Can plant-derived phytochemicals provide symptom relief for hair loss? A critical review.

It is known that hair growth disorders and hair loss can cause personal distress and affect well-being. Whilst clinical conditions remain a target for medical research, current research on hair follicle biology and hair growth control mechanisms also provides opportunities for a range of non-medical and cosmetic interventions that have a modulating effect on the scalp and follicle function. Furthermore, an improvement of the hair fibre characteristics (cuticle structure, cortex size and integrity) could add to the overall positive visual effect of the hair array. Since phytochemicals are a popular choice because of their traditional appeal, this review provides a critical evaluation of the available evidence of their activity for hair benefit, excluding data obtained from animal tests, and offers recommendations on improving study validity and the robustness of data collection in pre-clinical and clinical studies.

La perte des cheveux ou les troubles de la croissance sont connus pour engendrer une grande détresse et affecter le bien-être des individus. Bien que les maladies soient la cible principale de la recherche médicale, de récentes découvertes sur la biologie du follicule pileux et les mécanismes de contrôle de la pousse de cheveux pourraient donner lieu à des interventions non-médicales ou cosmétiques afin d'impacter le cuir chevelu et le follicule. De plus, améliorer les caractéristiques de la fibre capillaire (structure des cuticules, taille et intégrité du cortex) pourrait contribuer à embellir l'apparence de la masse capillaire. Les phytoingrédients sont populaires car traditionnellement utilisés dans les cosmétiques, et cette revue présente une évaluation critique de leurs bénéfices pour les cheveux, en excluant les données issues de tests sur les animaux. Des recommandations afin d'améliorer la collecte de données et la validité des études pré-cliniques et cliniques sont aussi présentées dans cette revue.

Exploring the effects of non-medical versus medical approaches to the management of skin aging in women over sixty.

This study was a pilot project, set up to assess ageing skin using a multi-disciplinary approach. The main aim of this study was to evaluate whether the use of more radical ('medical') treatments in the management of skin ageing would bring superior results and ultimately make people look younger, than the use of cosmetics ('non-medical' treatments). A simple post-hoc study design was used, whereby medical treatments varied within the group, all of them completed at least 2 weeks before the start of the study. In addition, it was of interest to assess the suitability of the proposed combination of methods. A total of 21 female participants were recruited for this study: 11 for the non-medical and 10 for the medical group. The multi-disciplinary approach consisted of instrumental measurements, self-assessment, expert assessment by Merz scales and a public perception survey. The majority of nearly 70 sets of instrumental skin data obtained in this study did not differ significantly between the non-medical and the medical group. However, the medical group gave higher self-assessment scores for their faces. The scores for hands were lower than scores for faces by both groups. This was partly supported by instrumental data (lower skin hydration on hands than on the face). The findings of the public perception survey of nine matched pairs of subjects scored the non-medical group as younger looking. Data analysis has shown that the judgement of youthfulness did not depend on either the gender or the age of observers.

An alkylpolyglucoside surfactant as a prospective pharmaceutical excipient for topical formulations: the influence of oil polarity on the colloidal structure and hydrocortisone in vitro/in vivo permeation.

There is a growing need for research into new skin- and environment-friendly surfactants. This paper focuses on a natural surfactant of an alkylpolyglucoside type, which can form both thermotropic and lyotropic liquid-crystalline phases. The aim of this study was to relate some physicochemical properties (characterised by polarisation and transmission electron microscopy, thermal analysis and rheology) of the three formulations based on cetearyl glucoside and cetearyl alcohol, to the results of in vitro and in vivo bioavailability of hydrocortisone (HC). The three formulations contained oils of different polarity (medium chain triglycerides: MG, isopropyl myristate: IPM and light liquid paraffin: LP), respectively. In vitro permeation was followed through the artificial skin constructs (ASC), while the parameters measured in vivo were erythema index: EI (using instrumental human skin blanching assay), transepidermal water loss (TEWL) and stratum corneum hydration (SCH). The vehicles based on cetearyl glucoside and cetearyl alcohol showed a complex colloidal structure of lamellar liquid-crystalline and lamellar gel-crystalline type, depending on oil polarity. Rheological profile of the vehicle was directly related to the in vitro profile of the HC permeation. In vivo results suggested that the vehicle with MG retarded the HC permeation, whereas less polar IPM and non-polar LP enhanced it. It is suggested that the enhancement is achieved either by a direct interaction with lipid lamellae of the SC or indirectly by improving skin hydration. There were no adverse effects during in vivo study, which indicates a good safety profile of this alkylpolyglucoside surfactant.

