Factors Influencing Microencapsulation of a Waxy Solid by Complex Coacervation

Microencapsulation of stearyl alcohol particles by complex coacervation in a gelatin-acacia system was studied. Spherical particles of solid stearyl alcohol were prepared by vibrating reed and vibrating capillary methods. Encapsulation was attempted on several size fractions of these particles by conventional procedures, but only particles below 250 μ in diameter were encapsulated. A modified procedure was developed to encapsulate particles larger than 250 μ. Microscopic observations indicated that the coacervate droplets had little affinity for the stearyl alcohol particles and that encapsulation of smaller particles was apparently accomplished by aggregation and coalescence of several droplets around the particles. Encapsulation of particles larger than 250 μ by the modified procedure was possibly the result of the direct interaction of gelatin with acacia on the surface of the particles.