Synthesis and Solubilization Properties of Miktoarm Star Polymers With Poly‐2‐Alkyl‐2‐Oxazoline and Poly(Ethylene Glycol) Arms

ABSTRACT Miktoarm star polymers with poly(ethylene glycol) and poly(2‐alkyl‐2‐oxazoline) arms were synthesized using a “grafting onto” scheme. At the first stage, α‐methoxy‐ω‐(2‐aminoethoxy)‐poly(ethylene glycol) chains were grafted to the chlorosulfonated calix[8]arene. The obtained star‐shaped poly(ethylene glycol) was treated with hydrazine hydrate under mild conditions in order to obtain acyl hydrazide moieties. The resulting compound was applied as a chain termination agent for the polymerization of 2‐alkyl‐2‐oxazolines. Two samples of A 8 B 8 star polymers were prepared with poly(ethylene glycol) arms grafted to the upper rim of calix[8]arene and 2‐ethyl/2‐isopropyl‐2‐oxazoline arms grafted to the lower rim of the macrocycle. Polymers are characterized by dispersity in the range of Ð = 1.31–1.44 and molecular weights equal to 29–32 kDa. The solution behavior and thermosensitivity of the polymers in aqueous 0.5% wt. solutions were studied by dynamic light scattering. The polymers were investigated to enhance the solubility of amphotericin B. AMT solutions were formulated by simple addition of the drug solution in dimethyl sulfoxide to the aqueous polymer solution. It was shown that solubilized amphotericin B exists in its monomeric form in the concentration range of 7.2–13.1 μg·mL −1 . The loading capacity of polymeric micelles was equal to 0.14%–0.26% wt. depending on the structure of the polyoxazoline arms.