Exposure Factor considerations for safety evaluation of modern disposable diapers

Abstract

Modern disposable diapers are complex products and ubiquitous globally. A robust safety assessment for disposable diapers include two important exposure parameters, i) frequency of diaper use & ii) constituent transfer from diaper to skin from direct and indirect skin contact materials. This article uses published information and original studies to quantify the exposure parameters for diapers. Using growth tables for the first three years of diapered life, an average body weight of 10-11 kg can be calculated, with a 10th percentile for females (8.5-8.8 kg). Data from surveys and diary studies were conducted to determine the frequency of use of diapers. The overall mean in the US is 4.7 diapers per day with a 75th, 90th, and 95th percentile of 5.0, 6.0, and 7.0 respectively. Using diaper topsheet-lotion transfer as a model, direct transfer to skin from the topsheet was 3.0-4.3% of the starting amount of lotion. Indirect transfer of diaper core materials as a measure of re-wetting of the skin via urine resurfacing back to the topsheet under pressure was estimated at a range of 0.32-0.66% averaging 0.46%. As described, a thorough data-based understanding of exposure is critical for a robust exposure based safety assessment of disposable diapers.

Safety Evaluation of Absorbent Hygiene Pads: A Review on Assessment Framework and Test Methods

“…One of the main improvements was made in the 1970s when the fastening adhesive was added to the back sheet of the pads, replacing pins and belts of the fastening system. Further improvement was made with the incorporation of superabsorbent gel particles in the absorbent core, which allowed a higher capacity and quick absorption of fluids [1][2][3][4]29,30,40].…”

“…Then, fluid is locked and stored within this core layer even under applied pressure. For the core constituents to be transferred to skin, the constituents need to be first solubilized in the fluid vehicle and then released from the layer upon the applied pressure [2,3,47]. As SAP is not water soluble, it is hardly released from the pad by wetting or reflux.…”

“…For example, phthalates [5] that are used as plasticizers of polymers and chlorine compounds [1,6,7] that are used as bleaching agents are identified as potential hazards, and as the absorbent pads are worn in a prolonged skin contact, the safety assurance of products has been regarded significant. [3]. 3 The 50 kg weight referenced from Woeller and Hochwalt's study [14] is noted, while it has a wide range.…”

“…[3]. 3 The 50 kg weight referenced from Woeller and Hochwalt's study [14] is noted, while it has a wide range. 4 Five pads/day is referred from Woeller and Hochwalt's study [14], while 7.5 pads/day is referred from Korean MFDS [54].…”

“…Although feminine pads and baby/adult diapers are used for different purposes, the main constituents of the absorbent hygiene products share similar functions and materials. The absorption capacity of disposable absorbent products had significantly improved with the implementation of superabsorbent polymer (SAP) in the core absorbent layer [1][2][3][4]. The safety of SAP material has been evaluated rather thoroughly including its potential risks involving ingestion and dermal contact [2][3][4].…”