Skin Irritation Potential Research Articles

Safety and efficacy of a feed additive consisting of Saccharomyces cerevisiaeMUCL 39885 (Biosprint®) for all pigs (other than sows and weaned piglets) and other minor porcine species (Prosol S.p.A.).

The additive Biosprint® contains viable cells of Saccharomyces cerevisiae MUCL 39885 and is authorised as a feed additive in sows, dairy cows, horses, piglets (weaned), cattle for fattening, minor ruminants for fattening and minor ruminants for dairy products. The applicant has requested to extend the use of the additive to all pigs (other than sows and weaned piglets) and other minor porcine species at a minimum inclusion level of 3 × 109 CFU/kg feed. S. cerevisiae is considered by EFSA to have qualified presumption of safety (QPS) status and consequently is considered safe for the target species, the consumers and the environment. The additive is considered as a potential skin and eye irritant and a skin and respiratory sensitiser. In previous evaluations, the FEEDAP Panel concluded that the additive is efficacious in sows and weaned piglets. In the current application, these conclusions are extrapolated to all pigs (other than sows and weaned piglets) and to other minor porcine species.

Safety and efficacy of a feed additive consisting of Saccharomyces cerevisiaeMUCL 39885 (Biosprint®) for cats and dogs (Prosol S.p.A.).

The additive Biosprint® contains viable cells of Saccharomyces cerevisiae MUCL 39885 and is authorised as a feed additive in sows, dairy cows, horses, piglets (weaned), cattle for fattening, minor ruminants for fattening and minor ruminants for dairy products. The applicant has requested to extend the use of the additive to cats and dogs at a minimum inclusion level of 7 × 1010 CFU/kg of complete feed. S. cerevisiae is considered by EFSA to have qualified presumption of safety status and consequently is considered safe for the target species. The additive is considered as a potential skin and eye irritant and a skin and respiratory sensitiser. Based on the results on efficacy studies provided, the FEEDAP Panel concludes that Biosprint® is efficacious when used in feeds for dogs. However, the FEEDAP Panel considered that the biological relevance of the magnitude of the effect detected is questionable. Based on the trial available, the FEEDAP Panel was unable to conclude on the efficacy of the additive when administered to cats.

Characterization and Antibacterial Properties of Autoclaved Carboxylated Wood Nanocellulose.

Cellulose nanofibrils (CNFs) were obtained by applying a chemical pretreatment consisting of autoclaving the pulp fibers in sodium hydroxide, combined with 2,2,6,6-tetramethylpiperidinyl-1-oxyl-mediated oxidation. Three levels of sodium hypochlorite were applied (2.5, 3.8, and 6.0 mmol/g) to obtain CNF qualities (CNF_2.5, CNF_3.8, and CNF_6.0) with varying content of carboxyl groups, that is, 1036, 1285, and 1593 μmol/g cellulose. The cytotoxicity and skin irritation potential (indirect tests) of the CNFs were determined according to standardized in vitro testing for medical devices. We here demonstrate that autoclaving (121 °C, 20 min), which was used to sterilize the gels, caused a modification of the CNF characteristics. This was confirmed by a reduction in the viscosity of the gels, a morphological change of the nanofibrils, by an increase of the ultraviolet-visible absorbance maxima at 250 nm, reduction of the absolute zeta potential, and by an increase in aldehyde content and reducing sugars after autoclaving. Fourier-transform infrared spectroscopy and wide-angle X-ray scattering complemented an extensive characterization of the CNF gels, before and after autoclaving. The antibacterial properties of autoclaved carboxylated CNFs were demonstrated in vitro (bacterial survival and swimming assays) on Pseudomonas aeruginosa and Staphylococcus aureus. Importantly, a mouse in vivo surgical-site infection model on S. aureus revealed that CNF_3.8 showed pronounced antibacterial effect and performed as good as the antiseptic Prontosan wound gel.

