Arachidonic acid release: an in vitro alternative for dermal irritancy testing

Efficacy, Safety and Targets in Topical and Transdermal Active and Excipient Delivery

A key requirement for topical and transdermal active delivery is the effective delivery of an active to a desired target site, to achieve both safe and efficacious outcomes. This chapter seeks to explore the importance of the pharmacological, toxicological and therapeutic properties of actives and excipients, as well as the site of action as complementary components in percutaneous absorption. This is crucial for optimized topical and transdermal product design.

Irritantcy potential and sub acute dermal toxicity study of Pistacia lentiscus fatty oil as a topical traditional remedy

The current study was undertaken to assess safety of Pistacia lentiscus fruits fatty oil (PLFO) as a topical traditional remedy. A primary skin and eye irritation tests were conducted with New Zealand white rabbits to determine the potential for PLFO to produce irritation from a single application. In addition, a sub acute dermal toxicity study was performed on 18 NZW rabbits to evaluate possible adverse effect following application of PLFO for 28 days. Based on the results of the current study, PLFO is classified as slightly irritating to the skin and the eye of rabbits (Primary Irritation Index (P.I.I.) = 1.037; Ocular Irritation Index (O.I.I.) = 5.33 at 1 h). In the sub-acute toxicity test, PLFO produced neither mortality nor significant differences in the body and organ weights between control group and treated rabbits. However, a reversible irritant contact dermatitis was observed in the treated areas from the end of the second week of application until the end of experiment. This local phenomenon was accompanied by a significant skin thickening (P≤0.01) since the 12(th) day (ANOVA, F = 11, 07143, P = 0, 00765) which is confirmed with an inflammatory granuloma in histological study. Haematological analysis and blood chemistry values of the 2 groups showed no significant differences in any of the parameters examined. In summary, PLFO is minimally irritating to the eye and skin after a single exposure, but it may cause irritant contact dermatitis and a reversible thickening of skin after prolonged use.

DNA damage in human lymphocytes exposed to four food additives in vitro

In vitro genotoxic effects of antioxidant additives, such as citric acid (CA) and phosphoric acid (PA) and their combination, as well as antimicrobial additives, such as benzoic acid (BA) and calcium propionate (CP), on human lymphocytes were determined using alkaline single-cell gel electrophoresis. There was a significant increase in the DNA damage in human lymphocytes after 1 h of in vitro exposure to CA, PA, BA and CP (200, 25–200, 50–500, 50–1000 μg/mL, respectively). The combination of CA and PA significantly increased the mean tail intensity at all the concentrations used (25–200 μg/mL) and significantly increased the mean tail length mainly after higher concentrations (100 and 200 μg/mL). Data in this study showed that the concentrations of food additives used induce DNA damage and PA was the most genotoxic and CA was less genotoxic additives among them.

In vitro genotoxicity and cytotoxicity of benzalkonium chloride

Benzalkonium chloride (BAC) acts as a preservative in numerous nasal preparations. Possible genotoxic and cytotoxic effects of BAC in human respiratory epithelial BEAS-2B cells should be investigated in vitro. Cell cultures were exposed for 2h to BAC in concentrations ranging from 0.002% to 0.05%. Methyl methanesulfonate served as positive control, PBS as negative control. The tail moment of single-cell gel-electrophoresis (SCGE) was used to assess BAC-induced DNA damage. Cell viability was measured by trypan blue dye exclusion staining. Additionally, the critical micellar concentration (CMC) of BAC in PBS was detected. The tail moment increased dose dependently with the maximum value at 0.02%, and declined for higher concentrations. Nearly all cells died at low BAC concentrations up to 0.01%. Above this concentration cell viability increased. The CMC of BAC in PBS was estimated to be 0.02%. BAC caused relevant DNA changes in respiratory epithelial cells in vitro at concentrations commonly employed in commercially available nasal preparations. Some of the exposed cells survived. In further studies it could be considered to look whether these cells would still be able to proliferate and possibly fix the damage that they have possibly accumulated into an actual mutation using for example the induction of micronuclei.