developing new antitumor agents, two groups of hydrazine compounds, having structural features in common with the antitumor agents procarbazine and 1-acetyl-2-picolinoylhydrazine, were synthesized. The L-1210 leukemia system was used to evaluate compounds of both groups. The aliphatic procarbazines also were screened for antitumor activity as bis(benzyloxycarbonyl) derivatives and as derivatives having a phthalazine nucleus. No L-1210 antitumor activity was exhibited by these compounds.

Animals↗
PubMed1977

High-pressure liquid chromatographic assay of netilmicin in plasma.

A high-pressure liquid chromatographic method for the quantitative determination of netilmicin in plasma was developed. The procedures involve acetonitrile protein precipitation, methylene chloride extraction, and dansylation to form the fluorescent dansyl derivative of netilmicin, which is extracted into ethyl acetate and chromatographed on a reverse-phase column with aqueous acetonitrile as the mobile phase. A good linear relationship between peak height measurements and netilmicin concentrations was found. This method is sensitive and reproducible; a netilmicin concentration as low as 0.5 mug/ml can be measured with only 0.1 ml of plasma sample. The results of assays of plasma or serum samples by this high-pressure liquid chromatographic method correlate well with those obtained by microbiological assays.

Chromatography, High Pressure Liquid↗
PubMed1977

High-pressure liquid-chromatographic method for determination of gentamicin in plasma.

A rapid, specific method for measuring gentamicin in plasma by high-pressure liquid chromatography was developed. After deproteinization, gentamicin in the supernate was dansylated and extracted into ethyl acetate. The organic extract was chromatographed on a microparticulate reversed-phase column, which was eluted with aqueous acetonitrile. Use of the dansyl derivative enables fluorometry, for more sensitive quantitation. Various factors that could affect the assay sensitivity were investigated. With 0.2-ml plasma samples, the method can accurately measure as little as 1 mg of gentamicin per liter. We encountered no interferences from plasma supplemented with various drugs or plasma of patients who were on therapy with other drugs. This method can also separate gentamicin C1 from C1a and C2, all of which are present in various ratios in commercial dosage forms. This method is also applicable to gentamicin determination in urine.

Animals↗
PubMed1977

High pressure liquid chromatographic determination of sulfisoxazole in plasma.

A high pressure liquid chromatographic method for the separation and quantitative determination of sulfisoxazole in plasma was developed. Plasma samples were vortex-mixed with acetonitrile and centrifuged to obtain clear supernatant solutions. The supernate was chromatographed on a reverse phase column using acidified aqueous ethanol as mobile phase to effect separation. The separated components were detected by UV absorption at 280 nm and the peak height measurement was used for quantitative determination. This assay is simple and rapid. Each assay takes less than 8 minutes to complete and can be carried out on as little as 10 microliter plasma samples to accurately measure 2.0 microgram/ml of sulfisoxazole in plasma. This method can be used for an efficient monitoring of sulfisoxazole in plasma during the chemotherapy of bacterial infections, and also for the bioavailability study of the drug from dosage forms.

Animals↗
PubMed1976

Study on the binding of trichloromonofluoromethane by bovine serum albumin using a fluorescent probe technique.

Protein binding of the aerosol propellant, trichloromonofluoromethane, was studied in bovine serum albumin (BSA) solutions using the fluorescent probe technique. The propellant displaced the probe, 8-anilino-1-naphthalenesulfonate, from its binding sites and reduced the fluorescence intensity. The binding association constants, the number of binding sites, and the competitive nature of the binding interaction were investigated. The hydrophobic nature of the binding and the implication of binding displacement interactions between the fluorocarbon and plasma-protein-bound drugs were also discussed. The fatty acid impurities present in the commercial BSA were found to have no effect on the protein binding of the propellant.

Aerosol Propellants↗
PubMed1976

A rapid and sensitive method for determination of theophylline in plasma and saliva by high pressure liquid chromatography.

A fast and sensitive high pressure liquid chromatographic method for the monitoring of theophylline concentrations in plasma or saliva was developed. Each sample requires only about 15 minutes for the completion of the assay after receiving the plasma or saliva sample. Only 0.1 ml of sample is required, and concentrations as low as 1 mcg/ml can be accurately measured.

Caffeine↗
PubMed1975

Potential central nervous system antitumor agents. Hydantoin derivatives.

Hydantoin derivatives of varying lipophilic character were prepared as nitrogen mustard carriers for CNS antitumor evaluation. Activity was studied in the murine ependymoblastoma brain tumor system. Multiple cures were observed for three of the four analogs examined. The compounds were also active in the intraperitoneal leukemia L1210 and P388 systems as well as in B16 melanoma and Lewis lung carcinoma.

Animals↗
PubMedDate not supplied

Rapid estimation of volume of distribution after a short intravenous infusion and its application to dosing adjustments.

A simple and a rapid method to estimate the apparent volume of distribution of drug after single or during multiple short-term intravenous infusion is proposed. This is based on the back extrapolation to the midpoint of infusion. An equation simpler than one previously reported in the literature is also derived to calculate the maintenance dose for multiple short-term intravenous infusion. In addition, an equation to estimate the "priming dose" for infusion during multiple infusion regimen is also derived. The derivations of the equations are based on a linear one-compartment open model for drug disposition in patients. The prposed method is thought to be adequate for the purpose of rapid individualization of dosage regimens. The simplicity of the method, in particular, the solution by the graphic method for estimation of the apparent volume of distribution, might be specially useful for clinicians not well versed in mathematics in applying clinical pharmacokinetics to drug therapy.

Humans↗