Polyoxyethylene POE

So the prediction is that in solution at fairly low to high dielectric constant, the anti-gauche conformation is likely to be the stable one. But, when we consider the conformational equilibrium in this molecule, we expect to find that since gauche 

TABLE 8.1. MM4 Conformational Energies (kcal/mol) of Polyoxyethylene Model (POE)  

Conformations Steiic Energy (Gas Phase) Steiic Energy (Solution, D = 5.0) 

---

Number of ethylene oxide groups in esterified polyoxyethylene (POE). See Table 1. 

The hydration of polyoxyethylene (POE) is dramatically affected by the anion present(J 0) in the aqueous phase. The adsorption of HEC (both 2.0 and 4.3 M.S.) was therefore studied in Na SO and Na PO, at equivalent normalities. The multivalent anions are more effective in precipitating POE than is the chloride ion. The amounts adsorbed and the interlayer expansions at normalities below precipitation conditions are given in Table III. The influence of multivalent anions on the intrinsic viscosity of variable M.S. HECs is illustrated in Figure 6. The increased amounts adsorbed are within experimental error, but the decrease in d. with the 4.3 M.S. HEC is notable. The d. changes in the absence of increased adsorption are not explainable in terms of solvation effects. 

Fig. 18 Plots of log Ceff vs chain length for polymethylene (PM) and polyoxyethylene (POE) chains under conditions, calculated from (56)...

This paper will discuss data from the recent literatures and from our laboratory on structural effects for the usual and novel types of polyoxyethylene(POE) nonionics listed in Table I. These will be described for each type of nonionic in the order listed in Table I. 

Kawaguchi et al.125) prepared an ionene-oxyethylene-ionene (IEI) triblock copolymer with the molecular weight 72 X 103 and measured its surface tension in aqueous KBr. They also determined by ellipsometry the adsorbance and the thickness of the adsorbed polyelectrolyte layer at the air-KBr solution interface as a function of the KBr concentration. The data obtained indicate that this copolymer is surface-active and that the effect of added KBr on the surface tension is stronger than in the case of polyoxyethylene (POE). 

In 1978, two papers, one from Israel and one from Japan, published in the same issue of the Journal of Pharmacy and Pharmacology reported successful rectal insulin absorption by use of polyoxyethylene (POE) ether nonionic surfactants [59,60], These reports led to further investigations on the use of surfactants for enhancing the absorption of macromolecules. Later in this chapter we will discuss the work done on the enteral delivery of large molecules with nonionic and anionic promoters, which have been the most investigated ones to date. 

Polyoxyethylene (POE) (20) sorbitan monooleate (Tween 80, Lot 36218, ICI Surfactants, Inc.) was used as received with no further purification. The average molecular weight of Tween 80 is 1310 g/mole, the density is 1.07 g/cm3, the hydrophile-lipophile balance (HLB) is 15, the critical micelle... 

Some studies reported that polyoxyethylene (POE) stearates (under the brand name Myrj) and alkyl-polyethyleneoxide (PEO) surfactants (under the brand name Brij) can inhibit efflux pumps. The oral bioavailability of the P-gp substrate cyclosporine A administered in a solid dispersion of polyoxyethylene 40 stearate (Myrj 52) was in the same range as the oral bioavailability of the commercial product Sandimmune Neoral (Liu et al. 2006). In a study by Lo, it has been shown that apical to basolateral epirubicin transport across Caco-2 cells was enhanced in the presence of polyoxyethylene 40 stearate and the basolateral to apical transport was decreased. These results indicate that polyoxyethylene stearates effect efflux pumps (Lo 2003). Similar results were gained when using polyoxyethylene laurylether (Brij 30). In another study, tablets based on polyoxyethylene 40 stearate containing the P-gp substrate rhodamine 123 increased the oral bioavailability in rats by about 2.4-fold (Foger et al. 2006a). 

Nonionic Polyoxyethylene (pOE or EO) Polyoxyethylene/polyoxypropylene (pOE/pOPor EO/PO) Carbohydrates... 

One may attempt to derive the ideal shear strength So of the van der Waals solid normal to the chain axis from the value of the lateral surface free energy, a. This value is well known for common polymers such as PE or polystyrene (PS) (Hoffman et al, 1976) or else can be calculated from the Thomas-Stavely (1952) relationship a = /a Ahf)y, where a is the chain cross-section in the crystalline phase, Ahf is the heat of fusion, and y is a constant equal to 0.12. If one now assumes that a displacement between adjacent molecules by Si within the crystal is sufficient for lattice destruction then the ultimate transverse stress per chain will be given by So = cr/31. The values so obtained are shown in Table 2.1 for various polymers. In some cases (nylon, polyoxymethylene, polyoxyethylene (POE)) the agreement with experiment is fair. In the others, deviations are more evident. In order to understand better the discrepancy between the experimentally observed and the theoretically derived compressive strength one has to consider more thoroughly the micromorphology of polymer solids and the phenomena caused by the applied stress before lattice destruction occurs. 

Polyoxyethylenated (POE) Fatty Alcohol Carboxylates (Alkyl Ether Carbox-ylates), R0(CH2CH20)xCH2C00M (x = 4, usually) Products of the reaction of the terminal OH group of an alcohol ethoxylate (AE) with sodium monochlor-oacetate. Less basic than soaps of comparable chain length, ascribed to the ether oxygen atom adjacent to the carboxylate group in the molecule. 

Polyoxyethylenated (POE) Fatty Acid Monoethanolamide Sulfates, RCONHCH2-CH20(CH2CH20)3S03Na RCO is usually derived from coconut oil. Produced by... 

Liquids, soft solids, solids or flakes. Solubility properties depend on length of polyoxyethylene (POE) segment added lo a specific fatty acid. Compounds are insol in water. Sol is oil and hydrocarbon solvents when ethylene oxide units are added. Soly in water begins when 12-IS ethylene oxide units are added. Specific gravity and viscosity increase with increasing ethylene oxide content. 

---