Synthesis and characterization of pH-sensitive conjugate of isoniazid--methoxypoly(ethylene glycol)-b-poly(L-lysine).

Abstract The present paper deals with the preparation and characterization of a conjugate of isoniazid (INH) with the block copolymer methoxypoly(ethylene glycol)- b -poly( l -lysine) (mPEG- b -PLL). The structure of the conjugate (mPEG- b -PLL-INH) was verified by means of 1 H NMR, GPC, infrared spectroscopy, elemental analysis and powder X-ray diffraction. The conjugate contains six l -lysine units with five INH molecules, which are attached by means of pH-sensitive amidine bond. Under in vitro conditions, the conjugate is hydrolyzed and isoniazid is released (pH 4; 37 °C; t 1/2 ≈ 10 h).