ABSTRACT
Frequent dosage is probably the major reason for noncompliance with prescribed schedules of administration. Moreover, especially in the case of ocular therapy, the precorneal disposition factors for all ocular drugs increase the difficulty of preparing an acceptable controlled-release formulation. J. W. Vanderhoff et al. developed one of the basic technologies of preparing the colloidal dispersions from already formed polymers. The impossibility of obtaining latex systems by emulsion polymerization from a large number of compounds, e.g., epoxy resins, cellulosic derivatives such as ethylcellulose, and elastomers such as cis-polyisoprene, led to this new technique. U. Ticho et al. worked on an aqueous polymer emulsion to be used as pilocarpine-releasing eye drops for the treatment of glaucoma. The active ingredient is chemically bound to the polymer. The cellulose acetate hydrogen phthalate latices containing the active compound adsorbed partially onto the surface of the colloidal polymeric beads of the dispersions have a pH of 4.5 and show Brookfield viscosities between 50 and 200 cps.
