PH-dependent binding of guests in the cavity of a polyhedral coordination cage: reversible uptake and release of drug molecules.

ABSTRACT: A range of organic molecules with acidic or basic groups exhibit strong pH-dependent binding inside the cavity of a polyhedral coordination cage. Guest binding in aqueous solution is dominated by a hydrophobic contribution which is compensated by stronger solvation when the guests become cationic (by protonation) or anionic (by deprotonation). The Parkinson's drug 1-amino-adamantane ('amantadine') binds with an association constant of 10⁴ M^-1 in the neutral form (pH greater than 11), but the stability of the complex is reduced by three orders of magnitude when the guest is protonated at lower pH. Monitoring the uptake of the guests into the cage cavity was facilitated by the large upfield shift for the ¹H NMR signals of bound guests due to the paramagnetism

SUBMITTER: Cullen W 

PROVIDER: S-EPMC5588781 | biostudies-literature | 2015 Jan

REPOSITORIES: biostudies-literature