Cholesterol monohydrate dissolution in bile salt-lecithin solutions

A modified dissolution rate equation was used to quantitatively investigate the contribution of simple bile salt (BS) micelles and mixed B S-lecithin (L) micelles to a cholesterol monohydrate (ChM) dissolution. Using a least- squares technique to assess the relationship between the ChM dissolution ra te and BS concentration at a constant , concentration, good curve-fittings were obtained when the BS monomer concentration was set to equal the critic al micellar concentration (CMC). For taurochenodeoxycholate (TCDC), a dihyd roxy BS, the resulting values of parameters show that the simple TCDC micel le rate constant (ks) increases, but the mixed TCDC-L micelle rate constant (kM) decreases with increasing L concentrations. As for taurocholate (TC), a trihydroxy BS, a ChM dissolution study was conducted over the initial 2 hour period in different TC-L solutions. A similar curve-fitting analysis r evealed that the simple TC micelle ks is independent oft concentration and is much higher than the kM of mixed TC-L micelles. Moreover, the outcome of the analysis supports previously reported equilibrium dialysis study resul ts concerning the BS to L ratio of mixed BS-L micelles. According to the co llision theory, the resulting kS and kM values are interpreted.