Safety Testing of Cosmetic Products: Overview of Established Methods and New Approach Methodologies (NAMs)

Cosmetic products need to have a proven efficacy combined with a comprehensive toxicological assessment. Before the current Cosmetic regulation N°1223/2009, the 7th Amendment to the European Cosmetics Directive has banned animal testing for cosmetic products and for cosmetic ingredients in 2004 and 2009, respectively. An increasing number of alternatives to animal testing has been developed and validated for safety and efficacy testing of cosmetic products and cosmetic ingredients. For example, 2D cell culture models derived from human skin can be used to evaluate anti-inflammatory properties, or to predict skin sensitization potential; 3D human skin equivalent models are used to evaluate skin irritation potential; and excised human skin is used as the gold standard for the evaluation of dermal absorption. The aim of this manuscript is to give an overview of the main in vitro and ex vivo alternative models used in the safety testing of cosmetic products with a focus on regulatory requirements, genotoxicity potential, skin sensitization potential, skin and eye irritation, endocrine properties, and dermal absorption. Advantages and limitations of each model in safety testing of cosmetic products are discussed and novel technologies capable of addressing these limitations are presented.

Formulations Based on Drug Loaded Aptamer-Conjugated Liposomes as a Viable Strategy for the Topical Treatment of Basal Cell Carcinoma-In Vitro Tests.

Topical liposomal drug formulations containing AS1411-aptamer conjugated liposomes were designed to deliver in a sustained way the 5-fluorouracil to the tumor site but also to increase the compliance of patients with basal cell carcinoma. The 5-fluorouracil penetrability efficiency through the Strat-M membrane and the skin irritation potential of the obtained topical liposomal formulations were evaluated in vitro and the Korsmeyer Peppas equation was considered as the most appropriate to model the drug release. Additionally, the efficiency of cytostatic activity for targeted antitumor therapy and the hemolytic capacity were performed in vitro. The obtained results showed that the optimal liposomal formulation is a crosslinked gel based on sodium alginate and hyaluronic acid containing AS1411-aptamer conjugated liposomes loaded with 5-fluorouracil, which appeared to have favorable biosafety effects and may be used as a new therapeutic approach for the topical treatment of basal cell carcinoma.

Antimicrobial properties of viscose yarns ring-spun with integrated amino-functionalized nanocellulose

Bio-based, renewable and biodegradable products with multifunctional properties are also becoming basic trends in the textile sector. In this frame, cellulose nanofibrils (CNFs) have been surface modified with hexamethylenediamine/HMDA and used as an antimicrobial additive to a ring-spun viscose yarn. The CNF-HMDA suspension was first characterized in relation to its skin irritation potential, antimicrobial properties, and technical performance (dispersability and suspensability in different media) to optimize its sprayability on a viscose fiber sliver with the lowest sticking, thus to enable its spinning without flowing and tearing problems. The impact of CNF-HMDA content has been examined on the yarn`s fineness, tensile strength, surface chemistry, wettability and antimicrobial properties. The yarn`s antimicrobial properties were increasing with the content of CNF-HMDA, given a 99% reduction for S. aureus and C. albicans (log 1.6–2.1) in up to 3 h of exposure at minimum 33 mg/g, and for E. coli (log 0.69–2.95) at 100 mg/g of its addition, yielding 45–21% of bactericidal efficacy. Such an effect is related to homogeneously distributed CNF-HMDA when sprayed from a fast-evaporated bi-polar medium and using small (0.4 mm) nozzle opennings, thus giving a high positive charge (0.663 mmol/g) without affecting the yarn`s tenacity and fineness, but improving its wettability. However, a non-ionic surfactant being used in the durability testing of functionalized yarn to 10-washing cycles, adheres onto it hydrophobically via the methylene chain of the HMDA, thus blocking its amino groups, and, as such, decreasing its antibacterial efficiency, which was slightly affected in the case when the washing was carried out without using it.

In Vitro and Clinical Safety Assessment of the Multiple W/O/W Emulsion Based on the Active Ingredients from Rosmarinus officinalis L., Avena sativa L. and Linum usitatissimum L.

The multiple W/O/W emulsion supplemented with the extracts of Rosmarinus officinalis L., Avena sativa L. and Linum usitatissimum L. was prepared in the study, its active compounds were determined by HPLC and its safety was evaluated in vitro by the means of reconstituted human skin model EpiDerm™ for the assessment of its irritation, phototoxicity and early skin inflammation effects and by the 48 h human skin patch test for its skin irritation and allergenic potential. The microbiological challenge test of W/O/W emulsion was performed to ensure its preservation efficiency. The results showed that the W/O/W emulsion loaded with self-preserving plant-based bio-actives had no irritant potential, was not phototoxic and did not provoke skin inflammation or sensitization and thus could be used as a safe base for cosmetic products. Furthermore, our results demonstrate that the safety evaluation of cosmetic ingredients of natural or organic origin could be easily performed using reconstructed human skin model EpiDerm™ similar to the well-defined chemicals used in the cosmetics industry.

