Block synperonic

The poloxamers manufactured by BASF (Cheadle, UK) are known as Pluronic PE block copolymers those manufactured by ICl (Cleveland, UK) as Synperonic PE nonionic surfactants. 

Microscopic foam films have been used to study the steric interaction between two liquid/gas interfaces [130]. Two ABA triblock copolymers of the Synperonic PE series were employed P85 and F108. These commercial non-ionic surfactant were used as obtained from ICI Surfactants, Witton, UK. Blocks A are hydrophilic polyethylene oxide (PEO) chains, while block B is a hydrophobic polypropylene oxide (PPO) chain. The molecular masses and average EO contents are known from the manufacturer and yield approximate chemical formulae (Table 3.3). Data about the surface tension of electrolyte-free aqueous copolymer solutions can be seen in Fig. 3.31 [130]. It was additionally checked that NaCl (up to 510 2 mol dm 3) had no influence on these values. 

CH2-CH-OH) -(CH2-CH(OCOCH3)-OH)y-(CH2-CH-OH) -. Block copolymers of ethylene oxide-propylene oxide (ABA block of PEO-PPO-PEO), Pluronics (BASF), Synperonic PE (ICI), H-(0-CH2-CH2) -(CH2-CH (CH3)-0) ,-(CH2-CH2-0) -H. Graft copolymers, for example a poly(methyhnethacrylate) (PMMA) backbone (with some polymethacryhc add) with grafted PEO chains (Atlox4913, Hypermer CG6 ICI). 

Model suspoemulsions of polystyrene latex (mean volume diameter 1.84 pm) were prepared using the surfactant-free method, and then stabilised with Synperonic PE P94 (an ABA block of PEO-PPO-PEO with 47 PPO units and 42 PEO units) and isoparaffinic O/W emulsion (stabilised with Synperonic PE L92 with 47 PPO units and 16 PEO units). 

Two emulsifier systems were used for the preparation of O/W emulsions. The first emulsifier was Synperonic PEE 127, an A-B-A block copolymer of poly(ethylene oxide), PEO (the A chains, were about 100 EO units each) and propylene oxide PPO (the B chain was about 55 PO units), supplied by UNIQEMA. The second emulsifier system was Arlatone V-100 (supplied by UNIQEMA), a nonionic emulsifier system composed of a blend of Steareth-100 (stearyl alcohol with 100 EO units), Steareth-2 (stearyl alcohol with 2 EO units), glyceryl stearate citrate, sucrose, and a mixture of two polysaccharides, namely mannan and xanthan gum (Keltrol F, supplied by Kelco). In some emulsions, xanthan gum was used as a thickener. AH emulsions contained a preservative (Nipaguard BPX). 

The above change was recently measured using O/W emulsions that were stabilised with an A-B-A block copolymer of poly(ethylene oxide) (A) poly(propylene oxide) (B) Synperonic NPE 127 (UNIQEMA). O/W emulsions (60/40) were prepared using 0.5, 1.0, 1.5, 2.0, 3, 4, and 5% emulsifier. Figure 21.15 shows the variation in droplet size with time at various Synperonic PEE 127 concentrations. 

Also the effect of block-copolymer surfactants (Synperonic NPE) on the viscosity and stability of suspensions as a function of the PEO chain length is studied [278], The critical volume fraction of coal in suspension and maximum stability were observed for a surfactant with 48 PEO units. At 27 PEO units, flocculation appeared. In the interval from 79 to 174 PEO, desorption resulted leding to an increase in suspension flocculation. Thus, the choice of an optimum PEO content is very important to obtain liquid and stable suspensions, considering the features of the coal nature. 

Synperonic PI 05, Synperonic PE/25R2, Synperonic PE30/10r, Synperonic PE30/20r, Synperonic PE30/40r, Synperonic PE30/80, Synperonic PE39/70. See EOiPO block polymer or copolymer Synperonic PE/F38. See Poloxamer 108 Synperonic PE/F68. See Poloxamer 188 Synperonic PE/F77. See EO/PO block polymer or copolymer... 

Synperonic PE/F87. See Poloxamer 237 Synperonic PE/F88. See Poloxamer 238 Synperonic PE/F98. See Poloxamer 288 Synperonic PE/F108. See Poloxamer 338 Synperonic PE/F127. See Poloxamer 407 Synperonic PE/L31. See EO/PO block polymer or copolymer... 

The most convenient polymeric surfactants are those of the block-and-graft copolymer type triblock polymeric surfactants—Pluronics (BASF) and Synperonic PE (ICI)—two... 

Figure 14 shows typical plots of G, G, G", and r as a function of frequency (Hz) for an isoparaffinic o/w emulsion (48) with = 0.6, which is stabilized using an ABA block copolymer of PEO-PPO-PEO (Synperonic PE), with an average of 47.3 polypropylene oxide (PPO) units and 41.6 polyethyleneoxide (PEO) units. The volume mean diameter of the droplets was 0.98 iim (as determined by the Coulter Counter). It can be seen from Eigure 14 that below a certain frequency G" > G, whereas above that frequency... 

Several examples of block and graft copolymers may be quoted. Triblock polymeric surfactants [ Pluronics (BASF) or Synperonic PE (ICI)] - two poly-A blocks of PEO and one block poly-B of poly(propylene oxide) (PPO) several chain lengths of PEO and PPO are available. Triblocks of PPO-PEO-PEO (inverse Pluronics ) are also available. Polymeric triblock surfactants can be applied as emulsifiers and dispersants. The hydrophobic PPO chain resides at the hydrophobic surface, leaving the two PEO chains dangling in aqueous solution (providing steric stabilisation). 

The most commonly employed polymeric surfactants used in pharmacy are the A-B-A block copolymers, with A being the hydrophilic chain [poly(ethylene oxide), PEO] and B being the hydrophobic chain [poly(propylene oxide), PPO). The general structure is PEO-PPO-PEO and is commercially available with different proportions of PEO and PPO (Pluronics, BASF or Synperonic PE, Poloxamers ICI). The commercial name is followed by a letter L (Liquid), P (Paste) and F (Flake). This is followed by two numbers that represent the composition - the first digit represents the PPO molecular mass and the second digit represents the % of PEO, e.g. Pluronic F68 (PPO Mol Wt 1501-1800) +140 mol EO, and Pluronic L62 (PPO Mol Wt 1501-1800) + 15 mol EO. 

Many polymers are used for the preparation of disperse systems (suspensions and emulsions) in pharmaceutical formulations. An example of such systems is the A-B-A block copolymer of poly(ethylene oxide)-poly(propylene oxide)-poly(ethyl-ene oxide), PEO-PPO-PEO, commercially available as Poloxamers (ICI), Pluronics (BASF) and Synperonic PE (ICI). On hydrophobic drug particles or oil droplets, the polymer adsorbs with the B hydrophobic chain (PPO) close to the surface, leaving the two hydrophilic A chains dangling in solution. 

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