Evaluation of epiandrosterone as a long-term marker of testosterone use.

Identification and evaluation of long-term markers is crucial in prolonging the detection window for anabolic steroid abuse in sport. Recently, sulfoconjugated epiandrosterone was identified as a potential long-term marker for the abuse of certain endogenous anabolic agents, including testosterone, which continues to be widely used as a performance enhancing agent in sport. To evaluate the applicability of epiandrosterone sulfate as a marker for testosterone use, administration studies were conducted with multiple modes of testosterone administration - transdermal, intramuscular, and subcutaneous. A modified sample preparation method was used to collect both glucuronidated and sulfoconjugated analytes of interest. Carbon isotope ratio measurements from the administration studies are presented here. Epiandrosterone was less effective than the conventionally used target compounds for detection of the low dose application (transdermal gel). With intramuscular administration, epiandrosterone was more diagnostic than with transdermal administration, but it did not prolong the detection window more than the conventional target compounds. With subcutaneous administration, the doses administered to the subjects were varied and the effect on the epiandrosterone values was dependent on the magnitude of the dose administered. Epiandrosterone does not appear to be a useful marker in the detection of low dose testosterone administration. It is responsive to higher dose administration, but it does not provide an extension of the detection window relative to conventional target compounds.

The pharmacokinetics of ketamine following intramuscular injection to F344 rats.

Ketamine is a glutamate N-methyl-D-aspartate receptor antagonist that is a rapid-acting dissociative anesthetic. It has been proposed as an adjuvant treatment along with other drugs (atropine, midazolam, pralidoxime) used in the current standard of care (SOC) for organophosphate and nerve agent exposures. Ketamine is a pharmaceutical agent that is readily available to most clinicians in emergency departments and possesses a broad therapeutic index with well-characterized effects in humans. The objective of this study was to determine the pharmacokinetic profile of ketamine and its active metabolite, norketamine, in F344 rats following single or repeated intramuscular administrations of subanesthetic levels (7.5 mg/kg or 30 mg/kg) of ketamine with or without the SOC. Following administration, plasma and brain tissues were collected and analyzed using a liquid chromatography-mass spectrometry method to quantitate ketamine and norketamine. Following sample analysis, the pharmacokinetics were determined using non-compartmental analysis. The addition of the current SOC had a minimal impact on the pharmacokinetics of ketamine following intramuscular administration and repeated dosing at 7.5 mg/kg every 90 minutes allows for sustained plasma concentrations above 100 ng/mL. The pharmacokinetics of ketamine with and without the SOC in rats supports further investigation of the efficacy of ketamine co-administration with the SOC following nerve agent exposure in animal models.

Aripiprazole and impulse control disorders: higher risk with the intramuscular depot formulation?

Dopamine agonists have been associated with an increased risk of developing impulse control disorders (ICDs). The US Food and Drug Administration (FDA) issued a safety warning in 2016 of a possible association between ICDs and aripiprazole. Recently, one large epidemiological study has confirmed this risk. In the present study, we aim to determine whether the safety signal of ICDs associated with aripiprazole detected by the FDA is replicated in the European pharmacovigilance database (EudraVigilance). We searched for all suspected spontaneous cases of ICDs associated with aripiprazole in EudraVigilance up to 23 February 2017. To assess the association between ICD cases and each dopamine agonist drug, we calculated the proportional reporting ratios (PRRs). Among 4 905 110 events of all types recorded in EudraVigilance, we found 160 cases of ICDs associated with aripiprazole. Aripiprazole fulfilled the criteria to generate a safety signal; PRR (95% confidence interval): 16.39 (13.97-19.24). Notably, the association seemed the strongest for the depot formulation of aripiprazole; PRR (95% confidence interval): 27.13 (17.22-42.75). Our analysis of the data contained in EudraVigilance confirms the safety signal detected last year by the FDA. Interestingly, for the first time, we show that the association seems the strongest for the intramuscular depot formulation of aripiprazole.

Effect of exposure routes on the relationships of lethal toxicity to rats from oral, intravenous, intraperitoneal and intramuscular routes.

The lethal toxicity values (log 1/LD(50)) of 527 aliphatic and aromatic compounds in oral, intravenous, intramuscular and intraperitoneal routes were used to investigate the relationships of log 1/LD(50) from different exposure routes. Regression analysis shows that the log 1/LD(50) values are well correlated between intravenous and intraperitoneal or intramuscular injections. However, the correlations between oral and intravenous or intraperitoneal routes are relatively poor. Comparison of the average residuals indicates that intravenous injection is the most sensitive exposure route and oral administration is the least sensitive exposure route. This is attributed to the difference in kinetic process of toxicity testing. The toxic effect of a chemical can be similar or significantly different between exposure routes, depending on the absorption rates of chemicals into blood. Inclusion of hydrophobic parameter and fractions of ionic forms can improve the correlations between intravenous and intraperitoneal or oral routes, but not between intraperitoneal and oral routes. This is due to the differences of absorption rate in different exposure environments from different routes. Several factors, such as experimental uncertainty, metabolism and toxic kinetics, can affect the correlations between intravenous and intraperitoneal or oral routes.