A comparative study of chemical constituents and safety of Thai herbal medicated oil formula and traditional medicated oil.

Medicated oil has been traditionally used as an analgesic medicine to relieve pain by applying to the skin over painful muscles, and has been established in The National List of Essential Medicines (2556B.E.). Traditional Medicated oil (TMO) consists of cassumunar ginger, Wan En Lueang, and Wan Ron Thong. It is prepared by frying herbs in coconut oil which is a traditional method. Thai Herbal Medicated oil formula (MOF) comprises cassumunar ginger, sweet flag, lesser galangal, wild turmeric, Wan En Lueang, and Wan Ron Thong. Its preparation by maceration with methyl salicylate is modified method to avoid the heat in the traditional preparation. Since both recipes have different methods of extraction and compositions, it is necessary to determine the chemical constituents and acute skin irritation potential of MOF and TMO. This study applied Gas Chromatography-Mass Spectrometry (GC-MS) for quality assessment of MOF extract and TMO extract. The mass spectra of the compounds matched with authentic standards from the NIST library. The compounds were identified by comparing their retention time and peak area, and the percentage of matched factor was more than 80%. The safety assessment on acute skin irritation used the 4h human patch test (4h HPT) in 36 healthy subjects. The 37 compounds were found in MOF extract. The most common chemical constituents were terpene derivatives; monoterpenes and sesquiterpenes, and others, namely benzene derivatives, ester, phenylpropanoid, and other compounds. The 33 compounds were found in TMO extract and the chemical groups were similar to MOF extract. The 4h HPT demonstrated that the MOF extract, TMO extract, methyl salicylate solvent, and coconut oil solvent, did not induce skin irritation. However, the vehicle of the formulae and the whole formulae as MOF and TMO clinically induced skin irritation and accorded with rubefacient. The characteristic as mild erythema or dryness, but not erythema with edema, could appear after the use of rubbing skin products. The chemical constituents found in MOF and TMO extracts were partially different and their acute skin irritation reactions were not significantly different. A study on the efficacy of both remedies should be performed in the future, as well as a study on active chemical constituents. This study provides scientific evidences of quality and safety, including GC-MS condition for poly-herbal medicated oil standardization.

Topical Delivery of Apremilast Loaded Nanostructured Lipid Carrier Based Hydrogel for Psoriasis Therapy

Background: Apremilast (APR) is an orally administered selective phosphodiesterase 4 inhibitor approved to treat plaque psoriasis and psoriatic arthritis and is available as an oral tablet formulation. However, its systemic side effects limit its application. The low solubility and permeability of apremilast make it difficult to administer it through the skin. Hence an attempt is made to incorporate apremilast into a suitable nanocarrier to facilitate its topical delivery.
 Aims: To formulate and characterize Apremilast loaded nanostructured lipid carriers for the management of psoriasis to reduce the systemic side effects.
 Methodology: Apremilast loaded Nanostructured Lipid carriers (NLC) were prepared by melt emulsification accompanied by probe sonication. The formulation was prepared using GMS, Sefsol 218, Tween 80 and Transcutol P as Solid Lipid, Liquid lipid, Surfactant and Penetration Enhancer. The NLC was incorporated into carbapol 934 dispersion to convert it into a gel. The NLC formulation was evaluated for size, Polydispersity Index, Zeta Potential, Entrapment efficiency, Transmission Electron Microscopy. After that, the NLC gel was examined for Spreadability, Extrudabilty, Viscosity, In vitro drug release, Ex vivo permeation, Skin deposition and In vivo studies.
 Results: The formulated Apremilast loaded showed particle size of less than 200 nm (i.e.170.32nm) with a narrow PDI of 0.267. Entrapment efficiency revealed that 89.26±01.22% of the drug was entrapped. Transmission electron microscopy images confirmed the spherical nature of the nanocarrier. The extended-release pattern of the formulated NLC for 24h was observed in the in vitro release studies and followed the Higuchi model(R2=0.9966). Ex vivo permeability showed a 6.14 fold increase in permeability and 74.05±0.25% deposition of apremilast loaded NLC gel compared to apremilast gel. The formulation was stable for three months without significant changes. In vivo skin studies showed that the prepared NLC did not have any skin irritation potential. The antipsoriatic activity demonstrated by the Apremilast loaded NLC gel in the imiquimod induced psoriasis model in mice was comparable to the standard treatment.
 Conclusion: Apremilast loaded NLC demonstrated enhanced permeation, improved skin retention and extended-release compared to conventional gel. The developed formulation can be an alternative for psoriasis therapy after clinical trials in the future.

