γ-Hydroxybutyric Acid (GHB) Pharmacokinetics and Pharmacodynamics: Semi-Mechanistic and Physiologically Relevant PK/PD Model

Enhanced efficacy of brucine dissolving-microneedles as a targeted delivery system in rheumatoid arthritis treatment: a comprehensive pharmacokinetic-pharmacodynamic analysis

Our previous studies have shown the therapeutic efficacy of brucine dissolving-microneedles (Bru-DMNs) in treating rheumatoid arthritis (RA). Bru delivered via the DMNs can bypass some of the issues related to oral and systemic delivery, including extensive enzymatic activity, liver metabolism and in the case of systemic delivery via hypodermic needles, pain resulting from injections and needle stick injury. However, the underlying mechanism of Bru-DMNs against RA has not been investigated in depth at the pharmacokinetic-pharmacodynamic (PK-PD) level. In this study, a microdialysis-based method combined with ultra-performance liquid chromatography-tandem mass spectrometry was developed for the simultaneous and continuous sampling and quantitative analysis of blood and joint cavities in fully awake RA rats. The acquired data were analyzed by the PK-PD analysis method. Bru delivered via microneedles showed enhanced distribution and prolonged retention in the joint cavity compared to its administration in blood. The correlation between the effect of Bru and its concentration at the action site was indirect. In this study, we explored the mechanism of Bru-DMNs against RA and established a visualization method to express the PK-PD relationship of Bru-DMNs against RA. This study provides insights into the mechanism of action of drugs with potential side effects administered transdermally for RA treatment.

Acute Sodium Oxybate Intoxication: A Case Report and Review of the Literature

PURPOSE

Despite a better safety profile than illicit γ-hydroxybutyric acid (GHB) and other GHB analogs, sodium oxybate continues to raise serious concerns regarding clinical safety. In this study, the authors report the case of near-fatal intoxication involving sodium oxybate-alcohol combination in a 40-year-old woman. In addition, a review of the literature on published cases of intoxication involving this pharmaceutical form of GHB was conducted. A 40-year-old woman was admitted to the intensive care unit in a coma after voluntary ingestion of 18 g of sodium oxybate and alcohol.

METHODS

The GHB plasma concentration was quantified to be 146 mg/L using liquid chromatography coupled with tandem mass spectrometry. An English literature search was performed using PubMed without any limiting period to identify all available scientific publications involving cases of sodium oxybate intoxication.

RESULTS

Six cases were identified. Five involved fatal intoxication cases, with GHB postmortem blood concentrations ranging from 11.5 to 3500 mg/L. One involved a nonfatal intoxication case with a GHB serum concentration of 569 mg/L 7 hours postingestion.

CONCLUSIONS

In the present case, the estimated elimination half-life was 154 minutes. The risk of acute poisoning seems to be high considering the pharmacokinetic properties of sodium oxybate. Physicians and toxicologists must take such properties into account.