Microencapsulation drug release control

Dhoot, N. O., and Wheatley, M. A. (2003), Microencapsulated liposomes in controlled drug delivery Strategies to modulate drug release and eliminate the burst effect, /. Pharm. Sci., 92(3), 679-689. 

Manca D and Rovaglio M. Modeling the controlled release of microencapsulated drugs Theory and experimental validation. Chem. Eng. Sci. 2003 58 1337-1351. 

Chowdary KP, Ramesh KV. Microencapsulation of solid dispersions of nifedipine-novel approach for controlling drug release. Indian Drugs 1995 32(Oct) 477-483. 

Microencapsulation of therapeutic agents provides local controlled drug release in the central nervous system across the blood-brain barrier. 

Controlled drug release properties are achieved through the application of coating to the surface of the capsule. A surface coating is applied in a microencapsulation process that frequently uses a plasticized aciylic copolymer. The type and concentration of plasticizer determines the rate of drag release. Trietltyl citrate is a typical plasticizer used in such microencapsulation. 

Budhian A, Siegel SJ, Winey KI (2005) Production of haloperidol-loaded PLGA nanoparticles for extended controlled drug release of halopmdol. J Microencapsul 22 773-785... 

Journal of Microencapsulation 21, No.2, March 2004, p. 137-49 MICROENCAPSULATION OF HYDROPHILIC DRUG SUBSTANCES USING BIODEGRADABLE POLYESTERS. II. IMPLANTS ALLOWING CONTROLLED DRUG RELEASE - A FEASIBILITY STUDY USING BISPHOSPHONATES Weidenauer U Bodmer D Kissel T Marburg,Philipps University Novartis Pharma Corp. 

D. Manca, and M. Rovaglio, Modeling the controlled release of microencapsulated drugs theory and experimental vahdation. Chemical Engineering Science, 58 (7), 1337-1351,2003. 

Muramyl dipeptide derivatives have also been microencapsulated in lactide/glycolide copolymers for use alone as an immuno potentiator. L-lactide/glycolide copolymers were used to deliver MDP-B30, a lipophilic compound, from very small microspheres (less than 5 pm in diameter). The amount of MDP-B30 required for tumor growth inhibitory activity of mouse peritoneal macrophages was 2000 times less for the controlled release MDP-B30 microspheres than for the unen-capsulated drug (134). 

Microencapsulation has been the subject of massive research efforts since its inception around 1950. Today, it is the mechanism utilized by approximately 65% of all sustained-release systems [35], The technique s popularity can be attributed mainly to its wide variety of applications. Hundreds of drugs have been microencapsulated and used as controlled-release systems. Some examples are Arthritis Bayer, Dexatrim Capsules, and Dimetapp Elixir. 

In addition to microelectronic and optical applications, polymers deposited using thermal and plasma assisted CVD are increasingly being used in several biomedical applications as well. For instance, drug particles microencapsulated with parylenes provide effective control release activity. Plasma polymerized tetrafiuoroethylene, parylenes and ethylene/nitrogen mixtures can be used as blood compatible materials. An excellent review of plasma polymers used in biomedical applications can be found in reference 131. 

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