The "Maskne" microbiome - pathophysiology and therapeutics.

“Maskne” is a new term coined during the 2020 COVID‐19 pandemic. It refers to a subset of acne mechanica, deserving consideration in view of widespread reusable fabric mask‐wearing to control the pandemic worldwide. Understanding of underlying pathophysiology directly relates to the novel skin microenvironment and textile–skin friction created by mask‐wearing, distinct from nontextile‐related acne mechanica previously linked to wearing of headgear. Specifically, the occlusive microenvironment leads to microbiome dysbiosis, which is linked to various dermatological conditions. Additional textile–skin interactions include factors such as breathability, stickiness sensations, moisture saturation, and hygiene maintenance. Increased skin temperatures can trigger sweat/heat‐related dermatoses, and ear loops potentially trigger pressure‐induced dermatoses. Important therapeutic considerations include increased skin irritation potential of conventional acne treatments under occlusion, exacerbation of chronic dermatoses, that is, perioral dermatitis, rosacea, and eczema, and susceptibility of these same patient groups to heightened discomfort with mask‐wearing. Cotton, as the traditional fabric of choice for dermatology patients, has limited benefits in the context of face masks – increased subjective discomfort relates to increased moisture saturation and stickiness, inevitable because of high biofluid load of the nasal and oral orifices. Prolonged textile–skin contact time, directly proportional to the risk of maskne, can be an opportunity for the application of biofunctional textiles.

Assessment of the application for renewal of authorisation of Biosprint® (Saccharomyces cerevisiae MUCL 39885) as a feed additive for weaned piglets.

Following a request from the European Commission, the EFSA Panel on Additives and Products or Substances used in Animal Feed (FEEDAP) was asked to deliver a scientific opinion on the assessment of the application for renewal of the authorisation of the product Biosprint® (Saccharomyces cerevisiae MUCL 39885) as a feed additive for weaned piglets. Biosprint® is composed of only viable cells of Saccharomyces cerevisiae MUCL 39885. S. cerevisiae is considered by EFSA to have qualified presumption of safety status. The applicant has provided data demonstrating that the additive currently in the market complies with the conditions of the authorisation. The FEEDAP Panel confirms that the use of Biosprint® under the current authorised conditions of use is safe for weaned piglets, the consumers and the environment. The additive is considered as a potential skin and eye irritant and a skin and respiratory sensitiser. There is no need to assess the efficacy of Biosprint® in the context of the renewal of the authorisation.

Planarian toxicity fluorescent assay: A rapid and cheap pre-screening tool for potential skin irritants

Here we report a new planarian (Dugesia lugubris) fluorescent assay as a rapid and cheap pre-screening tool to predict strong skin irritants. Our aim was to provide a simple and cost-effective in vivo method that avoided use of higher vertebrates. Adapting previously reported methods for planaria mobility alongside an acute toxicity assay, different irritants at five concentrations (0.1%, 0.05%, 0.025%, 0.01% and 0.005% w/v) were tested but both methods failed to discriminate the irritation potential of the test compounds. Therefore, a new alternative fluorescence assay was developed, hypothesising that increasing damage from the irritant to the planarian outer protective membrane will increase accumulation of sodium fluorescein in the flatworm. Fourteen test chemicals were selected representing strong, moderate, mild and non-irritants. In general, results showed increasing sodium fluorescein accumulation within planaria following acute exposure to increasingly strong skin irritants; on exposure to the strong irritants, benzalkonium chloride, citronellal, methyl palmitate, 1-bromohexane and carvacrol, fluorescence within the planaria was significantly greater (P < 0.05) than the negative controls and the common non-irritants PEG-400, dipropylene glycol and isopropyl alcohol; fluorescence values of planaria tested with negative controls and non-irritants were not significantly different. For all test compounds, Fluorescence Intensity of the planaria was compared with literature Primary Irritation Index data and generated a statistically significant (P < 0.005) Pearson correlation (r) of 0.87. Thus, the planarian fluorescent assay is a promising tool for rapid early testing of potential strong skin irritants, and non-irritants, and avoids use of higher vertebrate models.

