MICROENCAPSULATION USING POLY(DL-LACTIC ACID) .1. EFFECT OF PREPARATIVE VARIABLES ON THE MICROCAPSULE CHARACTERISTICS AND RELEASE KINETICS

被引：19

作者：

JALIL, R ^{[1
]}

NIXON, JR ^{[1
]}

机构：

[1] UNIV LONDON,KINGS COLL LONDON,CHELSEA DEPT PHARM,MANRESA RD,LONDON SW3 6LX,ENGLAND

来源：

JOURNAL OF MICROENCAPSULATION | 1990年 / 7卷 / 02期

关键词：

D O I：

10.3109/02652049009021836

中图分类号：

O69 [应用化学];

学科分类号：

081704 ;

摘要：

Poly(DL-lactic acid) (DL-PLA, molecular weight 20 500) microcapsules containing phenobarbitone (PB) as a reference core were prepared using a water/oil (W/O) emulsion system. Surface morphology, particle size and 'encapsulation efficiency> of the microcapsules prepared using different preparative variables have been investigated. Buffer pH 9 was used as a dissolution medium to determine the affect of preparative variables on the release rate from these microcapsules. With an increase in temperature of evaporation the microcapsule surface became increasingly irregular and porous, due to deposition of phenobarbitone crystals near the vicinity of the microcapsule surface leading to rapid release of the core. The normalized release rate was found to increase exponentially with an increase in the temperature of evaporation. Microcapsule morphology was also severely affected due to differences in polymer concentration in the disperse phase solvent. With the increase in polymer concentration, the microcapsule surface was found to be increasingly irregular and non-continuous, due to rapid precipitation of the polymer. Increased polymer concentrations also increased mean microcapsule diameter. The release rate increased with the increase in polymer concentration due to surface defects and did not exhibit a straight line correlation. When core loading was very high (e.g. C:P, 2:1 and 1:1), crystals of phenobarbitone appeared at the surface and these caused a very rapid burst effect. However, microcapsules containing a lower phenobarbitone content were found to follow t1/2 dependent release. The encapsulation efficiency was not seriously affected due to variations in temperature of preparation and polymer concentration. However, with the decrease in initial core loading the encapsulation efficiency of microcapsules was found to be reduced. © 1990 Informa UK Ltd All rights reserved: reproduction in whole or part not permitted.

引用

页码：229 / 244

页数：16

共 16 条

[1]

Beck L.R., Cowsar D.R., Lewis D.H., Cosgrove R.J., Riddel C.T., Lowry S.L., Epperly T., A new long acting injectable microcapsule system for administration of progesterone, Fertility and Sterility, 31, (1979)

[2]

Beck L.R., Cowsar D.R., Lewis D.H., Gibson J.W., Flowers C.E., New long acting injectable microcapsule contraceptive system, American Journal of Obstetrics and Gynecology, 135, (1979)

[3]

Benita S., Benoit J.P., Puisieux F., Thies C., Characterization of drug loaded Poly(d,l-lactide) microspheres, Journal of Pharmaceutical Sciences, 73, pp. 1721-1724, (1984)

[4]

Bodmeier R., McGinity J.W., The preparation and evaluation of drug containing poly(d,l-lactide) microspheres formed by the solvent evaporation, Pharmaceutical Research, 4, pp. 465-471, (1987)

[5]

Fong J.W., Nazareno J.P., Pearson J., Maulding H.V., Evaluation of biodegradable microcapsules prepared by solvent evaporation process using sodium oleate as emulsifier, Journal of Controlled Release, 3, pp. 119-130, (1986)

[6]

Jalil R., Nixon J.R., Microencapsulation using poly(L-lactic acid). I: Microcapsule properties affected by the preparative technique, Journal of Microencapsulation, 6, pp. 473-484, (1989)

[7]

Jalil R., Nixon J.R., Microencapsulation using poly(L-lactic acid). II. Preparative variables affecting microcapsule properties, Journal of Microencapsulation, 7, pp. 25-39, (1990)

[8]

Jalil R., Nixon J.R., Microencapsulation using poly(L-latic acid). IV. Release properties of microcapsules containing phenobarbitone, Journal of Microencapsulation, 7, pp. 53-66, (1990)

[9]

Kulkarni R.K., Moore E.G., Hegyeli A.F., Leonard F., Biodegradable poly(lactic acid) polymers, Journal of Biomedical Materials Research, 5, pp. 169-181, (1971)

[10]

Spenlehauer G., Veillard M., Beniot J.P., Formation and characterization of cisplatin loaded poly(d,l-lactide) microspheres for chemoembolization, Journal of Pharmaceutical Sciences, 75, pp. 750-755, (1986)

← 1 2 →