title: In vitro dissolution methods for hydrophilic and hydrophobic porous silicon microparticles.
abstract: Porous silicon (PSi) is an innovative inorganic material that has been recently developed for various drug delivery systems. For example, hydrophilic and hydrophobic PSi microparticles have been utilized to improve the dissolution rate of poorly soluble drugs and to sustain peptide delivery. Previously, the well-plate method has been demonstrated to be a suitable in vitro dissolution method for hydrophilic PSi particles but it was not applicable to poorly wetting hydrophobic thermally hydrocarbonized PSi (THCPSi) particles. In this work, three different in vitro dissolution techniques, namely centrifuge, USP Apparatus 1 (basket) and well-plate methods were compared by using hydrophilic thermally carbonized PSi (TCPSi) microparticles loaded with poorly soluble ibuprofen or freely soluble antipyrine. All the methods showed a fast and complete or nearly complete release of both model compounds from the TCPSi microparticles indicating that all methods described in vitro dissolution equally. Based on these results, the centrifuge method was chosen to study the release of a peptide (ghrelin antagonist) from the THCPSi microparticles since it requires small sample amounts and achieves good particle suspendability. Sustained peptide release from the THCPSi microparticles was observed, which is in agreement with an earlier in vivo study. In conclusion, the centrifuge method was demonstrated to be a suitable tool for the evaluation of drug release from hydrophobic THCPSi particles, and the sustained peptide release from THCPSi microparticles was detected.
authors: School of Pharmacy, Pharmaceutical Technology, Faculty of Health Sciences, University of Eastern Finland, 70211 Kuopio, Finland. juha.monkare@uef.fi.
authors: Juha
authors: J
authors: Mönkäre
authors: Joakim
authors: J
authors: Riikonen
authors: Elina
authors: E
authors: Rauma
authors: Jarno
authors: J
authors: Salonen
authors: Vesa-Pekka
authors: VP
authors: Lehto
authors: Kristiina
authors: K
authors: Järvinen