The First Human Clinical Trial on the Skin Depigmentation Efficacy of Glycinamide Hydrochloride

A previous study identified certain low molecular anti-melanogenic peptides that share a common sequence with α-melanocyte stimulating hormone (MSH) and end with a glycinamide moiety. Glycinamide itself also showed anti-melanogenic activity in cell-based assays, but neither glycine nor acetyl glycinamide were active, which indicated a special structure and activity relationship. The aim of this study was to examine the skin depigmentation efficacy of glycinamide hydrochloride in human subjects. The primary skin irritation potential of glycinamide hydrochloride was evaluated by patch testing in 30 human subjects. The skin depigmentation efficacy of glycinamide hydrochloride was evaluated in a double-blinded clinical test in 21 human subjects. The test product and a control product were applied to designated sites on the right or left side of the face twice daily for eight weeks. Skin color parameters, i.e., the melanin index, the L* value (representing skin lightness), a* value (redness), and b* value (yellowness) were measured using instruments. The individual topology angle (ITAo, representing skin color) was calculated from L* and b values. The degree of skin pigmentation was visually assessed by two testers. The primary skin irritation test showed that a solution containing glycinamide hydrochloride up to 10% did not induce any adverse skin responses. In the efficacy test, the test product significantly reduced the melanin index, and increased L* value and ITAo after two weeks of application relative to the baseline value at the start of the test. It also significantly lowered the degree of pigmentation after 6 weeks of application, relative to the baseline value. Differences in the melanin index, L* value, ITAo and the degree of pigmentation between the test and control groups became statistically significant after six weeks or eight weeks of application. No signs of skin irritation were observed during the efficacy test. The present study suggests that glycinamide hydrochloride has great potential to be used in the control of skin hyperpigmentation.

Preparation and Characterization of Nanostructured Lipid Carriers for Improved Topical Drug Delivery: Evaluation in Cutaneous Leishmaniasis and Vaginal Candidiasis Animal Models.

The present study aimed to develop, characterize and evaluate the amphotericin B-loaded nanostructured lipid carriers (AmB-NLCs) for topical treatment of cutaneous leishmaniasis (CL) and vulvovaginal candidiasis (VVC). AmB-NLCs were characterized for particle size, zeta potential, encapsulation efficiency and surface morphology. Prepared NLCs were also characterized for in vitro drug release, ex vivo skin permeation and deposition before evaluating their in vitro and in vivo efficacy. Cytotoxicity of NLCs was assessed on MRC-5 cells, whereas skin irritation potential was evaluated in vivo using rats. Significant accumulation of drug in to the skin supported the topical application potential of drug-loaded NLCs. Encapsulation of AmB in NLCs resulted in enhanced in vitro potency against promastigotes and intracellular amastigotes of L. major JISH 118 (IC50 ± SEM = 0.02 ± 0.1μM for both) compared with free drug (IC50 ± SEM = 0.15 ± 0.2 & 0.14 ± 0.0, respectively). Similar improved potency of AmB-NLCs was also observed for other Leishmania and fungal strains compared with drug solution. Topical application of AmB-NLCs on L. major-infected BALB/c mice caused a significant reduction in parasite burden per mg of lesion (65 × 108 ± 13) compared with the control group (> 167.8 × 108 ± 11). Topical AmB-NLCs gel demonstrated superior efficacy in the vaginal C. albicans rat model for VVC as compared with plain AmB gel. Moreover, results of in vitro cytotoxicity assay and in vivo skin irritation test confirmed AmB-NLCs to be non-toxic and safe for topical use. In conclusion, NLCs may have promising potential as carrier for topical treatment of various conditions of skin and mucosa.

Adapting epicutaneous patch testing protocols to assess immediate-type skin reactions.

