Sodium taurocholate interaction

Naylor et al. (1993) studied the ability of lecithin to modify the rate and mechanism of dissolution of hydrocortisone in the presence of sodium taurocholate (NaTC) solutions. They found that in the presence of lecithin, the CMC of NaTC dropped owing to the more effective solubilization capacity of the mixed micelle. Furthermore, the CMC value dropped more on saturation with hydrocortisone, implying some interaction between hydrocortisone and the NaTC/lecithin micelles. These results indicated that in the NaTC-only system, wetting effects predominated dissolution, whereas in the NaTC/lecithin system, the dissolution rate of hydrocortisone was enhanced mainly through solubilization. 

Consistent with the notion that this is an active process was the observation that metabolic inhibitors compromised transport (Fig. 1). The mechanism of coupling taurocholate translocation to metabohc energy is poorly understood. Some evidence is consistent with recent hypotheses developed for the transport of other organic compounds. An example of these hypotheses was presented by Curran et al. (18) and involves the interaction of sodium ions and amino acid transport. It is postulated that the uphill transport of amino acids into the mucosal cell depends on the maintenance of high extracellular and low intracellular sodium ion concentrations. The high extracellular sodium concentration, by enhancing sodium binding to a... 

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