Stability of diltiazem in whole blood: forensic implications.

The stability of diltiazem (DTZ) in whole blood and in postmortem samples was investigated. In the first study, an aliquot of outdated Red Cross blood with sodium fluoride added as a preservative was spiked with DTZ and stored for one year under three separate conditions: room temperature, 4 degrees C, and -20 degrees C. DTZ and one of its major metabolites, desacetyldiltiazem (DAD), were quantitated at given intervals during this period. In the second study, case postmortem blood samples (n = 36) that exhibited different degrees of putrefaction were spiked in a similar fashion and the stability of DTZ was determined after storage at 4 degrees C for 92 days. DTZ and DAD were extracted as bases, using mild pH conditions to prevent the hydrolysis of DTZ, and quantitated by an HPLC system equipped with a diode array detector and a Supelcosil LCDP column, 5 microns, 250 mm x 4.6 mm inside diameter. Approximately 50% of DTZ was lost in the Red Cross blood stored at room temperature and 4 degrees C, after 19 and 124 days, respectively. This was associated with concomitant appearance and comparable increase in DAD concentration, presumably due to the in vitro hydrolysis of DTZ to DAD. No significant loss of DTZ was observed in the -20 degrees C samples. Similar changes in DTZ and DAD concentrations were seen in postmortem blood samples stored at 4 degrees C for 92 days, though notably, the extent of loss of DTZ varied from complete to negligible. The data suggest that the potential for in vitro conversion of DTZ to DAD should be considered for proper interpretation of postmortem DTZ/DAD findings. Several cases examined in this laboratory will be used to discuss other forensic implications.

Use of high-performance liquid chromatography-diode array detection in forensic toxicology.

A comprehensive approach to the analysis for many drugs in postmortem blood and biological fluids using high-performance liquid chromatography and diode array detection has been developed. To reduce the likelihood of co-eluting interference components of postmortem blood or other drugs, selective back-extraction was also used to screen and quantitate drugs in blood and biofluids. An isocratic mobile phase (acetonitrile, phosphoric acid and triethylamine buffer, pH 3.4) was developed and found stable, reliable and convenient for general drug screening and quantitation. A library of drug spectra in the ultraviolet wavelength range (210-367 nm) was established for 272 drugs on two reversed-phase columns: Supelcosil (biphenyl) and LiChrospher RP-8. The application of several methods to whole blood, the analysis of complex cases and the use of multicomponent analysis for qualitative and quantitative analysis is discussed.

Eficacia y seguridad del fluconazol a dosis de 150 mg. semanal comparado con clotrimazol en el tratamiento de pacientes con tinea corporis, crusis o pedis / Efficacy and securety the fluconazole a 150 mg weekly doses, comparative with clotrimazole in the treatment of patients with tinea crusis and pedis

Se estudiaron 60 pacientes con Tinea corporis, crusis y pedis, en un estudio abierto multicéntrico comparativo, para evaluar la eficacia y seguridad del fluconazol a dosis única semanal comparándolo con clotrimazol. El hongo más frecuentemente aislado fue el T.rubrum. La respuesta clínica y micológica fue satisfactoria en ambos grupos al final del tratamiento (93 por ciento para ambos) y en el control a largo plazo (28-35 días después de la última dosis, con curación y erradicación micológica en el 71 por ciento y 74 por ciento (fluconazol) vs. 64 por ciento y 61,5 por ciento (clotrimazol), respectivamente. No se observaron efectos adversos con ninguna de las drogas. Se concluye que el fluconazol a dosis únicas semanales de 150 mg, es una buena alternativa en el tratamiento de las dermatofitosis

Gas chromatography/mass spectrometry for the determination of cocaine and benzoylecgonine over a wide concentration range (< 0.005-5 mg/dL) in postmortem blood.

