Physical factors affecting microencapsulation by simple coacervation of gelatin

Abstract

Gelatin has been coacervated at 60 degrees C using sodium sulphate. Interfacial tensions between coacervate and supernatant liquid, coacervate and two oils (with and without one of two drugs, clofibrate and chlormethiazole) and supernatant liquid and the oils (+/- drug) have been measured by a drop volume technique, in the presence and absence of one of three surfactants, cetrimide, sodium lauryl sulphate and hexadecyltrimethylammonium lauryl sulphate (double salt). Spreading coefficients calculated from tensions indicate that coacervate should spread readily over oil droplets in presence of double salt, less readily with cetrimide and spreading is unlikely in the presence of sodium lauryl sulphate. The sign of the charge on coacervate droplets and oil droplets was identified under different conditions and showed coacervate droplets and oil droplets have opposite charges except in the presence of sodium lauryl sulphate. Microcapsules were prepared using cetrimide or 'double salt' as emulsifier and release of drug measured. Those prepared with 'double salt' released more slowly than those prepared with cetrimide.

Green assessment of polymer microparticles production processes: a critical review

“…5), 89,90 and (4) drying: post-processing through an energy-consuming process like spray drying or freeze drying. There are two classifications of coacervation systems based on the phase separation mechanism occurring in the second step: simple (salting out) 91,92 or complex (interaction of oppositely charged polymers. 93,94…”

Formulation of Enalapril-Loaded Microspheres Using Emulsion Solvent Evaporation Technique for Bitter Taste Masking

“…The size and the shape of the particles depend on the emulsifier concentration, stirring rate and the volume of the organic phase [9] . Successful microencapsulation of lipid-soluble drugs such as steroids [10] , topical anesthetics [11] , bleomycin sulfate [12] , doxorubicin [13] , naltrexone, and promethazine [14] has been reported. A major drawback of the method is the low efficiency of incorporation of water-soluble substances and the right choice of polymer is very important [15] .…”