During the development of cosmetic formulations, in vitro and in vivo methods are essential tools used to reliably assess the skin irritation potential of a product or ingredient. Epicutaneous patch testing (single and/or multiple application protocols) has long been used as an initial in vivo method to screen for possible skin irritation properties of a substance or formulation. To confirm the mildness and dermatological and/or consumer acceptance of a product, use tests are often subsequently conducted. A study was therefore initiated to see how well patch test results correlate with use tests with respect to irritation elicited by skincare (leave-on) products. A number of different cosmetic formulations were assessed in both tests. Although the patch test results did not indicate substantial irritation potentials, immediate-type reactions (stinging and redness) were observed in some volunteers which disappeared within approx. 1h. Although transient, these reactions suggested that consumer acceptance would probably be low and the studies were discontinued. Immediate-type reactions are rare but have been described for some substances used in cosmetics. These unexpected results were nevertheless intriguing and prompted the start of a journey to see if patch test protocols could be modified to assess these reactions. An occlusive short-term patch test protocol with an application period of 20min was developed. Successful identification of the spontaneous reactions became possible. Furthermore, there was a correlation between the intensity of reactions observed in the short-term patch test and those observed in the controlled in-use studies. Short-term patch testing using the developed protocol can therefore reliably be used as a screening method, for example in the development and optimization of cosmetic formulations containing ingredients that could cause spontaneous reactions, for instance of non-immunological contact urticaria type. The lessons learned from this studies indicate that simple modifications of existing test protocols can lead to important insights into skin reactions. These modifications can then be used to create further building blocks in the development and optimization of test strategies for cosmetic formulations which offer reliable study designs for possible reactions product developers may encounter.

Skin irritation potential of cosmetic preservatives: An exposure-relevant study.

Preservatives represent one of the main causes of skin irritation and contact allergies. To comprehensively evaluate the skin irritation potential of phenoxyethanol, methylparaben, propylparaben, imidazolidinyl urea, and DMDM hydantoin under regulatory acceptable concentrations. A patch test and repeated open application test (ROAT) were applied to evaluate skin irritation in vivo. In vitro alternative methods consisting of the keratinocyte cytotoxicity assay, red blood cell (RBC) test, and hen's egg test-chorioallantoic membrane (HET-CAM) were performed to elucidate the mechanism of preservative-induced irritation responses. The patch test showed that all test substances showed a weak erythema response. Propylparaben had the highest occlusive irritancy potential in the patch test, owing to damage to the cell membrane. The two formaldehyde releasers showed noticeable skin irritation potential in the ROAT through their cytotoxicity to keratinocytes, while a visible response was observed after applying phenoxyethanol and the two parabens. No filtration was noticed in the in vivo tests, which might be attributed to the failure of subcutaneous vessel alteration by the preservatives. Commonly used cosmetic preservatives have minor skin irritation potential with mild erythema reaction under practical use, especially formaldehyde releasers and propylparaben.

Safety and efficacy of Capsozyme SB Plus (α-galactosidase and endo-1,4-β-xylanase) as a feed additive for poultry species for fattening or reared for laying and ornamental birds.

Following a request from the European Commission, the EFSA Panel on Additives and Products or Substances used in Animal Feed (FEEDAP) was asked to deliver a scientific opinion on the safety and efficacy of Capsozyme SB Plus as a zootechnical feed additive (digestibility enhancers) for poultry species and ornamental birds. The additive contains two enzyme activities (α‐galactosidase and endo‐1,4‐β‐xylanase) and it is presented in solid form. The α‐galactosidase is produced by a non‐genetically modified strain of Aspergillus tubingensis and the xylanase is produced by a non‐genetically modified strain of Trichoderma longibrachiatum. Based on the results obtained in a tolerance trial performed in chickens for fattening, the FEEDAP Panel concluded that the additive is safe for the target species at the recommended levels. The mixture of the two enzyme concentrates that are used to formulate the additive, did not show any potential for a genotoxic effect in a bacterial reverse mutation assay and an in vitro mammalian cell micronucleus test. However, owing to the limitations identified in the subchronic oral toxicity study, the Panel could not conclude on the toxicological potential of the additive. No studies were submitted by the applicant to address the safety aspects related to the user. Therefore, the Panel could not conclude on the skin or eye irritation potential of the additive nor on its skin sensitisation potential. Owing to the proteinaceous nature of the additive it should be regarded as a potential respiratory sensitiser, but the exposure is presumed to be limited due to the low dusting potential. The Panel considered that the product, used as feed additive, poses no risks to the environment and no further environmental risk assessment is required. The Panel considered a total of five efficacy trials, however, the limited evidence of the efficacy provided by those studies did not allow the Panel to conclude on the efficacy.

