Animals primary irritation

Propylene oxide is a primary irritant, a mild protoplasmic poison, and a mild depressant of the central nervous system. Skin contact, even in dilute solution (1%), may cause irritation to the eyes, respiratory tract, and lungs. Propylene oxide is a suspected carcinogen in animals. The LC q (lowest lethal concentration by inhalation in tats) is 4000 mg/kg body weight. The LD q (oral) is 930 mg/kg. The LD q (dermal) is 1500 mg/kg. The TWA (8-h exposure) is 100 ppm and the STEP (15-min exposure) is 150 ppm. 

D. Analysis of data The data from the irradiated and nonirradiated sites are evaluated separately. The scores from erythema and eschar formation, and edema at 24, 48, and 72 hr, are added for each animal (six values). The six values are then divided by 3, yielding six individual scores. The mean of the six individual animal irritation scores represents the mean primary irritation score (maximum score = 8, as in the primary dermal irritation study). This method was developed after a human model had been developed. 

Toxicology. Formaldehyde is an irritant of the eyes and respiratory tract it causes both primary irritation and sensitization dermatitis at high levels it is carcinogenic in experimental animals and, although results are equivocal in humans, it is considered a suspected human carcinogen. 

Dry nonionic and cationic material caused no skin and minimal eye irritation during primary irritation studies with rabbits. Dry anionic polyaciylamide did not produce any eye or skin irritation in Laboratory animals. Emulsion nonionic polyacrylamide produced severe eye irritation in rabbits, while anionic and cationic material produced minimal eye irritation in rabbits. Polyacrylamides arc used safely for numerous indirect food packaging applications, potable water, and direct food applications. 

Repeated chemical patch applications to both humans and animals reveal that certain chemicals at a given concentration do not produce primary irritation, but may elicit severe skin reactions after a number of exposures. Nevertheless, these reactions may not be considered incidents of sensitization, because after 10 to 14 days of rest, the skin recovers its original resistance to the chemical injury. Such chemicals are neither primary irritants nor sensitizers. 

According to Draize, a primary irritation index was calculated by adding the results from the 6 animals 24 and 72 hours after administration and dividing the score by 12 (6 animals x 2 observations) of the mean of grades from both the intact skin site and the braded site. He graded the irritation index into the following irritation indices ... 

There are several types of irritancy testing protocols that are used to comply with federal and international safety regulations. The classic Draize test was developed in 1944 to measure acute primary irritation. The test compound is applied in an occluded fashion to a clipped area of abraded and intact skin of at least six albino rabbits and evaluated 24 hr and 72 hr after patch removal. The degree of erythema and edema, ranging from one to four, is recorded to reflect severity of the irritation. Because these tests are occluded, irritancy is potentiated due to hydration, which reduces the skin barrier. The Draize test may be modified to assess sensitization by preexposing animals to a sensitizing dose of the study chemical and then rechallenging the animals at a later date to illicit the immune-mediated response. 

Methyinitrosourea causes dermatitis however, it appears to be due to sensitization rather than primary irritation. Although carcinogenicity data are not available for humans, N-Nitroso-N-methylurea is reasonably anticipated to be a human carcinogen based on sufficient evidence of carcinogenicity in experimental animals. 

In animals, pyrene is a mild dermal irritant and primary irritant. The oral LD50 is 2.7gkg in rats and 800 mg kg ... 

Human Toxicity Skin contact results in primary irritation with redness, itching and sometimes scaling. Urticaria] wheals are not uncommon. Corneal opacities have been produced in exptl animals. 

Toxicology LD50 (oral, rat) 1260 mg/kg LDLo (rabbit, skin) 1260 mg/kg primary irritant mod. skin and eye irritant may cause changes to respiration, Gl, liver, and food intake (animal)... 

In contrast, hexavalent chromium species, predominantly chromate at physiological pH, behave very differently and are toxic for bacteria, plants, and animals. Primary effects are related to the oxidative nature of Cr(VI), which manifests itself in irritation of the skin and the mucous membranes and allergic effects on lung and bronchia. Cr(VI) that survives reduction by body fluids is rapidly taken up by the... 

Tests for irritancy in vitro and in vivo, in both animals and humans, have also been developed. Primary irritation is most often evaluated by modifications of the method described by Draize et al. [47]. 

Local Not a primary irritant. Slight erythema and irritation have been noted in animals when applied to abraded skin or under occlusive dressing. 

SM is widely known for its vesicating properties. There are no documented studies that conform to any standard regulatory test method for dermal irritation/corrosivity. However, there is sufficient information from observations and tests in humans to establish SM as a primary irritant, and further tests in animals are not required. 

The primary routes of entry for animal exposure to chromium compounds are inhalation, ingestion, and, for hexavalent compounds, skin penetration. This last route is more important in industrial exposures. Most hexavalent chromium compounds are readily absorbed, are more soluble than trivalent chromium in the pH range 5 to 7, and react with cell membranes. Although hexavalent compounds are more toxic than those of Cr(III), an overexposure to compounds of either oxidation state may lead to inflammation and irritation of the eyes, skin, and the mucous membranes associated with the respiratory and gastrointestinal tracts. Skin ulcers and perforations of nasal septa have been observed in some industrial workers after prolonged exposure to certain hexavalent chromium compounds (108—110), ie, to chromic acid mist or sodium and potassium dichromate. 

Troop exposure to these materials could result from leaking DF containers, accidents that disrupt packaging, spills at production or storage facilities, or accidents during transport. Because DF and DC are relatively volatile compounds, the primary route of exposure is expected to be the respiratory system. However, ingestion also results from inhalation exposures in animals and could occur in humans. DF and DC vapors have a pungent odor and may cause severe and painful irritation of the eyes, nose, throat, and lungs. Data provided are for DF only, DC has similar properties. 

For the skin, this scale is used in the primary dermal irritation test, which is performed for those agents that are to be administered to patients by application to the skin. As with all local tolerance tests, it is essential that the material be evaluated in condition of use, that is, in the final formulated form, applied to test animals in the same manner that the agent is to be used clinically. 

---