Trelstar® is an injectable formulation of polylactide-co-glycolide (PLGA) microspheres encapsulating triptorelin palmoate (Mw 13115 Da), a synthetic decapeptide agonist analog of gonadotropin...

Trelstar® is an injectable formulation of polylactide-co-glycolide (PLGA) microspheres
encapsulating triptorelin palmoate (Mw 13115 Da), a synthetic decapeptide agonist analog of
gonadotropin releasing hormone (GnRH). The medicine is used in treatment of patients with
prostate cancer. The pharmacokinetics of triptorelin palmoate as free drug follows a 3 compartment
model with drug half-lives estimated to be 6 minutes, 45 minutes, and 3 hours, respectively. Three
different dosing intervals of Trelstar® are available in clinic: 1 month (3.75 mg), 3 month (11.25
mg) and 6 month (containing 22.5 mg of drug).
Discuss how encapsulation into PLGA microspheres improves patient therapy with triptorelin
palmoate, and how three dosing intervals available in clinic may have been achieved by
modifications in the formulation