Liquid Paraffin Emulsions Research Articles

Self-crosslinked admicelle of sodium conjugated linoleate@nano-CaCO3 and its stimuli–response to Ca2+/pH/CO2 triple triggers

Adsorption of fatty acids and soaps on solid surfaces is widely-used to modify solids but easy to be desorbed and forming soap scum in acidic and hard water. The admicelle of sodium conjugated linoleate (ASCL) on nano-CaCO3 was applied to fabricate stable [email protected]3, via SCL bilayer adsorption followed by simple thermo-curing the conjugated double bonds of SCL within an admicelle to anchor the admicelle around a nano-CaCO3 core. The structure, morphology, and properties of [email protected]3 were characterized by FT-IR, UV, TG, TEM, and contact angle measurements. High internal phase Pickering emulsions of liquid paraffin in water with oil volume fractions up to 80% could be stabilized with 1 wt% of the [email protected]3 as particle emulsifier. The stable SCL bilayer on the CaCO3 surface brings variable surface affinity in response to Ca2+/pH/CO2 triple triggers, endowing the [email protected]3 to stabilize high internal phase emulsions, switch on/off Pickering emulsions, and even lead to emulsion inversion. Therefore, the triple stimuli-responsive properties of the [email protected]3 can be effectively applied in emulsion preparation–separation and drug delivery systems.

A fluorescent pickering-emulsion stabilizer prepared using carbon nitride quantum dots and laponite nanoparticles

In this paper, a fluorescent particulate stabilizer was developed for fluorescently labeling the oil-water interface of Pickering-emulsions. In this method, carbon nitride quantum dots (CNQDs) were selected to modify liquid paraffin emulsions, which were then stabilized by Laponite. This method avoids the adverse effect of dyes in studying the droplet interfaces of Pickering-emulsions. Our results indicated that the CNQDs are stable and monodispersed due to negative electrostatic repulsions, and no fluorescence quenching was found after the introduction of Laponite. The CNQDs obviously improved the particle wettability of Laponite to liquid paraffin, suggesting that they conferred increased particle hydrophobicity, which may in turn contribute higher stability to Pickering emulsions. With tunable wettability, CNQDs@Laponite nanoparticles standing at the oil-water interface may act as an identifiable, green-fluorescent interfacial film responsible for stabilizing and labelling oil-in-water Pickering emulsions. In addition, these results indicate an improved storage stability of Pickering emulsions compared with those stabilized by Laponite.

A New Emulsifying Agent: Cucumis sativus Linnaeus Mucilage

Aim: This study aims at investigating the emulsifying properties of Cucumis sativus mucilage, compare with gelatin and tragacanth with further assessment of their combined effects on the emulsion properties. Place and Duration of Study: Department of Pharmaceutics and Pharmaceutical Technology, Olabisi Onabanjo University, Nigeria and Department of Pharmaceutics and Industrial Pharmacy, University of Ibadan, Nigeria between September 2014 and July 2015. Methodology: Cod liver oil and liquid paraffin emulsions were prepared by the wet gum method with the different emulsifying agents. Primary emulsions of cod liver oil were prepared using a ratio of 4:2:1 for oil, water and gum while 3:2:1 was used for liquid paraffin. Cucumis was also combined with gelatin and tragacanth respectively at different ratios (1:1, 1:2 and 1:3). The emulsions were assessed for emulsion type, creaming, viscosity, globule sizes and size distribution. Results: The emulsions formulated were creamy and dilution tests showed that they were oil-in-water in nature. The ranking of the creaming for cod liver oil and liquid paraffin emulsions was tragacanth>Cucumis>gelatin and gelatin>Cucumis>tragacanth respectively. There were significant differences (p<0.001) in the viscosities of the emulsions with tragacanth having the highest values. The average globule sizes ranged between 2.5-97.5 µm. The effect of storage on the viscosity showed that viscosity of emulsions decreased with time. Conclusion: The results of this study indicates Cucumis sativus mucilage could be useful as a primary emulsifying agent in oil-in-water emulsions.

