Quantitative gas chromatographic analysis of 3-cyano-3,3-diphenylpropionic acid, the acidic metabolite of bezitramide (Burgodin), in urine

Derivatization procedures for gas chromatographic-mass spectrometric determination of xenobiotics in biological samples, with special attention to drugs of abuse and doping agents

The development of low cost MS detectors in recent years has promoted an important increase in the applicability of GC-MS system to analyze for the presence of foreign substances in the human body. Drugs and toxic agents are in vivo metabolized in such a way that more polar compounds are usually formed. Derivatization of these metabolites is often an unavoidable requirement for gas chromatographic analysis. Application of derivatization methods in recent years has been relevant, especially for silylation, acylation, alkylation and the formation of cyclic or diastereomeric derivatives. Given the relevance of drug of abuse testing in modern toxicology, main derivatization procedures for opiates, cocaine, cannabis, amphetamines, benzodiazepines and LSD have been reviewed. Papers describing the analyses of drugs of abuse in matrixes other than blood, such as hair or sweat, have received special attention. Advances in derivatization for sports drug testing have been particularly relevant for anabolic steroids, diuretics and corticosteroids. Among the several methodologies applied, the formation of trimethylsilyl, perfluoroacyl or methylated derivatives have proved to be both versatile and extensively used. Further advances in derivatization for GC-MS applications in clinical and forensic toxicology will depend on the one hand on the degree of further use of GC-MS for routine applications and, on the other hand, on the alternative progress made for developments in LC-MS or CE-MS. Last but not least, the appearance of comprehensive libraries in which reference spectra for different derivatives of many drugs and their metabolites are collected will have an important impact on the expansion of derivatization in GC-MS for toxicological applications.

Quantitative analysis of despropionyl-bezitramide, the active metabolite of bezitramide (Burgodin), in biological samples by high-performance liquid chromatography with fluorescence detection

A sensitive high-performance liquid chromatographic procedure with fluorescence detection was developed for the quantitative determination of despropionyl-bezitramide, the active metabolite of bezitramide (Burgodin), in biological samples. Chromatographic separation was achieved on a Hypersil ODS (C18) 5-micron column, using a 31:69 (v/v) mixture of 0.1 M ammonium acetate and methanol/acetonitrile (50:50, v/v)-0.1 M ammonium acetate as the eluent. Internal standardization with N-methyldespropionyl-bezitramide was used in order to enhance the precision and the accuracy of the method. For the isolation of the compound from biological samples, a liquid-liquid extraction with n-hexane-isoamyl alcohol (93:7 v/v) was performed. Calibration graphs were prepared for blood and urine, and linearity was achieved over a concentration range 1-50 ng/mL. The quantitation limit for despropionyl-bezitramide in blood and urine was 1 ng/mL. At a 10 ng/mL concentration in blood, coefficients of variation of 3.3 and 6.5% were obtained for within-day and between-day precisions, respectively. For urine, the respective coefficient of variation values of 4.3 and 4.9% were obtained. The selectivity and the accuracy of the method were satisfactory. Samples (blood, urine, stomach contents, bile, liver, kidney) from five fatalities that were due to the combined intake of several drugs, including bezitramide, were analyzed and the results are reported. In addition, one blood sample and 14 urine samples from persons suspected of using bezitramide were analyzed, revealing despropionyl-bezitramide concentrations in urine ranging from 1.3 to 72.3 ng/mL.