Validation of the SL3 beta-Lactam Test for screening milk in compliance with U.S. pasteurized milk ordinance: performance tested method 040701.

The SL3 beta-Lactam Test is a 3 min, receptor-based lateral flow Rapid One Step Assay (ROSA) that detects 5 of 6 beta-lactam drugs approved for dairy cattle in the United States. The method was evaluated through the AOAC Research Institute Performance-Tested Method program following a U.S. Food and Drug Administration protocol. Three combined lots detected penicillin G 4.2 parts per billion (ppb), ampicillin 8.7 ppb, amoxicillin 7.8 ppb, cephapirin 16.0 ppb, and ceftiofur (total metabolites) 51 ppb at least 90% of the time, with 95% confidence as determined by dose response probit analysis. These detection levels are less than safe level/tolerances but not more than 50% less. Lot repeatability was within 20%. Incurred residues were detected comparably or more sensitively to fortified samples due to the cumulative effect of biologically active metabolites. There were no interferences from somatic cells at 1 M/mL, bacterial cells 500 000 colony-forming units/mL, or 30 other non-beta-lactam drugs. These performances met approval conditions of the National Conference on Interstate Milk Shipments. Ruggedness conditions were incorporated into public health procedures for annual laboratory proficiency and certification.

Stability of benzylpenicillin during continuous home intravenous therapy.

OBJECTIVES: The aim of this study was to investigate the temperature profile of home intravenous (iv) antibiotic reservoirs and the stability of 16 megaunits of benzylpenicillin sodium in 120 mL of sodium chloride 0.9% at constant and variable temperatures. METHODS: A Tinytag computerized thermometer recorded temperatures every minute in the home iv antibiotic reservoir pouches of nine patients over a 24 h period. Similar bags containing benzylpenicillin sodium (16 megaunits) were maintained either at a constant 36 degrees C, 26 degrees C or 21-22 degrees C or were worn in a pouch by five healthy volunteers for a 24 h period. Other bags were stored at 3-5 degrees C for 10 days. The bags were sampled at timed intervals and benzylpenicillin concentrations assayed by HPLC. RESULTS: Median temperatures recorded in the infusion bags worn by the nine patients were in the range 16.7-34.1 degrees C. For infusion bags maintained at 36 degrees C, 26 degrees C and 21-22 degrees C, the concentrations of benzylpenicillin dropped below 90% of the initial concentration at a mean time of 5 h 18 min, 12 h 54 min and 13 h 20 min, respectively, whereas for bags worn by the healthy volunteers the mean time for 10% loss of benzylpenicillin was 9 h 20 min. In contrast, at 3-5 degrees C, concentrations of benzylpenicillin only dropped below 90% of the initial concentration at 8 days. CONCLUSIONS: Significant temperature-dependent degradation of benzylpenicillin occurs during continuous home iv antibiotic programme infusions, which could result in loss of efficacy.

Methods for the assessment of quality and stability of azidocillin.

UV and VIS spectrophotometric methods, after previous chromatographic separation (TLC/UV) and iodometric methods were adapted for the determination of azidocillin in presence of its breakdown products. These methods were applied for kinetic measurement of changes in the azidocillin concentration with time in water solutions and solid state. Using thin layer chromatography several decomposition products of azidocillin were detected.

Immunological properties of dialysis retentates from penicillin.

Retentates from benzylpenicillin preparations marketed in Canada were used in immunological studies in order to determine if they were immunogenic in experimental animals with respect to anaphylactic antibody production. The retentates obtained consisted mainly of penicillin polymers. Impurities of protein nature were either insignificant or absent. The penicillin polymers were found to be non-immunogenic in Albino Wistar rats, Wistar Furth rats and Hartley guinea pigs. Furthermore, they were unable to effect positive PCA tests in rats passively sensitized to the penicilloyl determinant.