Collaborative permeation of drug and excipients in transdermal formulations. In vitro scrutiny for ethanol:limonene combinations

Enhancement of skin permeation of drugs is affected by the simultaneous co-permeation of excipients that hinder the predictivity of in vitro tests. The collaborative effects of two permeation enhancers (ethanol and d-limonene) of a lipophilic drug (alprazolam) have been simultaneously assessed in human skin under different in vitro conditions: integrated setups of diffusion cell experiments with selective concentration gradients of permeants (asymmetric) or without (symmetric) have been combined with coadministration dosages (all-in-one) at different concentrations or short-time skin pretreatment to scrutiny this mutual performance. Findings: Drug permeation is increased under moderated supersaturation but reaches a stationary level above 33 % of its solubility. Ethanol in absence of a concentration gradient increases ca.5 times basal drug permeation. Limonene until 20 % permeates human skin proportionally to its donor concentration but its effect does not depend on ethanol in symmetric conditions and is based on skin imbibition rather than on a carry-on effect. Simultaneous permeation of ethanol and limonene reaches a stationary state after 1.5 h, enough time to achieve maximal enhancement of alprazolam permeation. Additive enhancement is based on ethanol solubilisation maximized by skin saturation of terpene. Complementary analyses of skin disruption published in the literature are in line with these assessments and consolidate them.

Comparing surgeons' skin tolerance and acceptability to alcohol-based surgical hand preparation vs traditional surgical scrub: A matched quasi-experimental study

BACKGROUND

We aimed to compare the tolerance and acceptability of alcohol-based surgical hand preparation versus handscrubbing with antimicrobial soap and water by surgeons.

METHODS

Matched quasi-experimental trial in an academic quaternary care hospital in Ribeirão Preto, Brazil, from April 1 to October, 31, 2017. Participants were cardiac and orthopedics surgeons from the study facility. In the first study phase, they performed handscrubbing with either 2% chlorhexidine (CHG) or 10% iodopovidone (PVP-I) and, in the second phase, they performed handrubbing with alcohol-based handrub (ABHR). Surgeons' skin tolerance and acceptability were evaluated using WHO-validated tools. Data were analyzed using the MacNemar's test within STATA.

RESULTS

A total of 33 surgeons participated to the "per protocol" population; the majority were male (94%); mean age of 35 years (SD, 8.5). On product tolerance, there was a minimal variation in redness, scaliness, fissures, and visual evaluation of the skin when handrubbing with ABHR was compared to handscrubbing with either PVP-I or CHX. Regarding acceptability, participants rated better handrubbing with ABHR than handscrubbing with PVP-I when assessing product smell (66.6% vs 0%, p=0.002), color (73.3% vs 0%, p=0.001), product texture (60% vs 0%, p=0.004), skin dryness (60% vs 0%, p=0.004), ease of application (66.6% vs 0%, p=0.002) and overall satisfaction (66.6% vs 6.7% p=0.011). Participants rated similarly handrubbing with ABHR and handscrubbing with CHX, except for product texture, where handrubbing rated better (71,4% vs. 0%, p=0.002). Handrubbing with ABHR was preferred by 73.3%.

CONCLUSION

Although handrubbing and handscrubbing were equally well tolerated by surgeons, alcohol-based surgical hand preparation fell into the personal preference for most of them.

TRIAL REGISTRATION

Brazilian Clinical Trials Registry (ReBEC), RBR-8ym9yj.

[Malassezia spp.: interactions with topically applied lipids-a review : Malassezia and topically applied lipids]

Lipophilic Malassezia yeasts are an important part of the human resident skin flora, especially in seborrheic areas. Besides mutualistic interactions with the host they are also linked to diseases although the specific causes are not yet comprehensively understood. The amount of available lipids on the skin correlates with the Malassezia density and also with the occurrence of certain diseases like tinea versicolor. Here, the naturally produced lipids of the sebaceous glands play a role. Hardly studied thus far is the impact of topically applied lipids. Here, growth promotion as well as inhibition of Malassezia cells as well as the production of new metabolites through ester cleavage are possible. One example is the release of antimicrobial fatty acids from hydroxypropyl caprylate through the action of Malassezia lipases. This "self-kill" principle results in the reduction of the amount of Malassezia cells and can be applied as new therapy option for dandruff treatment. A better understanding of the interaction between topica and Malassezia would increase their skin tolerance and open new therapy options.

Biopharmaceutical profile of hydrogels containing pranoprofen-loaded PLGA nanoparticles for skin administration: In vitro, ex vivo and in vivo characterization

Pranoprofen (PF)-loaded nanoparticles (PF-F1NPs and PF-F2NPs) have been formulated into blank hydrogels (HG_PF-F1NPs and HG_PF-F1NPs) or into hydrogels composed of 3% azone (HG_PF-F1NPs-Azone and HG_PF-F2NPs-Azone), as innovative strategy to improve the biopharmaceutical profile of the selected non-steroidal anti-inflammatory drug (Pranoprofen, PF) for topical application. The purpose of this approach has been to increase the contact of PF with the skin, improve its retention in deeper layers, thus enhancing its anti-inflammatory and analgesic effects. The physicochemical characterization of the developed hydrogels showed a non-Newtonian behaviour, typical of semi-solid formulations for skin administration, with sustained release profile. The results obtained from ex vivo skin human permeation and in vivo anti-inflammatory efficacy studies suggest that topical application of HG_PF-F2NPs has been more effective in the treatment of oedema on the skin' surface in comparison to other hydrogels. No signs of skin irritancy have been detected for all the semi-solid formulations containing 0% or 3% azone.