The development of orally administrable gemcitabine prodrugs with d-enantiomer amino acids: Enhanced membrane permeability and enzymatic stability

Abstract

Gemcitabine prodrugs with D- and L-configuration amino acids were synthesized and their chemical stability in buffers, resistance to glycosidic bond metabolism, enzymatic activation, permeability in Caco-2 cells and mouse intestinal membrane, anti-proliferation activity in cancer cell were determined and compared to that of parent drug, gemcitabine. Prodrugs containing D-configuration amino acids were enzymatically more stable than ones with L-configuration amino acids. The activation of all gemcitabine prodrugs was 1.3–17.6-fold faster in cancer cell homogenate than their hydrolysis in buffer, suggesting enzymatic action. The enzymatic activation of amino acid monoester prodrugs containing D-configuration amino acids in cell homogenates was 2.2–10.9-fold slower than one of amino acid monoester prodrugs with L-configuration amino acids. All prodrugs exhibited enhanced resistance to glycosidic bond metabolism by thymidine phosphorylase compared to parent gemcitabine. Gemcitabine prodrugs showed superior the effective permeability in mouse jejunum to gemcitabine. More importantly, the high plasma concentration of D-amino acid gemcitabine prodrugs was observed more than one of L-amino acid gem-citabine prodrugs. In general, the 5′-mono-amino acid monoester gemcitabine prodrugs exhibited higher permeability and uptake than their parent drug, gemcitabine. Cell proliferation assays in AsPC-1 pancreatic ductal cell line indicated that gemcitabine prodrugs were more potent than their parent drug, gemcitabine. The transport and enzymatic profiles of 5′-D-valyl-gemcitabine and 5′-D-phenylalanyl-gem-citabine suggest their potential for increased oral uptake and delayed enzymatic bioconversion as well as enhanced uptake and cytotoxic activity in cancer cells, would facilitate the development of oral dosage form for anti-cancer agents and, hence, improve the quality of life for the cancer patients.

Pancreatic Cancer Chemoresistance to Gemcitabine

“…Prodrugs containing D-amino acid gemcitabine showed higher plasma concentration and superior enzymatic stability compared to L-amino acid gemcitabine prodrugs. Both prodrugs were more potent than parent gemcitabine in AsPC-1 pancreatic cancer cells [ 121 ]. Likewise, in another report, the dipeptide prodrugs of gemcitabine showed significantly higher uptake and superior anti-proliferative ability compared to the parent drug in the pancreatic cancer cell lines AsPC-1 and PANC-1 [ 122 ].…”

Amino Acid Derivatives as Palmitoylethanolamide Prodrugs: Synthesis, In Vitro Metabolism and In Vivo Plasma Profile in Rats

“…Finally, we also tested the importance of amino acid chirality on PEA prodrug stability, synthesizing D-asparagine ( 27 ) and D-valine ( 28 ) ester derivatives. D-amino acid esters are usually characterized by a slower transformation rate to the parent compound compared to the corresponding L-amino acids in a biological setting, which could potentially lead to an improved tissue distribution [ 30 , 31 ].…”

Encapsulating a Hydrophilic Chemotherapeutic into Rod‐Like Nanoparticles of a Genetically Encoded Asymmetric Triblock Polypeptide Improves Its Efficacy

“…However, the in vivo antitumor efficacy was not significantly improved in Swiss mice bearing Ehrlich ascites carcinoma. In another approach, GEM prodrugs have been synthesized by chemically conjugating GEM with d ‐amino acids or valproic acid . These formulations only moderately inhibit tumor progression in mice …”