Basic Drug Screening Research Articles

The advantage of dual‐column approach and retention indices combined with refined reporting in gas chromatographic drug screening

AbstractA dual‐column gas chromatographic retention index method was evaluated for the toxicological screening for basic drugs in autopsy blood samples. The dual‐column approach with DB‐5 and DB‐1701 capillary columns doubles the Identification Power of the corresponding single column methods. The long‐term intralaboratory variation of the dialkylfluoroaniline series based retention indices of drugs in blood ranged from 0.03% to 0.2% which was generally better than that obtained using the relative retention time. Novel software is described for the processing and reporting of the dual‐column chromatographic data in analytically useful form. Besides retention data, the response factors served as an additional identification factor.

Screening of basic drugs in biological samples using dual column capillary chromatography and nitrogen-phosphorus detectors.

A method is presented for the extraction and screening of basic and neutral drugs, including amphetamines. Two milliliters of blood are buffered to pH 9.0 and extracted with n-chlorobutane. Underivatized extracts are analyzed simultaneously on two complementary capillary columns placed together in one injection port using split injection. A relative retention time list comprised of 110 common drugs of abuse and metabolites has been compiled for both capillary columns. The internal standard used is SKF-525A. The success of the method depends upon four areas: inertness of the system, nitrogen detector optimization, extraction technique, and lack of contamination. The percent recovery has been calculated for twelve commonly encountered drugs. The within-run and day-to-day recoveries and retention time reproducibility have been investigated for the internal standard SKF-525A. The authors have found the combination of fused silica capillary columns and nitrogen-phosphorus detectors makes for a stable screening system for basic and neutral drugs in biological samples.

An Evaluation of Fused Silica Capillary Columns for the Screening of Basic Drugs in Postmortem Blood: Qualitative and Quantitative Analysis

Fused silica capillary columns (Durabond) have been evaluated for the screening of more than 100 basic drugs in postmortem blood samples. The combination of these columns, nitrogen-phosphorus detectors, and SKF-525A (internal standard) allows for the simultaneous screening and quantitation of several basic drugs such as amphetamines, amitriptyline, and codeine. Approximately 2000 blood samples have been analyzed by this procedure. The use of capillary columns results in excellent baseline stability and this, together with an autosampler and data system, enables unattended overnight operation. "Double peaking" associated with splitless injection can be a problem as can sensitivity for some of the polar drugs; however, with the extraction procedure described and the equipment used, the screening of blood for basic drugs is improved when compared with packed column technology.

System evaluation and substance identification in systematic toxicological analysis by the mean list length approach.

In systematic toxicological analyses (STA), analytical methods are needed with a high Identification Power. The mean list length (MLL) approach, which is an improved and extended version of the Identification Power concept, provides an objective tool for the evaluation and optimum choice of analytical methods for STA. The MLL approach is elucidated and applied to the screening for basic drugs by thin layer chromatography (TLC) and gas-liquid chromatography (GLC). Its usefulness for TLC and GLC systems for the identification of these basic drugs has been evaluated for both single systems and combinations of systems. The MLL approach is also substance directed and can be applied to computerized data searches and substance identification. The method is applicable for single analytical systems and combinations of systems. Mixtures of substances can also be handled.

The General Toxicology Unknown I. The Systematic Approach

The general toxicology unknown often presents challenges and interests to toxicologists. A systematic analytical approach to search for drugs or poisons is presented here. The preliminary screening analyses were as follows: alcohol by gas chromatography (GC), ethchlorvynol colorimetric analysis, enzyme multiplied immunoassay technique (EMIT), basic drug screening by GC, and neutral and weakly acidic drug screening by GC. Other additional analyses were performed depending on the special circumstance of each individual case and the results of these preliminary analyses. Positive findings were confirmed by computerized gas chromatography/mass spectrometry when practical. Quantitation was performed by GC whenever possible.

An Integrated Methodological Approach to the Computer-Assisted Gas Chromatographic Screening of Basic Drugs in Biological Fluids Using Nitrogen Selective Detection

This paper presents the methodological aspects of a computerized system for the gas-chromatographic screening and primary identification of central nervous system stimulants and narcotic analgesics (including some of their respective metabolites) extracted from urine. The operating conditions of a selective nitrogen detector for optimized analytical functions are discussed, particularly the effect of carrier and fuel gas on the detector's sensitivity to nitrogen-containing molecules and discriminating performance toward biological matrix interferences. Application of simple extraction techniques, combined with rapid derivatization procedures, computer data acquisition, and reduction of chromatographic data are presented. Results show that this system approach allows for the screening of several drugs and their metabolites in a short amount of time. The reliability and stability of the system have been tested by analyzing several thousand samples for doping control at major international sporting events and for monitoring drug intake in addicts participating in a rehabilitation program. Results indicate that these techniques can be used and adapted to many different analytical toxicology situations.