Creaming, emulsions

Use of a shoe poHsh imparts high gloss, maintains the supple hand of the leather (qv), and increases the weather resistance of the leather (3,57—59). Three general types of poHshes are produced solvent pastes, self-polishing Hquids, and emulsion creams. Solvent pastes represent ca 60% of the market (58). 

Emulsions - creaming and rheology), Curr. Opin. Colloid Interface Sci. 7, 419. 

The stability of suspensions, emulsions, creams, and ointments is dealt with in other chapters. The unique characteristics of solid-state decomposition processes have been described in reviews by D. C. Monkhouse [79,80] and in the monograph on drug stability by J. T. Carstensen [81]. Baitalow et al. have applied an unconventional approach to the kinetic analysis of solid-state reactions [82], The recently published monograph on solid-state chemistry of drugs also treats this topic in great detail [83],... 

MM Robins. Emulsions-creaming phenomena. Curr Opin Colloid Interf Sci 5 265-272, 2000. 

FIG. 11. Transmission electron micrographs of freeze fractured oily droplets dispersed (a) in a hexagonal and (b) in a cubic liquid crystalline phase, bar 100 nm. From Mueller-Goymann, C., Liquid crystals in emulsions, creams and gels, containing ethoxylated sterols as surfactant, Pharm. Res. 1 154-158 (1984). 

The human skin is a rather complex structure, which protects the body against the environment. The aim of the different cosmetics is to repair and restore the original balance of elements in skin structure. Cosmetic preparations would need to consider any reaction between them and the components of the skin. Skin creams are known to be composed of a variety of ingredients, which are based on end use (hands, feet, face, hair, etc.), and some speciality products that are applied to the skin to repair effects such as dryness. We will now consider some recipes for skin creams. Since the number of personal care emulsion creams is very large, only a few typical examples are given here. A variety of emulsion skin care products are found commercially that claim to exhibit properties for nurturing and protecting the skin. 

Infant formula, tocopherol/tocotrienol analysis, 479, 487, 489 (table) Infrared spectroscopy, see also Fourier transform infrared spectroscopy fat measurement, 572 trans fatty acids, 505 Infrared/ultrasonic scanner for emulsion creaming, 597-598 Injection techniques for GC, 449 Insoluble recombinant proteins, purification of, 276... 

Stern model in interface studies, 626 Stokes law, in emulsion creaming, 601 Storage, of emulsions, stability test, 591-594, 597-598, 604-606 Straight-phase HPLC, lipoxygenase activity measurement, 411-412 Strain response, see Stress/strain responses... 

The product we have selected for examination is an emulsion cream of the oil-in-water type. We will refer to this product as drug E. The directions for manufacture call for addition of the active ingredient to a methylcellulose solution,... 

This equation shows why, for example, aggregated droplets in an emulsion cream faster than individual droplets, and why coagulated solids in a suspension usually sediment faster than individual particles (in both cases the effective radius is larger). 

The process of emulsion droplets floating upwards under gravity or in a centrifugal field to form a concentrated emulsion (cream) quite distinct from the underlying dilute emulsion. This is not the same as the breaking of an emulsion. See also Sedimentation. 

In many emulsions) creaming rather than sedimentation takes place. 

Mileller-Goymann, C. Liquid crystals in emulsions, creams and gels, containing ethoxylated sterols as surfactant. Pharm. Res. 1984,1, 154-158. 

Mineral oil (liquid paraffin) and light mineral oil (light liquid paraffin) are widely used components of topical formulations such as emulsions, creams. 

When the density difference between the suspension particles and emulsion droplets was not large and (fxO.l, the emulsion creamed and the suspension... 

Lidocaine is a local anaesthetic which is available as a free base and hydrochloride salt. Lidocaine base is known to form eutectic mixture with prilocaine base and this eutectic mixture forms a dispersed phase of EMLA emulsion cream. Shukla et al. reported that with the help of microemulsification, the drug loading can be increased from 5% (present in EMLA cream) to 20% which may result in quick action by virtue of higher concentration gradient across the skin [49]. 

Direct and inverse emulsions are found in everyday-life products. For instance, both types of emulsion are common in food oil-in-water emulsions include milk, cream, and mayonnaise butter and margarine are examples of water-in-oil emulsions. Furthermore, recent studies were carried out, with the help of professional sensory panelists, to determine the influence of emulsion type on the perception of taste [36], In relation to the breakdown mechanisms of emulsions (creaming/sedimentation, flocculation, coalescence, and Ostwald ripening), controlling emulsion type can be regarded as a key parameter to design stabilization/destabilization processes. In cosmetic... 

Only a few studies about aqueous films of amphiphilic random polyelectrolytes are reported in the literature. Millet et al. [239-241] have investigated by x-ray reflectivity the behavior of vertical free-standing films (Figure 29) of a series of hydrophobically modified poly(acrylic acid) sodium salt (HMPAANa) and poly(acrylic acid) (HMPAAH). The chemical structure of the polymer was presented in Sec. II.C (Eq. 2a). One of the aims of this work was to determine the microscopic structure of the films to explain the (macroscopic) stability behavior of the dodecane-in-water emulsions studied by Perrin et al. [188,189], who used the same series of amphiphilic polyelectrolytes as primary emulsifiers. The aqueous polyelectrolyte films have been used as model systems for the interstitial films separating two neighboring oil droplets of an emulsion creamed layer. The authors have assumed that the oil/water interface encountered in emulsions was suitably described by the air/water interface of the films. The HMPAANa and HMPAAH co-... 

Polymer solutions and melts, residual oils, rubber solutions, many petroleum products, paper pulps, biological fluids (blood, plasma), pharmaceutical compounds (emulsions, creams, and pastes), various food products (fats and sour cream) can serve as examples of pseudoplastic fluids. Dilatant properties are mainly exhibited by high-concentration or coarse-disperse systems (such as... 

Active ingredient solubility and particle size are generally important ingredient characteristics that need to be controlled to ensure potency uniformity in many topical drug products such as emulsions, creams, and ointments. Crystalline form is also important where the active ingredient is dispersed as a solid phase in either the oil or water phase of an emulsion, cream, or ointment. 

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