Assessment of dermal bioavailability: predicting the input function for topical glucocorticoids using stratum corneum sampling

Predicting the dermal bioavailability of topically delivered drugs is challenging. In this work, minimally invasive stratum corneum (SC) sampling was used to quantify the delivery of betamethasone valerate (BMV) into the viable skin. Betnovate® cream (0.1% w/w BMV) was applied at three doses (2, 5, and 10 mg cm−2) to the ventral forearms of 12 healthy volunteers. The mass of drug in the SC was measured using a validated tape-stripping method (a) after a 4-h “uptake” period, and (b) following a 6-h “clearance” period subsequent to cream removal. Concomitantly, the skin blanching responses to the same doses were assessed with a chromameter over 22 h post-application. BMV uptake into the SC was significantly higher for the 5 mg cm−2 dose compared to those of 2 and 10 mg cm−2. In all cases, ~30% of the drug in the SC at the end of the uptake period was cleared in the subsequent 6 h. From the SC sampling data, the average drug flux into the viable epidermis and its first-order elimination rate constant from the SC were estimated as 4 ng cm−2 h−1 and 0.07 h−1, respectively. In contrast, skin blanching results were highly variable and insensitive to the dose of cream applied. The SC sampling method was able to detect a 50% difference between two applied doses with 80% power; detection of a 20% difference would require a larger sample size. SC sampling enabled quantitative metrics describing corticosteroid delivery to the viable epidermis to be determined. Graphical abstract

Study on Electrochemical Stripping Method of Graphene Electrode and Its Capacitive Properties

Graphene has excellent properties, such as excellent conductivity, more pores, stable chemical and structural properties, high specific surface area, so it is usually used in the battery fields. In order to further explore the capacitive properties of graphene, this experiment used electrochemical stripping method, the electrochemical electrode was characterized by constant potential treatment methods, cyclic voltammetry curve, and constant current charging–discharging curve. The capacitive performance of modified graphene at different potentials was compared. If a constant potential peeling treatment is performed, the interlayer spacing of graphene increases, and this time, the specific surface area is enlarged, and the electrical properties of the graphene electrode material are correspondingly improved. Cyclic voltammetry curve results show that the graphene electrode exhibits better capacitance performance after being treated with a constant potential in neutral electrolyte. When treating with 3.1 V constant potential and voltage range of -1.1 V–1.1 V, capacitance can reach 327.273 F. The chronopotentiometry curve results show that 3.1 V graphene electrode mass ratio capacitance can reach 218.182 F/g under voltage range of -0.3 V–0.3 V, meeting the energy storage requirements of the battery industry, and it is expected to become an ideal electrode material in the field of supercapacitors.

A Novel Method for Rapid Extraction Of Biofibres from Waste Chicken Feathers

South Africa is the biggest chicken meat producer in Southern Africa and generates about 258 million kg of waste feathers. Although some of this waste is beneficiated into animal feed and fertiliser there are problems in adequate digestion of the feed by animals. Consequently, there is a need to find other innovative ways of beneficiating the waste. In this paper, beneficiating of feathers by extraction of fibres for possible conversion into high value products was explored. Three mechanical methods for extracting fibres from feathers were evaluated and the properties of the resultant fibres were studied and compared: they were using a tweezer, a blender, and a novel stripping method using a pulp fluffer. The results revealed that fibres extracted from chicken feathers using a tweezer or a blender had a hollow structure whereas those from the fluffer exhibited pronounced damaging effects on the fibre structure as some barbules were detached from their rami. Fluffer fibres had the highest average length of 16.56 mm followed by blender (16.15 mm) and tweezer (14.84 mm); they were also the most flexible with an aspect ratio of 476.29. The modified pulp fluffer appeared to be a cost-effective and an efficient method of grinding feathers into commercial fibres.

Investigation on the biodegradation levels of super heavy oils by parameter-striping method and refined Manco scale: a case study from the Chepaizi Uplift of Junggar Basin

The Carboniferous volcanic reservoir in the Chepaizi Uplift became an exploration hot target in recent years for its substantial amount of oils discovered. However, most of the Carboniferous heavy oils were biodegraded to PM7 or higher with orders of magnitude variation in oil viscosities. Two oil groups (I and II) exactly corresponding to the western and eastern Chepaizi Uplift were distinguished according to their source diagnose. Furthermore, three oil families (II1, II2 and II3), with the biodegradation level of PM7, PM8–8+, PM9+, respectively, were classified based on molecular compositions and parameter-stripping method of strongly bioresistant parameters. Allowing for this extremely high biodegradation case, more biodegradation refractory compound class were added to establish a refined Manco scale to quantitatively evaluate the biodegradation extent. Refined Manco number (RMN2) positively correlated with the oil density, NSO contents, and absolute concentrations of diasteranes and gammacerane, negatively correlated with the absolute concentrations of diahopane, summed tricyclic terpanes and pentacyclic terpanes. This refined scale showed higher resolution than the PM one to differentiate the biodegradation extent of Carboniferous heavy oils from the Chepaizi Uplift, especially those with same PM values but different oil viscosities.

Template Stripping Method-Based Au Nanoarray for Surface-Enhanced Raman Scattering Detection of Antiepileptic Drug

Surface-enhanced Raman scattering (SERS) is a potential candidate for highly sensitive detection of target molecules. A SERS active substrate with a noble metal nanostructure is required for this. However, a SERS active substrate requires complicated fabrication procedures. This in turn makes it difficult to fabricate highly sensitive SERS active substrates with high reproducibility. To overcome this difficulty, a plasmonic crystal (PC) with periodic noble metal nanostructures was fabricated via the template-stripping method using a polymer-based template. Using SERS active substrates, SERS was successfully achieved using the PC by detecting low concentrations of phenobarbital which is an antiepileptic drug using a commercially available portable Raman module. The PC can be fabricated by demolding the deposited gold layer from a polymer-based template. This method is rapid, economic, and has high reproducibility. SERS can be achieved easily using this PC for a wide variety of applications such as medical, pharmaceutical, and environmental protection.

Tape stripping method is useful for the quantification of antimicrobial peptides on the human skin surface including the stratum corneum

Antimicrobial peptides (AMPs) play an important role in innate immunity in human skin. It is known that AMPs mainly function in the stratum corneum. Therefore, AMP concentrations in the stratum corneum need to be precisely measured to clarify functional and physiological importance of AMPs in cutaneous defence. Tape stripping (TS) is a well-established method by which components in the stratum corneum can be collected. However, the usefulness of the TS method for measuring AMP concentration in human skin remains unclear. Therefore, we compared it with another popular method, skin rinsing, which had been established as a method for measuring AMP concentration in human skin. When investigated on healthy medial forearm using RNase 7, which is one of the typical AMPs, as an index, there was a significant positive correlation between RNase 7 concentrations measured by the TS method at adjacent forearm sites, demonstrating the reproducibility of the TS method. Next, a significant positive correlation was detected in RNase 7 concentrations measured using the TS and the skin rinsing method, indicating that the TS method is comparable to the skin rinsing method. Thus, we speculate that the TS method is useful for measuring AMP concentration in human skin.