Transdermal Delivery of the Free Base of 3-Fluoroamphetamine: In Vitro Skin Permeation and Irritation Potential.

This work aimed to continue our effort in establishing the feasibility of 3-fluoroamphetamine (also known as PAL-353) to be a transdermal drug candidate by studying the delivery of the base form through the human cadaver skin in lieu of the previously investigated salt form, and for the first time using an EPIDERM™-reconstructed human epidermal model to predict the skin irritation potential of PAL-353, in support of development for a matrix-type transdermal delivery system. Passive and enhanced (with chemical permeation enhancers) transdermal delivery were investigated via in vitro permeation studies that were performed on Franz diffusion cells with dermatomed human cadaver skin. After 24h, PAL-353 free base revealed high passive permeation of 417.49 ± 30.12, 1577.68 ± 165.41, and 4295.16 ± 264.36μg/cm2, with applied formulation concentrations of 5.5 (F1), 20 (F2), and 40 (F3) mg/mL, respectively. Oleyl alcohol produced an approximately threefold steady-state flux enhancement at 5% or 10% w/w but may not be needed as the free base alone provided therapeutically relevant permeation. Further, it was predicted that therapeutically relevant delivery would be unlikely to cause skin irritation using the EPIDERM™-reconstructed human epidermal model. In conclusion, the present study further supported the development of PAL-353 transdermal delivery systems.

Exploration of Mucuna pruriens (Linn) starch powder formulations as a natural non-lethal riot control agent

In this study, we explore the dermal toxicity profile of Mucuna pruriens (Linn) hair lining in starch-embedded powder formulations from the natural resources of northeastern part of India and also to explore further the potentiality of this plant as a natural non-lethal riot control agent. The skin irritating, sensitizing and acute dermal toxicity potential of Mucuna pruriens (Linn) embedded in starch powder formulations were investigated in rabbits, guinea pigs, and Wistar albino rats, respectively, as per standard experimental protocol. It was found that the hair lining of M. pruriens showed moderate to severe skin irritation effect on rabbits. Regarding skin sensitization study, hair lining of M. pruriens indicates extreme sensitization on Guinea pigs. In the case of acute dermal toxicity, interestingly, there were no statistically significant changes in blood and serum biochemistry level. In a hematological study, WBC parameters were slightly increased, but after 3–4 days, it declines to a reasonable value. Histopathology of skin showed no detectable abnormality. Therefore, it may be concluded based on these findings that M. pruriens starch powder formulation can be explored as a natural non-lethal riot control agent to create initial skin irritating and sensitizing effect without the antecedence of acute dermal toxicity.

Biocompatible topical microemulsions – use and perspectives as cutaneous delivery systems for medicines

This review refers to biocompatible microemulsions, which in recent decades have attracted the interest of formulators as nanosystems useful for the skin drug delivery. Microemulsions are homogeneous pseudoternary colloidal dispersions, thermodynamically stable, fluid, transparent, isotropic, consisting of an oil phase and an aqueous phase, stabilized by a mixture of surfactant and cosurfactant and with the droplet diameter of the dispersed phase usually within the range 10-100 nm. To support the potential of biocompatible microemulsions as an innovative topical pharmaceutical form, this paper provides an overview of their type, formulation, structure, composition and characterization, as well as their advantages and disadvantages. Currently, the main purpose of the dermal microemulsion formulation is to obtain optimal drug bioavailability under conditions of minimal skin irritability. Numerous studies carried out in the last two decades have shown the potential of microemulsions to increase the percutaneous penetration of drugs, acting as penetration enhancers due to the following advantageous characteristics: high solubilization capacity of natural and synthetic lipophilic and hydrophilic compounds; the release of a large amount of active ingredient in the skin, followed by an increased dermal distribution and permeation. Ensuring skin tolerance in the presence of large amounts of surfactant and co-surfactant in the formulation of microemulsions can be achieved by selecting clinically accepted excipients for topical preparations and generally recognized as safe (Food and Drug Administration). Therefore, biocompatible dermal microemulsions can be prepared using natural excipients (vegetable oils, non-ionic surfactants, volatile oils), which are biodegradable and have lower skin toxicity and irritant potential than synthetic ones.