Reaction mass of iodine and 2-Pyrrolidinone, 1-ethenyl-, homopolymer

Endpoint summary

Link to relevant study record(s)

Reference

Endpoint:

dermal absorption in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Principles of method if other than guideline:

The aim of the study was to study the skin absorption of iodine after the application on the skin of povidone-iodine solution, used by health care workers during surgical procedure. Franz diffusion static cells with human skin were used.

GLP compliance:

not specified

Specific details on test material used for the study:

- Name of the test material: Povidone iodine solution 10 %- Description: The povidone-iodine solution (10%) used in the experiments is a stable chemical complex of polyvinylpyrrolidone (povidone, PVP) and elemental iodine (Esoform Jod 75, that contains 10% (7.5 g) of polyvinylpyrrolidone–iodine with 0.75% of active iodine; Esoform S.P.A. Laboratorio Chimico Farmaceutico, Via del Lavoro 10, Rovigo, Italy).

Radiolabelling:

no

Species:

other: Human abdominal full thickness skin

Details on test animals or test system and environmental conditions:

Human abdominal full thickness skin was obtained as surgical waste after the authorization of the local Ethical Committee and it was used for the absorption experiments immediately after the surgical operations. Prior to freezing, the subcutaneous fat was removed and the hair shaved with a razor. All the pieces of full thickness skin were stored in freezer at -25 °C for a period up to two months. For each experiment, the skin of 2 different donors, male and female, with a range of age from 50 to 70 years was used.From each skin specimen, 4 x 4 cm² pieces were cut and mounted separately on the diffusion cells, that were previously washed the first time with freshly prepared aqua regia, the second time with diluted nitric acid, and rinsed three times with milliQ water. Skin integrity was tested before and after each experiment using electrical conductibility. Cells with a resistance lower than 3.95 ± 0.27 K Ohm cm-2 were considered to be damaged and rejected.

Type of coverage:

other: exposure through Franz diffusion cells

Vehicle:

other: Synthetic sweat

Duration of exposure:

24 hours

Doses:

Experiment 1: 1.0 mL of synthetic sweat and 2.0 mL of the povidone-iodine solution (10%) providing an amount of 0.606 g cm² of iodine in order to ensure an infinite dose.Experiment 2: Each donor chamber has been filled with 1.0 mL of the povidone-iodine solution (10%) and the skin has been carefully washed with a cotton balls for two minutes.

Details on in vitro test system (if applicable):

The experiments were carried out as follows:- Experiment 1: Exposure chambers of 6 Franz diffusion cells were filled with 1.0 mL of synthetic sweat and 2.0 mL of the povidone-iodine solution (10%) providing an amount of 0.606 g cm-2 of iodine. At 2, 4, 6, 8, 12, 20 and 24 h, 1.5 mL of the dermal bathing solution was removed and collected for the analyses. Each receptor sample was immediately replaced with an equal volume of fresh made physiological solution. At 24 h, the dermal bathing solutions were removed and stored in the freezer, the donor solutions were collected in order to verify the iodine concentration in the donor phase.- Experiment 2: experiment 1 was repeated miming the hand washing protocol used by nurses and medical doctors during surgery in Trieste Hospitals: each donor chamber has been filled with 1.0 mL of the povidone-iodine solution (10%) and the skin has been carefully washed with a cotton balls for two minutes. After that, the skin surface has been rinsed three time with 2.0 mL of physiological solution. The washing operation has been repeated twice. At 1, 2, 4, 6, 8,12, 20 and 24 ,) 1.5 mL of the dermal bathing solution was removed and collected for the analyses. Each receptor sample was immediately replaced with an equal volume of fresh made physiological solution. At 24 h, the dermal bathing solutions were removed and stored in the freezer, the donor solutions were collected in order to verify the iodine concentration in the donor phase.- Blanks: for each experiment, one cell was added as blank. The blank cells were treated as the other cells with the exception that no povidone-iodine solution (10%) has been introduced to the exposure chamber, but only synthetic sweat.Data analysisIodine concentration data (mg/cm-3) in the receptor solution were converted to the total amount that penetrated (mg/cm-2), with a correction for dilution due to sample removal. Data analysis was performed using the statistical software SPSS for Windows (version 15.0). Data are reported as mean ± standard deviation (SD). The difference between independent data was assessed by means of the Mann–Whitney and Kruskal–Wallis tests. A p value of 0.05 was considered as the limit of statistical significance.

Signs and symptoms of toxicity:

not examined

Dermal irritation:

not examined

Absorption in different matrices:

Estimation of free-iodine concentration by iodine permeation assay through the skin:The concentration of iodine in the acceptor compartment increased linearly over time in proportion to contact time between iodine and the intact skin in the donor compartment. After 24 h from the beginning of the measurement the concentration in the acceptor compartment was 11.59 ± 6.3 mg/cm², the total amount of iodine diffusing out during this period is proportional to the total iodine absorbed by the bloodstream. The medium flux calculated was 0.73 ± 0.33 mg/cm²/h and the lag time was 8.9 ±1.5 h.Residual effect of skin iodine:Even though the first two test tubes were marked as blank, an increased concentration was measured of free iodine in the acceptor compartment due to the presence of iodine into the skin and in synthetic sweat used in the donor phase. The concentration of iodine increased in the course of the first approximately 8 h until it reaches the plateau.

Additional information

Tthe skin absorption of iodine after the application on the skin of povidone-iodine solution, used by health care workers during surgical procedure, was studied (Nesvadbova 2015). Franz diffusion static cells with human skin were used. Human abdominal full thickness skin was obtained as surgical waste. Two experiments were performed. In experiment 1, the exposure chambers of 6 Franz diffusion cells were filled with synthetic sweat and povidone-iodine solution (10%) providing an amount of 0.606 g cm-2 of iodine. At 2, 4, 6, 8, 12, 20 and 24 h, dermal bathing solution was removed and collected for analysis. In experiment 2, experiment 1 was repeated miming the hand washing protocol used by nurses and medical doctors during surgery in Trieste Hospitals: each donor chamber has been filled with povidone-iodine solution (10%) and the skin has been carefully washed with a cotton balls for two minutes. After that, the skin surface has been rinsed three times with physiological solution. The washing operation has been repeated twice. At 1, 2, 4, 6, 8,12, 20 and 24 h, dermal bathing solution was removed and collected for the analyses. The concentration of iodine in the acceptor compartment increased linearly over time in proportion to contact time between iodine and the intact skin in the donor compartment. After 24 h from the beginning of the measurement, the concentration in the acceptor compartment was 11.59 ± 6.3 mg/cm², the total amount of iodine diffusing out during this period is proportional to the total iodine absorbed by the bloodstream. The medium flux calculated was 0.73 ± 0.33 mg/cm²/h and the lag time was 8.9 ±1.5 h.

In addition an absorption study in which the absorption of iodine from iodine-containing PVP preparations was investigated (Glöbel 1984) was identified. Also, the possibility of iodine being split off from the organic compound was tested. The study was perfomed in 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 an index of thyroid function, before and after the PVP application. Increase in iodine supply was up to 2 mg daily in the test subjects. The overwhelming proportion of the absorbed iodine (> 75 %) 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 biologogical half life of Iodine in an organism 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.