PDLLA microspheres containing steroids: spray-drying, o/w and w/o/w emulsifications as preparation methods.
Hydrocortisone and its more soluble ester, hydrocortisone 21-acetate, have been incorporated into poly(D,L-lactic) acid (PDLLA) microspheres using single, double emulsion/solvent evaporation and by spray-drying techniques. This paper describes the characterization of the microparticles obtained (morphology, particle size distribution, drug content, yield of production, in vitro drug release behaviour) and a comparison of the results (drug loading, drug release, size of the microspheres) obtained from the different techniques used. These results demonstrate that by using a relatively more soluble ester of an insoluble steroid, hydrocortisone, the drug content within the microspheres can be increased, together with a high efficiency of loading, irrespective of the technique employed. In the case of hydrocortisone, spray-drying produces the highest loading and encapsulation efficiency compared to both single and double emulsion methods for microspheres of similar size (about 2-4 microns) and suitable for lung delivery, but with lower yields (about 55% versus about 33%).
Giunchedi
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Dipartimento di Chimica Farmaceutica, Università di Pavia, Italy.
Alpar
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Conte
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D002152:Calorimetry, Differential Scanning; D002626:Chemistry, Pharmaceutical; D004339:Drug Compounding / Q000379:methods*; D016503:Drug Delivery Systems; D004655:Emulsions / Q000737:chemistry*; D006854:Hydrocortisone / Q000378:metabolism; D019344:Lactic Acid / Q000737:chemistry; D008855:Microscopy, Electron, Scanning; D008863:Microspheres; D010316:Particle Size; D011091:Polyesters; D011108:Polymers / Q000737:chemistry; D013256:Steroids / Q000378:metabolism*; D013696:Temperature
D004655:Emulsions; D011091:Polyesters; D011108:Polymers; D013256:Steroids; D019344:Lactic Acid; C033616:poly(lactide); D006854:Hydrocortisone