Sustained-release delivery of octreotide from biodegradable polymeric microspheres

Yun Seok Rhee, Minji Sohn, Byung H. Woo, B. C. Thanoo, Patrick P. Deluca, Heidi M. Mansour

Research output: Contribution to journalArticlepeer-review

37 Scopus citations


The study reports on the drug release behavior of a potent synthetic somatostatin analogue, octreotide acetate, from biocompatible and biodegradable microspheres composed of poly-lactic-co-glycolic acid (PLGA) following a single intramuscular depot injection. The serum octreotide levels of three Oakwood Laboratories formulations and one Sandostatin LAR® formulation were compared. Three formulations of octreotide acetate-loaded PLGA microspheres were prepared by a solvent extraction and evaporation procedure using PLGA polymers with different molecular weights. The in vivo drug release study was conducted in male Sprague-Dawley rats. Blood samples were taken at predetermined time points for up to 70 days. Drug serum concentrations were quantified using a radioimmunoassay procedure consisting of radiolabeled octreotide. The three octreotide PLGA microsphere formulations and Sandostatin LAR® all showed a two-phase drug release profile (i.e., bimodal). The peak serum drug concentration of octreotide was reached in 30 min for all formulations followed by a decline after 6 h. Following this initial burst and decline, a second-release phase occurred after 3 days. This second-release phase exhibited sustained-release behavior, as the drug serum levels were discernible between days 7 and 42. Using pharmacokinetic computer simulations, it was estimated that the steady-state octreotide serum drug levels would be predicted to fall in the range of 40-130 pg/10 μL and 20-100 pg/10 μL following repeat dosing of the Oakwood formulations and Sandostatin LAR® every 28 days and every 42 days at a dose of 3 mg/rat, respectively.

Original languageEnglish (US)
Pages (from-to)1293-1301
Number of pages9
JournalAAPS PharmSciTech
Issue number4
StatePublished - Dec 2011


  • PLGA microspheres
  • in vivo drug release
  • pharmacokinetic simulation
  • polypeptide/protein drug delivery
  • single depot injection

ASJC Scopus subject areas

  • Pharmaceutical Science


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