EMULSIFYING PROPERTIES OF AFZELIA GUM IN LIQUID PARAFFIN EMULSION

Objective: Afzelia africana gum has been shown to possess surface activity. It is a good alternative to sodium carboxy methylcellulose in terms of suspending properties. This work was aimed at evaluating the emulsifying properties of the gum in liquid paraffin emulsion.Methods: Liquid paraffin emulsions (200 ml each) were prepared with different concentrations (1, 2, 3, 5 and 10 % w/v) of afzelia gum as an emulsifying agent. Similar preparations containing standard acacia gum at corresponding concentrations were also made. Liquid paraffin emulsions (200 ml each) were equally prepared using 60 ml liquid paraffin as the oily phase and 6 g of various combinations of afzelia gum and tween 80 as emulsifier blends. The emulsifier blends were of ratio 1:5, 1:2, 1:1, 2:1 and 5:1. The preparations were assessed for density and viscosity; and then for stability after 5 d of storage.Results: The viscosity of emulsion containing 10 % w/v afzelia gum was 668.90 mPa.s while that of an emulsion containing the same concentration of acacia gum was 23.56 mPa. s. Emulsion containing 3 % w/v afzelia gum (having a creaming index of 16 %) was found to be more stable compared to the emulsion containing 10 % w/v acacia gum (having creaming index of 28 %). The viscosity and stability of emulsions containing emulsifier blends of afzelia gum and tween 80 increased with increase in the proportion of afzelia gum.Conclusion: The gum is suitable for use at a concentration of 3 % w/v as an emulsifier in 30 % v/v liquid paraffin emulsion, and it is about three times better than acacia gum as an emulsifier. It is a good alternative to standard acacia gum for emulsification.

CO2-responsive aliphatic tertiary amine-modified alginate and its application as a switchable surfactant

A new kind of hexyl diethyl tertiary amine-grafted amphiphilic alginate derivative (HDEA-Alg) was synthesized from (6-bromo-hexyl)-diethyl-amine (BHDEA) and sodium alginate (NaAlg) through esterification. The structure of HDEA-Alg was confirmed by FT-IR and NMR spectroscopies. The grafting ratio was calculated according elemental analysis and thermodynamic property was analyzed by TG. The CO2/N2-responsive performance of HDEA-Alg in aqueous solution was demonstrated by surface tension and conductivity measurements. Stable emulsions of liquid paraffin were easily prepared in the presence of the HDEA-Alg. These emulsions can be de-emulsified by bubbling CO2 through the emulsions at 5°C for 30min, resulting in complete oil/water phase separations. They can be re-emulsified by bubbling N2 through the solutions at 50°C for 30min with the aid of homogenization.

Water-soluble cellulose derivatives. Uses as primary emulsifying agents. Part II.

Abstract A study has been made of the effects of heat, acid and alkali, salts and alcohol on the stability of methyl-, methylethyl- and sodium carboxymethyl-cellulose emulsions of liquid paraffin. All were stable for 4 to 8 weeks at 40°, but at 80° deteriorated rapidly, the order of decreasing stability being methyl-, methylethyl- and sodium carboxy-methylcellulose emulsions. Heating at 115° for 30 minutes decreased the stability of sodium carboxymethylcellulose, but not of methyl- and methylethyl-cellulose emulsions. Stability in the presence of added substances depended largely on the physical properties of the reaction products. The results are related to the behaviour under similar conditions of aqueous dispersions of the three derivatives, and the influence on emulsion stability of dehydration and degradation of the emulsifying agent is discussed.

A new method for the determination of emulsion stability by dielectric constant measurement: a preliminary report

Abstract The creaming of emulsions of liquid paraffin in water stabilised by cetomacrogol 1000 has been studied in a specially designed capacitance cell. Before visual separation of the emulsion is detectable, changes in emulsion composition in the upper part of the cell result in a measurable decrease of dielectric constant. Differences in the creaming rates of a number of emulsions are easily detected and the rate of change of dielectric constant with time is dependent on globule size.

The use of the Coulter Counter for the particle size analysis of some emulsion systems.

Abstract The Coulter Counter is suitable for the particle size analysis of emulsions containing insoluble oils. All the emulsions obey the log normal distribution of particle size if allowance is made for particles below the lower limits of the apparatus. The variation of particle size with emulsifier concentration and volume fraction has been studied for liquid paraffin emulsions stabilized by potassium laurate and potassium arabate.

The effect of emulsifier concentration on the rheological properties of acacia emulsions.

Abstract The effect of potassium arabate concentration on the rheological properties of liquid paraffin emulsions has been examined over a range of emulsifier concentrations and volume fractions. The emulsions were of small particle size. Aggregation of the emulsions occurred when the volume fraction (ø) was in the region of 0·33–0·43, the exact value of ø depending on the emulsifier concentration. The aggregated emulsions demonstrated irreversible shear thinning and hysteresis loops were obtained. The aggregation only occurred during the emulsification process and was due to a macro-molecular bridging mechanism. The emulsifier concentration influenced aggregation and thereby influenced the rheological properties of the emulsions by two opposing mechanisms. It decreased the volume fraction at which aggregation first occurred (øagg), through its influence on particle size, but increased øagg through its effect on the degree of contraction of the acacia molecule.

