An ophthalmic formulation of a beta-adrenoceptor antagonist, levobetaxolol, using poly(acrylic acid) nanoparticles as carrier: Loading and release studies

Poly(acrylic acid) (PAA) nanoparticles were synthesized by reverse microemu lsion polymerization using an oil-soluble initiator. The particles had a na rrow size range, similar to 50 nm, and were stable in phosphate buffer. The particles were recovered and lyophilized in dry powder form and were redis persible in buffer. The drug levobetaxolol was loaded into the nanoparticle s from aqueous drug solutions. When the drug-loaded particles were disperse d in a phosphate buffer solution the drug was released over several hours. The drug formulation in PAA nanoparticles was stable for more than 2 months at 4 degreesC and at room temperature.