Objective irritation

Objective irritation is defined as nonimmunologically mediated, localized inflammation of the skin, usually resulting from contact with a substance that chemically damages the skin.2,9 The exact mechanism is unknown, and it is likely that both endogenous and exogenous factors are involved. In vivo predictive testing in animals (e.g., modified Draize test, repeated application patch tests,... 

Lammintausta, K., Maibach, H.I., and Wilson, D., Mechanisms of subjective (sensory) irritation. Propensity to non-immunologic contact urticaria and objective irritation in stingers, Derm. Beruf. Umwelt., 36, 45—49, 1988. 

Personal Subjective Perceived need value ease of use Personal Objective irritation potential fragrance feel drying feel perceived quality... 

Subjective and objective irritation must be mentioned in this context because they constitute the major differential diagnosis, which emphasizes the importance of patch testing. Subjective irritation refers to invisible changes burning, stinging, itching, and discomfort (Mathias and Maibach 1978). 

Eye and Skin Contact. Some nickel salts and aqueous solutions of these salts, eg, the sulfate and chloride, may cause a primary irritant reaction of the eye and skin. The most common effect of dermal exposure to nickel is allergic contact dermatitis. Nickel dermatitis may occur in sensitized individuals following close and prolonged contact with nickel-containing solutions or metallic objects such as jewelry, particularly pierced earrings. It is estimated that 8—15% of the female human population and 0.2—2% of the male human population is nickel-sensitized (125). 

Effects noted in study and corresponding doses Mild subjective neurological effects (eye and throat irritation, headache, fatigue, drowsiness) were reported at 200 ppm (LOAEL). No objective effects, as measured by dexterity and coordination tests, were seen. However, 50% of the subjects reported that the neurobehavioral tests required greater mental effort for them to perform. 

When monitoring efficacy of drug treatment for benign prostatic hyperplasia, subjective endpoints include relief of obstructive and irritative voiding symptoms. Objective endpoints include improvements of urinary flow rates, decreased post-void residual urinary volume, and decreased complications of disease. 

Lefebvre M, Yee D, Fritz D, et al. 1991. Objective measures of ocular irritation as a consequence of hydrogen sulphide exposure. Vet Hum Toxicol 33 564-566. 

The use of TLV-STELs and ceiling limits may be most appropriate if the objective is to identify effect zones in which the primary concerns include more transient effects, such as sensory irritation or odor perception. In general, persons located outside the zone that is based on these limits can be assumed to be unaffected by the release. 

F. Both the age of the test animal and the application site (saddle of the back versus flank) can markedly alter test outcome. Both of these factors are also operative in humans, of course (Mathias, 1983), but in dermal irritation tests, the objective is to remove all such sources of variability. In general, as an animal ages, sensitivity to irritation decreases. For the dermal test, the skin middle of the back (other than directly over the spine) tends to be thicker (and therefore less sensitive to irritations) than that on the flanks. 

A large fraction of such a material may quickly pass through the gastrointestinal tract and remain unabsorbed. Local irritation by a test substance generally decreases when the material is diluted. If the objective of the study is to establish systemic toxicity, the test substance should be administered in a constant volume to minimize gastrointestinal irritation that may, in turn, affect its absorption. If, however, the objective is to assess the irritation potential of the test substance, then it should be administered undiluted. 

Conquet, P., Durand, G., Lailler, J. and Plazonnet, B. (1977). Evaluation of ocular irritation in the rabbit Objective versus subjective assessment. Toxicol. Appl. Pharm. 39 129-139. 

The key objective of our efforts has been to develop a vaginal formulation that optimizes spermicidal and antiviral activity while enhancing spreading and true bioadhesiveness. Utilization of strict design principles for an excipient delivery vehicle, which included substantivity to vaginal mucosa, saline compatibility, compatibility with a wide range of spermicidal and antiviral compounds, low irritation potential, sperm impedance, system stability, and efficacy after stressed storage conditions, resulted in the development of DCE s [11,12,13]. Based on the results from in vitro studies, the DCE vehicle was selected for clinical development. 

For the two most prevalent symptoms related to photochemical-oxidant exposure—eye irritation and lacrimation—no method of quantification has been developed. Eye irritation, although undoubtedly real, is a purely subjective response of the subject, and no measurement, other than the complaint itself, has yet been developed. Similarly, a routine objective measure of lacrimation remains to be developed. However, studies on tears have demonstrated that, when a person is experiencing eye irritation, the lysozyme content of the tears is lower than normal. Measuring lysozyme content of the tears or the related pH variation appears promising, but more feasibility studies are necessary before the usefulness of the method is known. 

There can be no objection to the ingestion of bulk substances for the purpose of supplementing low-residue modern diets. However, use of irritant purgatives or cathartics is not without hazards. Specifically, there is a risk of laxative dependence, i.e the inability to do without them. Chronic intake of irritant purgatives disrupts the water and electrolyte balance of the body and can thus cause symptoms of illness (e.g., cardiac arrhythmias secondary to hypokalemia). 

The general objectives for assessing the potential of a substance to induce irritation or corrosion are to evaluate ... 

Human volunteers exposed to 100 ppm for 15 minutes experienced eye irritation and objected to the odor and taste nose and throat irritation occurred at levels greater than 100ppm. No chronic or systemic effects in humans have been reported. 

---