Development and validation of a reversed-phase high-performance liquid chromatographic method for the quantitation and stability of α-lipoic acid in cosmetic creams.

OBJECTIVE: To develop and validate a simple reversed-phase HPLC method for the quantitation and evaluation of stability of α-lipoic acid in cosmetics, according to International Conference on Harmonization (ICH) Guidelines. METHODS: The chromatography was performed on a reversed-phase Luna C18, analytical column (150 × 4.6 mm id, 5 µm particle size) with a mobile phase of potassium dihydrogen phosphate (pΗ 4.5; 0.05 M) and acetonitrile (60:40, v/v) and a flow rate of 1.0 mL min-1 with UV detection at 340 nm. Accelerated and long-term stability studies of α-lipoic acid in cosmetic cream were conducted under various degradation conditions including acid, basis, oxidation, and thermal and photolytic degradation, according to European Medicines Agency Guidelines CPMP/ICH/2736/99. RESULTS: The limit of detection (LOD) for the cosmetic cream was 0.9 µg mL-1 and the limit of quantitation (LOQ) was 2.8 µg mL-1 , while the retention time was 7.2 min. The method proved to be linear, precise and accurate. The stability results demonstrated the selectivity of the proposed method to the analysis of α-LA, and the degradation products were determined and evaluated in specific stress conditions in cosmetic creams. The applicability of the method was tested in two different developed cosmetic products (cream with 1.5 % w/w and emulsion with 1.0 % w/w of LA) and proved to be reliable. CONCLUSION: A reversed-phase HPLC-UV method was developed and fully validated for the analysis of α-lipoic acid in cosmetics. It is the first reported application on the quantitation of lipoic acid in cosmetic creams, while at the same time evaluates the stability in forced degradation conditions, in new cosmetic formulations. It proved to be suitable for the reliable quality control of cosmetic products, with a run time of <8 min that allows for the analysis of large number of samples per day.

OBJECTIF: Développer et valider une méthode HPLC (chromatographie en phase liquide à haute performance) simple en phase inversée pour la quantification et l'évaluation de la stabilité de l'acide α-lipoïque dans les cosmétiques, conformément aux Directives de la Conférence internationale sur l'harmonisation (ICH). MÉTHODE: La chromatographie a été réalisée sur une colonne analytique Luna C18 en phase inversée (150 × 4,6 mm id, taille des particules 5 µm) avec une phase mobile de dihydrogénophosphate de potassium (pH 4,5 ; 0,05 M) et d'acétonitrile (60:40, v/v) et un débit de 1,0 ml min−1 avec détection UV à 340 nm. Des études de stabilité accélérée et à longterme de l'acide α-lipoïque dans les crèmes cosmétiques ont été menées dans diverses conditions de dégradation, notamment en milieu acide, basique, par oxydation et dégradation thermique et photolytique, conformément aux lignes directrices de l'Agence européenne des médicaments CPMP/ICH/2736/99. RÉSULTAT: La limite de détection (LD) pour la crème cosmétique était de 0,9 µg ml et la limite de quantification (LQ) était de 2,8 µml−1 , tandis que le temps de rétention était de 7,2 min. La méthode s'est avérée linéaire, précise et exacte. Les résultats de stabilité ont démontré la sélectivité de la méthode proposée pour l'analyse de l'acide α-lipoïque et les produits de dégradation ont été déterminés et évalués dans des conditions de stress spécifiques dans les crèmes cosmétiques. L'applicabilité de la méthode a été testée dans deux produits cosmétiques différents développés (crème avec 1,5 % p/p et émulsion avec 1,0 % p/p d'acide lipoïque) et s'est avérée fiable. CONCLUSION: une méthode HPLC en phase inversée avec détection UV a été développée et entièrement validée pour l'analyse de l'acide α-lipoïque dans les cosmétiques. Il s'agit de la première application signalée concernant la quantification de l'acide lipoïque dans les crèmes cosmétiques et permettant en même temps d'évaluer la stabilité des conditions de dégradation forcée dans les nouvelles formulations cosmétiques. Cette méthode s'est avérée adaptée au contrôle de qualité fiable des produits cosmétiques, avec une durée d'exécution < 8 min qui permet l'analyse d'un grand nombre d'échantillons par jour.

Renewable sources: applications in personal care formulations.

