1-aminopropan-2-ol

Endpoint summary

Description of key information

In a questioning study by NIOSH after poisoning incidents due to unprotected skin irritation, five workers described experiences of direct contact dermatitis after contact to MIPA.

In a patch testing multicentre studys in 144 metalworkers, MIPA was not found to be an allergen, administered as a 2% solution.

Additional information

Skin irritation/corrosion, described for poisoning incidents in humans

In a questioning after a written request of a representative of employees to NIOSH, monoisopropanolamine (MIPA) and titaniurn dioxide (TiO2) in the milling department of a large plant producing TiO2 were investigated for its hazard potential. MIPA represented a definite cutaneous hazard upon direct contact with the skin to those workmen failing to utilize proper protective equipment (direct contact). Five individuals of 15 questioned employees experienced an irritant contact dermatitis after direct skin exposure to MIPA. Most employees working with the substance recognized irritant effects when not wearing appropriate protective clothing at the time of contact. Irritation of the upper respiratory tract and eye irritation were noted by another individual.

Patch testing in 144 metalworkers

The patch test study in humans was conducted to investigate sensitization to 10 frequently used metalworking fluids (MWF) components, which are not part of the established MWF test series, in metalworkers with suspected occupational dermatitis due to MWF. Besides others,1 -amino-2 -propanol (monoisopropanolamine; MIPA), has been patch tested in 144 patients. 1 patient reacted positively to MIPA.

Patch testing with well-known MWF allergens showed proportions of positive reactions, which were comparable to those from other studies, e.g. 11% to monoethanolamine, 8% to colophonium and 3%–5% to various preservatives. MIPA was found to be a far less important allergen in metalworking fluids.

Skin sensitization, tested with human volunteers

A modified Draize repeat insult patch test with a 2% aqueous solution of MIPA was used to determine the potential to cause sensibilization to humans. In two different approaches 150 male and female or 25 male and 25 female volunteers were applied at the back with patches to cause sensitization or photosensitization respectively. For the skin sensitization, volunteers were treated for 48 -72 h three times a week for three weeks and the sites were scored at patch removal. After two weeks, the challenge patch was applied to a naive side and scored at 48 and 96 h on a scale of 0 -4. For photosensitization, 25 male and 25 female volunteers were applied with 0.2 ml volume of the MIPA solution on patches of the lower backs of a 0.2 ml volume of the MIPA solution, and the patches were applied to the lower backs for 24 h three successive days a week for three successive weeks. The sites were irradiated with a combination of UV-A and UV-B at patch removal in a dose of three times the minimal erythema dose. Again, a challenge patch was applied. One patch remained in place for 24 h, and the site was irradiated at the second patch removal . The other patch remained in place for 48 h and was used to measure contact dermatitis. MIPA did not induce allergic, photoallergic or allergic contact dermatitis.

Nasal provocation test with Amines present in cleaning products

A nasal provocation test (NPT) was performed with an aliphatic or alicyclic amine in 37 patients. Most patients presented rhinitis associated with asthma-like symptoms. Women were overrepresented (F/M sex ratio=1.5). Nearly 40% of patients were considered to be atopic. Six patients reported a history of asthma (n=4), rhinitis (n=1) or atopic dermatitis (n=1, patient G), before they develop their work-related symptoms. All of them fulfilled a criteria of atopy (presence of a positive prick test to a common respiratory allergen or a positive Phadiatop test). More than two thirds worked as cleaners (industrial or domestic) or paramedics. An amine was tested in nearly 4 out of 5 patients, as it was present in the composition of a cleaning product (detergent, disinfectant, wax-remover, stripper, etc.) and, in most cases, it was sprayed. The other kinds of amine-containing products in this series were: lubricant/cuttingfluids (n=3 patients), resin hardeners (n=2), polishing agents (n=1), hair colour products (n=1), a brazing product (n=1). Six patients presented one positive NPT with an amine and another patient presented three positive NPTs performed with three different surfactant solutions (A, B1, B2: detergent A contained surfactant A and detergent B contained surfactants B1 and B2) present in the patient’s cleaning products. These surfactant solutions contained various alkylamine oxides: surfactant B1 contained a mixture of bis(2-hydroxyethyl)tallowamine oxides and surfactants A and B2 were both mixtures of C12-C18 alkyldimethylamine oxides (these mixtures were supplied for challenge by their respective industrial furnishers). Of the seven patients who had a positive NPT with an amine, at least one additional NPT with other compounds was performed in six patients and two patients had at least one positive additional NPT. Two of the four patients challenged with didecyldimethylammonium chloride had a positive response. Most patients (25 out of 30 patients) with a negative amine-NPT were subsequently tested with other agents. MIPA was tested to be negative in the assay.