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Copolymers of N ‐isopropylacrylamide can trigger pH sensitivity to stable liposomes
Author(s) -
Meyer Olivier,
Papahadjopoulos Demetrios,
Leroux Jean-Christophe
Publication year - 1998
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(97)01520-2
Subject(s) - liposome , chemistry , copolymer , poly(n isopropylacrylamide) , phosphatidylcholine , polymer , methacrylic acid , acrylate , drug carrier , solubility , drug delivery , chromatography , polymer chemistry , organic chemistry , membrane , biochemistry , phospholipid
Stable liposomes were rendered pH‐sensitive by complexation to a polymer that undergoes marked temperature‐ and pH‐dependent water solubility changes. The N ‐isopropylacrylamide‐methacrylic acid copolymer was prepared with or without octadecyl acrylate. At pH below the phase transition of the polymer, egg phosphatidylcholine liposomes quickly released a part of their contents only when associated with the octadecyl aliphatic chain grafted polymer at 37°C. Similarly, sterically stabilized liposomes also quickly released a significant part of the entrapped fluorescent markers at pH 5.5–4.9, values corresponding to those of endosomes/lysosomes. This new pH‐sensitive liposome‐polymer system may further improve the efficiency of liposomal drug delivery.