Amount Of Sodium Lauryl Sulfate Research Articles

Antimicrobial Activity of the Sodium Lauryl Sulphate Used as Surfactant in the Polymeric Encapsulation Processes

Miniemulsion polymerization process is a very versatile technique used for the polymeric encapsulation of the many essential oils. In this process some surfactant compounds are used to define the capsules characteristics, as an example the Sodium Lauryl Sulphate (SLS) that is one of the most used surfactants. But, after the miniemulsion polymerization synthesis the residual amount of SLS can manifest an antimicrobial action that can improve or to prejudice the final properties of the encapsulated products, depending of its percentual concentrations. In this sense, the objective of this work was to evaluate the antimicrobial activity of polycaprolactone (PCL) capsules synthesized with different residual concentrations of the SLS surfactant after the miniemulsion polymerization processes. The antimicrobial evaluations demonstrated from solid media diffusion test that the PCL microcapsules are microbiologically inactive for the bacteria Staphylococcus aureus and Escherichia coli when are synthetized with residual concentrations of SLS below 0.0125%. The minimum inhibitory concentration (MIC) of residual SLS for the bacteria Staphylococcus aureus is 0.0146% and for the bacteria Escherichia coli the complete bacterial inhibition not was detected at the maximum residual concentration studied of 0.1167%.

Development and Pre-clinical Study of Anti-Allergic Cream Containing Dexamethasone and Chlorpheniramine.

In this study, we aimed to develop and optimize an anti-allergic cream containing dexamethasone and chlorpheniramine using the design of experiments (DoE) method. The optimized product was investigated for its physicochemical properties and in vivo therapeutic effects in rabbits. The creams were formulated using the simple mixing process, which was optimized by the Design Expert software. The products were then evaluated the properties such as pH, skin diffusion profile, short-term stability, qualitative, and assay, using the newly validated UV-Vis spectrophotoscopy quantitative method. In vivo efficacy tests in rabbits of the best products were compared with the marketed Phenergan® (promethazine 2%). The UV-Vis method used to simultaneously determine the amount of both dexamethasone and chlorpheniramine was successfully developed and validated. Using the DoE method, it was clear that the release profile of dexamethasone depended on the amount of sodium lauryl sulfate, propylene glycol, and DMSO. In contrast, only DMSO affected the release pattern of chlorpheniramine. The best formulation was optimized by the software. The product showed acceptable parameters in pH (5.7±0.1), short-term stability over 10 days, and skin diffusion profiles of 20.47±1.25% and 4.92±0.42% after 40 min for dexamethasone and chlorpheniramine, respectively. In addition, the product demonstrated no observable inflammatory response in the experimental animals. Also, it illustrated 2-fold better anti-allergic efficacy than the marketed product (i.e., 27.2 compared with 43.4 min in the recovery time). We were successful in developing and optimizing an anti-allergic cream containing dexamethasone and chlorpheniramine. The best product satisfied all required parameters. Interestingly, our product showed higher efficacy than Phenergan®. These results can be a background for further clinical trials.

Improvement of the dissolution behavior of gliclazide, a slightly soluble drug, using solid dispersions

Gliclazide is a second generation sulphonylurea used in the treatment of type 2 diabetes characterized by a low risk of hypoglycaemia and cardiovascular disorders. This drug shows poor water solubility, particularly at low pH values, that may cause reduced and variable absorption after oral administration, above all in fasted state. To improve gliclazide dissolution behavior, different drug carrier systems were prepared and tested using two different methods: co-mixing and co-milling. The samples produced were characterized by differential scanning calorimetry, powder X-ray diffraction, and scanning electron microscopy. Their dissolution rate was tested and compared to an immediate release commercial product. Several approaches were effective for a rapid and complete dissolution of this drug: co-milling with suitable hydrophilic carriers such as cross-linked swellable polymers or amorphous silica and co-milling with a small amount of sodium lauryl sulphate (10 mg). In the case of the highest dose (80 mg) both approaches should be used at the same time to avoid saturation of the medium.

