Controlled release processes microparticles

Sam, A.P. Haan, F.D. Dirix, C. A Novel Process for Manufacturing PLG Microparticles by Spray Desolvation Avoiding the use of Toxic Solvents. International Symposium on Controlled Release of Bioactive Materials. Nice, France, 1994 198-199. 

Attempts have been made to manufacture particles on the nanometer scale for applications such as controlled release and intravenous delivery systems. A comparison evaluating the processability and solid dosage performance of spray-dried nanoparticles and microparticles was conducted (41). In this study, nanoparticle suspensions were prepared by wet comminution in the presence of stabilizers, converted into dried particles using a spray-drying process and subsequently compressed. Compacts prepared from microparticles and nanoparticles were found to differ in their internal structure and micromechanical deformations. 

In 2004, Barbe and coworkers reviewed sol-gel miCToencapsulation of bioactive molecules for drug-delivery. Four years later, the same team published a first summary of their studies on silica-based microparticles doped with hydrophilic molecules obtained from water-in-oil (W/O) microemulsions. The Australian scientists showed how both the particle size and the release rate of silica-based microparticles can be finely and easily tailored in a wide range by controlling the conditions affecting the sol-gel process. In 2006, van Driessche and Hoste published the first account on the topic in a book addressing microencapsulation techniques, mainly covering the findings of Barbe and cowoikers. 

In 1998, Avnir and coworkers patented the interfacial polymerization process in which the mild sol-gel production of silica glass is combined with emulsion chemistry to form sol-gel spherical microparticles in place of irregular granules. In brief, the emulsion droplets provide a microreactor environment for the hydrolysis and condensation reactions of Si alkoxides. All sorts of molecules can be entrapped and stabilized in similar ceramic microparticles with broad control over the release rate for a range of applications (such as drug delivery, release of specialty chemicals and cosmeceutical/ nutraceutical, and beyond, Figure 18.1), with no need for reformulation for different molecules. 

Biopolymer microparticles (Freiberg and Zhn, 2004) are gaining a great importance in the dmg delivery field, because they allow release of the active compound in a controlled and targeted manner. Microparticles can be obtained starting with monomer polymerization. This process requires a colloidal solution with the monomer dispersed in a liquid with the presence of a surfactant. Polymerization can be achieved with various techniques such as ... 

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