In vitro evaluation of the cytotoxicity and eye irritation potential of preservatives widely used in cosmetics

Abstract The consumption of cosmetics has been increasing every year and is expected to reach $675 billion by 2020 at an estimated growth rate of 6.4% per year. Exposure to skin irritants is the major cause of non-immunological inflammation of the skin. Therefore, the safety evaluation of cosmetic preservatives should be increased. Thus, the present work aimed to evaluate the cytotoxicity as the viability endpoint and the eye irritation potential of preservatives used in cosmetics. Cytotoxicity assays were performed using MTT and NRU in human keratinocytes (HaCaT), human dermal fibroblasts, adult (HDFa), and human hepatoma cells (HepG2). The eye irritation potential was evaluated using the Hen's Egg Test-chorioallantoic membrane (HET-CAM). The evaluated preservatives were methylparaben (MP), propylparaben (PP), phenoxyethanol (PE), and a mixture of methylchloroisothiazolinone and methylisothiazolinone (CMI/MI). All preservatives showed cytotoxic potential within the permitted concentrations for use in cosmetic products. In the HET-CAM test, PE and CMI/MI, MP, and PP were classified as severe, moderate, and poor irritants, respectively. Our results indicate that proper safety evaluations are required to ensure the beneficial properties of preservatives on cosmetic products without exceeding exposure levels that would result in adverse health effects for consumers.

Effect of mild irritant on gastric mucosal offensive and defensive factors.

The effect of hypotonic medium (Distilled water: DW) and hypertonic saline (HS: 5% NaCl) compared to control normal saline (NS) was studied on gastric ulcer induced by aspirin, 6 h cold restraint stress, ethanol, and pylorus ligation in rats. DW did not afford any protection while HS showed significant ulcer protective effects in all gastric ulcer models studied. The cytoprotective effect of HS seemed to be not only due to its effect on gastric acid secretion but also its effect on mucosal defensive factors like enhanced mucin secretion and decreased cell shedding. As determined by radioimmunoassay, DW did not produce any change in the accumulation of PGE and PGI2, while HS increased them significantly in the human gastric mucosal incubates compared to NS. However, in the incubates of human colonic mucosa, both DW and HS showed a significant increase in PGE with a tendency to increase in PGI2 accumulation.

A comparative study of biochemical changes induced by inhalation of aerosols of o-Chloroacetophenone & Dibenz (b,f)-1,4-oxazepine in rats.

The biochemical changes in blood samples of rats at different intervals after O-Chloroacetophenone (CN) and Dibenz (b,f)-1,4 oxazepine (CR) were studied. After a single subacute (1/10 LC50) exposure, both the compounds induced hyperglycaemia which was abolished within 24 h. The level of plasma urea was unaltered. CR exposed animals did not show any significant changes in plasma GOT, acid and alkaline phosphatase activities at different intervals. However, in CN exposed animals, a significant elevation of the activities of GOT, GPT, acid and alkaline phosphatase was observed at different intervals. All the parameters became normal within seven days after the exposure. Inhalation of CN aerosols can thus lead to tissue damaging effects in rats.

Avaliaçäo dos potenciais irritativo e bactericida de soluçöes de hidróxido de cálcio / Evaluation of irritative and bactericide potential of calcium hydroxide solutions

Através dos fenômenos exsudativos que ocorrem durante a fase aguda do processo inflamatório, o autor estudou, comparativamente entre si, o potencial irritativo de quatro soluçöes a base de hidróxido de cálcio (Pulprotec, Tergidrox, água de cal preparada por dentista e água de cal embalada em ampolas), em duas idades (nova e velha), pela determinaçäo quantitativa de um corante que extravaza juntamente com líquido plasmático. Em 40 ratos injetou intravenosamente 20 mg do corante azul de Evan por quilograma de peso corporal; imediatamente após, inoculou os medicamentos no dorso dos animais; após 3 horas, cada animal foi sacrificado e sua pele excisada; as áreas de interesse (halos azuis) foram recortadas e seus fragmentos imersos em formamida contida num frasco, o qual foi mantido a 45ºC por 72 horas, para extraçäo do corante pela formamida...