Lw. Chan et Pws. Heng, EFFECTS OF POLY(VINYLPYRROLIDONE) AND ETHYLCELLULOSE ON ALGINATE MICROSPHERES PREPARED BY EMULSIFICATION, Journal of microencapsulation, 15(4), 1998, pp. 409-420
Citations number
22
Categorie Soggetti
Pharmacology & Pharmacy","Chemistry Applied","Engineering, Chemical
Calcium alginate microspheres were prepared by an emulsification proce
ss. The effects of two co-polymers, namely poly(vinylpyrrolidone) and
ethylcellulose, on the properties of the microspheres were studied. Mi
crospheres prepared with and without poly(vinylpyrrolidone) were spher
ical and discrete. The microspheres containing poly(vinylpyrrolidone)
exhibited a better flow property but the drug content was lower and th
e drug release rate higher. The method of incorporating poly(vinylpyrr
olidone) was found to (significantly) affect the size distribution and
drug content of the microspheres. Ethylcellulose produced marked aggr
egation of the microspheres which also showed a lower drug content, bu
t a slower drug release. The retardation in drug release was attribute
d to the formation of aggregated microspheres with a less permeable ma
trix. The addition of triethyl citrate, which is a water-soluble plast
icizer, was found to increase the rate of drug release while the use o
f a higher viscosity grade of ethylcellulose produced the opposite eff
ect. Ethylcellulose improved the flowability of the microspheres to a
greater extent than poly(vinylpyrrolidone).