Purpose: To evaluate the effect of the atomizer on the properties of lipid microparticles producted by spray congealing. Two different air atomizers have been used to prepare the microparticles: a conventional air pressure nozzle (APN) and an atomizer recently developed and patented, called wide pneumatic nozzle (WPN). Methods: Milled theophylline and Compritol 888ATO were used to produce microparticles at drug to carrier ratios of 10:90, 20:80 and 30:70 using the two atomizers; morphology, particle size, drug loading and release profiles of the microparticles were then analysed. Results: SEM analysis shows that APN microparticles have a quite irregular shape with some imperfections on the surface. More than 80% of the microparticles have a diameter in the range 50-350 mm. The drug is not uniformely distributed in the size fraction, in particular for higher drug loading; i.e. for 30:70 drug to carrier ratio, the actual drug content is 27.7%, 24.7% and 23.6% for the 50-100 mm, 100-200 mm and for 200-355 mm fractions, respectively In contrast, non-aggregated microparticles with spherical shapes and smooth surfaces have been obtained from all drug to carrier ratios by WPN. The size distribution of WPN microspheres is similar to that of APN ones. The actual drug loading in each size fraction is close to the theoretical one (encapsulation efficiency close to 100%), showing that the drug is uniformely distributed in the microspheres. The in vitro release of theophlylline depends on both microparticle size and drug to carrier ratio. Finally, DSC and FT-IR analysis demonstrate the absence of interaction between drug and carrier and the stability of all the systems, at least for 6 months Conclusions: The characteristics of the atomizer employed in the spray congealing process strongly influence morphology and drug loading of the microparticles, while in vitro release of the drug is mostly affected by particle size and drug to carrier ratio.

Influence of the atomizer on the characteristics of microparticles producted by spray congealing.

PASSERINI, NADIA;ALBERTINI, BEATRICE;RODRIGUEZ, LORENZO;
2007

Abstract

Purpose: To evaluate the effect of the atomizer on the properties of lipid microparticles producted by spray congealing. Two different air atomizers have been used to prepare the microparticles: a conventional air pressure nozzle (APN) and an atomizer recently developed and patented, called wide pneumatic nozzle (WPN). Methods: Milled theophylline and Compritol 888ATO were used to produce microparticles at drug to carrier ratios of 10:90, 20:80 and 30:70 using the two atomizers; morphology, particle size, drug loading and release profiles of the microparticles were then analysed. Results: SEM analysis shows that APN microparticles have a quite irregular shape with some imperfections on the surface. More than 80% of the microparticles have a diameter in the range 50-350 mm. The drug is not uniformely distributed in the size fraction, in particular for higher drug loading; i.e. for 30:70 drug to carrier ratio, the actual drug content is 27.7%, 24.7% and 23.6% for the 50-100 mm, 100-200 mm and for 200-355 mm fractions, respectively In contrast, non-aggregated microparticles with spherical shapes and smooth surfaces have been obtained from all drug to carrier ratios by WPN. The size distribution of WPN microspheres is similar to that of APN ones. The actual drug loading in each size fraction is close to the theoretical one (encapsulation efficiency close to 100%), showing that the drug is uniformely distributed in the microspheres. The in vitro release of theophlylline depends on both microparticle size and drug to carrier ratio. Finally, DSC and FT-IR analysis demonstrate the absence of interaction between drug and carrier and the stability of all the systems, at least for 6 months Conclusions: The characteristics of the atomizer employed in the spray congealing process strongly influence morphology and drug loading of the microparticles, while in vitro release of the drug is mostly affected by particle size and drug to carrier ratio.
Proc. of the1st Conference on: Innovation in Drug Delivery: from biomaterials to devices.
299
299
N. Passerini; S. Qi; B. Albertini; L. Rodriguez; D.M.Q. Craig
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11585/53203
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