In Vitro Skin Co-Delivery and Antibacterial Properties of Chitosan-Based Microparticles Containing Ascorbic Acid and Nicotinamide.

Vitamins are widely found in nature, for example, in plants and fruits. Ascorbic acid and nicotinamide are examples of these compounds that have potent antioxidant properties, besides stimulating collagen production and depigmenting properties that protect the skin from premature aging. To overcome the skin barrier and reduce the instability of antioxidant compounds, alternative systems have been developed to facilitate the delivery of antioxidants, making them efficiently available to the tissue for an extended time without causing damage or toxicity. The objective of this study was to obtain chitosan biodegradable microparticles containing ascorbic acid and nicotinamide for topical delivery. The microparticles were obtained by spray drying and characterized chemically by means of scanning electron microscopy, infrared spectroscopy, X-ray diffraction, and differential exploratory calorimetry. The drugs were successfully encapsulated and the microparticles showed positive zeta potential. In vitro release assays showed a sustained release profile. The evaluation of ex vivo skin permeation and retention demonstrated low permeation and adequate retention of the compounds in the epidermis/dermis, suggesting the efficient delivery from the obtained microparticles. Antibacterial assays have shown that microparticles can inhibit the growth of microorganisms in a time- and dose-dependent manner, corroborating their use in cosmetic products for application on the skin.

New and potential properties, characteristics, and analytical methods of ferulic acid: A review

Abstract Phenolic compounds are widely distributed in the plant kingdom and in the microorganisms. Cinnamic acid and its hydroxylated derivative-ferulic acid, are phenolic compounds. Ferulic acid possesses antioxidant potential, as well as anti-cancer, anti-inflammatory, and antimicrobial properties. It prevents the harmful effects of radiation both as an ultraviolet absorber and as a free radical scavenger; it is not cytotoxic. Although ferulic acid has beneficial properties, it is hardly used in cosmetic preparations and has been rarely studied in the literature. Herein, we review the literature on ferulic acid, to provide information which can contribute to further research on the compound.

Caffeic acid skin absorption: Delivery of microparticles to hair follicles.

Caffeic acid (CA) is a polyphenol that can be found in a wide range of vegetal dietary sources. It presents a remarkable antioxidant potential, but what is more interesting from the therapeutic point of view is, that it has demonstrated in vitro antimicrobial properties. Folliculitis is a common skin condition, usually caused by a bacterial or fungal infection, in which hair follicles become inflamed. A typical challenge in dermal application when the actives diffuse passively through the skin in a quick manner, as it is the case of CA, is to provide the effective concentration of the compound at the target site for the sufficient time to finalize the treatment adequately and reduce the possibility to trigger systemic side effects. To achieve this goal, it is necessary to appropriately design the drug delivery system. In this case, we leverage the ability of microparticles to accumulate into the hair follicles to design O/W-emulsions containing CA-loaded controlled-release microparticles. Two different emulsion types containing CA were prepared, one containing free CA and the other containing microencapsulated CA. Traditional and differential tape stripping techniques were performed to investigate drug distribution within the different skin layers and into the hair follicles. The Tape stripping results demonstrated that the tapes S3-S5 and S6-S10 presented a higher total amount of CA. The strips are collected and extracted in groups to assure the extraction of quantifiable amounts of drug. Samples S11-15 and S16-20 show a decrease in the amount of quantified CA, as it was expected. Thus, it can be seen that the amount of active decreases while the stratum corneum depth increases. The retention studies demonstrated that, the microparticles tend to produce a more homogeneous distribution of CA, within the stratum corneum and a higher retention into the hair follicle, which can be attributed to their size and uniformity. Besides, MPs present an additional advantage because they guarantee a continuous release of CA in the target for a prolonged period, allowing the treatment of folliculitis with a single dose until the MPs are removed from the hair follicle by its natural regeneration process or particle depletion of CA.

In vitro methods to determine the antioxidant activity of caffeic acid.

Caffeic acid (CA) is a plant metabolite acting as a carcinogenic inhibitor, and exhibits a high antioxidant effect and some antimicrobial activity. Besides, this compound can be useful in the prevention of heart diseases and atherosclerosis, among others. The present study aims to determine the in vitro antioxidant activity of CA in order to increase the frequency of its use and reliability in the prevention of damage caused by free radicals and other reactive species. The tests performed were as follows: Radical anion superoxide capture; crocin bleaching assay; capturing ability of hypochlorous acid; H2O2 capture; capturing capacity of the ABTS•+/DPPH•; and SOD-like activity. The values of the CA antioxidant activity were very close to the values of standards in all tests. Besides, CA presented an antioxidant activity greater than that of ascorbic acid and trolox, and its advantages include higher stability than ascorbic acid and extraction from natural sources, as opposed to trolox.

Release and permeation profiles of spray-dried chitosan microparticles containing caffeic acid.

Caffeic acid (CA), a phenolic compound found in plants with antioxidant and antimicrobial activity, induces collagen production and prevents premature aging of the skin. The objective of this study was to develop two types of chitosan microparticles (MP) containing CA and to relate the morphology with the release and permeation profiles. One type of MP was prepared from a hydroalcoholic solution (MPI) and the other from an aqueous solution (MPII). Their morphology and size was evaluated by high-resolution scanning electron microscopy. The release profile of CA was evaluated using the cellulose membrane from the two MPs in Franz diffusion cells and the permeation profile was evaluated using human abdominal skin samples; the epidermal membranes were prepared by the heat-separation technique. MPII was spherical with a smooth surface, suitable for the controlled release of substances, whereas MPI was porous with non-internalized residual material. This result was consistent with their release and permeation profiles because MPII exhibited a slower and more controlled release than MPI. Thus, the method of preparation of MP and their composition influence the release profile of CA. Therefore, the production conditions must be closely controlled.

Validation of HPLC-UV Assay of Caffeic Acid in Emulsions.

An accurate, sensitive, precise and rapid reversed-phase high-performance liquid chromatographic method was successfully developed and validated for the determination of caffeic acid (CA) in emulsions. The best separation was achieved on a 250 × 4.6 mm, 5.0 µm particle size RP18 XDB Waters column using ethanol and purified water (40:60 v/v) adjusted to pH 2.5 with acetic acid as the mobile phase at a flow rate of 0.7 mL/min. Ultraviolet detection was performed at 325 nm at ambient column temperature (25°C). The method was linear over the concentration range of 10-60 µg/mL (r(2) = 0.9999) with limits of detection and quantification of 1.44 and 4.38 µg/mL, respectively. CA was subjected to oxidation, acid, base and neutral degradation, as well as photolysis and heat as stress conditions. There were no interfering peaks at or near the retention time of CA. The method was applied to the determination of CA in standard and pharmaceutical products with excellent recoveries. The method is applicable in the quality control of CA.