The determination of cocaine and benzoylecgonine in blood by gas chromatography/mass spectrometry using selected ion monitoring was investigated. The method involved an extraction using rotation of an Amberlite XAD-2-blood mixture and the use of deuterated internal standards with derivatization of benzoylecgonine using diazopropane. Standard curves with logarithmic-transformed data were constructed over the concentration range from 0.005 to 5 mg/dL. The use of a wide concentration range precludes using smaller sample sizes in repeated extractions to conform to a narrower concentration range of standards. The recovery of the extraction method was 85% for both cocaine and benzoylecgonine. The method was applied primarily to postmortem blood samples from 180 forensic cases and was statistically evaluated. The limit of detection for cocaine or benzoylecgonine extractions from 1 mL forensic blood samples is 0.00025 mg/dL. The method is routinely reliable and applicable to forensic toxicology investigations.

Evaluation of a photodiode array/HPLC-based system for the detection and quantitation of basic drugs in postmortem blood.

A systematic analytical approach has been developed for liquid chromatography determination of a number of basic drugs in postmortem blood. Using selective extraction, that is, back extraction into 0.2N sulfuric acid and 6N hydrochloric acid after the initial extraction with toluene under basic conditions (from 2 mL of blood), basic and weakly basic drugs, such as propranolol and diazepam, can be simultaneously quantitated and identified with a high degree of confidence. A microcomputer-based photodiode array detector was used to evaluate peak purity and facilitate peak identification. An automatic library search was performed at the end of each analysis using the system software. The method was validated for within-day and between-day precision for ten basic drugs at two concentrations. The coefficient of variation for the between-day precision was less than 8.7%. Accuracy of the assay was tested at four concentrations using linear regression analysis. The coefficients of determination (r2) for all ten drugs were greater than 0.99, and their slopes were close to unity. The chromatographic conditions developed are suitable for the screening of several basic, acidic, amphoteric, and neutral drugs. Retention data and ultraviolet spectral data for 119 drugs on two reversed-phase columns, using acidic mobile phases, are also presented.

The use of gas chromatography/negative ion chemical ionization mass spectrometry for the determination of lorazepam in whole blood.

The determination of lorazepam in blood by gas chromatography/mass spectrometry with selected ion monitoring (GC/MS/SIM) in the negative chemical ionization mode (NICI) was investigated. The method involves a single extraction with Amberlite XAD-2 resin and the use of [2H6]triazolam as an internal standard. The limit of detection is 0.5 ng/mL and standard curves are linear from 6.25 to 250 ng/mL. The applicability of the method to forensic toxicology is reported.

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.

Effect of metal ions on the aspartate transaminase (E.C.2.6.1.1.) activity in tobacco tissue culture.

Aspartate transaminase enzyme was prepared from tobacco tissue cultures. Effect of 13 different metal ions on the enzyme activity was preliminarily studied. The enzyme activity was inhibited by five ions, namely Cd2+, Hg2+, Zn2+, Cu2+, and Ag+. None of the ions investigated enhanced the activity. Fe2+ caused an apparent activity increase in the reaction mixture. Pyridoxal-phosphate enhanced this effect of the Fe2+.

Radioimmunological screening and gas chromatographic determination of morphine and related narcotic analgesics in post mortem blood.

A sensitive, reproducible, and relatively specific procedure is presented for the screening, identification, and quantitation of morphine, hydromorphone, codeine, oxycodone, and hydrocodone in autopsy blood. The drugs are isolated from whole blood by adsorption on an XAD-2 resin slurry and subsequent elution with an organic solvent mixture. Part of the resin extract is screened for morphine and related cross-reacting compounds by a commercially available radioimmunoassay (RIA) and the remainder of the same extract is analyzed by gas chromatography using a nitrogen/phosphorus detector (GC/NP). The procedure has been used frequently in forensic toxicological casework. Since toxic blood concentrations of hydrocodone have not been well documented, the results of toxicological examination of two fatalities involving this drug are presented.

The screening of blood by gas chromatography for basic and neutra drugs.

A GC procedure is described for the screening of biological fluids for the presence of basic and neutral drugs. Extracts are chromatographed simultaneously on a two-column system designed so that a wide range of drugs can be detected. A majority of the drugs is readily detectable in blood in concentrations of 0.1 mg per 100 ml. The procedure is illustrated with examples of casework as well as examples of "spiked" blood samples.