p H-Sensitive Liposomes: Possible Clinical Implications

Abstract
When p H-sensitive molecules are incorporated into liposomes, drugs can be specifically released from these vesicles by a change of p H in the ambient serum. Liposomes containing the p H-sensitive lipid palmitoyl homocysteine (PHC) were constructed so that the greatest p H differential (6.0 to 7.4) of drug release was obtained near physiological temperature. Such liposomes could be useful clinically if they enable drugs to be targeted to areas of the body in which p H is less than physiological, such as primary tumors and metastases or sites of inflammation and infection.