Interactions between active pharmaceutical ingredients and excipients affecting bioavailability: Impact on bioequivalence

The aim of the present paper is to illustrate the impact that excipients may have on the bioavailability of drugs and to review existing US-FDA, WHO and EMA regulatory guidelines on this topic. The first examples illustrate that small amounts of sorbitol (7, 50 or 60mg) affect the bioavailability of risperidone, a class I drug, oral solution, in contrast to what is stated in the US-FDA guidance. Another example suggests, in contrast to what is stated in the US-FDA BCS biowaivers guideline, that a small amount of sodium lauryl sulphate (SLS) (3.64mg) affects the bioavailability of risperidone tablets, although the reference product also includes SLS in an amount within the normal range for that type of dosage form. These factors are considered sufficient to ensure that excipients do not affect bioavailability according to the WHO guideline. The alternative criterion, defined in the WHO guideline and used in the FIP BCS biowaivers monographs, that asserts that excipients present in generic products of the ICH countries do not affect bioavailability if used in normal amounts, is shown to be incorrect with an example of alendronate (a class III drug) tablets, where 4mg of SLS increases bioavailability more than 5-fold, although a generic product in the USA contains SLS. Finally, another example illustrates that a 2mg difference in SLS may affect bioavailability of a generic product of a class II drug, even if SLS is contained in the comparator product, and in all cases its amount was within the normal range. Therefore, waivers of in vivo bioequivalence studies (e.g., BCS biowaivers, waivers of certain dosage forms in solution at the time of administration and variations in the excipient composition) should be assessed more cautiously.

Effect of surfactant on the co-electrodeposition of the nano-sized ceria particle in the nickel matrix

Abstract The nickel–ceria (Ni–CeO2) nanocomposite coatings have been pulse electrodeposited from a Watts-type electrolyte containing nano-sized CeO2 particles produced by high-energy ball milling technique (HEBM). Sodium Lauryl Sulphate (SLS) has been added in the electrolyte as a cationic surfactant. The effects of the surfactant on the zeta potential, co-deposition and distribution of ceria particles in the nickel matrix and hardness of composite coatings have been investigated. Experimental results show that the addition of SLS up to 0.10 g/l increases the amount of co-deposited ceria particles in the nickel matrix and microhardness of the nanocomposite. However, when the amount of SLS in the electrolyte is more than 0.1 g/l, there is a tendency to form agglomerates of ceria particles in the nickel matrix resulting no further increase in hardness of the Ni–CeO2 nanocomposite coatings.

Novel gelatin microcapsule with bioavailability enhancement of ibuprofen using spray-drying technique

A poorly water-soluble ibuprofen and ethanol can be encapsulated in gelatin microcapsule by spray-drying technique. To develop a novel ibuprofen-loaded gelatin microcapsule with bioavailability enhancement, the effect of spray-drying conditions, gelatin, ibuprofen and sodium lauryl sulfate on the ibuprofen solubility and the amount of ethanol encapsulated in gelatin microcapsule were investigated. The ibuprofen solubility and amount of encapsulated ethanol increased as inlet temperature and amount of sodium lauryl sulfate increased, reached maximum at 105 °C and 0.6%, respectively and after that followed a rapid decrease. Furthermore, they abruptly increased as the amount of gelatin increased, reaching maximum at 4% then remaining almost stable, but the encapsulated ethanol content decreased noticeably. Likewise, the ibuprofen solubility increased as the amount of ibuprofen increased, reaching maximum at 0.5% and beyond that, there was no change in the solubility. However, the encapsulated ethanol content hardly changed irrespective of the amount of ibuprofen. Furthermore, the formula of ibuprofen-loaded gelatin microcapsule at the ratio of gelatin/ibuprofen/sodium lauryl sulfate/water/ethanol of 4/0.5/0.6/30/70 showed ibuprofen solubility of about 290 μg/ml and ethanol content of about 160 μg/mg. This gelatin microcapsule dramatically increased the initial dissolution rate of ibuprofen compared to ibuprofen powder in pH 1.2 simulated gastric fluid. Moreover, it gave significantly higher initial plasma concentrations, C max and AUC of ibuprofen in rats than did ibuprofen powder, indicating that the drug from gelatin microcapsule could be more orally absorbed in rats. Our results suggested that the enhanced oral bioavailability of ibuprofen in the gelatin microcapsule was contributed by the marked increase in the absorption rate of ibuprofen due to the crystallinity change to amorphous form and increase in dissolution rate of ibuprofen in the gelatin microcapsule in rats. Thus, the ibuprofen-loaded gelatin microcapsule developed using spray-drying technique with gelatin would be useful to deliver ibuprofen in a pattern that allows fast absorption in the initial phase, leading to better absorption.

