title: Recent advances in polymeric microspheres for parenteral drug delivery--part 1.
abstract: BACKGROUND
  Polymeric microspheres have been established as a valuable parenteral drug delivery system for sustained release of therapeutic agents via subcutaneous or intramuscular injection.
  
  
  METHODS
  Biodegradable polymers which are either synthetic or from natural sources are reviewed with respect to recent advances in exploring their applications for microsphere fabrications. New information on the impact of formulation variables on the properties of microspheres formed by an emulsion method was also presented. The characterization of microspheres using advanced physical analytical techniques was also reviewed and the utilization of the information in assessing in vivo performance of the product was also highlighted.
  
  
  CONCLUSIONS
  The broad clinical use of microspheres for delivery of therapeutic agents in particular biologics such as proteins has not been realized commercially. The limited availability of biodegradable polymers with a long history of regulatory approval and the challenges in gaining regulatory approval of a new polymer have hindered the development of microspheres for parenteral drug delivery.
authors: Shenyang Pharmaceutical University, School of Pharmacy, Shenyang, China.
authors: Shirui
authors: S
authors: Mao
authors: Chunqiang
authors: C
authors: Guo
authors: Yi
authors: Y
authors: Shi
authors: Luk Chiu
authors: LC
authors: Li
mesh_terms: D000818:Animals; D016503:Drug Delivery Systems; D006801:Humans; D007263:Infusions, Parenteral; D008863:Microspheres; D011108:Polymers / Q000737:chemistry*
chemical_list: D011108:Polymers