Chemically functionalized congeners of N6-phenyladenosine and 1,3-dipropyl-8-phenylxanthine have been covalently coupled to fatty acids, diglycerides, and a phospholipid. The lipid-drug conjugates inhibit R-[3H]-phenylisopropyladenosine binding to A1-adenosine receptors in rat cerebral cortex membranes. A xanthine-phosphatidylethanolamine conjugate bound with a Ki value of 19 nM. Various xanthine esters of low potency are potential prodrugs. Amides of an adenosine amine congener (ADAC) with 18-carbon fatty acids exhibited Ki values at A1-adenosine receptors of 70 pM, representing a 130-fold enhancement over the affinity of the corresponding acetyl amide. The very high affinity of adenosine-lipid conjugates may be due to stabilization of these adducts in the phospholipid microenvironment of the receptor protein. © 1987.
Jacobson, K. A., Zimmet, J., Schulick, R., Barone, S., Daly, J. W., & Kirk, K. L. (1987). Adenosine analogs with covalently attached lipids have enhanced potency at A1-adenosine receptors. FEBS Letters, 225(1–2), 97–102. https://doi.org/10.1016/0014-5793(87)81138-9