Polyoxyethylenated mercaptans

NON-IONIC SURFACTANTS Polyoxyethylenated alkylphenols, alkylphenol ethoxylates Polyoxyethylenated straight- chain alcohols, alcohol ethoxylates Polyoxyethylenated polyoxypropylene glycols Polyoxyethylenated mercaptans Long-chain carboxylic acid esters Alkanolamine condensates, alkanolamides Tertiary acetylenic glycols Polyoxyethylenated silicones N-alkylpyrrolidones Alkylpolyglycosides... 

The difficulty with HLB as an index of physicochemical properties is that it is not a unique value, as the data of Zaslavsky et al. (1) on the haemolytic activity of three alkyl mercaptan polyoxyethylene derivatives clearly show in Table 1. Nevertheless data on promotion of the absorption of drugs by series of nonionic surfactants, when plotted as a function of HLB do show patterns of behaviour which can assist in pin-pointing the necessary lipophilicity required for optimal biological activity. It is evident however, that structural specificity plays a part in interactions of nonionic surfactants with biomembranes as shown in Table 1. It is reasonable to assume that membranes with different lipophilicities will"require" surfactants of different HLB to achieve penetration and fluidization one of the difficulties in discerning this optimal value of HLB resides in the problems of analysis of data in the literature. For example, Hirai et al. (8 ) examined the effect of a large series of alkyl polyoxyethylene ethers (C4,C0, Cj2 and C 2 series) on the absorption of insulin through the nasal mucosa of rats. Some results are shown in Table II. 

Polyoxyethylene mereaptans, obtained from the reaction between an alkyl mercaptan and ethylene oxide, have been demonstrated to be good nonionic... 

Novel surface-active macromonomers were prepared via a two-step synthesis shown in Figs. 13 and 14 [47-49]. Hydrophobic alkyl methacrylate or, as shown in Fig. 13, fluoroalkyl methacrylate monomers were dissolved in a mutual solvent along with a polyoxyethylene methacrylate, a functional mercaptan, and free radically copolymerized. Utilizing the hydroxyl or carboxylate functionality of the end group, the copolymer was then rendered polymerizable by reaction with an appropriate methacrylate-containing reactant as shown in Fig. 14. 

The use of polymerizahle surfactants (surface-active macromer, SAM) in sihcone formulations has been explored to form hydrogel-like surfaces without a surface treatment (124). Several surface-active water-soluble macromers were evaluated. The SAMs were prepared using a two-step S5mthetic procedime. In this procedure, hydrophobic alkylmethacrylates or fluoromethacrylates monomers are pol5unerized with polyoxyethylene methacrylates using afunctional mercaptan as a chain-transfer agent. The resultant hydroxyl or carboxylate capped macromer (22) is further fimctionalized with a polymerizable methacrylate. 

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