Search

Therapeutic serum concentrations of codeine can be virtually completely extracted and obtained sufficiently concentrated for g.c. measurement without distillation, by acid extraction of the drug from the initial crude organic extracts of alkalinized serum followed by a micro-phase back extraction step. The procedure has simplicity, rapidity and eliminates concentration by distillation and background interference. The method can be readily adapted for the seperate measurements of codeine and norcodeine and it can also be used for similar analysis of other body fluids.

The separation of basic, acidic and neutral drugs from propanol-2 extracts of serum, urine and tissue homogenates at different pH values using a micro-phase extraction technique is described. Following preliminary screening, the various drug-containing fractions obtained are further examined by two-dimensional thin-layer chromatography. The drugs present are identified with reference to documented standards with the aid of a drug colour profile system and RF values relative to three different reference standards. By means of gas chromatographic analysis of the same extracts, semi-quantitative estimates of the amounts of drugs present, which are sufficiently accurate for clinical emergency purposes, can be made in many instances. The main advantages of the system are "clean" extracts with a minimum of background interference, rapidity (4-6 h for a complete analysis) and systematically documented and visually presented behaviour of drugs after spraying with various chromogenic and fluorogenic reagents, allowing the systematic identification of unknown substances.

It has been demonstrated that potentially corcinogenic nitroso compounds are readily formed when certain widely used drugs with secondary alkylaminostructures (e.g. nortriptyline and fenfluramine) or drug metabolities with such structures (e.g. norpropoxyphene) are reacted with nitrite in dilute acid aqueous medium or in human gastric juice under simulated gastric conditions. The reactions occur so readily in vitro that new quantitative procedures for the determination of these drugs have been developed and based on these principles. The potential hazards associated with the long term clinical use of such drugs are discussed.

The fact that the polyanionic long chains of mucopolysaccharides (MPS) can be precipitated with detergents such as cetylpiridiniumchloride (CPC) has been used in the development of a method for the quantitative estimation of total MPS in urine. Urine samples are all brought to an osmolarity of 300, after which an equal volume of 0,1% CPC is added to each sample. The turbidity is determined spectrophotometrically after 5 minutes. Chondroitin sulphate A was used as an internal standard. Normal values obtained for different age groups in the population of Pretoria are discussed.