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Background: The optimization of polymer-drug conjugate design is important in effective and efficient delivery of poorly soluble drugs.

Objectives: This work focuses on the formulation of novel amorphous ibuprofen-polymer nanoconjugates based on the polymer-drug complexation in order to improve its physical characteristics in the absence of toxic organic solvents.

Methods: Amorphous Ibuprofen – DEAE-Dextran nanoconjugates were prepared using surfactant solubilization method. Physical characterization of the nanoconjugates was carried out via conductivity, surface tension, viscosity, transmittance/turbidity, particle size measurement, zeta potential, conjugation efficiency and Scanning Electron Microscopy (SEM) techniques.

Results: A remarkably high loading capacity was achieved ranging from 89.05 to 96.34%. The conductivity measurements showed that the critical association concentration (cac) was exhibited at 2.34 mg/mL and critical micellar concentration (cmc) at 8.0 mg/mL. The presence of DEAE-Dextran decreased the cac of ibuprofen significantly (p < 0.05, n = 6) confirming the electrostatic interaction between DEAE-Dextran and ibuprofen. DEAE-Dextran showed surface activity and were adsorbed significantly at the water surface. The surface morphologies of the nanoconjugates singly and in aggregates were all spherical in shape. The formulation of ibuprofen-DEAE-Dextran conjugate reduced the size of ibuprofen (2.87 μm) significantly to 13.02 nm (268-fold) -2 at 1.6% (3.2 x 10 mM) DEAE-Dextran concentration. The zeta potential values obtained were relatively low (-3.04 to +13.87 mV) indicating low repulsion stabilization.

Conclusion: This work shows the formulation of amorphous ibuprofen-DEAE-Dextran nanoconjugates via the surfactant solubilization with the potential of improving the delivery of ibuprofen.

KeyWords: Ibuprofen, surfactant solubilization, DEAE-Dextran and nanoconjugate