HPMC-salicylate conjugates as macromolecular prodrugs: Design, characterization, and nano-rods formation

The design, characterization, and nano-rods formation of hydroxypropylmethylcellulose (HPMC)-salicylate conjugates as macromolecular prodrugs, was described. HPMC, obtained from Zhejiang Zhongbao Imp and Exp Corp, was dried under vacuum at 110°C for 8 hr. Nanoparticles were prepared using dialysis process in which 170 mg of HPMC-salicylate sample was dissolved in 5 mL of purified DMSO and was dialyzed against distilled water for 4 days. HPMC-salicylic acid conjugates reveal the absence of sulfur in all of the samples showing that there is no introduction to tosylate groups either covalently bounded or as an impurity. Transmission electron microscopic (TEM) imaging of molecular assembly on carbon coated TEM grids show particulate aggregation in nano-rod shape. After the attachment of hydrophobic salicylic acid moieties onto hydrophilic HPMC polymer backbone, amphiphilic character is established which tends to from nanorods.