A comparison of the bioconversion rates and the Caco-2 cell permeation characteristics of coumarin-based cyclic prodrugs and methylester-based linear prodrugs of RGD peptidomimetics

Gian P. Camenisch, Wei Wang, Binghe Wang, Ronald T. Borchardt

Research output: Contribution to journalArticlepeer-review

31 Scopus citations

Abstract

Purpose. To compare the bioconversion rates in various biological media and the Caco-2 cell permeation characteristics of coumarin-based cyclic prodrugs (3a, 3b) and methylester-based linear prodrugs (1b, 2b) of two RGD peptidomimetics (1a, 2a). Methods. Bioconversion rates of the prodrugs to the RGD peptidomimetics were determined in Hank balanced salt solution (HBSS), pH 7.4, at 37°C and in various biological media (human blood plasma, rat liver homogenate, Caco-2 cell homogenate) known to have esterase activity. Transport rates of the prodrugs and the RGD peptidomimetics were determined using Caco-2 cell monolayers, an in vitro cell culture model of the intestinal mucosa. Results. In HBSS, pH 7.4, the coumarin-based cyclic prodrugs 3a and 3b degraded slowly and quantitatively to the RGD peptidomimetics 1a and 2a, respectively (3a, t(1/2) = 630 ± 14 min; 3b, t(1/2) = 301 ± 12 min). The methylester-based linear prodrugs 1b and 2b were more stable to chemical hydrolysis (1b and 2b, t(1/2) > 2000 min). Both the coumarin-based cyclic prodrugs and the methylester-based linear prodrugs degraded more rapidly in biological media containing esterase activity (e.g., 90% human blood plasma: 1b, t(1/2) < 5 min; 2b, t(1/2) < 5 min; 3a, t(1/2) < 91 ± 1 min; 3b, t(1/2) < 57 ± 2 min). When the apical (AP)-to-basolateral (BL) permeation characteristics were determined using Caco-2 cell monolayers, it was found that the methylester prodrugs 1b and 2b underwent esterase bioconversion (>80%) to the RGD peptidomimetics 1a and 2a, respectively. In contrast, the cyclic prodrugs 3a and 3b permeated the cell monolayers intact. Considering the appearance of both the prodrug and the RGD peptidomimetic on the BL side, the methylester prodrugs 1b and 2b were approximately 12-fold more able to permeate than were the RGD peptidomimetics 1a and 2a. When a similar analysis of the transport data for the coumarin prodrugs 3a and 3b was performed, they were shown to be approximately 6-fold and 5-fold more able to permeate than were the RGD peptidomimetics 1a and 2a, respectively. Conclusions. The coumarin-based cyclic prodrugs 3a and 3b were chemically less stable, but metabolically more stable, than the methylester-based linear prodrugs. The esterase stability of the cyclic prodrugs 3a and 3b means that they are transported intact across the Caco-2 cell monolayer in contrast to the methylester prodrugs 1b and 2b, which undergo facile bioconversion during their transport to the RGD peptidomimetics. However, both prodrug systems successfully delivered more (5-12-fold) of the RGD peptidomimetic and/or the precursor (prodrug) than did the RGD peptidomimetics themselves.

Original languageEnglish (US)
Pages (from-to)1174-1181
Number of pages8
JournalPharmaceutical Research
Volume15
Issue number8
DOIs
StatePublished - 1998
Externally publishedYes

Keywords

  • Caco-2 cells
  • Chemical and enzymatic stability
  • Drug delivery
  • Esterase-sensitive prodrugs
  • Membrane permeability
  • Peptidomimetic

ASJC Scopus subject areas

  • Biotechnology
  • Molecular Medicine
  • Pharmacology
  • Pharmaceutical Science
  • Organic Chemistry
  • Pharmacology (medical)

Fingerprint

Dive into the research topics of 'A comparison of the bioconversion rates and the Caco-2 cell permeation characteristics of coumarin-based cyclic prodrugs and methylester-based linear prodrugs of RGD peptidomimetics'. Together they form a unique fingerprint.

Cite this