Vehicle-controlled effect of urea on normal and SLS-irritated skin.

It is known that, depending on the concentration, treatment with urea could improve skin barrier function, despite its penetration-enhancing properties. This controversial skin effect of urea has been explored systematically in this study in terms of the effect of vehicle on the performance of urea. In the first part, a series of four semi-solid emulsions with 5% (w/w) urea, varying in the type of emulsion, nature of emulsifier and polarity of oil ingredients, have been evaluated with regard to their skin hydrating and transepidermal water loss (TEWL)-modifying properties. Placebo samples were tested alongside the urea-containing ones. Two best performing moisturisers from the above were chosen for the second part of the study, in which sodium lauryl sulphate (SLS)-irritated skin was treated with both placebo and urea-containing samples. In addition to TEWL and skin hydration level, the erythema index (EI) was measured before, during and after the treatment. The results have shown that barrier-improving and hydrating abilities of urea are bi-directional and dependent on both the type of vehicle used for its delivery and the state of skin.

An investigation into interactions between polyacrylic polymers and a non-ionic surfactant: an emulsion preformulation study.

The aim of this study was to investigate possible interactions between a polymeric emulsifier and a non-ionic surfactant, with a view of achieving better understanding of emulsion stabilisation mechanisms. The polymeric emulsifier used was acrylates/C10-30 alkyl acrylate crosspolymer (Pemulen TR-2(R)), while Polyoxyethylene 20 sorbitan mono-oleate (Polysorbate 80) has been chosen as a model surfactant. Both materials were used within the concentration range relevant for their practical application. A 0.2%w/w aqueous dispersion of polymeric emulsifier, containing various amounts of surfactant (from 0.01 to 1.0% w/w) was used throughout the study. Interfacial aspects of the proposed polymer/surfactant interactions were analysed by means of surface tension measurements. Changes in the network structure of the test dispersions were quantified by continuous shear rheometry, supported by the texture analysis. To analyse the influence of hydrophobic alkyl groups present on the Pemulen TR-2(R) chains, an unmodified, hydrophilic polyacrylic acid polymer, Carbopol 934P(R), was assessed under the same conditions. The results obtained by both surface tension and rheological studies have revealed large differences in behaviour of the two polymers in the presence of the model surfactant. Pemulen TR-2(R) was shown to desorb the surfactant from the surface, within the whole concentration range studied. Furthermore, an increase in viscosity and texture profile parameters with increasing Polysorbate 80 concentration up to 0.3% w/w was evident in the case of Pemulen TR-2(R) dispersions. This was followed by a decrease in the gel network strength at higher surfactant concentrations. On the other hand, Carbopol 934P(R) has shown no signs of surfactant desorption and only small changes in the network structure with the increasing concentration of surfactant. It is shown in this study that an interaction between a polymeric emulsifier Pemulen TR-2(R) and a non-ionic surfactant Polysorbate 80 does occur in their aqueous dispersion, and that it is: (a) hydrophobic in nature; (b) concentration-dependent; and (c) has an impact on the rheological properties of dispersion.

An investigation into the temperature dependence of the rheological synergy between xanthan gum and locust bean gum mixtures.

The interaction between xanthan gum (XG) and locust bean gum (LBG) in water has been investigated using texture analysis, thermorheological analysis and high sensitivity differential scanning calorimetry. For the batches of XG and LBG used in the present study and at a total polymer concentration of 1% w/v, texture analysis indicated that the greatest synergy occurred at approximately 10% w/w XG, while the technique also allowed measurement of the increase in strength resulting from heating the mixes to 70 and 80 degrees C and cooling to room temperature. Thermorheological studies showed a maximum in viscosity for the xanthan gum gels at approximately 45 degrees C; this maximum became less pronounced as the concentration of XG decreased. High sensitivity differential scanning calorimetry indicated that XG undergoes two transitions at approximately 30 and 80 degrees C on heating, but on cycling a single transition is seen at approximately 74 degrees C. It was also noted that the transitions were diminished or were absent in the presence of LBG.

An investigation into the use of thermorheology and texture analysis in the evaluation of W/O creams stabilized with a silicone emulsifier.

