Premium
Role of Ethylene Oxide and Propylene Oxide Groups of Pluronics in Binding of Fatty Acid to Pluronics in Microemulsions
Author(s) -
JamesSmith Monica A.,
Shekhawat Dushyant,
Cheung Sally,
Moudgil Brij M.,
Shah Dinesh O.
Publication year - 2008
Publication title -
journal of surfactants and detergents
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.349
H-Index - 48
eISSN - 1558-9293
pISSN - 1097-3958
DOI - 10.1007/s11743-008-1077-3
Subject(s) - chemistry , microemulsion , poloxamer , propylene oxide , ethylene oxide , fatty acid , oxide , fatty acid ester , organic chemistry , pulmonary surfactant , biochemistry , copolymer , polymer
We investigated the drug and fatty acid binding capacity of Pluronic‐based microemulsions through simple turbidity experiments. Pluronic‐based oil‐in‐water microemulsions of various compositions were synthesized and titrated to turbidity with concentrated amitriptyline, an antidepressant drug. The BASF Pluronic grid was used to select two series of Pluronic surfactants: (1) those having the same number of ethylene oxide (EO) groups, with an increasing number of propylene oxide (PO) groups and (2) those having the same number of propylene oxide groups with an increasing number of ethylene oxide groups. We observed that the binding of sodium caprylate fatty acid and amitriptyline drug increases with increasing hydrophobicity (i.e., increasing number of PO groups). This is attributed to the greater number of binding sites for the sodium caprylate, which results in more charge on the microemulsion, subsequently leading to increased drug binding. We also determined that when the number of PO groups was held fixed and the number of EO groups was increased, there is no direct correlation to the binding behavior of fatty acid and drug. This is due to the fact that the hydrophilic groups (EO) do not play a direct role in the binding of fatty acid molecules. In fact, when there are a significantly large number of EO groups present, they can act to inhibit binding of fatty acid and hence, drug, to the microemulsion.