Development of a rapidly dispersing tablet of a poorly wettable compound—formulation DOE and mechanistic study of effect of formulation excipients on wetting of celecoxib

Celecoxib has extremely poor aqueous wettability and dispersibility. A dispersibility method was developed to study the effects of formulation excipients and processing methods on wetting of celecoxib. In this method, a tablet or powder was placed in water and the turbidity of the resulting “dynamic” suspension was measured. Higher turbidity values reflect better dispersibility. Results show that wet granulation facilitates better drug dispersion than does dry granulation or direct compression. Results from a screening formulation statistical design of experiments (DOE) show that sodium lauryl sulfate (SLS), an anionic surfactant, gives higher celecoxib dispersibility than polysorbate 80, a neutral surfactant. Polyplasdone XL as a disintegrant results in better celecoxib dispersibility than sodium starch glycolate. The binder Kollidon 30 leads to better dispersibility, but slower disintegration than Kollidon 12. Jet-milling celecoxib with excipients not only improves dispersibility of the drug but also the ease of material handling. The method of microcrystalline cellulose addition does not significantly impact tablet properties. The effect of critical formulation variables on the wettability of celecoxib was further examined in prototype formulations. It is found that ionic surfactant resulted in better dispersibility than a neutral surfactant, probably due to charge dispersion. Kollidon 30 gives better drug dispersion than hydroxypropylmethyl cellulose and hydroxypropyl cellulose. This may be explained through a surface energy calculation, where the spreading coefficients between Kollidon 30 and celecoxib indicate formation of open porous granules in which pores can facilitate water uptake. The mode of disintegrant addition also impacts dispersibility of the drug. Dense granules were formed when the disintegrant, Polyplasdone, was added intra-granularly. As the extra-granular portion of the disintegrant increases, the dispersibility of the drug increases as well. The drug initial dispersibility (turbidity at 5 min during the dispersibility test) increases as the tablet porosity increases. A 3-factor face-centered experimental design was conducted to optimize the levels of surfactant (SLS), binder (Kollidon 30) and disintegrant (Polyplasdone). Within the range that was studied, the dispersibility of micronized drug increases as the amount of SLS and Kollidon 30 increases. The level of Polyplasdone has no significant impact on the dispersibility of micronized drug; however, higher levels of Polyplasdone lead to significantly harder tablets.

Percutaneous penetration of sodium lauryl sulphate is increased in uninvolved skin of patients with atopic dermatitis compared with control subjects

Involved regions of the skin in patients with atopic dermatitis (AD) have been shown to have higher transepidermal water loss (TEWL), indicating a compromised skin barrier. Whether uninvolved skin also has diminished barrier characteristics is controversial. To study the penetration of sodium lauryl sulphate (SLS) into uninvolved skin of patients with AD compared with the skin of control subjects. Percutaneous penetration was assessed using the tape stripping technique on the stratum corneum (SC). Twenty patients with AD and 20 healthy subjects were exposed to 1% SLS for 4 h on the mid-volar forearm. After the end of exposure the SC was removed by adhesive tape. The amount of SLS was determined in each consecutive strip. Fick's second law of diffusion was used to deduce the diffusivity and the partition coefficient of SLS between water and the SC. The SC thickness was similar in both groups; however, the TEWL was higher in patients with AD compared with that of the control group (mean+/-SD 8.4+/-4.3 and 6.3+/-2.0 g m-2 h-1, respectively). There was a correlation between SC thickness and TEWL in control subjects but no correlation was found in patients with AD. The diffusivity of SLS through uninvolved AD skin was higher compared with normal skin (mean+/-SD 12.7+/-5.8x10(-9) and 6.2+/-3.0x10(-9) cm-2 h-1, respectively), while the partition coefficient between SC and water was lower (mean+/-SD 137+/-64 and 196+/-107, respectively). The results show a different penetration profile of SLS into the SC of patients with AD compared with control subjects. This indicates that even noninvolved skin in patients with AD has altered barrier characteristics, emphasizing the importance of skin protection and prevention of skin contact with chemicals.

