Dissolution Kinetics of Griseofulvin in Sodium Dodecylsulphate Solutions

Drug Dissolution Into Micellar Solutions: Development of a Convective Diffusion Model and Comparison to the Film Equilibrium Model with Application to Surfactant-Facilitated Dissolution of Carbamazepine

“…The difference in the 20-fold increase and the 6-fold increase observed between the solubility and dissolution is due to the contribution to the total transport of both the enhanced solubility from the micelle solubilization, a 20-fold increase, and the effective diffusivity of the micelle-solute complex, a 3-fold decrease, hence the net 6-fold enhancement in dissolution. [4][5][6][7][8][9][10][11] Regression analysis of the data in Figure 5 yielded an intercept of 2, which is statistically different from the theoretical intercept of 1 predicted by eq 15 (p < 0.01). A possible explanation for this deviation may be found in the model assumption of constant micelle size for all concentrations of surfactant.…”

“…approximated by the Levich equation (eq 9) is Equation 9 can be applied to micelle-facilitated dissolution by substituting D eff for D i and c total for c s(o) to give [6][7][8][9][10] The reaction factor, φ FM , which is the total flux divided by the flux of the free solute, is given by Equation 12 is based on the assumption that the diffusional boundary layer, as defined by the effective diffusivity, is the same for both the solute and the micelle. This is a reasonable approximation when the diffusivities of all species are similar.…”

“…[1][2][3][4][5][6][7][8][9][10][11] Models commonly used to describe dissolution in general, such as the film equilibrium, reaction plane, and surface renewal, have been applied to micelle-facilitated dissolution problems. 1,3,[6][7][8][9][10][11][12] The most often used is the film equilibrium model, which assumes simultaneous diffusive transport of the free solute and micelle in equilibrium within a common stagnant film at the surface of the solid (Figure 1). An effective diffusivity is defined to describe the total diffusion component of the micelle and free solute.…”

“…This model has been adapted to include convective diffusion transport for the welldefined hydrodynamics of the rotating disk by substituting the effective diffusivity of the free solute and drug-loaded micelle for the diffusion term in the Levich equation. [6][7][8][9][10][11][12] A drawback to using this adaptation for convective diffusion transport problems is that the effective diffusivity of the solute and micelle is approximated for a common boundary layer. 10 By contrast, the reaction plane model explicitly includes the individual transport properties of each reacting species, i.e., diffusion and convection, but is limited to irreversible reactions ( Figure 1).…”

Dissolution of Ionizable Water‐Insoluble Drugs: The Combined Effect of pH and Surfactant

“…Singh et al 6 investigated the influence of micelle-drug solubilization on the dissolution rate for the benzocainepolysorbate 80 system under different hydrodynamic models. De Smidt et al [7][8][9] reported the effect of sodium lauryl sulfate on the dissolution of griseofulvin, a poorly soluble drug. On the other hand, Mooney et al 10,11 investigated the effect of pH on the solubility and dissolution of ionizable drugs based on a film model with total component material balances for reactive species, proposed by Olander.…”