Losartan potassium is most commonly used for the treatment of hypertension. In recent years, new applications of this drug have emerged, encouraging the design of novel nanoporous carriers for its adsorption and release. The purpose of this study was to synthesize ordered mesoporous carbon vehicles via a soft-templating method altered with the use of nitrogen precursors and via a hard-templating method followed by chitosan functionalization. As a result, the materials obtained differed in nitrogen content as well as in the number of total surface functional groups. The impact of the modification on the physicochemical properties of carbon carriers and their interaction with losartan potassium during adsorption and release processes was examined. The materials were characterized by various morphologies, specific surface areas (101-1180 m2 g-1), and the amount of acidic/basic oxygen-containing functional groups (1.26-4.27 mmol g-1). These features, along with pore sizes and volumes, had a key effect on the sorption capacity of carbon carriers towards losartan potassium (59-161 mg g-1). Moreover, they contributed to the differential release of the drug (18.56-90.46%). Losartan potassium adsorption onto the surface of carbonaceous materials was mainly based on the formation of hydrogen bonds and π-π interactions and followed the Langmuir type isotherm. It has been shown that the choice of the method of carbon carriers' synthesis and their modification allows for the precise control of the kinetics of the losartan potassium release from their surface, resulting in rapid or sustained drug liberation.
Keywords: adsorption of losartan potassium; chitosan; drug liberation; mesoporous carbon vehicles; nitrogen doping; surface modification.