Surfactant effects upon dissolution patterns of carbamazepine immediate release tablet

The objective of this study was to investigate the effects of sodium lauryl sulfate upon the saturation solubility of carbamazepine, its dissolution kinetics, and T50% defined as the time required for dissolving 50% of carbamazepine. Water, 0.1 N-HCl, and phosphate buffers at pH 4.0 and 6.8 containing 0.1, 0.5, 1, and 2% sodium lauryl sulfate were used as dissolution media. The dissolution study was conducted by using the USP dissolution apparatus II with an agitation rate of 75 rpm. Samples of the dissolution media were taken in 7, 15, 30, 45, 60, 75, and 90 min, and the amounts of carbamazepine were determined spectrophotometrically at 285 nm. All dissolution data were fitted well into a four-parameter exponential equation: Q = a(1 - e(-b x t)) + c(1 - e(-d x t)). In this equation Q represented % carbamazepine dissolved at a time t, and a, b, c, and d were constants. This equation led to the calculation of dissolution rates at various time points and T50%. It was found that the dissolution rate of carbamazepine was directly proportional to the aqueous concentration of sodium lauryl sulfate. In addition, under our experimental conditions T50% values ranged from 37.8 to 4.9 min. It was interesting to note that T50% declined rapidly as the surfactant concentration increased from 0.1 to 0.5%, whereas it declined more slowly at concentrations greater than 1%. These results clearly demonstrated that the dissolution rate of carbamazepine and duration of its dissolution test could be tailored by optimizing the amount of sodium lauryl sulfate in a dissolution medium.

A Remarkably Efficient Coupling of Acid Chlorides with Alkynes in Water.

AbstractFor Abstract see ChemInform Abstract in Full Text.

A remarkably efficient coupling of acid chlorides with alkynes in water.

[reaction: see text] A highly effective direct coupling of acid chloride with terminal alkynes catalyzed by PdCl(2)(PPh(3))(2)/CuI together with a catalytic amount of sodium lauryl sulfate as the surfactant and K(2)CO(3) as the base provided ynones in high yields in water.

Synthesis of monodisperse polymeric microspheres including polyimide prepolymer by using SPG emulsification technique

An occlusion of a functional material, polyimide prepolymer (PIP), into uniform polymeric microspheres was attempted in order to demonstrate the versatility of the SPG (Shirasu porous glass) membrane emulsification technique. An oil phase consisting of hydrophobic monomers (styrene and acrylates with a longer side chain) and, although not necessarily, a water-insoluble reagent (lauryl alcohol) dissolved PIP up to 50 wt.%, and also an initiator (ADVN). An aqueous phase contained polyvinyl alcohol (PVA) and a small amount of sodium lauryl sulfate (SLS) as a stabilizing pair. The former was permeated through a SPG membrane, and uniform droplets were suspended in the latter. The seed droplets were swollen with the hydrophilic components, MMA and EGDMA, with a selective addition of isoamyl acetate, hexanol or octanol. After the swelling, an additional amount of the stabilizer solution was added. Polymerization was carried out at 343 K for 24 h. Uniform polymeric spheres, the coefficient of variation approximately 10% and occluding a maximum 28.4 wt.% of PIP were obtained. The entrapment of PIP was improved when the matrix polymer chains were crosslinked with EGDMA (but not with DVB), and an employment of the acrylates with a longer side chain, implying that the presence of ester groups are favored for a stable occlusion. A co-monomer system composed of MMA, 2-ethylhexyl acrylate and butyl acrylate plus octyl alcohol was able to occlude almost 100% of PIP in a stable condition without the presence of EGDMA.

