The self-bodying action of alkyltrimethylammonium bromides/cetostearyl alcohol mixed emulsifiers; Influence of quaternary chain length

Barry, Brian W.; Saunders, G.M

doi:10.1016/0021-9797(71)90229-3

Cited by 31 publications

(6 citation statements)

References 11 publications

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“…The formation of multimolecular micelles leads to a loss of chain mobility and the formation of a viscoelastic gel network, discernible by a sudden increase in G ′. The formation of micellar gel networks has previously been reported to give rise to considerable viscoelastic properties in other pharmaceutical semisolids such as creams 24, 25. Above the critical micelle temperature ( T m ), the poloxamer systems exhibited rheological properties that were typical of physically entangled (pseudocrosslinked) gels, evident from the relative plateau in G ′ over 2 decades of oscillation frequencies 17, 26.…”

Section: Discussionmentioning

confidence: 96%

Solute and solvent effects on the thermorheological properties of poly(oxyethylene)–poly(oxypropylene) block copolymers: Implications for pharmaceutical dosage form design

Jones

Brown

Woolfson

2002

J of Applied Polymer Sci

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Despite their widespread use as platforms for topical drug delivery systems, there is a relative lack of information concerning the thermorheological and viscoelastic properties of poloxamer systems and the effects of formulation components on these properties. To address this deficit, we examined the effects of the poloxamer concentration (25 and 35% w/w), molecular weight blend (poloxamer 407 and poloxamer 188), cosolvents (ethanol, propylene glycol, and glycerol), and presence of inorganic and organic electrolytes (sodium chloride and tetracaine hydrochloride, respectively) on these properties. The rheological properties were examined with a rheometer (4-cmdiameter, stainless steel, parallel-plate geometry) in either thermal sweep (0.5 Hz) or frequency sweep (0.01-1.0 Hz and 37°C) modes. Increasing the poloxamer concentration increased the elasticity [i.e., increased the storage modulus (GЈ) and reduced the loss tangent (tan ␦)] and reduced the sol-gel transition temperature (T m ) of all the formulations. Decreasing the ratio (407:188) increased T m and reduced the elasticity of all the formulations. Increasing the concentration of ethanol, propylene glycol, or glycerol in the solvent reduced T m . The presence of ethanol reduced GЈ and increased tan ␦ in a concentration-dependent fashion, whereas the viscoelastic properties of the poloxamers were more tolerant of glycerol (in particular) and propylene glycol. The elasticity of the formulations containing up to 10% glycerol and 5% propylene glycol was increased with respect to their aqueous counterparts. The presence of sodium chloride reduced T m and, at lower concentrations (1 and 3%), increased GЈ and reduced tan ␦ for aqueous poloxamer systems. Conversely, the addition of a model therapeutic agent, tetracaine hydrochloride (5 and 7% w/w), significantly increased T m and altered the viscoelastic character of the poloxamer system, notably reducing GЈ and increasing the loss modulus and tan ␦. Alterations in the viscoelastic and thermorheological properties of aqueous poloxamer systems will have implications for their clinical performance. This study, therefore, has highlighted the need for the rational selection of components in the formulation of poloxamer systems as platforms for topical drug delivery.

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Section: Discussionmentioning

confidence: 96%

Solute and solvent effects on the thermorheological properties of poly(oxyethylene)–poly(oxypropylene) block copolymers: Implications for pharmaceutical dosage form design

Jones

Brown

Woolfson

2002

J of Applied Polymer Sci

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“…The ability to produce stable emulsions of practically any desired consistency by altering the concentration of mixed emulsifier is valuable in formulation work. The self-bodying action of anionic (sodium dodecyl sulphatelcetyl alcohol), cationic (alkyltrimethylammonium bromides/cetostearyl alcohol) and non-ionic (cetomacrogol/ cetostearyl alcohol) types were examined by Barry (1968) and Barry and Saunders (1970a, 1971a, 1972a.…”

Section: Effect Of Mixed Emulsifier Concentration; the Self-bodyinmentioning

confidence: 99%

“…The influence of surfactant chain length on the properties of ternary system and emulsion networks was examined using mixed emulsifiers prepared with a homologous series of alkyltrimethylammonium bromides (C, & chain lengths) and cetostearyl alcohol (Barry and Saunders, 1971a, b).…”

Section: E Influence Of Surfactant Chain Lengthmentioning

confidence: 99%

“…In the past, it was often assumed that the solid nature of the interfacial monomolecular film imparted solid properties to the bulk preparation. However, in a series of emulsions stabilised by fatty alcohols and various ionic and non-ionic surfactants, the mixed emulsifier concentration in each emulsion was considerably greater than that required to form the condensed, monomolecular film, although emulsion consistencies ranged from fluid to semisolid (Barry, 1968;Barry and Saunders, 1970a, 1971a, 1972a. Thus, interfacial film rheology was not the dominant factor determining consistency.…”

Section: Introductionmentioning

confidence: 99%

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Influence of Gel Networks in Controlling Consistency of O/W Emulsions Stabilised by Mixed Emulsifiers

