Development of membranes based on carboxymethyl cellulose/acetylated arrowroot starch containing bromelain extract carried on nanoparticles and liposomes.

Polymeric membranes have been used in several applications, including their use as curatives in cutaneous wounds. Bromelain has long been used for anti-inflammatory purposes, so the objective of this work was to produce carboxymethylcellulose-acetylated blends, incorporate bromelain, characterize the systems, compare the blends with bromelain loaded in nanoparticles and liposomes and, finally, to evaluate their healing potential. Four membrane formulations were produced by solvent evaporation: the control, membranes containing free bromelain, bromelain-loaded nanoparticles (NPs) and bromelain-loaded liposomes (LIPs). The enzyme concentration was the same for all formulations. Transparent, flexible and intact films were obtained. The membranes containing free bromelain, bromelain-loaded NPs and bromelain-loaded LIPs had higher water content, lower water vapor permeability and maximum tensile strength, and greater elongation at rupture. The capacity to absorb simulated exudate was higher in samples containing free bromelain, and bioadhesion was reduced in the presence of free bromelain compared to the control. An in vivo assay was performed to verify the membranes' healing potential. Histological analysis revealed no edema on the 14th day in animals treated with membranes containing bromelain-loaded NPs and LIPs.

Hyaluronate nanoparticles included in polymer films for the prolonged release of vitamin E for the management of skin wounds.

Lecithin and hyaluronic acid were used for the preparation of polysaccharide decorated nanoparticles loaded with vitamin E using the cationic lipid dioctadecyldimethylammonium bromide (DODMA). Nanoparticles showed mean particle size in the range 130-350 nm and narrow size distribution. Vitamin E encapsulation efficiency was higher than 99%. These nanoparticles were incorporated in polymeric films containing Aloe vera extract, hyaluronic acid, sodium alginate, polyethyleneoxide (PEO) and polyvinylalcohol (PVA) as an innovative treatment in skin wounds. Films were thin, flexible, resistant and suitable for application on burn wounds. Additionally, in vitro occlusion study highlighted the dependence of the occlusive effect on the presence of nanoparticles. The results obtained show that the bioadhesive films containing vitamin E acetate and Aloe vera could be an innovative therapeutic system for the treatment of skin wounds, such as burns. The controlled release of the vitamin along with a reduction in water loss through damaged skin provided by the nanoparticle-loaded polymer film are considered important features for an improvement in wound healing and skin regeneration.

Determination of in vitro usnic acid delivery into porcine skin using a HPLC method.

Usnic acid, a lichen metabolite, has been proposed as a potential topical treatment for microbial skin lesions, burn wounds as well as a sunscreen. An isocratic HPLC method was validated according to FDA's Guidance for Industry: Bioanalytical Method Validation to determine skin penetration and permeation of usnic acid. The penetration and permeation of usnic acid was evaluated using Franz cells and porcine skin. The method was valid according to selectivity, linearity, precision, accuracy and stability. Usnic acid was quantified in the skin surface (6.13 µg cm(2)), stratum corneum (34.4 µg cm(2)), viable epidermis (5.6 µg cm(2)), dermis (28.2 µg cm(2)) and receptor compartment (3.2 µg cm(2)). These results help us to understand the penetration profile of usnic acid and plan topical therapeutic approaches as well as new topical delivery systems to modulate this penetration profile.

UVA-UVB photoprotective activity of topical formulations containing Morinda citrifolia extract.

Exposure to solar radiation, particularly its ultraviolet (UV) component, has a variety of harmful effects on human health. Some of these effects include sunburn cell formations, basal and squamous cell cancers, melanoma, cataracts, photoaging of the skin, and immune suppression. The beneficial photoprotective effects of topical formulations with the extract, Morinda citrifolia, have not been investigated. This present study aims to investigate the potential benefits of M. citrifolia topical application on the dorsal skin of mice, exposed to UVA-UVB light. Using 7 days of treatment, [before (baseline values) and 20 h after UV exposure], the thickness, skin barrier damage (TEWL), erythema, and histological alterations were evaluated. The results showed that the formulations containing the extract protected the skin against UV-induced damage.

Poly(ϵ-caprolactone) microcapsules and nanocapsules in drug delivery.

INTRODUCTION: Poly(ϵ-caprolactone) (PCL), a biodegradable and biocompatible polymer, is useful to encapsulate a wide range of drugs making it an interesting material for the preparation of carriers with potential applications in therapeutics. AREAS COVERED: The design and development of those carriers to modulate drug release, to improve the drug stability or apparent solubility in aqueous media, as well as to target tissues and organs are discussed. EXPERT OPINION: Microencapsulation is a well-established process in pharmaceutical industry to protect drugs from chemical degradation and to control drug release. In this context, PCL is a useful polymer to prepare microcapsules. Nanoencapsulation, a more recent approach, offers new possibilities in drug delivery. PCL can be used as polymer to prepare different types of nanocapsules presenting diverse flexibility according to the chemical nature of the core. Those nanocapsules are capable of controlling drug release and improving photochemical stability. In addition, they can modulate cutaneous drug penetration/permeation and act as physical sunscreen due to their capability of light scattering. Considering the pharmaceutical point of view, PCL nanocapsules are versatile formulations, once they can be used in the liquid form, as well as incorporated into semi-solid or solid dosage forms.

Photostability and skin penetration of different E-resveratrol-loaded supramolecular structures.

It is desirable and challenging to prevent E-resveratrol (E-RSV) from photoisomerizing to its Z-configuration to preserve its biological and pharmacological activities. The aim of this research was to evaluate the photostability of E-RSV-loaded supramolecular structures and the skin penetration profile of chemically and physically stable nanoestructured formulations. Different supramolecular structures were developed to act as carriers for E-RSV, that is, liposomes, polymeric lipid-core nanocapsules and nanospheres and solid lipid nanoparticles. The degrees of photostability of these formulations were compared with that of an ethanolic solution of E-RSV. The skin penetration profiles of the stable formulations were obtained using vertical diffusion cells (protected from light and under UVA radiation) with porcine skin as the membrane, followed by tape stripping and separation of the viable epidermis and dermis in a heated water bath. Photoisomerization was significantly delayed by the association of resveratrol with the nanocarriers independently of the supramolecular structure. Liposomes were the particles capable of maintaining E-RSV concentration for the longest time. On the other hand, E-RSV-loaded liposomes reduced in size showing low physical stability under UVA radiation. In the dark, the skin penetration profiles were very similar, but under UVA radiation the E-RSV-loaded nanocarriers showed increasing amounts in the total epidermis.