Stability of acrylic latices in a semibatch reactor

The effects of various reaction variables on the stability of acrylic latices in a semibatch reactor were investigated by measuring the amount of coagulum formed and particle volume changes caused by limited flocculation. The amount of coagulum could be reduced signif-icantly with an increase in the level of sodium lauryl sulfate (SLS) in the monomer emulsion feed. An increase in the amount of SLS in the initial reactor charge resulted in an increase in the particle volume change due to limited flocculation later in the process. The larger the ratio of methyl methacrylate (MMA) to butyl acrylate (BA) in the copolymer, the greater the amount of coagulum produced. Both coagulum and particle volume change increased with an increase in the electrolyte concentration. Within the range studied (500–800 rpm), the agitation speed was not important to the coagulation process. Experimental data also indicated that the polymer particles could lose their stability rapidly above 40% total solids content because of the crowding effect. © 1996 John Wiley & Sons, Inc.

Sodium lauryl sulphate penetration in an in vitro model using human skin

Because of their ability to impair the skin barrier function, detergents constitute a major risk factor for the development of irritant contact dermatitis. Sodium lauryl sulphate (SLS) is a commonly used detergent for experimental studies within the area of irritant contact dermatitis. In the present study, penetration of S35-labelled SLS was studied in an in vitro model using human cadaver skin. The investigations showed that SLS is capable of permeating the skin barrier when applied under occlusion. SLS could be detected in the dermis and the amount of SLS found here was shown to depend on the dose of SLS applied on the skin. Penetration of SLS continued after removal of the SLS applied as a patch test on the skin surface. Considerable inter-individual variation in the penetration of SLS was demonstrated between different donors.

Dissolution of Lithium and Magnesium from Lithium Carbonate Capsules Containing Magnesium Stearate

A lithium carbonate capsule mix designed for an automatic capsule-filling machine used about 0.25% magnesium stearate as a lubricant. While the formulation ran well, it had an undesirably long disintegration time and a slow dissolution rate due to the waterproofing effect of the lubricant. Studies on the addition of sodium lauryl sulfate separately to both the formulation and the dissolution medium showed that 2mg (0.002%) added to the capsule (12mg/600ml of 0.3% HCl) was more effective in improving lithium dissolution than 6g (1%) added directly to 600ml of medium. Furthermore, while the addition of 0.02% sodium lauryl sulfate to the dissolution medium reduced the surface tension of the medium by more than 50%, it had no effect on dissolution rate; increasing the amount of sodium lauryl sulfate from 0.03 to 0.5% in the dissolution medium had a pronounced effect on dissolution rate. Magnesium dissolution from magnesium stearate and lithium dissolution from lithium carbonate were directly related.

Selective Bacteriostatic Action of Sodium Lauryl Sulfate and of "Dreft."

The bacteriostatic action of various soaps has undergone a considerable amount of study by many investigators. Recently, a somewhat related class of substances, the sodium alkyl sulfates, has been synthesized. These substances have also been made use of as detergents in such preparations as “Dreft,” “Drene” and other commercial products.The alkyl sulfates are half-esters of sulfuric acid. In this respect they differ from soaps which are combinations of fatty acids and alkalis. In both cases, however, the alkyl chain probably determines its bactericidal effectiveness. Sodium lauryl sulfate is a sodium alkyl sulfate containing 12 carbon atoms.The similarity of these substances to soaps suggested the possibility that similar bacteriostatic action might be exhibited by them. Accordingly, sodium lauryl sulfate as such, and “Dreft” which contains a large amount of sodium lauryl sulfate were tested for their bacteriostatic action. Twenty-one strains of Gram positive bacteria, 20 strains of Gram negative bacteria...