Barry

Eccleston

1973

Journal of Texture Studies

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A coherent explanation is presented of the mechanisms by which mixed emulsifiers of the surfactant/fatty alcohol type both stabilise and control the consistencies of oil‐in‐water emulsions. Original and published data are used to develop a theory in which the semisolid and other flow properties of emulsions are related to the nature, strength and extent of viscoelastic networks present in the continuous phases. These networks form from the interaction of surfactant solution with fatty alcohol and have similar properties to ternary system gels formed when the mixed emulsifiers disperse in water, in the absence of an oil. The theory is discussed with particular reference to liquid paraffin‐in‐water emulsions prepared with the surfactants anionic sodium dodecyl sulphate, cationic alkyltrimethylammonium bromides or non‐ionic cetomacrogol and fatty alcohols cetyl and stearyl and their mixtures, especially cetostearyl. It may be used also to explain the properties of emulsions prepared with a variety of oils, surfactants and amphiphiles. The effects of variation in storage time, surfactant type (ionic or non‐ionic), temperature, mixed emulsifier concentration, and alcohol and surfactant chain lengths on the rheological and microscopical properties of ternary systems and emulsions support this theory. The importance of small strain experiments (creep and oscillatory) in providing a true measure of consistency is emphasized. Continuous shear experiments, although theoretically less satisfactory, provide useful additional information when correlated with the small strain data.

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“…creep or oscillatory techniques). In these the systems are examined in their rheological ground states, and the results are analysed on the basis of linear viscoelastic theory to provide fundamental viscoelastic parameters.Creep experiments provided valuable information about the self-bodying action of various ionic and non-ionic mixed emulsifiers (Barry, 1968;Barry & Saunders, 1970a,b, 1971a,b, 1972a. Transient experiments, however, are restricted by the response time of the apparatus and recording system and by the impossibility of applying a truly instantaneous stress at the beginning of each experiment.…”

mentioning

confidence: 99%

Oscillatory testing of o/w emulsions containing mixed emulsifiers of the surfactant-long chain alcohol type: self-bodying action

Barry

Eccleston

1973

Journal of Pharmacy and Pharmacology

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Liquid paraffin-in-water emulsions stabilized by cationic (cetrimide) or non-ionic (cetomacrogol) surfactants and cetostearyl alcohol were examined at 25" in oscillatory mode, using the Weissenberg Rheogoniometer with parallel plates coupled to a digital transfer function analyser. Ternary systems, formed by dispersing the mixed emulsifiers in water, were similarly investigated. Each preparation was tested in the linear viscoelastic region, and fundamental rheological parameters, the storage modulus (G) and the real viscosity (7') were derived as functions of frequency over the range 7.91 x to 25 Hz. All ternary systems behaved similarly with respect to frequency. As this increased, G' rose and 7' fell. These trends were related to the viscoelastic nature of the systems. Both mixed emulsifiers exhibited self-bodying mechanisms, so that emulsion consistency increased as the mixed emulsifier concentration rose. This was shown by increases in G' and 7' at each frequency. The shapes of the plots and other rheological properties were related to viscoelastic gel networks formed in the emulsion continuous phases. The ternary system parameters implied that emulsion networks were similar to ternary gels, that is, they formed by the interaction of long chain alcohol and aqueous surfactant solution. The oscillatory data were compared and correlated with creep data derived for similar ionic and non-ionic dispersed systems, previously described.The self-bodying action of mixed emulsifiers of the surfactant-long chain alcohol type is their ability both to stabilize oil-in-water emulsions and to control their consistencies between wide limits. An essential feature of this action is that a significant elastic component is introduced into the rheological behaviour which distinguishes such emulsions from preparations with simple emulsifiers since these do not exhibit a prominent elastic component.Many self-bodied emulsions are semisolid and this phenomenon can be investigated by small strain experiments (e.g. creep or oscillatory techniques). In these the systems are examined in their rheological ground states, and the results are analysed on the basis of linear viscoelastic theory to provide fundamental viscoelastic parameters.Creep experiments provided valuable information about the self-bodying action of various ionic and non-ionic mixed emulsifiers (Barry, 1968;Barry & Saunders, 1970a,b, 1971a,b, 1972a. Transient experiments, however, are restricted by the response time of the apparatus and recording system and by the impossibility of applying a truly instantaneous stress at the beginning of each experiment.* nie Saunders.

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The self-bodying action of alkyltrimethylammonium bromides/cetostearyl alcohol mixed emulsifiers; Influence of quaternary chain length

Cited by 31 publications

References 11 publications

Solute and solvent effects on the thermorheological properties of poly(oxyethylene)–poly(oxypropylene) block copolymers: Implications for pharmaceutical dosage form design

Solute and solvent effects on the thermorheological properties of poly(oxyethylene)–poly(oxypropylene) block copolymers: Implications for pharmaceutical dosage form design

Influence of Gel Networks in Controlling Consistency of O/W Emulsions Stabilised by Mixed Emulsifiers

Oscillatory testing of o/w emulsions containing mixed emulsifiers of the surfactant-long chain alcohol type: self-bodying action

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