Pilot Study to Assess the Quantitative Dermal Transfer Efficiencies of Solids for Multiple Transfer Pathways

University of Minnesota (UMN)

Status: Completed

Conditions: Environmental Exposure

Treatments: Other: Participants for Surface Skin Sampling; Other: Elemental metallic lead; Other: Tinopal

Study type: Interventional

Funder types: Other

Identifiers

NCT02529748

1506M73781

Details and patient eligibility

About

Dermal transfer efficiency has been defined as the amount of material that moves from one surface to another following contact. The investigators propose to measure dermal transfer efficiency for the following pathways: (1) object to skin, (2) skin to skin, (3) skin to mouth, (4) clothing to skin, (5) gloves to skin, and (6) air to skin. First, the quantitative dermal transfer will be measured for the two selected test substances (lead, Tinopal) for each of these six pathways. The relative quantities of dermal transfer will also then be compared between the different transfer pathways (e.g., is skin to skin transfer greater or less than clothing to skin transfer?). And second, the pattern of transfer will be characterized semi-quantitatively (e.g., does dermal transfer occur consistently and evenly to the skin from different reservoirs?).

Full description

Each of the six transfer pathways will be tested and measured in a controlled, ventilated study chamber at the University of Minnesota's School of Public Health Industrial Hygiene Laboratory. To test each pathway, human volunteers will perform repeated contact activities using an identical protocol (e.g., identical number of contacts, type of material contacted, measured pressure of contact, measured time of contact, measured temperature and humidity) so that inter- and intra-individual variability can be characterized.

The qualitative and quantitative sampling methods that will be used have been developed, tested, and published by researchers from the National Institute for Occupational Safety and Health (NIOSH) and other institutions such as ASTM. Specifically, quantitative transfer efficiencies will be measured using accepted wipe sampling protocols taken from several papers in the peer-reviewed literature. Semi-quantitative transfer patterns will be measured using fluorescent tracer intensity techniques that have also been presented in the peer-reviewed literature. The skin surface wipe samples will be sent to an accredited American Industrial Hygiene Association (AIHA) laboratory for analysis.

These sampling results will allow the investigators to report the measured quantitative dermal transfer efficiencies of elemental metallic lead and Tinopal for each pathway in mass per square surface area of skin, and also calculate the relative transfer efficiencies in terms of percent transferred versus originally loaded. Fluorescent tracer maps will allow the investigators to demonstrate the patterns of transfer for each pathway using intensity of the tracer following transfer. Following this analysis, the investigators will then use the data to better inform the relative importance of the pathways in the conceptual model with respect to dermal exposure assessment and modeling efforts. These results are very important for improving the quality of workplace dermal exposure assessments and techniques. The current approaches are not well validated, and it is unknown if the results of existing dermal exposure models are accurate. It is expected that the results of this study will help to improve the protection of workers from certain dermal exposure hazards in the workplace by providing better inputs to the existing dermal exposure models, since it is not possible to collect exposure samples for each job task in the workplace.

Enrollment: 10 patients

Sex: All

Ages: 18+ years old

Volunteers: Accepts Healthy Volunteers

Inclusion criteria

• Adult volunteers with healthy intact skin.

Exclusion criteria

• Children will be excluded from the study.
• Adults with a past history of dermal sensitization, skin allergy, or dermal irritation or dermatitis because of the potential to have compromised barrier function in the skin.
• Adults who are unwilling to follow protocol requirements.
• Adults who have a documented history of lead poisoning.
• Adults who have a concurrent contagious illness or other stressor which in the opinion of the investigator may interfere with the subject's ability to perform the study's requirements.
• Adults who have open wounds or otherwise compromised skin integrity on their hands.
• Adults who are pregnant or nursing.
• Adults who lack the capacity to provide informed voluntary consent to participate in the study.

Trial design

Primary purpose: Basic Science

Allocation: N/A

Interventional model: Single Group Assignment

Masking: None (Open label)

---

10 participants in 1 patient group

Participants for Surface Skin Sampling

Experimental group

Description:

Adult volunteers with healthy, intact skin will have surface skin wipe samples collected following contact with the approved test substances to measure the quantitative transfer of the test substances to and from the skin surface.

Treatment:

Other: Tinopal

Other: Elemental metallic lead

Other: Participants for Surface Skin Sampling