The aim of the study was to evaluate a range of W/O semisolid emulsion systems (creams) containing white soft paraffin (petrolatum) and a new type of nonionic lipophilic silicone emulsifier (Abil EM 90) using a novel combination of rheological tests. Emulsifier concentrations from 1.5% to 3.0% w/w were used with two manufacturing procedures, cold (25 degrees C) and warm (70 degrees C) emulsification, to determine whether and to what extent these variables alter the structure and consistency of the creams. The techniques comprised linear (continuous flow) and dynamic (oscillatory) rheometry at 25 degrees C, thermal flow experiments (from 10 degrees to 90 degrees C and back to 10 degrees C), and penetrometry studies. The differences in emulsifier concentration produced effects on the rheological properties of the W/ O creams, although the manufacturing process was much more influential. Cold emulsification led to creams with higher viscosity, lower thixotropy, and better elastic properties. The results of penetration tests on creams correlated with those of the rheological studies. The flow properties of white soft paraffin at 25 degrees C were comparable with the creams obtained by cold emulsification, while the elasticity was considerably lower. Thermorheological studies showed evidence for transitional behavior for white soft paraffin on heating, but not for the creams. White soft paraffin showed a higher viscosity (and resistance to the penetrating force) when melted at 70 degrees C and left to solidify at room temperature, compared to the "unmelted" sample. This was the opposite trend to that found with warm and cold emulsified creams. The input of heat during the emulsification process showed a strong effect on the structure and consistency of the W/O creams containing petrolatum and silicone emulsifier, resulting in a less viscous product. The use of the aforementioned techniques represents a useful and novel approach to the evaluation of cream consistency.

The effects of ageing on the rheological, dielectric and mucoadhesive properties of poly(acrylic acid) gel systems.

PURPOSE: The purpose of this study was to investigate the effects of storage on the physical properties of a series of poly(acrylic acid) (PAA) hydrogels, using two dynamic techniques, oscillatory rheology and dielectric spectroscopy. Furthermore, the effects of ageing on the mucoadhesive properties were evaluated and related to the changes in structure. METHODS: Three carbomers (Carbopols 934P, 974P and EX-214) and polycarbophil (Noveon AA-1) have been formulated as hydrogels with a range of neutralising agents (NaOH, triethanolamine and tromethamine). The effects of storage for six months on the gel structure were measured using oscillatory rheology and low frequency dielectric analysis. Mucoadhesive performance was studied by means of a detachment force test. RESULTS: A substantial decrease in the rheological storage moduli was noted for all samples, while the tan delta values remained unchanged for the majority of systems. Dielectric studies revealed that gels neutralised with triethanolamine showed a greater degree of binding of neutralising ions to the gel network than did the other two agents. It was also found by the dielectric analysis that, on storage, the distribution of ions within the gel systems changed. This may be due to the neutralising ions being liberated from the gel network into the bulk aqueous phase, thereby contributing to the decrease in rheological storage modulus. Mucoadhesion studies indicated that, despite the substantial changes in gel structure, there was no alteration in the bioadhesive force of detachment for the majority of systems during a six month period. CONCLUSIONS: A redistribution of cations between the polymer cluster and the bulk of medium is proposed as a possible additional mechanism of ageing of PAA hydrogels. The results obtained support the hypothesis outlined previously that the mucoadhesive strength is related to the tan delta value rather than the viscosity of the gel.

In vitro release of calcium and hydroxyl ions from two types of calcium hydroxide preparation.

Non-setting and setting pastes are the most common forms of calcium hydroxide, used in endodontics. The aim of this study was to investigate the differences in the availability of calcium and hydroxyl ions from some commercial preparations of both types. In vitro released calcium and hydroxyl ions were determined by a potentiometric method, after diffusion through sintered glass. The non-setting pastes evaluated were Calcipulpe, Calxyl Red, Calxyl Blue and Cinacal; while setting base materials were represented by Dycal, Nu-Cap and Reolit. The data obtained showed significantly higher availability of calcium and hydroxyl ions from non-setting pastes, compared with 'alkaline cements' (P < 0.05). Great variations in the amount of released ions were also found among samples of the same material.

[New medicine forms of controlled release of fluorides into enamel]. / Novi lekoviti oblici za kontrolisano oslobadanje fluorida na povrsinu gledi.

The article deals with the description of the therapeutic system for the local application on fluorides, principles of its functioning, advantage upon classical dosages, as well as a short survey of previous attempts of its formulation.