Acetanilides solubilization

Figure 5.19 Slope (X) for plots of mol of p-substituted acetanilide solubilized mol" of poloxamer against the percentage oxyethylene in the poloxamer molecule as a function of the n value of the substituent group on the acetanilide molecule. From Collett and Tobin [83] with permission.

Table 6.28 The slopes for plots of mol p-substituted acetanilide solubilized mol" poloxamer (pH 1.0, 37° C) against percentage oxyethylene in the poloxam molecule and the n value of the substituent (from [247])...

Figure 6.33(a) Solubilization of 4-fluoroacetanilide in aqueous solutions of poloxamers L62, L63, L64, P65 and F68 expressed as equivalents of drug per equivalent of ethylene oxide against the poloxamer mole ratio. Ordinate 5/Ceo x 10 (equivalents of drug solubilized per equivalent of ethylene oxide). Abscissa Cr/Ceo x 10 (propylene oxide-ethylene oxide mol ratio), (b) The amount of p-substituted acetanilide solubilized (B) by the hydrophobe of poloxamer molecules as a function of the n value of the substituent group on the acetanilide molecule. From Collett and Tobin [247]. 

Yellow Couplers. The most important classes of yeHow dye-forming couplers are derived from P-ketocarboxamides, speciftcaHy the benzoyl acetanilides (6) (66) and the pi val oyl a ceta n il i des (7) (67). Substituents Y and Z can be used to attach baHasting or solubilization groups as weH as to alter the reactivity of the coupler and the hue of the resulting dyes. Typical coupling-off groups (X) cited in the Hterature are also shown. 

A combination of salting-out and solubilization chromatography may be employed. Thus separation of acetanilide and the three compounds derived from acetylation of p-aminophenol was successfully carried out by using solutions of potassium phosphate in aqueous methanol. 

The importance of a consideration of both solubilizate and solubilizer structure in the selection of a particular surfactant for the solubilization of a given solute is illustrated by studies of the solubilization of para-substituted acetanilides by a series of structurally related poloxamer (polyoxyethylene-polypropylene) ABA block co-polymers (Pluronic surfactants) [83]. Fig. 5.19 shows the relation between the n value for the p-substituent group of the acetanilides and the slope K of plots of the amount of drug solubilized per... 

Cross-linked gels formed by irradiation have a high water uptake capacity and sorb drugs thus giving rise to the possibility of using these systems as delayed release devices. Fig. 11.27 compares the release of acetanilide from a dialysis bag from a Pluronic F68 solution and from a gel, the drug having been solubilized in... 

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