Sodium lauryl sulfate, effect

Sodium Lauryl Sulfate Effects on Polydimethylsiloxane Absorption of Chemical Mixtures... 

Detergents are designed to be effective in hard water meaning water containing calcium salts that form insoluble calcium carboxylates with soaps These precipitates rob the soap of Its cleansing power and form an unpleasant scum The calcium salts of synthetic deter gents such as sodium lauryl sulfate however are soluble and retain their micelle forming ability even m hard water... 

Whipping aids help to preserve the whipping properties of dried egg white. Sodium lauryl sulfate [151 -21 -3] is preferred, but other approved whipping aids include triethyl citrate, triacetin [102-76-17, and sodium desoxycholate [302-95 ]. These additives are effective at levels of less than 0.02% on a soHds basis. 

Water serves as a base value in this test and sodium lauryl sulfate as a well-known irritating surfactant. Lauryl ether sulfate served as a substance with high sales volume and good skin tolerance. As was to be expected, lauryl ether sulfate scored only slightly better than lauryl sulfate. Sulfosuccinate values obtained were classified under little skin roughening effect. ... 

The active ingredients in a shampoo play three fundamental roles. Some allow water to wash away the substances that make hair dirty. Others adhere to hair to impart a desirable feel and texture. The rest are emulsifiers that keep the mixture from separating into its components. To accomplish these effects, ingredients combine two types of interactions a strong attraction to water (hydrophilic) and an aversion to water (hydrophobic). It may seem that these properties are incompatible, but shampoos contain molecules that are designed to be simultaneously hydrophilic and hydrophobic. One example is sodium lauryl sulfate, our inset molecule. The ionic head of the molecule is hydrophilic, so it interacts attractively with water. The hydrocarbon tail is hydrophobic, so it interacts attractively with grease and dirt. Molecules of the shampoo associate with hydrophobic dirt particles to form hydrophilic clumps that dissolve in water and wash away. 

Carboxypolymethylene exhibits a stabilizing effect against separation and viscosity change of a cetyl alcohol-stearic acid-sodium lauryl sulfate system. Samples 1 and 2 are identical, except that the former contains carboxypolymethylene (adjusted to pH 7). Sample 1 shows no separation, while sample 2 shows 13% separation after 6 months. Figure 8 shows the viscosity characteristics of the above samples. The broken line represents the viscosities of sample 1 at different time intervals, and the unbroken line, the viscosities at the same time intervals for sample 2. Apparently the carboxypolymethylene prevents the agglomeration and precipitation of stearic acid, which would result in separation and loss of viscosity. 

Carboxypolymethylene also exerts a stabilizing effect on a cetyl alcohol-sodium lauryl sulfate emulsion containing 15% of talc. The differential in the distribution of particles at all levels of those stabilized systems discussed above can be considered negligible for all practical purposes. 

Fig. 16 Effect of lubricant on dissolution of rate of salicylic acid contained in compressed tablets, x, 3% magnesium stearate , no lubricant 0> 3% sodium lauryl sulfate. (From Ref. 21.).

Ong et al. [134] found that several hydrophilic anionic, non ionic, or cationic surfactants can alleviate the deleterious effect of magnesium stearate over-mixing on dissolution from capsules when added with the lubricant in a ratio as low as 1 5 (w/w). These successful surfactants were sodium A-lauroyl sarcosinate, sodium stearoyl-2-lactylate, sodium stearate, polox-amer 188, cetylpyridinium chloride, and sodium lauryl sulfate. The lipophilic surfactant glyceryl monostearate did not alleviate the magnesium stearate mixing effect. A reduction in thier particle size was shown to enhance effectiveness, particularly in the case of surfactants with low solubility and slow dissolution rate. 

Fig. 24 The effect of percentage of sodium lauryl sulfate in the formulation on the dissolution of hydrochlorothiazide from capsules containing dicalcium phosphate as filler, 0.75% magnesium stearate, and filled on a dosator machine with 300 N tamping force (USP method 2, 900 mL 0.1 N HC1, 50 rpm). (Adapted from Ref. 71.)... 

JR Crison, ND Weiner, GL Amidon. Dissolution media for in vitro testing of water-insoluble drugs Effect of surfactant purity on in vitro dissolution of carbama-zepine in aqueous solutions of sodium lauryl sulfate. J Pharm Sci 86 384-388, 1997. 

Fig. 16 Effect of paracetamol granule size on tablet hardness. Curve 1 paracetamol granules with no added surfactant curve 2 paracetamol granules with 0.2% w/v sodium lauryl sulfate. (From Ref. 81.)...

Ross and Miles foam heights with amide fatty acid amides, 2 456t viscosity enhancement, 2 455t Sodium lauryl sulfate, 24 145 cosmetic surfactant, 7 834t effect of coconut diethanolamide on foaming, 2 453t... 

Besides the test substance, a positive control substance (a known skin irritant, 1% sodium lauryl sulfate in distilled water) and a negative control (untreated patch) are applied to the skin. When a vehicle is used for diluting, suspending, or moistening the test substance, a vehicle control patch is required, especially if the vehicle is known to cause any toxic dermal reactions or if there is insufficient information about the dermal effects of the vehicle. 

Various detergents were examined for their effect on lather properties. It was observed that alkyl aryl sulfonates (like sodium dodecyl benzene sulfonate) and alkyl sulfates (like sodium lauryl sulfate) had the biggest impact as foam boosters. This is not surprising, as both surfactants have head groups with high charge density, which is important for achieving rapid and stable foam [20],... 

However, one can change the structure in a known fashion, micelle to rod, etc., with remarkable precision [Thomas, J. K. Chem. Rev. 1980, 80, 283]. In actual fact, a sodium lauryl sulfate micelle is a very precise entity containing 71 1 units. A precise cooperative effect forms the micelle. If you change the conditions of the solution, such as the salt concentration, etc., then you can make other structures which are well identified. 

Fig. 13. Comparison of effect of sodium lauryl sulfate on the transfer of acetic acid from water to benzene at 25°C. in an unstirred (36, 37), and in a stirred cell (60).

Frankild S, Andersen KE, Nielsen GD. 1995. Effect of sodium lauryl sulfate (SLS) on in vitro percutaneous penetration of water, hydrocortisone and nickel. Contact Dermatitis 32 338-345. 

According to results, squalene-including mixtures were able to increase the barrier to maintain hydration in a comparable manner to vernix caseosa. Five percent sodium lauryl sulfate-treated rat and human skin showed increased transepidermal water loss and riboflavin penetration. However, squalene treatment reverts the effects of sodium lauryl sulfate. 

The use of skin permeation enhancers in combination for synergistic effects has been studied in the transdermal literature (70). Such synergistic methods can be grouped in three categories (i) combination of two physical methods, e.g., ultrasound and iontophoresis (71-75) (ii) combination of a physical method with a chemical enhancer, e.g., use of ultrasound with sodium lauryl sulfate or isopropyl myristate (76-80) and (iii) combination of two chemicals, e.g., terpenes and propylene glycol (46,81-88). Numerous studies have been published on using combination of two physical methods or use of a physical method in conjunction with a chemical enhancer. Use of a physical method, by itself or in combination with another physical method, increases application cost for delivery purposes as mentioned before. In addition, there are unexplored safety and membrane recovery issues associated with these methods. A few reports have also been published on the use of a mixture of chemical enhancers for enhancing transdermal delivery. Typically, such studies use... 

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