LIPOPHILIC DRUG DERIVATIVES IN LIPOSOMES

The drug molecules can be classified into four categories, i.e. highly hydrophilic, highly lipophilic, amphiphilic and those with biphasic i nsolubility. These are located differently in the liposomes and exhibi t different entrapment and release behaviour. Problems like poor entra pment efficiency in addition to physical as well as chemical instabili ty have been found to be associated with the liposomal entrapment of d rug molecules other than those that are highly lipophilic. Therefore, a number of problem drugs have been synthesised into lipophilic deriva tives and targeted to the phospholipid bilayer. Some other approaches have also been used for the purpose, which include ion pair formation and pharmacosomes. The present review discusses the advantages of inco rporating drugs in the lipid domain of the vesicle. Taking examples of different drug classes, the success and limitations of the approach i s discussed. (C) 1998 Elsevier Science B.V. All rights reserved.