A NOVEL-APPROACH TO THE PREPARATION OF INJECTABLE EMULSIONS BY A SPONTANEOUS EMULSIFICATION PROCESS

Submicronic emulsions of muramyltripeptide-cholesterol (MTP-Chol), diazepam and amphotericin B were prepared using an original and simple method. This procedure is based on a spontaneous emulsification process, comprising the following steps: (1) dissolving the oil phase containing phospholipid in the alcoholic solution; (2) optionally dissolving the drug into the oily alcoholic phase and (3) mixing the product of step (2) with an aqueous preparation of surfactant, forming an oil-in-water emulsion, and finally, (4) removing at least most of any co-solvent which is present. The emulsions exhibited a mean droplet size in the range 200-300 nm. The results indicated that emulsions prepared by this method are very stable. They can also be sterilized by heat sterilisation or by filtration. In the case of MTP-Chol, the emulsion retained biological activity. Taken together, these results suggest that an emulsion obtained by spontaneous emulsification process would be very suitable for use as a drug carrier.