Taurodeoxycholic acid conjugates

A further group of AT-[(acyloxy)methyl] pro-moieties contains acidic and/or lipid-like substituents. Here again, most published results concern phenytoin. Thus, some phenytoin-lipid conjugates such as 8.183 and 8.186 (with R = various fatty acyl moieties) were reported [233]. Such prodrugs are, of course, insoluble in water but formed dispersions when briefly sonicated in EtOH/water mixtures containing sodium taurodeoxycholate. No significant hydrolysis was seen in buffer or plasma. In contrast, incubation with pancreatic lipase yielded the bis-deacyl derivatives (i.e., 8.182 and 8.185, respectively), with subsequent liberation of phenytoin the time for 50% liberation of phenytoin varied from 20 to 200 min under the conditions of the studies [233][234], The intermediates 8.182, 8.184, and 8.185 were also substrates for human and rat plasma hydrolases. 

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