Evaluation of a twice-a-week application of 1% niclosamide lotion in preventing Schistosoma haematobium reinfection.

A randomized double-blind trial was conducted to assess the efficacy of a twice-a-week application of 1% niclosamide lotion for prevention of Schistosoma haematobium reinfection. Six hundred farmers in Fayoum, Egypt, 18-40 years of age, were treated to cure their S. haematobium infection, then randomly assigned to self-apply niclosamide or placebo lotion to their limbs, neck, and torso. Subjects were exposed to schistosomal-infested water during routine irrigation activities from April to October 1992. Three hundred fifty subjects met the inclusion criteria and completed the trial, 169 (48.3%) in the niclosamide group and 181 (51.7%) in the placebo group. The subjects assigned to the niclosamide-treated group were comparable with those in the placebo group in age (27.2 versus 27.8 years), total water contact (101.9 versus 109.0 hr), lotion application compliance (93.5% versus 90.6%), and avoidance of whole body water contact (94.7% versus 96.7%). The reinfection rate with S. haematobium was 30.8% in the niclosamide-treated group and 28.2% in the placebo group. Niclosamide lotion applied to the limbs and trunk twice a week failed to prevent S. haematobium reinfection.

Solid phase extraction of phencyclidine from urine followed by capillary gas chromatography/mass spectrometry.

This communication describes a method for the solid phase extraction of phencyclidine (PCP) from urine, followed by GC/MS analysis. The method is linear over the range 5-1000 ng/mL and consistently produces cleaner chromatograms than can be obtained by liquid-liquid extraction. The limits of detection and quantitation are 0.47 and 1.38 ng/mL, respectively. Extraction efficiency, or recovery, was found to be 100.8 +/- 6.5%, and the between-run precision was 3.5% (25 ng/mL, n = 51). This solid phase method for extraction of PCP from urine has several advantages over liquid-liquid extraction for laboratories of any size.

Solid Phase Extraction of Abused Drugs.

The current standard for acceptable practice in forensic urine drug testing, as reflected in both National Institute for Drug Abuse (NIDA) and military guidelines, requires an initial immunoassay followed by gas chromatography/mass spectrometry (GC/MS) confirmation. The GC/MS confirmatory procedures mandate extraction of the drug from the urine matrix, followed in most cases by chemical derivatization, prior to injection into the gas chromatograph. Classically, the extraction step has been accomplished using liquid-liquid techniques, but in recent years, the use of solid phase chromatographic techniques has become increasingly popular. Numerous companies now market solid phase columns that are designed specifically for extraction of drugs, some of them containing as many as three different components for extracting acidic, basic, and neutral drugs. A survey of NIDA laboratories, conducted specifically for this review article, revealed that 40 to 50% of the extraction procedures currently performed involved the use of solid phase cartridges. This article reviews chromatographic separation techniques in general, specific products that are currently available on the market, the performance of those products, and examines the results of the survey of NIDA-certified laboratories.

Rapid drug screening using Toxi-Lab extraction followed by capillary gas chromatography/mass spectroscopy.

We report here a method of analyzing drugs in body fluids by gas chromatography/mass spectroscopy (GC/MS) without the necessity for derivatization. Specimens (urine and serum) were extracted one time using Toxi-Lab extraction tubes. The organic extract was evaporated to dryness, taken up in methanol, and injected directly onto a Hewlett-Packard 5995B GC/MS equipped with a 20-m, 5% phenylmethylsilicone capillary column. Most drugs of clinical interest eluted in 1-10 min and were identified by their mass spectra. Amphetamines were readily distinguished from other sympathomimetic amines; cocaine and its principal metabolite ecgonine methyl ester were readily detected without derivatization. We conclude that the combination of Toxi-Lab extraction and capillary GC/MS analysis provided a rapid, versatile, and efficient method for screening and/or confirming the presence of drugs in biological specimens.