2019 · Journal of the Endocrine Society · paywalled
Pharmacokinetics and Acceptability of Subcutaneous Injection of Testosterone Undecanoate
Turner et al.
The finding, in our words
Subcutaneous testosterone undecanoate injection was equally acceptable to intramuscular injection despite causing more pain at 24 hours, with most men preferring the intramuscular route. Pharmacokinetic analysis using dried blood spots showed a later peak concentration after subcutaneous injection, but no clinically meaningful differences in overall exposure, suggesting subcutaneous administration is a viable alternative without dose adjustment.
A paraphrase to the Library’s standard, never the abstract. The source is one link away and is always the authority.
Home DBS sampling gave testosterone results that agreed well with venous blood in men on intramuscular testosterone undecanoate, but showed falsely high values in those using topical gel, likely from skin contamination. Patients preferred home collection for its convenience, suggesting DBS is viable for decentralised monitoring of injectable testosterone if patients are taught proper technique.
This review found that volumetric microsampling devices, such as Mitra, HemaPEN, HemaXis DB10, and Tasso-M20, overcome haematocrit bias, whilst Telimmune plasma separation cards enable direct plasma collection without centrifugation. These technologies support patient-centric, decentralised sampling, though the authors note that clinical validation remains limited across different drugs and patient populations.
The study found that quantitative dried blood spot sampling provided high clinical agreement for tacrolimus and creatinine monitoring, with patients rating the self-collection devices as user-friendly. These results support the feasibility of decentralised therapeutic drug monitoring for immunosuppressants.
Dried blood spot collection proved feasible during parabolic flight, with seventeen of twenty volunteers successfully providing samples for caffeine pharmacokinetic profiling. The method yielded stable metabolic ratios between ground and weightless conditions, and participants reported high satisfaction, suggesting DBS could support therapeutic drug monitoring in remote or extreme environments such as long-term spaceflight.
This study compared four dried blood spot devices for glucocorticoid detection, finding that the Mitra VAMS device offered the best combination of analytical recovery and user usability, whilst the HemaXis DB10 showed the least bias compared to whole blood.