Strategy for Traceless Codrug Delivery with Platinum(IV) Prodrug Complexes Using Self-Immolative Linkers

Area of Science:

• Medicinal Chemistry
• Drug Delivery Systems
• Platinum-based Therapeutics

Background:

• Platinum(IV) prodrugs offer advantages over platinum(II) drugs but face challenges in linker stability.
• Existing linkers are often too stable or too unstable, leading to incomplete or premature drug release.
• A need exists for linkers that provide controlled and traceless payload release from Pt(IV) prodrugs.

Purpose of the Study:

• To synthesize and evaluate a new class of Pt(IV) prodrugs utilizing masked self-immolative 4-aminobenzyl linkers.
• To achieve controlled and traceless codrug delivery of bioactive payloads.
• To improve the stability and efficacy of Pt(IV) prodrugs.

Main Methods:

• Synthesis of novel Pt(IV) prodrugs incorporating masked self-immolative 4-aminobenzyl linkers.
• Evaluation of prodrug stability in aqueous conditions.
• Investigation of payload release mechanisms, including decarboxylation and 1,6-elimination.
• In vitro potency assessment compared to coadministration strategies.

Main Results:

• The synthesized Pt(IV) prodrugs exhibited good aqueous stability.
• The self-immolative linkers facilitated controlled and traceless payload release via decarboxylation and 1,6-elimination.
• Efficient 1,6-elimination was attributed to the stabilization of the p-aza-quinone-methide intermediate.
• Pt(IV) prodrugs with cinnamate and coumarin payloads showed enhanced in vitro potency compared to unconjugated payloads.

Conclusions:

• Masked self-immolative 4-aminobenzyl linkers represent a promising strategy for Pt(IV) prodrug design.
• This approach enables controlled and traceless codrug delivery, overcoming limitations of existing linkers.
• The developed Pt(IV) prodrugs demonstrate improved stability and enhanced in vitro efficacy, paving the way for new cancer therapeutics.