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Description of key information

The possible effect of long-term use of the test substance on thyroid functions was investigated and observed in a case report. The long-term treatment with the test substance was considered the probable cause for abnormalities in thyroid function.

Key value for chemical safety assessment

Repeated dose toxicity: via oral route - systemic effects

Endpoint conclusion
Endpoint conclusion:
no study available

Repeated dose toxicity: inhalation - systemic effects

Endpoint conclusion
Endpoint conclusion:
no study available

Repeated dose toxicity: inhalation - local effects

Endpoint conclusion
Endpoint conclusion:
no study available

Repeated dose toxicity: dermal - systemic effects

Endpoint conclusion
Endpoint conclusion:
no adverse effect observed
Species:
other: Human
System:
other: Thyroid function
Organ:
thyroid gland

Repeated dose toxicity: dermal - local effects

Endpoint conclusion
Endpoint conclusion:
no study available

Additional information

The effect of long-term treatment with the test substance on thyroid function was assessed in a study by Nobukuni (1997). In 40 patients of the department of neurology, the status of the use of PVP-I preparations and their effects on serum inorganic iodine levels and thyroid functions were investigated. Serum level of total iodine, thyroxine (T2), triiodothyronine (T3), free thyroxine (FT4), free triiodolhyronine (FT3) and thyrotropin (TSH) were determined. In 27 patients treated with PVP-I for a long term, inorganic iodine levels were significantly increased as compared to those in 13 patients without PVP-I treatment. Clinical symptoms considered to be attributable to thyroid dysfunctions were seen in none of the subjects. Also levels of FT4 and T4 were significantly increased. In levels of TSH, T3 and FT3, no significant intergroup difference was seen. The duration of PVP-I treatment was significantly correlated with the serum FT4 level and also with the serum FT3 level. Based on the thyroid parameters the following conclusion were drawn: out of the 27 patients treated with PVP-I in the long term, subclinical hypothyroidism was seen in 3 patients, mild hyperthyroidism was seen in 1 patient, and subclinical hyperthyroidism was suspected in 7 patients. According to the authors, the long-term treatment with PVP-I was probably the cause for these abnormalities in thyroid functions.

Burches-Feliciano et al. (2015) published a case report of a patient with ischemic lesions in both feet requiring the daily application of povidone iodine for periods ranging from 60 to 90 min. The patient stayed at the ICU for 26 days and was later transferred to the hospitalization ward. After hospital discharge the patient was regularly monitored for one year. No thyroid functional impairment was observed until 6 months after hospital discharge when a routine test showed decreased levels of TSH and high levels of free T4 and free T3. There was no associated clinical evidence of low thyroid function. This finding, consistent with subclinical hyperthyroidism, persisted over time. The patient had no family or personal history of thyroid disease, thyroid gland palpation revealed no goiter or nodules, thyroglobulin antibodies were slightly positive and peroxidase antibodies were negative. A thyroid ultrasound examination was normal. A thyroid scan with technetium 99m showed low thyroid uptake, which was attributed to repeated application of povidone iodine to the ischemic lesions of the feet. The patient showed normalization of TSH levels two weeks after iodine exposure was stopped.

Glöbel (1984) tested the absorption of iodine from iodine-containing PVP preparations and the possibility of iodide being split off from the organic compound in subjects with normal thyroid function after they had used PVP-iodine as mouth-antiseptic (15 subjects), vaginal gel (20 subjects) or liquid soap (20 subjects). Serum I-, T3, T4, TSH and urinary iodide excretion were measured, as a parameter of thyroid function, before and after the PVP-I application. Increase in iodine supply was up to 2 mg daily in the test subjects. >75 % of the absorbed iodine was as organically bound iodine. The measurement of total iodine in the serum and urine showed a significant increase after application of vaginal gel. Also, the measurement of total iodine in the serum and urine showed a distinct increase after administration of the oral antiseptics. The biological half-life of Iodine was estimated to be ca. 2 days based on urinary excretion levels. In none of the subjects there was evidence of developing hyper- or hypothyroidism as a result of the additional iodine supply. The serum levels of T3, T4 and TSH were in the normal range for all subject and time points.

Justification for classification or non-classification

Classification for Specific target organ toxicity (repeated exposure) was based on the definitions and considerations provided in chapter 3.9.1.3 and 3.9.2.6 of regulation (EC) No 1272/2008. The results of the available data show significant changes to the biochemistry of the subjects investigated, which pose a probable cause of thyroid dysfunction after long term treatment with the test substance. Based on the nature of the observed effects and lack of severity thereof, the test substance is classified for Specific target organ toxicity Catagory 2 (H373: May cause damage to organs through prolonged or repeated exposure) in accordance with EU Classification, Labeling and Packaging of Substances and Mixtures (CLP) Regulation No. 1272/2008.