Raman Spectroscopic Tools to Probe the Skin-(Trans)dermal Formulation Interface.

Medicines designed to deliver the active pharmaceutical ingredient either into or through the skin─often referred to as topicals and transdermals, respectively─are generally considered to be complex drug products. A particular challenge faced by these formulations is identifying a suitable method (ideally, in terms of specificity, accuracy, precision, and robustness) or combination of methods with which to assess the amount and rate of drug delivery to the target site. Significant research currently aims to identify and validate relevant and minimally invasive techniques that can be used to quantify both the levels of the drug attained within different parts of the skin and the kinetics with which the drug is taken up into the skin and cleared therefrom into the systemic circulation.

"It is the future. Clinical pharmaceutical care simply has to be a matter of course." - Community pharmacy clinical service providers' and service developers' views on complex implementation factors.

Background: While there is a lot of documented evidence about the clinical and cost effectiveness of pharmacists' role extensions there is an inherent gap between service development and implementation.

Objective(s): This study aims to better understand the complex factors that influence the implementation of clinical pharmacy services from both the perspective of the community pharmacy service providers and service developers.

Methods: A prospective qualitative interview study using purposive sampling of twelve service developers and twelve community pharmacy service providers from across all nine Federal States of Austria.

Self-assembled nanostructured aqueous dispersions as dermal delivery systems.

Due to their high interfacial area and capability of loading hydrophobic, hydrophilic and amphiphilic drugs, self-assembled nanoparticles are the subject of much attention in view of an application of these dispersions as carrier systems for a variety of different active ingredients. Therefore, the effect of the internal nanostructure of oil-loaded monoglyceride-based nanoparticles on the dermal delivery of diclofenac sodium was investigated. The different self-assembled phases of the nanostructured aqueous dispersions were characterized by small angle X-ray scattering (SAXS).

Monitoring the distribution of surfactants in the stratum corneum by combined ATR-FTIR and tape-stripping experiments.

Combined ATR-FTIR (attenuated total reflection-Fourier transform infrared) spectroscopy and tape-stripping experiments in vitro on porcine ear skin were used to investigate the spatial distribution of different surfactants in the stratum corneum (SC). To reveal a possible connection between the size of the formed micelles and skin penetration, dynamic light-scattering measurements of the aqueous surfactant solutions were also taken. Compared to an alkyl polyglycoside and sucrose laurate, a deeper skin penetration of the anionic surfactants sodium dodecyl sulfate (SDS) und sodium lauryl ether sulfate (SLES) could be related to a smaller size of the formed micelles.

Effect of monoacyl phosphatidylcholine content on the formation of microemulsions and the dermal delivery of flufenamic acid.

The choice of appropriate excipients is crucial for the success of a dermal drug delivery system. Especially surfactants should be chosen carefully, because of their possible interactions with the skin or the applied drug. Since monoacyl phosphatidylcholine (MAPL) exhibits great emulsification properties and can be derived from natural sources, it is of great interest as surfactant in microemulsions.

Topical delivery of acetyl hexapeptide-8 from different emulsions: influence of emulsion composition and internal structure.

Acetyl hexapeptide-8 (AH-8) is a well-known component of anti-aging products and was recently explored as a promising topical treatment of blepharospasm. Although AH-8 appears in a variety of cosmetic products, its skin penetration is sparsely studied and controversially discussed. Therefore, the aim of the present study was to investigate the influence of the vehicle type on the AH-8 delivery to the skin.

Influence of the composition of monoacyl phosphatidylcholine based microemulsions on the dermal delivery of flufenamic acid.

Although microemulsions are one of the most promising dermal carrier systems, their clinical use is limited due to their skin irritation potential. Therefore, microemulsions based on naturally derived monoacyl phosphatidylcholine (MAPL) were developed. The influence of the water, oil and surfactant content on dermal delivery of flufenamic acid was systematically investigated for the first time.

Validation of the combined ATR-FTIR/tape stripping technique for monitoring the distribution of surfactants in the stratum corneum.

The physical presence of surfactants in the skin is linked to their skin irritation potential. Combined ATR-FTIR spectroscopy and tape stripping experiments in vitro on porcine ear skin were used to investigate the spatial distribution of sodium lauryl ether sulfate (SLES) in the stratum corneum and to assess its effects on conformational order of stratum corneum intercellular lipids, secondary structure of keratin and skin hydration. It was possible to monitor the spatial distribution of SLES in the stratum corneum for the first time by subtracting spectra of untreated from treated skin samples and without the need of a perdeuterated form.

Simultaneous analysis of skin penetration of surfactant and active drug from fluorosurfactant-based microemulsions.

The purpose of this study was to investigate the penetrated amount of the incorporated model drug diclofenac-sodium and of a fluorosurfactant as specific vehicle constituent of topically applied microemulsions at the same time. To this end, the penetration depth of each compound was elucidated through tape stripping studies by the simultaneous quantification of diclofenac-sodium and the fluorosurfactant from the same sample. A new approach was made by using the very sensitive and specific (19)F NMR (nuclear magnetic resonance) for quantification of the fluorinated vehicle component.

Natural polymer-stabilized multiple water-in-oil-in-water emulsions: a novel dermal drug delivery system for 5-fluorouracil.

Objectives: The aim of this study was to create multiple water-in-oil-in-water (W/O/W) emulsions with an increased long-term stability as skin delivery systems for the hydrophilic model drug 5-fluorouracil.

Methods: Multiple W/O/W emulsions were prepared in a one-step emulsification process, and were characterized regarding particle size, microstructure and viscosity. In-vitro studies on porcine skin with Franz-type diffusion cells, tape stripping experiments and attenuated total reflectance-fourier transform infrared spectroscopy (ATR-FTIR) were performed.

Application of quantitative (19) F nuclear magnetic resonance spectroscopy in tape-stripping experiments with natural microemulsions.

The skin penetration of flufenamic acid (Fluf) and fluconazole (Fluc) from innovative natural microemulsions was investigated in tape-stripping experiments on pig ears. The formulations were based on the eudermic surfactants lecithin, sucrose laurate, alkylpolyglycoside or a mixture thereof. The quantification of the penetrated drug amounts was executed by (19) F nuclear magnetic resonance (NMR) in comparison with high-performance liquid chromatography (HPLC).

Ultra-small NLC for improved dermal delivery of coenyzme Q10.

Coenzyme Q10 (CoQ10) acts as an antioxidant in the skin and is frequently contained in anti-aging products. In previous studies, it could be shown that nano-structured lipid carriers (NLC) with a size of about 230 nm are beneficial for the dermal delivery of CoQ10. They increased Q10 skin penetration when compared to equally sized nanoemulsion.

Natural microemulsions: formulation design and skin interaction.

Microemulsions are thermodynamically stable, colloidal drug delivery systems. This study presents the first substantiated comparison of natural, skin-compatible and biodegradable surfactants in terms of their suitability to form isotropic microemulsions and their skin interaction. Pseudoternery phase diagrams were constructed for lecithin, sucrose laurate and alkylpolyglycoside as single surfactants.