Natural-Origin Betaine Surfactants as Promising Components for the Stabilization of Lipid Carriers

In the present work, we demonstrate studies involving the influence of the formulation composition on the physicochemical properties of nanocarriers: solid lipid nanoparticles (SLNs) and nanostructured lipid carriers (NLCs). Novel lipid-origin platforms were prepared using two "green" betaine-based surfactants, cocamidopropyl betaine (ROKAmina K30) and coco betaine (ROKAmina K30B), in combination with three different solid lipids, cetyl palmitate (CRODAMOL CP), trimyristin (Dynasan 114), and tristearin (Dynasan 118). Extensive optimization studies included the selection of the most appropriate lipid and surfactant concentration for effective SLN and NLC stabilization. The control parameters involving the hydrodynamic diameters of the obtained nanocarriers along with the size distribution (polydispersity index) were determined by dynamic light scattering (DLS), while shape and morphology were evaluated by atomic force microscopy (AFM) and transmission electron microscopy (TEM). Electrophoretic light scattering (ELS) and turbidimetric method (backscattering profiles) were used to assess colloidal stability. The studied results revealed that both betaine-stabilized SLN and NLC formulations containing CRODAMOL CP as lipid matrix are the most monodisperse and colloidally stable regardless of the other components and their concentrations used, indicating them as the most promising candidates for drug delivery nanosystems with a diverse range of potential uses.

Toothpastes for children and their detergent contents affect molecular mechanisms of odontogenesis in zebrafish embryos

We aimed to evaluate how different types of toothpaste (TP) for children affected molecular mechanisms of odontogenesis in zebrafish embryos. Commercially available TPs were selected according to their detergent contents as the cocamidopropyl betaine (CAPB) containing TP (TP1) and sodium lauryl sulfate (SLS) containing TP (TP2). TP3 contained no detergent. Effects of SLS, and CAPB alone were also examined. TP and detergent concentrations affecting development were determined as 750 mg/L and 4 mg/L, respectively. Embryos were exposed to TP1, TP2, TP3, SLS, CAPB, and embryo medium (control) for 72 h post fertilization. Acetylcholinesterase (AChE) activity and oxidant-antioxidant parameters were analyzed spectrophotometrically. Expressions of tooth development genes were evaluated by reverse transcription PCR (RT-PCR). Intraocular distance, lower jaw, and ceratohyal cartilage length were displayed using Alcian Blue staining. axin2 and wnt10a expressions increased in SLS and TP2 groups. igf2a and eve1 expressions decreased in all groups except TP3. nrOb1 expression decreased in TP1, SLS, and CAPB groups. Oxidant-antioxidant balance was disturbed in all groups except TP3, evidenced by increased lipid peroxidation, nitric oxide. SLS, and CAPB groups were more affected in terms of AChE, glutathione-S-transferase, and superoxide dismutase; perturbations were observed in cartilage structures. Altered expression of tooth development gene axin2 correlated with wnt10a, and with changes in cartilage structures in SLS and TP2 groups. TP3 group presented no disruptions in oxidant-antioxidant balance. Our study shows the availability of externally developing zebrafish embryos in examining the effects of TP' contents on embryogenesis.

Analysis of patch testing with cocamidopropyl betaine and its impurities in patients with intractable scalp dermatitis in a single clinic in Japan

BACKGROUND

The allergen responsible for cocamidopropyl betaine (CAPB) allergies has been debated.

OBJECTIVES

To investigate the sensitizing agents of CAPB, the patch test positivity rates of impurities were examined in Japanese patients with CAPB-related allergic contact dermatitis.

MATERIALS AND METHODS

Thirty patients with scalp dermatitis and positive patch tests for CAPB and/or lauramidopropyl betaine (LAPB) were enrolled in this study. They were patch tested with the detergents that they had been using at the time of their first visit and with the impurities dimethylaminopropylamine (DMAPA) and lauramidopropyl dimethylamine (LAPDMA).

RESULTS

The positivity rate in patch tests of the 37 detergents that the patients had been using was 78.4% (29/37). The positivity rates of DMAPA 1% pet., 1% aq. and 0.2% aq. were 32.1% (9/28), 14.3% (4/28) and 13.3% (4/30), respectively, whereas those of LAPDMA 0.1% and 0.05% were 30.0% (9/30) and 16.7% (5/30), respectively. Among the 30 patients, 6 exhibited positive results for both DMAPA and LAPDMA, 3 showed positive results for DMAPA alone and 6 produced positive results for LAPDMA alone.

