Preparation of liposomes containing lysosomal enzymes for therapeutic use

Abstract

The preparation of fused materials using liposomes has been examined for several decades as a tool for the stabilization of heterogeneous enzymes. We investigated the liposomal encapsulation of lysosomal enzymes extracted from Saccharomyces cerevisiae. Liposomes were formed with L-α-phosphatidylcholine from egg yolk and cholesterol. To encapsulate whole lysosomal enzymes in liposomes made with and without cholesterol, L-α-phosphatidylcholine and cholesterol were added to chloroform at a ratio of 10:0 (L-α-phosphatidylcholine:cholesterol) and then evaporated for 10 min at 4°C. The residue after evaporation was mixed with lysosomal enzymes at the same ratio and then vortexed for 1 min and sonicated for 5 sec to encapsulate the enzymes. Liposome-encapsulated lysosomal enzymes were created using various amounts of lysosomal enzymes and cholesterol. The results indicated that the optimal encapsulation conditions were lipid:cholesterol ratios of 7:3 and 8:2. Liposome formation was confirmed by TEM imaging. After 1 day, two types of liposomes released small amounts of lysosomal enzymes. However, after 6 days, liposomes formed from mixtures of lipid and cholesterol did not exhibit any changes, whereas liposomes formed from only lipids released high amounts of lysosomal enzymes. Lysosomal enzymes encapsulated in liposomes have potential as important drug delivery carriers, as liposomes are able to control drug release and bioavailability.