In vitro percutaneous permeation of the repellent DEET and the sunscreen oxybenzone across human skin.
Bibliographic record
Abstract
PURPOSE: DEET and oxybenzone are two essential active ingredients in repellent and sunscreen products. The percutaneous permeation of the two compounds across human skin from five commercially available repellent and sunscreen products was investigated in vitro. METHODS: Diffusion studies were carried out at 37 degrees C, using Franz-style diffusion cells and human epidermis (380 microm in thickness). The test products were evaluated either individually or in various combinations for up to 6 hours. Concentrations of both compounds permeated through the skin were measured using an HPLC assay. Permeability and permeation percentage of DEET and oxybenzone from different application approaches were calculated and statistically compared. RESULTS: The accumulated transdermal permeation was 0.5-25.7% for DEET and 0.3-1.6% for oxybenzone, respectively. Repellent lotion produced an 18-fold increase in transdermal permeation in comparison to that of repellent spray, while using repellent spray prior to sunscreen lotion resulted in the highest penetration of DEET among the study groups. Premixing sunscreen lotion with repellent spray at different ratios also produced significantly higher permeation of oxybenzone across the skin than the control, but other application approaches did not differentiate from the single sunscreen lotion. CONCLUSION: It was concluded from this study that human skin was less permeable to DEET and oxybenzone than artificial membranes, but was comparable to pig skin in permeability. DEET permeated transdermally more across human skin than oxybenzone, and both compounds acted as permeation enhancers when used simultaneously. Premixing repellent and sunscreen enhanced the overall penetration of both DEET and oxybenzone. Using different application sequences and amounts resulted in variable percutaneous permeation of DEET and oxybenzone through the skin.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.002 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".