CONCLUSION

Patch tests produced an overall positivity rate for DMAPA, LAPDMA or both of 50.0% (15/30) in patients with scalp dermatitis and positive patch test results for CAPB and/or LAPB.

[ANALYSIS OF PATCH TEST RESULTS USING COCAMIDOPROPYL BETAINE-RELATED SURFACTANTS]

BACKGROUND

A few previous studies have compared the patch test (PT) results obtained using different types of PT units.

OBJECTIVES

This study aimed to compare PT results between the Patch Tester 'Torii' and Finn Chamber.

METHODS

Thirty-four patients with intractable scalp dermatitis were enrolled in this study. PT were performed with three kinds of amphoteric surfactants, cocamidopropyl betaine (CAPB), high-concentration CAPB (h-CAPB), and lauramidopropyl betaine (LAPB), using both the Patch Tester 'Torii' and Finn Chamber, and the changes in the subjects' symptoms after they stopped using these surfactants were examined.

RESULTS

Regarding the PT results for CAPB, h-CAPB, and LAPB, the results obtained with the Finn Chamber included a significantly lower frequency of irritant reactions (CAPB; p=0.003, h-CAPB; p=0.046, LAPB; p=0.002) than those obtained with the Patch Tester 'Torii'. However, there were no significant differences in the frequencies of positive reactions between the Patch Tester 'Torii' and Finn Chamber in each surfactant. The same tendency was seen in PT with LAPB (p=0.041) in 17 selected patients, who showed positive or doubtful reactions in PT performed with the surfactant-containing products they had used and whose symptoms 'markedly improved' or 'improved' after they stopped using these products. Among these surfactants, CAPB exhibited the highest positivity rate; however, the differences were not significant.

CONCLUSION

In patients with intractable scalp dermatitis, PT of the abovementioned surfactants performed using the Finn Chamber were superior to those conducted using the Patch Tester 'Torii' because they resulted in fewer irritant reactions.

[A CASE OF ALLERGIC CONTACT DERMATITIS CAUSED BY DETERGENTS CONTAINING COCAMIDOPROPYL BETAINE IN WHICH AN IMPURITY WAS THE POSSIBLE CAUSATIVE AGENT]

Cocamidopropyl betaine (CAPB) is an amphoteric surfactant. It has several functions, including producing effervescence and washing effects, and thus, it is used in many cleansing products, such as shampoo and liquid body cleansers. Recently, it has become clear that some impurities that arise during the manufacturing process can have sensitizing effects. Herein, we report a case of allergic contact dermatitis caused by detergents containing CAPB, in which an impurity was determined to be the possible causative agent by patch testing and chemical analysis.A 64-year-old Japanese female developed a skin rash on the hairlines of her forehead and nuchal region one month before her first visit to our clinic. Later, the rashes, which were composed of desquamative erythema, expanded to her face, neck, upper back, and chest. Patch tests produced positive results for a shampoo and liquid body cleanser (1% aq.) that she had used as well as for CAPB (1% aq.); lauramidopropyl betaine (LAPB) (1% aq.); and lauramidopropyl dimethylamine (LAPDMA) (0.05% aq.), which is an impurity of CAPB. The rashes resolved completely after we instructed her to use products without CAPB and LAPB. When issuing such instructions, clinicians should have correct knowledge about surfactants, such as the differences between cosmetic ingredient names and quasi-drug ingredient names.

