Injectable Sustained-Release Depots of PLGA Microspheres for Insoluble Drugs Prepared by hot-Melt Extrusion.
Pharm Res 2017;
34:2211-2222. [PMID:
28741064 DOI:
10.1007/s11095-017-2228-x]
[Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2017] [Accepted: 07/03/2017] [Indexed: 11/29/2022]
Abstract
PURPOSE
Progesterone (PRG) was selected as a model drug to develop a long-acting injection system for poorly water-soluble drugs.
METHODS
Microspheres with high density-low porosity were prepared by hot-melt extrusion (HME) combined with wet-milling as the representative formulation, and a microcrystal suspension was also studied as a comparison. The morphology, particle size and distribution, polymorphism, drug distribution, density and porosity were characterized by scanning electron microscopy, laser diffraction particle size analyzer, power X-ray diffraction and DSC respectively. The in vivo performance of the different formulations within 7 days after intramuscular injection was evaluated in male SD rats.
RESULTS
The drug-loading rate of the microspheres could be as high as 40%. The average initial burst release of the microspheres (PLGA lactide:glycolide = 75:25) was only 6.7% much lower than that of the microsuspension (25.7%) and a sustained release was exhibited for at least 7 days. The release mechanism was speculated to be as follows. The microspheres are a drug depot with drug microcrystals in the PLGA matrix which is a layer by layer honeycomb structure.
CONCLUSIONS
Microspheres prepared by HME combined with wet-milling could achieve a long-term sustained release effect as a novel long-acting formulation strategy.
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