Factors influencing the release of peptides and proteins from biodegradable parenteral depot systems

Synthesis and evaluation of biodegradable PCL/PEG nanoparticles for neuroendocrine tumor targeted delivery of somatostatin analog

“…The results correlate well with the similar studies (Jeon et al, 2000). Previously, Bodmer et al (1992) reported the maximal solubility and stability of octreotide in acetate buffer (pH 4.0) (Liebow et al, 1989). Likewise, when Octreotide microspheres were subjected to in vitro release in acetate buffers, '100% drug release with insignificant degradation products' while testing were observed.…”

Sustained release of bioactive glycosylated glial cell-line derived neurotrophic factor from biodegradable polymeric microspheres

“…This could be the case for GDNF, since it has a pI of 9.44 and it is positively charged at pH 7.9, the inner water phase pH. Such interactions could explain the faster drug release observed at higher polymer molecular weights [36]. After one week, GDNF released from PLGA microspheres were not strongly affected by polymer molecular weight.…”

“…On the other hand, the blend of Resomer RG 502H and RG 503H released 6.3% and Resomer RG 502H released 5.7% of the total dose. Positively charged molecules could potentially interact with PLGA negatively charged carboxylic end groups [36]. This could be the case for GDNF, since it has a pI of 9.44 and it is positively charged at pH 7.9, the inner water phase pH.…”

How to achieve sustained and complete protein release from PLGA-based microparticles?

“…Authors have suggested that the increased ionic strength may reduce the swelling of the polymer matrix by reducing the diffusion of the protein from the microspheres (Hora et al, 1990;Bodmer et al, 1992). Moreover, the increase of ionic strength can affect protein stability leading to aggregation.…”