Purpose. The aim of this study was to evaluate the influence of operating parameters on the characteristics of methacrylate microparticles prepared by spray drying technique. Methods. Eudragit microparticles were prepared by a spray drying method. The influence of different experimental parameters (i.e. solvent, feed rate, air flow rate, air drying temperature and aspiration flow rate) was studied on microparticle morphology, size distribution and recovery. In addition different Eudragit type and Eudragit RS concentration were employed. Optical and electron microscopy were employed in order to analyse microparticle morphology and dimensional distribution. Finally prednisolone as model drug was encapsulated in Eudragit RS microparticles. Results. Low feed rate values enabled to obtain the best results in term of microparticle morphology. Changes in nebulizing air flow did not result in a corresponding effect on microparticle characteristics. An increase of air drying temperature resulted in a reduction of microparticle dimension and recovery. A low flow of drying air was preferable as this resulted in microparticles with an optimal morphology. The polymer concentration affected both morphology and dimensions of microparticles. The encapsulation of prednisolone led to good incorporation efficiencies without altering percentage of recovery, morphology and mean dimension of the microparticles. Conclusions. The selection of appropriate parameters enabled to obtain spray dried Eudragit RS microparticles characterized by good morphology and narrow dimensional distribution.
Production of Eudragit microparticles by spray-drying technique: Influence of experimental parameters on morphological and dimensional characteristics
ESPOSITO, Elisabetta;CORTESI, Rita;CERVELLATI, Franco;NASTRUZZI, Claudio
2000
Abstract
Purpose. The aim of this study was to evaluate the influence of operating parameters on the characteristics of methacrylate microparticles prepared by spray drying technique. Methods. Eudragit microparticles were prepared by a spray drying method. The influence of different experimental parameters (i.e. solvent, feed rate, air flow rate, air drying temperature and aspiration flow rate) was studied on microparticle morphology, size distribution and recovery. In addition different Eudragit type and Eudragit RS concentration were employed. Optical and electron microscopy were employed in order to analyse microparticle morphology and dimensional distribution. Finally prednisolone as model drug was encapsulated in Eudragit RS microparticles. Results. Low feed rate values enabled to obtain the best results in term of microparticle morphology. Changes in nebulizing air flow did not result in a corresponding effect on microparticle characteristics. An increase of air drying temperature resulted in a reduction of microparticle dimension and recovery. A low flow of drying air was preferable as this resulted in microparticles with an optimal morphology. The polymer concentration affected both morphology and dimensions of microparticles. The encapsulation of prednisolone led to good incorporation efficiencies without altering percentage of recovery, morphology and mean dimension of the microparticles. Conclusions. The selection of appropriate parameters enabled to obtain spray dried Eudragit RS microparticles characterized by good morphology and narrow dimensional distribution.I documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
