Application of a spray drying technique in the production of TRH-containing injectable sustained-release microparticles of biodegradable polymers
Takada, S.; Uda, Y.; Toguchi, H.; Ogawa, Y.
PDA Journal of Pharmaceutical Science and Technology 49(4): 180-184
1995
ISSN/ISBN: 1079-7440 PMID: 7552237 Document Number: 439195
Copoly (dl-lactic/glycolic acid) microparticles for sustained release of a water-soluble drug (Thyrotropin releasing hormone: TRH) were prepared by a spray drying method. A higher entrapment ratio was achieved with the spray drying method with the in-water drying method. In order to avoid agglomeration of the microparticles, a double-nozzle spray drying method was designed using mannitol as an anti-adherent. The surface of the spray-dried microparticles was coated with mannitol, and the extent of agglomeration was decreased. Acetonitrile was the most suitable solvent for microencapsulation using the double-nozzle spray drying method because the initial burst of TRH from the microparticles during the first day was the smallest. When PLGA with a weight-average molecular weight of 14,000 was used, constant release of TRH continued for one month with a small initial burst. In conclusion, the production of biodegradable microparticles by the double-nozzle spray drying method appears to be an attractive alternative to conventional microencapsulation methods.
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