Binary mixed micellar systems of PEO-PPO-PEO block copolymers for lamotrigine solubilization: a comparative study with hydrophobic and hydrophilic copolymer

Polyethyelene oxide-polypropylene oxide-polyethyelene oxide, PEO-PPO-PEO triblock copolymers, Pluronics® are considered to be the best nanocarrier for hydrophobic substances on account of their wonderful solubilization power over other ionic and non-ionic surfactants. In the present manuscript, the Pluronic® binary mixtures (two systems, F127/P123 and F127/L35) as micellar nanocarriers for solubilization of lamotrigine (LTG) drug were investigated through UV-Visible spectroscopy, dynamic light scattering (DLS) and small angle neutron scattering (SANS) analysis. Both the binary systems form stable mixed micelles had low CMC in water. The CMC of binary systems, F127/P123 was located in the middle of the CMC of each copolymer, but it was slightly increased in the F127/L35 mixed systems. Results of DLS and SANS data were proven the spherical shape of micelles for both the binary systems with less than 30-nm diameter in sizes. Not much but mixed micelle became slightly larger after solubilizing of LTG drug. The solubilization capacity (SCP) of the binary systems was monitored using UV-Visible spectroscopy. The F127/P123 system shows relatively high solubilization capacity (SCP) due to a more hydrophobic system as copolymers with similar PPO block lengths. The F127/L35 system has been given the low SCP because of hydrophilic nature of L35. The micellar water partition coefficient (P) and Gibbs free energy changes (ΔG°) of solubilized LTG drug were also evaluated from a thermodynamics viewpoint. In conclusion, these binary micellar systems may be considered as the effective nanocarriers for LTG drug and F127/P123 mixed micelles proven better than the F127/L35 system for LTG drug.