THE EFFECT OF ACACIA, GELATIN AND POLYVINYLPYRROLIDONE ON CHLOROQUINE TRANSPORT FROM MULTIPLE W/O/W EMULSIONS

The formation of multiple w/o/w emulsions with improved stability due to the formation of interfacial complex films between acacia, gelatin, polyvinylpyrrolidone and sorbitan monooleate is described. The long-term stability of the emulsions as assessed by microscopy showed no significant changes in w/o/w emulsions prepared with acacia in the internal phase, indicating good stability in these systems. Multiple emulsions containing chloroquine phosphate in the internal phase and which had been stored for 2 weeks surprisingly showed a reduced rate of release of chloroquine phosphate as compared with freshly prepared emulsions, suggesting that the release of chloroquine phosphate from these systems occurs by the process of diffusion as opposed to the physical breakdown of emulsions. It is suggested that the intramuscular administration of chloroquine in the form of w/o/w emulsions could reduce the frequency of administration, improve patient compliance and increase the therapeutic efficacy of chloroquine. The drug can be formulated as a single dose system in which the starting dose is incorporated into the external phase while the maintenance dose is encapsulated in the internal phase of the emulsion. © 1990.