Biodegradable Amphoteric Surfactants in Titration-Ultrasound Formulation of Oil-in-Water Nanoemulsions: Rational Design, Development, and Kinetic Stability

Amphoteric amphiphilic compounds, due to their unique properties, may represent a group of safe and biocompatible surface-active agents for effective colloidal stabilization of nanoformulations. For this reason, the aim of this work was to develop and characterize the oil-in-water nanoemulsions based on two betaine-derived surfactants with high biodegradability, i.e., cocamidopropyl betaine and coco-betaine. In the first step, we investigated ternary phase diagrams of surfactant-oil-water systems containing different weight ratios of surfactant and oil, as the betaine-type surfactant entity (S), linoleic acid, or oleic acid as the oil phase (O), and the aqueous phase (W) using the titration-ultrasound approach. All the received nanoemulsion systems were then characterized upon droplets size (dynamic light scattering), surface charge (electrophoretic light scattering), and morphology (transmission electron as well as atomic force microscopy). Thermal and spinning tests revealed the most stable compositions, which were subjected to further kinetic stability analysis, including turbidimetric evaluation. Finally, the backscattering profiles revealed the most promising candidate with a size <200 nm for potential delivery of active agents in the future cosmetic, pharmaceutical, and biomedical applications.

Investigation of the interactions of cationic guar with human hair by electrokinetic analysis

Objective

Cationic guar is an important polysaccharide used as a hair conditioning agent in personal care products. In this article, we report streaming potential data demonstrating its behaviour as it interacts electrostatically with hair. Several cationic guar variants with different molecular weights (MWs) and charge densities (CDs) were examined.

Methods

All experiments were carried out with a custom‐designed streaming potential instrument so that in situ, real‐time data were monitored during the treatment of a hair plug with aqueous solutions of cationic guar and subsequent treatment with anionic surfactants—sodium laureth sulfate (SLES) and cocamidopropyl betaine (CAPB)—commonly found in contemporary shampoo formulations.

Results

The MW of the cationic guar variants plays an integral role in determining the thickness of the adsorbed polymer layer on the hair surface while CD influences the zeta potential. Data were also generated for the treatment of hair with a cationic flexible polymer (polyquaternium‐28) and cationic conditioning surfactant (behentrimonium chloride) to provide a frame of reference. The deposition behaviour on hair of high MW cationic guar variants is distinct from these conventional molecules in terms of its electrokinetic properties. We also examined the electrokinetic behaviour of cationic guar on hair types from different racial backgrounds. While the cationic guar treatment yielded similar results for the different hair types, anionic surfactant treatment resulted in quicker sorption and desorption from African, European 65% grey, and Mulatto hair as compared to Chinese, European dark brown, and Indian hair.

Conclusion

We introduce an in situ technique for measuring the dynamic sorption/desorption of charged molecules on the surface of human hair. Evaluation of a series of cationic guar species revealed varying behaviour depending on the MW and CD of the polysaccharide. Our data also demonstrate differences in the desorption properties of typical shampoo surfactants for hair from diverse racial backgrounds.

Cytotoxicity of the Ingredients of Commonly Used Toothpastes and Mouthwashes on Human Gingival Fibroblasts

Objectives:

Toothpastes and mouthwashes contain ingredients that may be toxic for oral mucosal tissues. This study aimed to assess the cytotoxicity of the ingredients of commonly used toothpastes and mouthwashes.

Materials and Methods:

This experimental study was performed on 16 toothpastes and four mouthwashes widely available in the Iranian market. First, the concentration of six main ingredients of these products, namely sodium fluoride (NaF), sodium lauryl sulfate, cocamidopropyl betaine, zinc lactate, paraben, and sodium benzoate, was determined. The methyl thiazolyl tetrazolium (MTT) assay was used to assess the cytotoxicity of these materials for human gingival fibroblasts (HGFs). The MTT assay was performed at 1, 15, and 30 minutes following exposure to five concentrations of each material in triplicate (according to the concentrations obtained in the isolation step). Data were analyzed using three-way analysis of variance (ANOVA).

Results:

The difference in the cytotoxicity of the materials was statistically significant (P<0.001). Cytotoxicity was time- and concentration-dependent; by an increase in the concentration of the materials, their cytotoxicity increased over time. The cytotoxicity of sodium lauryl sulfate and cocamidopropyl betaine was >90%. The cytotoxicity of NaF varied from 25% to 70%, and the cytotoxicity of all concentrations of zinc lactate and sodium benzoate was <50% for HGFs.

Conclusion:

To decrease the cytotoxic effects of toothpastes, sodium lauryl sulfate and cocamidopropyl betaine should be replaced with safer detergents, and the concentration of fluoride should be decreased to 400 parts per million (ppm). Alternatively, fluoride may be replaced with other antibacterial and cariostatic agents.