More Data on the Relative Bioavailabilities of Uridine and Triacetyluridine

These articles [Al Safarjalani et al., 2005: (http://www.ncbi.nlm.nih.gov/pubmed/15729584); Ashour et al., 1996: (http://www.ncbi.nlm.nih.gov/pubmed/8687475)] show that the relative bioavailability of oral uridine (URD) at a dose of 1320 mg/kg, in comparison to the response to intraperitoneal URD, was about 7.7 percent (Ashour et al., 1996). Al Safarjalani et al. (2005) looked at the relative bioavailability of URD at different dosages, and I don't have time to check the full text of that article right now. Ashour et al. (1996) found that the relative bioavailability of triacetyluridine (TAU) (oral vs. parenteral) was 53 percent. The 7.7-percent value is about ten times the relative bioavailability, crudely calculated, in that older study I linked to in a recent posting, and that difference might be attributed to differences in methodologies or to the limits in oral bioavailability that one would expect to see, because of the low solubility of uridine, at higher single dosages of uridine (it would slow the entry into solution and essentially mimick the effects of a time release preparation, because the absorption of uridine would gradually allow more uridine to enter solution in the intraluminal fluid in the small intestine, etc.).