Getting stoned: Characterisation of the coagulotoxic and neurotoxic effects of reef stonefish (Synanceia verrucosa) venom

The reef stonefish (Synanceia verrucosa) is a venomous fish which causes excruciatingly painful envenomations. While some research on the pathophysiology and functions of the venom have been conducted, there are still some gaps in the understanding of the venom effects due to the extreme lability of fish venom toxins and the lack of available testing platforms. Here we set out to assess new functions of the venom whilst also attempting to address some unclear pathophysiological effects from previous literature. Utilising a biolayer interferometry assay, our results highlight that the venom binds to the orthosteric site of the α-1 nicotinic acetylcholine receptor as well as the domain IV of voltage-gated Ca²⁺ (Ca_V1.2) channel mimotopes. Both these results add some clarity to the previously ambiguous literature. We further assessed the coagulotoxic effects of the venom using thromboelastography and Stago STA-R Max coagulation analyser assays. We reveal that the venom produced anticoagulant activity and significantly delayed time until clot formation of recalcified human plasma which is likely through the degradation of phospholipids. There was a difference between fresh and lyophilised venom activity toward the nicotinic acetylcholine receptor mimotopes and coagulation assays, whilst no difference was observed in the activity toward the domain IV of Ca_V1.2 mimotopes. This research adds further insights into the neglected area of fish venom whilst also highlighting the extreme labile nature of fish venom toxins.

Randomised Comparison of a Novel Buprenorphine Oral Lyophilisate versus Existing Buprenorphine Sublingual Tablets in Opioid-Dependent Patients: A First-in-Patient Phase II Randomised Open Label Safety Study

AIMS

To test the safety of new buprenorphine oral lyophilisate wafer ("bup-lyo") versus standard sub-lingual buprenorphine ("bup-SL").

DESIGN

Randomised (2:1) open-label study; opioid-dependent subjects; subsequent partial cross-over.

SETTINGS

Specialised clinical trials facility and addictions treatment facility.

PARTICIPANTS

Opioid-dependent subjects (n = 36) commencing buprenorphine maintenance (personalised dose-titration) including patients co-using alcohol, cocaine and benzodiazepines (below thresholds).

MEASUREMENTS

Respiratory function (respiratory rate, pulse-oximetry); medication hold and dose adequacy; opiate withdrawal signs and symptoms; tablet disintegration times; treatment retention. Pharmacokinetics (PK) for plasma buprenorphine and norbuprenorphine (n = 11).

FINDINGS

Oral lyophilised buprenorphine ("bup-lyo") completely dissolved within 2 min for 58 vs. 5% for "bup-SL." Dose titration resulted in similar maintenance dosing (10.8 vs. 9.6 mg). There were no significant between-group differences in opiate-withdrawal phenomena, craving, adequacy of "hold," respiratory function. No serious adverse events (AEs), nor "severe" AEs, although more AEs and Treatment-Emergent AEs with "bup-lyo" (mostly "mild"). PK found greater bioavailability of buprenorphine with "bup-lyo" (but not norbuprenorphine).

CONCLUSIONS

Orally disintegrating buprenorphine oral lyophilisate wafer disintegrated rapidly. No increased respiratory depression was found and clinically no difference between medications was observed. PK found substantially increased bioavailability of buprenorphine (but not of nor-buprenorphine) with "bup-lyo" relative to "bup-SL." In supervised dosing contexts, rapidly disintegrating formulations may enable wider buprenorphine prescribing.