This is a paper describing the pharmacokinetics (the rates of various phases of entering the blood and clearing out of the body) for various formulations of the drug, and their hypotheses for why this might be the case:
tl;dr: the molecule is poorly soluble in water, so by suspending a bunch of microparticles and injecting them subcutaneously, the drug very slowly dissolves over time, and it’s very potent, so only a little bit is necessary to do its job.
https://pubs.acs.org/doi/10.1021/acs.molpharmaceut.3c00626
tl;dr: the molecule is poorly soluble in water, so by suspending a bunch of microparticles and injecting them subcutaneously, the drug very slowly dissolves over time, and it’s very potent, so only a little bit is necessary to do its job.