Diffusion of camptothecin immobilized with cationic surfactant into agarose hydrogel containing anionic carrageenan

Camptothecin (CPT) is a hydrophobic antitumor drug. Controlled release of CPT from hydrogel has not been satisfactorily achieved because of its poor compatibility and weak interaction with a hydrophilic hydrogel matrix. A new approach has been attempted in this work to solve these problems. In our approach, CPT was first solubilized in a micellar solution of cetyltrimethylammonium bromide (CTAB), a cationic surfactant. It was found that the solubility of CPT could be enhanced by CTAB (10 mM) to 0.17 mg/mL, which is 127 times higher than that in pure water, providing a great feasibility of drug loading. The micellar drug solution of CTAB-CPT was subsequently used to prepare agarose hydrogels containing a small content (