Trelstar™ Depot

Nilutamide (Nilandron) Tamoxifen Triptorelin (Trelstar Depot, Trelstar LA)... 

Trelstar Depot PLGA Triptorelin pamoate Prostate cancer... 

Trelstar Depot microgranules for injection, lyophilized equivalent to 3.75 mg triptorelin peptide base, Trelstar LA microgranules for injection, lyophilized equivalent to 11.25 mg triptorelin peptide base)... 

Table 20.6 lists FDA-approved PLGA-based parenteral microsphere products available on the US market. These formulations are based on the degradation of PLGA to achieve sustained release in vivo from 1 month to 3 months. According to the FDA dissolution method database, only Trelstar Depot has a standardized dissolution method listed using USP apparatus 2. FDA recommends using USP apparatus 2 or USP apparatus 4 to develop dissolution methods for four of the products, while for the other two products, there are no dissolution methods listed. Recent workshop reports have recommended the use of USP apparatus 4 for microsphere products [82]. 

Controlled Release of Peptides and Proteins. Sustained release applications are especially useful for proteins/peptides because of their short half-lives (62). This concept was first utilized commercially in Lupron Depot, which was introduced as a sustained release formulation of a lutenizing hormone-releasing hormone (LHRH), leuprolide acetate, with poly(lactic acid) as the polymer (63). Following the success of Lupron Depot, other sustained release formulations of LHRH analogues have also been commercialized, including Zoladex wherein the LHRH peptide is encapsulated in PLA-extruded rods, and Trelstar depot wherein the peptide is encapsulated in PLGA polymer matrices. 

The biggest success of pol5mier controlled release systems in cancer therapy however has been in the area of prostate cancer treatment. This therapy is luiique since it uses a hormone-suppressant rather than a chemotherapeutic agent to minimize cancer cell growth in the prostate. Several products include Lupron Depot (TAP Pharmaceuticals), Zoladex (Astra-Zeneca), and Trelstar Depot (Debio RP, Pharmacia). Lupron Depot involves PLA microspheres, Zoladex formulation is an extruded rod, whereas Trelstar depot consists of PLGA microspheres, all of which incorporate LHRH analogues. 

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