A global tendency for products considered environmentally sustainable, and ecologically obtained led the industry related to personal care formulations to fund the research and the development of personal care/cosmetics containing ingredients from natural resources. Furthermore, consumers are aware of environmental and sustainability issueans, thus not harming the environment represents a key consideration when developing a new cosmetic ingredient. In this study we review some examples of active ingredients or raw materials used in cosmetics/personal care/biomedical products that are coming from either through biotechnological systems, or as byproducts of several industries. A skin formulation containing biosynthetic actives, prepared by us and the study regarding its dermocosmetic properties are also described. The need for the standardization processes, the safety assessment tools, the improvement of the exploitation methods of these renewable sources in order the production to be ecologically and economically better are also discussed.

Une tendance globale en faveur des produits considérés comme écologiquement viables et obtenus par des méthodes écologiques a conduit l'industrie liée aux formulations des soins personnels à financer la recherche et le développement de soins personnels/cosmétiques contenant des ingrédients provenant de ressources naturelles. Les consommateurs sont, en outre, sensibilisés aux questions de l'environnement et de la durabilité, et la préservation de l'environnement représente donc un facteur essentiel dans le développement de nouveaux ingrédients cosmétiques. Dans cette étude, nous examinons quelques exemples de principes actifs ou de matières premières utilisé(e)s dans les produits cosmétiques/soins personnels/produits biomédicaux issus de systèmes biotechnologiques, ou dérivés de plusieurs industries. Nous présentons également une formulation pour la peau contenant des agents actifs biosynthétiques préparée par nous, et décrivons l'étude concernant ses propriétés dermocosmétiques. Nous discutons également de la nécessité des processus de standardisation, des outils d'évaluation de la sécurité d'emploi, de l'amélioration des méthodes d'exploitation de ces sources renouvelables afin d'optimiser la production tant sur le plan écologique qu'économique.

Biosurfactants in cosmetics and biopharmaceuticals.

Biosurfactants are surface-active biomolecules that are produced by various micro-organisms. They show unique properties i.e. lower toxicity, higher biodegradability and environmental compatibility compared to their chemical counterparts. Glycolipids and lipopeptides have prompted application in biotechnology and cosmetics due to their multi-functional profile i.e. detergency, emulsifying, foaming and skin hydrating properties. Additionally, some of them can be served as antimicrobials. In this study the current status of research and development on rhamnolipids, sophorolipids, mannosyloerythritol lipids, trehalipids, xylolipids and lipopeptides particularly their commercial application in cosmetics and biopharmaceuticals, is described.

New alternatives to cosmetics preservation.

In recent years, there is a considerable interest in the development of preservative-free or self-preserving cosmetics. The aim of our work was to develop new cosmetic formulations by replacing chemical preservatives with ingredients with antimicrobial properties that are not legislated as preservatives according to Annex VI of Commission Directive 76/768/EEC. This paper describes the preservative efficacy of the well-known antimicrobial extracts of Lonicera caprifoleum and Lonicera japonica in combination with glyceryl caprylate and/or levulinic acid, p-anisic acid, and ethanol. We prepared a series of acidic (pH = 5.5) aqueous and O/W formulations, i.e., tonic lotion, shampoo, shower gel, conditioning cream, anticellulite cream, cleansing milk and peeling cream, containing (0.2% w/w) Lonicera extracts, alone in the case of tonic lotion and in combination with (1% w/w) glyceryl caprylate in the other products, and we performed challenge tests according to the European Pharmacopoeia procedures and criteria. Formulations such as shampoo, shower gel, and conditioning cream fulfilled criterion A, while tonic lotion, anticellulite cream, cleansing milk, and peeling cream fulfilled criterion B, in regard to contamination from A. niger. Furthermore, we evaluated the efficacy of the antimicrobial systems in two states of use: the intact product and after three weeks of consumer use. The results showed that A. niger was also detected during use by consumers in the products that satisfied only criterion B in challenge tests. The addition of antimicrobial fragrance ingredients such (< or = 0.3% w/w) levulinic acid or (0.1% w/w) p-anisic acid and/or (5% w/w) ethanol afforded products that met criterion A in challenge tests and were also microbiologically safe during use. The small quantity (5% w/w) of ethanol gave an important assistance in order to boost the self-preserving system and to produce stable and safe products.

Self-preserving cosmetics.

