Laboratory information management system chain of custody: reliability and security

A chain of custody (COC) is required in many laboratories that handle forensics, drugs of abuse, environmental, clinical, and DNA testing, as well as other laboratories that want to assure reliability of reported results. Maintaining a dependable COC can be laborious, but with the recent establishment of the criteria for electronic records and signatures by US regulatory agencies, laboratory information management systems (LIMSs) are now being developed to fully automate COCs. The extent of automation and of data reliability can vary, and FDA- and EPA-compliant electronic signatures and system security are rare.

Sex and age differences in the pharmacokinetics of alosetron

AIMS

To determine the effects of sex and age on the pharmacokinetics of alosetron.

METHODS

Single oral and intravenous 2 mg doses of alosetron were administered on separate occasions to 48 healthy, young and elderly, males and females. Serum was sampled for 12 h post-dose to measure alosetron concentrations.

RESULTS

Serum concentrations of alosetron were higher in females than in males, resulting from a sex difference in clearance by metabolism. Mean clearance values were 504 vs 677 ml min(-1) in young females vs males (mean ratio 0.75), and 461 vs 670 ml min(-1) in elderly females vs males (mean ratio 0.69). The sex difference in alosetron pharmacokinetics achieved statistical significance in the elderly, but not in the young. Irrespective of sex, alosetron clearance was increased by smoking. Serum concentrations tended to be higher in the elderly, although the effect of age was generally not significant. Volume of distribution was smaller in females (approximately 63 l) compared with males (approximately 84 l), regardless of age or the sex difference in body weight.

CONCLUSIONS

A significant difference in clearance by metabolism of alosetron between the sexes, and possibly between the young and elderly was observed.

Effect of sodium acid pyrophosphate on ranitidine bioavailability and gastrointestinal transit time

During development of a ranitidine effervescent oral solution dosage form, a marked decrease was observed in the extent of ranitidine absorption relative to the conventional oral tablet. Two studies were conducted in healthy volunteers to confirm the involvement of an excipient, SAPP (sodium acid pyrophosphate), and the mechanism of interaction, altered gastrointestinal transit. The first study (n = 12) involved single-dose crossover comparisons of (A) 150 mg ranitidine with 1132 mg SAPP versus (B) 150 mg ranitidine and (C) 150 mg ranitidine with all the effervescent tablet excipients except SAPP versus (D) a 150-mg ranitidine effervescent tablet, all administered as oral solutions. Serum ranitidine AUC, Cmax, and tmax were compared using two one-sided t test 90% confidence intervals (CI). Comparing treatments A to B and D to C, all 90% CI were below the 80-120% range, indicating significantly less extensive ranitidine absorption (54% based on AUC) from the oral solutions containing SAPP. The second study (n = 12) was a single-dose crossover comparing 50 microCi 111 InCl solutions with and without 1132 mg SAPP. Gastrointestinal transit times, determined by scintigraphic imaging, were compared between treatments. Gastric emptying time was unchanged, but small intestinal transit time was decreased to 56% in the presence of SAPP. More rapid small intestinal transit associated with an excipient of a solution dosage form apparently resulted in a decreased extent of ranitidine absorption. This observation contradicts the conventional wisdom that oral solutions are unlikely to fall short of bioequivalence relative to solid oral formulations.

Robotic solid phase extraction and high performance liquid chromatographic analysis of ranitidine in serum or plasma

A fully automated assay for the analysis of ranitidine in serum and plasma, with and without an internal standard, was validated. It utilizes robotic solid phase extraction with on-line high performance liquid chromatographic (HPLC) analysis. The ruggedness of the assay was demonstrated over a three-year period. A Zymark Py Technology II robotic system was used for serial processing from initial aspiration of samples from original collection containers, to final direct injection onto the on-line HPLC system. Automated serial processing with on-line analysis provided uniform sample history and increased productivity by freeing the chemist to analyse data and perform other tasks. The solid phase extraction efficiency was 94% throughout the assay range of 10-250 ng/mL. The coefficients of variation for within- and between-day quality control samples ranged from 1 to 6% and 1 to 5%, respectively. Mean accuracy for between-day standards and quality control results ranged from 97 to 102% of the respective theoretical concentrations.