Andris, D. (Dani)

Filtering

20001

Settings

Author search.filters.isAuthorOfPublication.2cea28ef-dc93-4b06-9ade-6436cc83f889

Search Results

Now showing 1 - 1 of 1
  • Thumbnail Image
    In vitro and in vivo evaluation of a somatostatin analogue released from PLGA microspheres
    (Elsevier, 2000-06) Gander, B. (Bruno); Zerbe, O. (Oliver); Orsolini, P. (Piero); Blanco-Prieto, M.J. (María José); Heimgartner, F. (Fréderic); Merkle, H.P. (Hans P.); Andris, D. (Dani); Besseghir, K. (Kamel)
    The purpose of this study was to design poly(lactide-co-glycolide) (PLGA) microspheres for the continuous delivery of the somatostatin analogue, vapreotide, over 2–4 weeks. The microspheres were produced by spray-drying and the desired characteristics, i.e. high encapsulation efficiency and controlled release over 2–4 weeks, achieved through optimizing the type of polymer, processing solvent, and co-encapsulated additive. The in vitro release was tested in fetal bovine serum preserved with 0.02% of thiomersal. Furthermore, formulations were injected intramuscularly into rats to obtain pharmacokinetic profiles. Encapsulation efficiency was between 34 and 91%, depending on the particular formulation. The initial peptide release (within 6 h) was lowest, i.e. <20%, when acetic acid was used as processing solvent and highest, i.e. 57%, with dichloromethane. The various co-encapsulated additives generally lowered the encapsulation efficiency by 15–30%. The best formulation in terms of low burst and effective drug serum levels (>1 ng/ml) over 21–28 days in rats was the one made with end-group uncapped PLGA 50:50, the solvent acetic acid and the additive polyethyleneglycol. In conclusion, the optimization of formulation parameters allowed us to produce vapreotide-loaded PLGA microspheres of suitable characteristics for therapeutic use.