Preservatives are added to products for two reasons: first, to prevent microbial spoilage and therefore to prolong the shelf life of the product; second, to protect the consumer from a potential infection. Although chemical preservatives prevent microbial growth, their safety is questioned by a growing segment of consumers. Therefore, there is a considerable interest in the development of preservative-free or self-preserving cosmetics. In these formulations traditional/chemical preservatives have been replaced by other cosmetic ingredients with antimicrobial properties that are not legislated as preservatives according to the Annex VI of the Commission Directive 76/768/EEC and the amending directives (2003/15/EC, 2007/17/EC and 2007/22/EC). 'Hurdle Technology', a technology that has been used for the control of product safety in the food industry since 1970s, has also been applied for the production of self-preserving cosmetics. 'Hurdle Technology' is a term used to describe the intelligent combination of different preservation factors or hurdles to deteriorate the growth of microorganisms. Adherence to current good manufacturing practice, appropriate packaging, careful choice of the form of the emulsion, low water activity and low or high pH values are significant variables for the control of microbial growth in cosmetic formulations. This paper describes the application of the basic principles of 'Hurdle Technology' in the production of self-preserving cosmetics. Multifunctional antimicrobial ingredients and plant-derived essential oils and extracts that are used as alternative or natural preservatives and are not listed in Annex VI of the Cosmetic Directive are also reported.

Antitumor activity of imidazothioxanthones in murine and human tumor models in vitro and in vivo.

BACKGROUND: A new series of imidazothioxanthones has recently been synthesized as potential anticancer agents with the aim of overcoming drug resistance. The route of synthesis and DNA-binding properties of the compounds were reported previously. This paper describes the general structure-activity relationships for the class of imidazothioxanthones in panels of human and murine tumor cell lines in vitro, and the in vivo activity against human and murine solid tumors of the most potent compound, N-[3-(Dimethylamino)propylo]-11-oxo-11H-benzothiopyrano [3',2':2,3]pyrido[1,2-a]imidazo-2-carboxamide (10a). In addition, the interaction between compound 10a and DNA is also considered in terms of molecular mechanics methods and flexible docking techniques. MATERIALS AND METHODS: The cytotoxicity of compounds 10a, 11-oxo-N-[2-(pyrrolidino)ethylo]-11H-benzothiopyrano [3',2':2,3]pyrido[1,2-a]imidazo-2-carboxamide, 11-oxo-N-[2-(piperidino)ethylo]-11H-benzothiopyrano [3',2':2,3]pyrido[1,2-a]imidazo-2-carboxamide and N-[2-(morpholino)ethylo]-11-oxo-11H-benzothiopyrano [3',2':2,3]pyrido[1,2-a]imidazo-2-carboxamide (10c-10e) was assessed in human tumor cell lines and xenografts using the sulforhodamine B assay, MTT assay and the clonogenic assay. The human ovarian xenograft, PXN/109TC, two human breast carcinomas, MT-1 and MCF-7, and the murine colon adenocarcinoma, MAC15A were used for the in vivo testing of compound 10a. In addition, the interaction between compound 10a and DNA is also considered in terms of molecular mechanics methods and flexible docking techniques. RESULTS: Two compounds, 10a and 10c, showed cytotoxic activity below 10 mM in the NCI in vitro screen of 60 human tumor cell lines. The IC50 value of compound 10a was 6.8 mM and that of 10c, 8.3 mM. In addition, both compounds possessed differential activity against leukemia, colon and mammary cancer. The activity pattern was confirmed in two further screens using monolayer and clonogenic, assays. In vivo antitumor studies showed that 10a was active against the human mammary carcinoma MT-1 and murine colon cancer MAC15A. Marginal activity was observed in human ovarian cancer model PXN/109T/C and the compound was inactive in human mammary cancer MCF-7. CONCLUSION: The results warrant further in vivo testing of 10a in additional human solid tumor models. The molecular modeling showed that the planarity of the chromophore and the side-chain conformation could assist the insertion of compound 10a between the base pairs of the double helix. On the other hand, docking to the nucleotide sequence GGAATTGCCTCA suggested that the molecule could also act as a minor groove binder.

Design, synthesis and biological evaluation of novel beta-substituted indol-3-yl ethylamido melatoninergic analogues.

A series of new melatonin analogues have been synthesized. Interestingly, two of the new compounds, 11c and 11e, which did not show any appreciable affinity for the melatonin receptor, were found to be potent inhibitors of lipid peroxidation in rat liver microsomes. Analogue 11c, in particular, is a better antioxidant than melatonin.

Synthesis, antiretroviral and antioxidant evaluation of a series of new benzo[b]furan derivatives.