The influence of emulsifer concentration on the rheological properites of an oil-in-water emulsion stabilized by an anionic soap.

Abstract The rheological properties of liquid paraffin emulsions stabilized by potassium laurate have been found to be markedly dependent on emulsifier concentration. Reversible aggregation of the emulsion began at 1.0% soap and the more highly aggregated systems demonstrated pseudoplastic flow. A maximum relative viscosity was found at 5.0% soap concentration. The viscosity was dependent on particle size but correction for particle size differences did not alter the viscosity concentration relation. The addition of electrolytes to the emulsion demonstrated the difference between surfactant aggregation and electrolyte aggregation. The latter was explained by the Derjaguin-Verwey-Overbeek theory of colloid stability, whilst the former was only satisfactorily explained by the theory advanced by Cockbain in 1952 involving polymolecular adsorption at the oil-water interface and hydrophobic bonding.

Emulsifying and suspending properties of cashew gum

The emulsifying and suspending (thickening) potentials of the gummy exudates derived from cashew (Anacardium occidentale L.) tree were investigated and compared (at selected concentrations) with those of standard acacia. Both gums were found to form deflocculated suspensions when used to prepare 10%w/v sulphamethoxazole suspensions. Cashew gum (CG) gave suspensions that appear fluffier and were easier to re-disperse than does acacia gum (AG) atsame concentrations. Emulsifying abilities of CG were juxtaposed with those of established AG and both gums were found to produce emulsions of liquid paraffin with varying stabilities. At 10%w/v emulsifier concentration, emulsions made with CG creamed within 24 hours of formulation but at 20%w/v, the emulsion remained stable throughout the 8 weeks period of observation. While none of the emulsion samples cracked over the period of observation a directcorrelation was noticed between globule size and emulsion age. Nonetheless 15%w/v CG suffices as appropriate for thestabilization of extemporaneous preparations

US 4,923,916 &amp; US 4,923,917 Fire retardants for polystyrene and sma

Liquid paraffin emulsions stabilized by sodium dodecyl sulfate with long-chain alcohols have been examined by microscopy, particle-size analysis, continuous shear rheometry, and creep. The disperse phases were aggregated and emulsions were viscoelastic and thixotropic and developed crystals on storage. Emulsions were firm and rheologically stable when cetostearyl alcohol was used. They were similar but slightly less stable when formulated with (a) a mixture of C16 and C18 alcohols in the ratio present in cetostearyl alcohol and (b) a mixture of C10, C12, C14, C16, and C18 alcohols in similar ratios. Emulsions were less stable when formulated either with C16 or with mixtures of C16 and C18 alcohols in ratios 31, 11, and 13. A more mobile, less stable emulsion was obtained with C18 alone, but a stiff emulsion was formed provided that the ratio of C16 to total alcohol (C16 plus C18) was greater than approximately 0.07. Differences between emulsions were not related to particle-size distribution but to the nature and content of the C18 alcohol, which influenced the strength of the viscoelastic network formed. Trace amounts of unidentified compounds exerted a minor effect.

Rheology of systems containing cetomacrogol 1000—cetostearyl alcohol. I. Self-bodying action

Emulsions of liquid paraffin in water stabilized by the mixed emulsifier cetomacrogol 1000-cetostearyl alcohol have been examined using rheological, microscopical, and particle size analytical techniques. The rheological properties of the emulsions were related to gel networks formed in the continuous phases. These networks had similar properties to ternary systems formed by dispersing the mixed emulsifier in water. The networks were not fully formed immediately after preparation; they built up over a period of time at 25°C, and thus the creep compliances fell and the viscosities rose on storage. The mechanisms responsible for the formation of the nonionic networks are discussed and compared with the mechanisms which function in gels formed by ionic surfactant/long-chain alcohol mixed emulsifiers.

Rheology of systems containing cetomacrogol 1000—cetostearyl alcohol. II. Variation with temperature

Gel networks in the continuous phases of emulsions of liquid paraffin in water stabilized by cetomacrogol 1000-cetostearyl alcohol mixed emulsifier have similar properties to those of ternary systems which form on dispersing the mixed emulsifier in water. The rheological changes with temperature of a typical emulsion and ternary system were examined by continuous shear (cone/plate viscometer) and creep (concentric cylinder viscometer) experiments. Variations in the viscosities and compliances were correlated with thermal-phase transitions determined microscopically. The nonionic network was tenuous. At high rates of shear, it fractured in the cone- and-plate gap, and further investigations were performed at lower shear rates. In creep, the extent of viscoelastic linearity was restricted, especially at high temperatures. The consistency of the ternary system increased to a maximum, as the temperature rose. The temperature of maximum consistency was close to the temperature at which the gel melted to form the liquid crystalline phase. At higher temperatures, the consistency decreased as the network weakened and finally dissolved to form isotropic solution. The emulsion plots did not reveal a temperature of maximum consistency. Abrupt changes in the compliance and viscosity plots vs temperature indicated that the emulsion network melted at a lower temperature than the ternary system. This was due to the liquid paraffin which lowered the temperature of phase transitions.

