A drug delivery system, the process of getting drugs to their intended target without unleashing toxic side effects on healthy cells, represents an area of great significance in medical research. At its core, this system seeks to achieve a number of objectives, including mitigating toxicity, bolstering stability, improving bioavailability, minimizing degradation, and maintaining a consistent and efficacious blood drug concentration.
There exist two primary approaches to crafting drug delivery systems. One method involves the use of delivery carriers, which serve to augment the stability of drugs. The other tactic, the prodrug strategy, operates by inhibiting drug activity temporarily through covalent modification. Of the two methods, the prodrug strategy may offer the most utility, as it can sidestep safety concerns such as immunogenicity and toxicity brought about by delivery carriers. Additionally, it may alleviate the metabolic burden placed on patients by these carriers, a benefit that may expand its overall applicability in the medical field.
Peptide-drug conjugates (PDCs) are a new emerging prodrug strategy in targeted drug delivery systems, consisting of peptides, linkers, and drugs. The mechanism of action varies depending on the types of peptides and linkers. Firstly, the peptide enters the cell by recognizing specific receptors on the cell surface, then the linker disintegrates under certain stimuli, releasing the drug and exerting its therapeutic effect. This prodrug strategy has the potential to improve the targeting of drugs and reduce the toxic side effects on other cells.
Advantages of peptide-drug conjugates
When comparing drug delivery approaches, one finds that the use of antibody-drug conjugates (ADCs) and peptide-drug conjugates (PDCs) share a construction strategy. However, the latter stands out due to its unique advantages.
Firstly, the small molecular size and high drug-loading capacity of peptides render them more adept at penetrating tumor stroma and infiltrating tumor cells. As an added benefit, peptides are highly biodegradable and do not prompt any immunogenic reactions in the body.
Furthermore, certain targeted peptides possess the ability to overcome tumor cell resistance by altering the drug’s cellular entry mechanism, thereby achieving the effective killing of drug-resistant tumors.
What’s more, the structural flexibility of PDCs, attributed to their short peptide characteristics, enables them to undergo easier modification and conjugation with a range of drugs, such as chemical, protein, and peptide drugs. As a result, targeted drug preparation becomes more effective, significantly reducing off-target toxicity.
Lastly, the production process of peptide fragments remains simple and easily scalable, suggesting the vast potential of PDCs in the development of targeted drug delivery systems.