The antiretroviral and anti-oxidant profile of a series of new C-2 and C-7 substituted benzo[b]furans was explored by employing well established antiviral and antioxidant protocols. The most potent antioxidant compound tested was analog 7, which bears an OH at C-7 and a benzoyl group at C-2. In the influenza A type H3N2 virus screens analog 8a was almost five-fold more active than its counterparts and equipotent to rimantadine and amantadine. In the influenza B screening all of the new compounds tested were at least ten-fold more active than the control drug amantadine. The anti-HIV screening, using acutely infected MT-4 cells, showed that compound 8f (n = 4), was fifteen-fold more active than its monomer congeners, 8a and 8c, d and almost five-fold more potent than monomer 8b and dimer 8f (n = 3).

Synthesis and biological evaluation of indole containing derivatives of thiosemicarbazide and their cyclic 1,2,4-triazole and 1,3,4-thiadiazole analogs.

New indolic derivatives of thiosemicarbazides and some cyclic 1,2,4-triazol-5-thione analogs were synthesized. The newly synthesized compounds as well as some indole containing thiosemicarbazides, 1,2,4-triazoles and 1,3,4- thiadiazoles, which have been reported previously, were investigated for antimicrobial, antifungal and antiphage activity. Certain thiosemicarbazide derivatives and the corresponding cyclic 1,2,4-triazole analogs showed selective antimicrobial or antifungal activity, while they lack any antiphage activity. Antiphage activity was detected for one compound, bearing the 1,3,4-thiadiazole nucleus. The selectively active compounds cover a wide range of lipophilicity. Structure-activity relations show a remarkably similarity in the antimicrobial and antifungal behaviour of the thiosemicarbazides and their cyclic triazo-thien-5-yl analogs, while alpha-naphtyl substitution in the non indolic portion of the molecule is favorable. C5 substitution on the indolic nucleus may also be critical for selective activity.

Synthesis, lipophilicity and biological evaluation of indole-containing derivatives of 1,3,4-thiadiazole and 1,2, 4-triazole.

3-[(2-Methyl-1H-3-indolyl) methyl]-4-aryl-4, 5-dihydro-1H-1,2,4-triazole-5-thiones 6a-c and their respective N-¿5-[2-methyl-1H-3-indolyl) methyl]-1,3,4-thiadiazol-2-yl¿-N-arylamines 7a,b have been prepared. The antidepressant profile of 6a,c and 7a was studied on mice with respect to that of the analogous 3-(1H-1-indolylmethyl)-4-aryl-4,5-dihydro-1H-1,2,4-triazole-5-thio nes 1a-c and the respective N-¿5-[(2-methyl-1H-3-indolyl) methyl]-1,3,4-thiadiazole-2-yl¿-N-arylamines 2a-c, the synthesis and antimicrobial potency of which we have recently reported. Behavioral effects, induced by the members of both series, in conjunction with their activity in some specific tests (forced swim, pentetrazole convulsions) on mice, show that these derivatives cross the blood-brain barrier and could develop an antidepressant activity comparable to that of imipramine. Blood-brain barrier penetration is also supported by the lipophilicity data obtained for all analogs.

Synthesis and antimicrobial evaluation of indole containing derivatives of 1,3,4-thiadiazole, 1,2,4-triazole and their open-chain counterparts.

The increasing clinical importance of drug-resistant bacterial pathogens has lent additional urgency to microbiological and antibacterial research. New indolic derivatives of triazoles, thiadiazoles and their respective open-chain thiosemicarbazides were evaluated for antibacterial and antifungal activity. The microorganisms used were the Gram-negative bacteria Escherichia coli ATCC 35218 and Pseudomonas aeruginosa ATCC 27853, the Gram-positive bacteria Staphylococcus aureus ATCC 25923 and Bacillus subtilis BBL 12084 and the yeasts Candida and Saccharomyces cerevisiae ATCC 2366. The most potent compounds were indole derivatives (12a-c) bearing 1,2,4-triazo-thien-5-yl moiety, which exhibit interesting antibacterial and antifungal activities.

A novel series of DNA triple helix-binding ligands.

We have examined the effect of a series of substituted imidazothioxanthones on the stability of an intermolecular DNA triple helix by DNase I footprinting. We find that several of these compounds promote the formation of a complex between T5C5 and the target site A6G6.C6T6, suggesting that they bind specifically to triplex DNA. The only inactive derivative lacked a protonatable function in the side chain, suggesting that this is an essential feature for triplex stabilization. These compounds, which are amongst the first triplex-binding ligands which possess an uncharged chromophore, are selective for the T.AT rather than the C+.GC triplet.