The self-bodying action of the mixed emulsifier cetrimide-cetostearyl alcohol.

Liquid paraffin emulsions stabilized by the mixed emulsifier cetrimide/cetostearyl alcohol have been examined by microscopy, particle size analysis, continuous shear rheometry, and creep. The disperse phase of each emulsion was aggregated, and many of the nonspherical particles contained crystals of cetostearyl alcohol. The rheological properties of each emulsion were not related directly to the particle size distribution but to a gel network present in the continuous phase. This gel network was shown to be similar to that formed by dispersing cetrimide and cetostearyl alcohol in water so as to form a ternary system. All the systems showed complex flow properties in continuous shear experiments, e.g., hysteresis loops denoting irreversible shear breakdown. Additional complex flow properties, i.e., spur points and dilatancy, apparent in emulsions containing greater than 5% mixed emulsifier, were related to the structure in the continuous phase. In creep, mechanical models of three Voigt Units in series with a Maxwell Unit were deduced. In ternary systems and emulsions, the compliances decreased and the viscosities increased as the cetrimide/cetostearyl alcohol concetration increased. The creep parameters indicated that emulsions containing greater than 5% mixed emulsifier increased in consistency on aging, owing to the orientation of gel structure in the continuous phase.

Rheology of emulsions stabilized by sodium dodecyl alcohols

Liquid paraffin emulsions stabilized by sodium dodecyl sulfate with long-chain alcohols have been examined by microscopy, particle-size analysis, continuous shear rheometry, and creep. The disperse phases were aggregated and emulsions were viscoelastic and thixotropic and developed crystals on storage. Emulsions were firm and rheologically stable when cetostearyl alcohol was used. They were similar but slightly less stable when formulated with (a) a mixture of C16 and C18 alcohols in the ratio present in cetostearyl alcohol and (b) a mixture of C10, C12, C14, C16, and C18 alcohols in similar ratios. Emulsions were less stable when formulated either with C16 or with mixtures of C16 and C18 alcohols in ratios 31, 11, and 13. A more mobile, less stable emulsion was obtained with C18 alone, but a stiff emulsion was formed provided that the ratio of C16 to total alcohol (C16 plus C18) was greater than approximately 0.07. Differences between emulsions were not related to particle-size distribution but to the nature and content of the C18 alcohol, which influenced the strength of the viscoelastic network formed. Trace amounts of unidentified compounds exerted a minor effect.

The Effect of Electrolytes on O/W Emulsions Stabilized by Alkyl Phosphoric Surfactants

The effect of electrolytes on the viscosity of the emulsions of liquid paraffin stabilized by a series of alkyl ethoxy phosphates have been investigated.It is a well known fact that the viscosity of emulsions is changed by the addition of electrolytes. Our experiments showed that the viscosiy of the emulsions decreased as the added electrolytes increased and it began to rise again after passing through a minimum point of viscosity. The viscosity of the emulsions stabilized by trilauryl ethoxy phosphate decreased most remarkably by the addition of electrolytes. By using this surfactant we obtained the following facts.The minimum points of viscosity were included in the concentration range between 20 and 60m equiv./1 of the electrolytes and they had no relation to the valence of ions or their characteristics: and anions of electrolytes exert influenec on the decrease of the viscosity while cations have the reincreasing effect. However, the above-mentioned principles are not applicable to salts such as Na2CO3 or Na3PO4, which are hydrolized in aqueous solutions to make them alkaline.Friling et al. recently reported that a latex emulsion stabilized by soap is obtained in the form of gel when the concentration of electrolyte is low. But when the concentration of elecrolyte increased, the viscosity of emulsion was decreased. The reasons are as follows: the droplets are surrounded by the water layer which is more highly viscous than ordinary liquid water, and these hydrated particles approach the state of close packing. Supposedly, the effective volume concentration was decided by the volume of the polymer plus the volume of the charged double layer which prevented the particles from approaching one another.According to our data, it may be assumed that not only the electrical double layer but also the hydration layer on the surface of droplets exert effect on the change of the viscosity.

Emulsions of Liquid Paraffin and Castor Oil in Chronic Dyspepsia in Childhood

Emulsions of Liquid Paraffin and Castor Oil in Chronic Dyspepsia in Childhood