Drug delivery by phospholipase A(2) degradable liposomes.
The effect of poly(ethylene glycol)-phospholipid (PE-PEG) lipopolymers on phospholipase A(2) (PLA(2)) hydrolysis of liposomes composed of stearoyl-oleoylphosphatidylcholine (SOPC) was investigated. The PLA(2) lag-time, which is inversely related to the enzymatic activity, was determined by fluorescence, and the zeta-potentials of the liposomes were measured as a function of PE-PEG lipopolymer concentration. A significant decrease in the lag-time, and hence an increase in enzymatic activity, was observed with increasing amounts of the negatively charged PE-PEG lipopolymers incorporated into the SOPC liposomes. The enhancement of the PLA(2) enzymatic activity might involve a stronger PLA(2) binding affinity towards the negatively charged and polymer covered PEG liposomes.
Davidsen
J
J
Department of Pharmaceutics, The Royal Danish School of Pharmacy, Universitetsparken 2, 2100 Copenhagen, Denmark.
Vermehren
C
C
Frokjaer
S
S
Mouritsen
O G
OG
Jørgensen
K
K
D016503:Drug Delivery Systems; D006868:Hydrolysis; D008081:Liposomes / Q000378:metabolism*; D010539:Permeability; D010741:Phospholipases A / Q000378:metabolism*
D008081:Liposomes; D010741:Phospholipases A