The EPA and the SC Johnson manufacturer faced a critical challenge: assessing the efficacy and safety of insect repellent products containing Picaridin and PMD (p-Menthane-3,8-diol) for consumer use. They needed reliable data to determine how well these products protected users from mosquito bites and evaluate the potential chemical exposure risks associated with repeated topical application. Given the rising demand for effective insect repellents due to vector-borne diseases, providing accurate information for product labeling, ensuring user safety, supporting informed consumer choices, and regulatory compliance was essential.
Project Objectives and Data
The study’s primary objective was to evaluate the Complete Protection Time (CPT) provided by Picaridin and PMD repellents against mosquito bites and to assess **chemical exposure levels** among users. We gathered extensive data on the following:
Efficacy variables: duration of CPT, defined as the time until the first mosquito bite after repellent application.
Exposure variables include the concentration of Picaridin and PMD on the skin surface over time, absorption rates, and any adverse reactions reported by participants.
Participant variables: individual skin sensitivity and reaction to the repellents.
The study was designed to provide robust data on the repellents’ efficacy while estimating the exposure levels for safe usage.
Hypotheses and Analytical Approach
We hypothesized that Picaridin and PMD would provide extended protection times under controlled field conditions, with safe exposure levels that complied with EPA safety guidelines. Specifically, the study aimed to estimate CPT parameters and determine each product’s safety profile through chemical exposure measurements.
Our analysis used a combination of efficacy testing and exposure assessment. We applied repellents on human subjects in controlled field settings and measured the time until the first mosquito bite. To capture exposure levels, we conducted skin swab analyses at intervals post-application, quantifying the concentration of Picaridin and PMD remaining on the skin. We also used statistical models to analyze CPT data, looking for significant differences in protection time between products, and compared exposure results against regulatory thresholds for chemical safety.
Findings
The study demonstrated that Picaridin and PMD provided significant CPT, effectively protecting users from mosquito bites for several hours. Exposure assessments showed that the residual chemical levels on the skin were within safe limits, with minimal absorption, even after prolonged application. Our results clearly showed each repellent’s effectiveness and safety, affirming that the products could be used safely under the specified application guidelines.
Impact on the Client and Benefits
The data allowed SC Johnson to proceed with regulatory registration of their Picaridin and PMD products, providing the EPA with the evidence to confirm product safety and efficacy. With this information, SC Johnson could confidently label their products with accurate protection times, assuring consumers of effective mosquito bite prevention. Additionally, the EPA used our data to validate the exposure safety of these products, enhancing public health protection by setting well-informed guidelines for usage.
Through this project, we helped the client achieve regulatory approval and market readiness while contributing to public safety by providing data-backed recommendations for repellent use. Completing the project on time and within budget underscored our ability to execute rigorous, ethically sound scientific studies supporting consumer safety and regulatory needs.