Browsing by Author "Pessi, Jenni"

Polymer microspheres hold great potential as oral drug delivery system for therapeutic proteins. Microspheres prepared with biocompatible and biodegredable polymers have been extensively studied, since the oral delivery of therapeutic proteins is challenging due to the conditions in the GI-tract. The aims of this research were to apply microfluidics on polymeric microsphere preparation process, to determine what kind of formulations are suitable for this technology, to establish a controlled preparation process that produces advanced particles and to create a template for oral protein drug delivery. With microfluidic fabrication it is possible to gain control over the process and content of each droplet. However, finding suitable formulations for microfluidics is demanding. In this study, biphasic flow was employed to successfully produce double (W/O/W) emulsion droplets with ultra thin shells. Once the process and formulation variables were optimized constant droplet production was achieved. Flow rates used were 500 µl/h in the inner and in the middle phase and 2500 µl/h in the outer phase, respectively. Two formulations were selected for further characterization: 5 % poly(vinyl alcohol) in water in the outer phase, 3 % polycaprolactone in ethyl acetate in the middle phase and either 10 % or 20 % poly(vinyl alcohol) and polyethylenglycol (1:4) in water in the inner phase. All the particles were found to be intact and contain the inner phase, as verified by confocal microscopy. Further, the particles were monodisperse and non-porous, as observed by scanning electron microscopy. Particle size was found to be around 20-40 µm, variation in the particle size within one batch was small and the particles were stable up to 4 weeks. The encapsulation efficiency of the particles was remarkable; as high as 85 % loading of the model compound, bovine serum albumin. Particles released 30 % of their content within 48 hours. In conlusion, developing functional formulations for micfoluidic technology was possible, the microparticles encapsulated the model protein extremely well and all in all microfluidic technology had a lot of potential for droplet manufacturing for pharmaceutical applications.