Cisplatin is a
platinum (Pt)-based anticancer drug with broad-scale clinical utility. However, due to its hydrophilic nature and high kinetic reactivity, it offers numerous drug delivery challenges. Limitations such as severe systemic toxicities, chemoresistance, extensive
cisplatin-
plasma protein interaction, and limited cellular drug uptake reduce the therapeutic impact of
cisplatin therapy.
Cisplatin(IV)
prodrug formation can effectively resolve these challenges. The selection of axial
ligands could play a key role in determining the fate of
cisplatin(IV)
prodrugs by modulating the therapeutic and biopharmaceutical outcomes of
therapy. Hereby, three
cisplatin(IV) derivatives were developed utilizing
valproate,
tocopherol, and
chlorambucil as axial
ligands, and their biopharmaceutical performance was compared along with
cisplatin. The impact of
cisplatin(IV) derivative formation on their kinetic stability, drug-
albumin interaction, cytotoxicity profile, cellular uptake pattern, self-assembling behavior, hemotoxicity, and
tumor biodistribution pattern was analyzed to establish the correlation between the structural properties of
cisplatin(IV) agents and their biopharmaceutical outcomes. The kinetic inertness of the designed
cisplatin(IV) compounds helped in minimizing their
plasma protein interactions and ensuring their stability in the blood environment. The lipophilicity enhancement due to Pt(IV)
prodrug formation critically helped in enhancing the cellular drug uptake and reduced the dependence on transporters for drug uptake. The lipophilicity and activity of axial
ligands were the key drivers governing the biopharmaceutical performance of the Pt(IV) derivatives. The properties of the axial
ligand, such as its therapeutic activity, chemical backbone, and functional groups present in its structure, were the critical factors determining their
plasma protein interaction, cellular uptake, anticancer activity, and self-assembly pattern.
Cisplatin(IV) derivative formation further improved the amount of
platinum accumulated in
tumors after
intravenous injection compared to free
cisplatin therapy (2.7-5.4 folds increment) and reduced drug-erythrocyte interactions. Overall, the results highlighted the potential of
cisplatin(IV) agents in resolving
cisplatin drug delivery challenges and denoted the critical role of axial
ligand selection in Pt(IV)
prodrug designing.