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Biomedical subjects

G Andermann

Publications and source records attributed to G Andermann.

At least 37 records · Page 2Linked to original sources
PubMed1983

[Determination of free and conjugated cis-3,3,5-trimethylcyclohexanol in plasma and urine].

A gas chromatographic procedure was developed to determine free and conjugated cis-3,3,5-trimethylcylcohexanol in plasma and urine. The sample is extracted with dichloromethane when free cis-3,3,5-trimethylcyclohexanol is determined, or with hexane after enzymatic hydrolysis, when conjugated cis-3,3,5-trimethylcyclohexanol is determined. An aliquot of the organic extract is injected into a stainless-steel column (packed with Carbowax 20M, 15% on Chromosorb W AW 100-120 mesh) and detected with a flame ionization detector. Extraction recovery from plasma and urine was almost 100% and the limit of quantification was fixed at 100 ng/ml plasma or urine. The procedure was evaluated in a pharmacokinetic study of cyclandelate and its metabolite cis-3,3,5-trimethylcyclohexanol.

Animals↗
PubMed1983

Are local tolerance tests in animals always necessary?

The Draize test was introduced in 1944 as a toxicological standardization method to study irritation and toxicity of substances applied to the eye (and the skin). It has been considered, from that time on, as a routine toxicological protocol by most regulatory agencies to test eye-tolerance of chemicals. The authors think that for ethical and scientific reasons, this test is obsolete and should be changed or eliminated. They suggest the use of cell cultures or an in vitro technique for ocular safety assessment. The described technique uses a bovine cornea clamped in vitro between two chambers and kept alive in physiological conditions during six hours. This in vitro corneal perfusion system replaces in vivo irritation tests and enables quantitation of corneal drug uptake at the same time. This system provides reproducible results and can be used in ocular toxicological studies as well as in pharmacokinetic modeling.

Animals↗
PubMed1982

The bioavailability and pharmacokinetics of three zinc salts: zinc pantothenate, zinc sulfate and zinc orotate.

In this study the authors compared the pharmacokinetics of three zinc salts after parenteral and oral administration to rabbits: zinc sulfate, a soluble mineral salt; zinc pantothenate, a soluble organic salt; and zinc orotate, an insoluble organic salt. The results obtained with the two soluble salts were not significantly different (p less than 0.05). Therefore they appear to be bioequivalent. The plasma concentration curve for zinc orotate shows a faster distribution (alpha) and elimination phase (beta) after parenteral administration, and a slower absorption phase (Ka) after oral administration, when compared with that of the other two salts. It was shown that the dissolution behaviour of these zinc salts in water does not correlate with the parameters found in vivo.

Administration, Oral↗
PubMed1982

[Comparative study of the antiglaucomatous activity of Glauplex 2 and pilocarpine nitrate on alpha-chymotrypsin-induced experimental glaucoma].

The antiglaucomatous effects of Glauplex 2 and pilocarpine nitrate on alpha-chymotrypsine-induced experimental glaucoma were studied in 8 rabbits. Changes in intraocular pressure were measured over a period of 12 hours after a single instillation of Glauplex 2 or two instillations of 2.6 p. cent pilocarpine nitrate at t = 0 and t = 6 hours. The antihypertensive effect of a single instillation of Glauplex 2 was shown to be approximately equivalent to that of two instillations of 2.6 p. cent pilocarpine nitrate.

Animals↗
PubMed1981

Simultaneous determination of cyclandelate and its metabolite in human plasma by capillary column gas-liquid chromatography.

A method was developed for the simultaneous determination of cyclandelate and mandelic acid concentrations in plasma, involving extraction from plasma followed by trimethylsilylation and chromatography of the derivatives on a glass capillary column with hydrogen flame-ionization detection. Calibration graphs were linear down to at least 20 microgram/ml for each substance. The precision was excellent with a pooled relative standard deviation of 6.3% and 6.4% for cyclandelate and mandelic acid serum samples, respectively. Concentrations below 500 ng/ml of each substance could be detected in human plasma. The method was developed for use in bioavailability and metabolism studies.

Animals↗
PubMed1980

Rapid colorimetric analysis of chlorhexidine in pharmaceutical preparations.

A colorimetric determination of chlorhexidine is described. The method is based on the formation of a yellow complex between the drug and bromcresol green. The absorption peak of this complex, extracted by chloroform, is at 410 nm, and linear response is obtained from 2.5 to 30 micrograms of chlorhexidine/ml. The accuracy and reproducibility of this rapid method make it useful for chlorhexidine determination in the manufacturing control of pharmaceutical mixtures.

Chlorhexidine↗
PubMed1980

[Study on phototoxicity and photoallergy of a preparation containing 10 p. 100 benzoyl peroxide after topical application on guinea-pigs (author's transl)].

Attention is focused on benzoyl peroxide as a possible phototoxic derivate. To ascertain this activity, the compound, in a pharmaceutical composition, was tested by skin painting on guinea-pigs. The preparation, containing 10 p. 100 benzoyl peroxide, was applied topically. Irradiation was carried out by an artificial source of UVA and UVB.

Animals↗
PubMed1979

Simultaneous spectrophotometric determination of oxidized and reduced glutathione in human and rabbit red cells.

An improved spectrophotometric procedure for oxidized and reduced glutathione determination in erythrocytes is described. The method is based upon a reaction using Ellman's reagent. It gave recoveries of 99 and 90% for both GSH and GSSG. The use of oxidized glutathione as an internal standard makes it accurate for simultaneous assay. The method offers the advantage of not having to use alkylation products to prevent oxidation of GSH during protein precipitation. Data are presented to demonstrate reliability and simplicity of rapid estimation of GSH and GSSG.

Animals↗
PubMedDate not supplied

The influence of the route of administration on the bioavailability of an endogenous macromolecule: chondroitin sulphate (CSA).

The absorption of chondroitin sulphate (CSA) has been investigated in rabbits after the oral administration of a single dose of 100 mg of CSA per kg of body weight. The oral dose was administered as a lipid suspension or in enteric capsules. No absorption of CSA could be demonstrated. Oral administration did not cause the release of a clearing factor into the bloodstream, a phenomenon that is known to occur in the presence of CSA. The concentration of this factor did not decrease after oral administration of CSA.

Administration, Oral↗