Influencia del contraión en las propiedades biológicas de tensioactivos aniónicos derivados de N-alfa, N-epsilon-dioctanoillisina: citotoxicidad y ecotoxicidad "in vitro"
SUMMARY: Surfactants are common constituents in many topical drugs and cosmetics. Application of active ingredients and pharmaceuticals additives may cause ocular and skin irritation; the majority of irritant responses to personal-care products are presumed to be caused by surfactants. Besides, some surfactants can pose toxicity problems for aquatic organisms due to their high polarity. As a result of increasing environmental and toxicological concerns, there is great industrial demand for high-performing surfactants with low toxicity. One interesting strategy to minimize environmental and irritant effects involves the synthesis of amino acid-based surfactants with analogues structures to natural compounds. The toxicological profile of anionic lysine-based surfactants with different counterions has been investigated: 1) Skin irritation potential has been evaluated by cytotoxicity in cell cultures and IL-1-alpha production as an inflammatory indicator. Surfactants were less irritant than commercial ones, with a light trend to surfactants with heavy counterions to be less cytotoxic and less potent in stimulating IL-1-alpha synthesis and release. 2) Surfactants were not phototoxic as evaluated by photohemolysis. Therefore, they can be used in topical formulations, including sun protectors. 3) Lysine derivatives were less hemolytic and less denaturing of hemoglobin than commercial surfactants by evaluating their ocular potential by hemolysis. Our surfactants can be classified as slight irritants. 4) Aquatic toxicity results by "Daphnia magna" immobilisation test revealed that 77KT and 77KL were the less toxic. 5) Antimicrobial activity by determining the minimal inhibitory concentration showed low antibacterial activity of lysine derivatives but high activity against yeasts, independently of the counterions. Therefore, they could respect skin bacterial flora in topical applications. 6) Surfactant-membrane interactions have been studied by hypotonic hemolysis and membrane fluidity. All surfactants protected against hypotonic hemolysis but solely 77KK, 77KT and 77KP increased membrane fluidity of the external region of the lipid bilayer. The counterion did not affect membrane fluidity. It could not be found a relationship between hypotonic protection and membrane fluidity. To sum up, lysine derivatives are a promising alternative to commercial surfactants due to their low ocular and dermal irritation potential and no phototoxic action. Therefore, they can be included in topical products without involving environmental risk.
Advisor:Infante Martínez-Prado, María Rosa; Vinardell Martínez-Hidalgo, Pilar
School:Universitat de Barcelona
Source Type:Master's Thesis
Keywords:fisiologia fac farmàcia
Date of Publication:11/13/2006