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MANUFACTURING

Medical Device & Diagnostic Industry Magazine
MDDI Article Index

Wava Truscott

In the medical device and diagnostic industry, gloves routinely serve a dual purpose: protection of the employees and of the products they manufacture. Glove selection must not only be based on their ability to protect employees from processing agents used in manufacturing and microorganisms in laboratory environments, but the choice must also take into account the very real problem of potential reactions related to wearing the gloves themselves. In addition, the chosen gloves must protect work-in-progress from particles, skin oils, extractable chemicals, microorganisms, endotoxins, and any other substances defined as contaminants by product requirements; they must not, themselves, contribute such contaminants to the product. And, finally, to maintain their role as a safeguard throughout their time in use, gloves must be durable. This article reviews the key criteria for the selection of gloves for manufacturing personnel and addresses concerns related to their use and disposal. Also discussed is the real concern that glove use may affect product performance.

The importance of fit in glove selection depends on the task being performed. Factors to consider when evaluating gloves include the following:

  • Grip. The evaluation of a glove's gripping potential should incorporate actual or simulated work conditions, such as wet or dry, hot or cold; actual materials handled (e.g., metal, glass, plastic); and processing aids used (e.g., solvents, lubricants, alcohols). A slippery glove leads to wasted time recovering dropped parts and increased employee frustration as workers physically strain to fight the slick exterior. Any savings realized by buying low-quality gloves will be offset by the financial impact of scrap from suboptimally assembled and broken parts.
  • Style. The choice between hand-specific and ambidextrous styles should be based on the application. Long-term assembly of intricate pieces often requires the fit and comfort of an anatomically designed hand- specific glove. If work procedures are less tedious or glove removal frequent, an ambidextrous style may be adequate.
  • Fit. Baggy gloves can cause wearers to execute procedures awkwardly. If infectious agents or hazardous chemicals are used, any accidental spills can put staff at personal risk. Gloves should conform to the hands yet allow ease of movement (low modulus) to minimize fatigue.
  • Cuff beading. A beaded cuff can facilitate the removal of gloves from their packaging and make donning easier. Beading also seems to improve fit, reduce cuff roll-down, and provide resistance against drips from processing fluids.
  • Durability. Gloves are worn in the manufacturing environment to protect the product from contaminants generated or spread by employees and to protect the employees from potentially harmful solutions or substances. When a glove tears, both functions are compromised. Therefore, it is critical to choose glove materials carefully. Vinyl, for instance, does not have the strength, elongation potential, or flexibility of latex; it breaks rather than gives. This weakness is apparent at the microscopic and macroscopic levels, with tears occurring most notably between fingers and at finger tips during strenuous, friction-creating, and torquing manipulations. During the glove evaluation period, gloves should be worn while simulating routine tasks. After each task is accomplished, the gloves should be filled with water and observed for leaks.
  • Lotion compatibility. Most lotions should not be worn under gloves. Those that contain oil (mineral, jojoba, coconut, or palm), petroleum (gels and salves), or lanolin degrade latex and vinyl gloves, compromising barrier integrity.1 Although a hand-care regimen incorporating these products is encouraged away from the workplace, only compatible lotions should be worn under gloves. Alternatives for use with gloves include lotions formulated with a water, glycerin, or other nonoil base.

To assess the potential degradative properties of a particular lotion, the following simple experiment may be performed. Cut two equal 0.25- to 2-in. strips from the palm or back surface of a glove, and then stretch and secure the strips to approximately 3 times their length. Coat one with the lotion in question, leaving the other uncoated as a control. After 30 minutes, release the strips and place them side by side. If the lotion-treated sample has enlarged either in length or width, and breaks more easily than the control, the material's mechanical stability has been degraded and the lotion is unacceptable.

Chemical compatibility. Gloves should also be evaluated for chemical compatibility with the various solutions that the employees will handle. Evaluations should be performed with the correct chemical concentration, contact (splash or immersion), and length of exposure to ensure relevancy. Indicators of degradation include glove softening, tackiness, brittleness, finger elongation (creep), increased transparency, loss of strength, and loss of elasticity. (Hazardous chemicals require sophisticated methods of permeation analysis, and such tests should only be undertaken by individuals trained for such procedures.) If the glove degrades quickly during routine chemical contact, it will be necessary for workers to change gloves frequently, wear double gloves, decrease chemical contact time, or choose a different glove material.

Staining and discoloration. A discolored glove may or may not be a symptom of glove degradation. Most amber or brown discoloration that is apparent when gloves are removed from their container is a result of overchlorination, excessive heat, overdrying, or contact with copper, brass, iron, or other interactive metals during manufacturing. Such "browning" may or may not indicate a loss of material strength. A variation in the intensity of yellow from one natural rubber glove to another may be a function of the trees used in the respective batch of latex or a very mild case of the browning detailed above. Translucency is caused by insufficient leaching or an excessive use of defoaming agents, emulsifiers, or surfactants during glove manufacture.

Hazing or whitish regions on unused gloves indicate areas of ozone attack. Ozone is created by energy-generating sources such as fluorescent and ultraviolet lights, x-ray machines, heavy-duty fans, and similar equipment. In its attempt to become more stable, ozone breaks the chemical bonds between elastomer chains in latex and most synthetic gloves, leaving the material weaker. This activity begins in creases and folds where the glove material is most stressed, resulting in a line of holes or cracks. Ozone will attack only unwrapped gloves and those enclosed in packages containing excessive amounts of air (available oxygen); therefore, unless the glove manufacturer erred significantly in the addition of antiozonates or exposed the gloves to ozone prior to packaging, this phenomenon can largely be controlled in-house by paying careful attention to glove storage conditions.

If discoloration occurs during use, it is termed staining and may be caused by chemicals from the glove reacting with chemicals secreted by the wearer. For example, carbamate, the least sensitizing of the accelerators used in latex processing, reacts with lactic and uric acid from human perspiration to cause an amber or brown stain. Nicotine from the skin of smokers turns gloves brown, as do copper and iron, excreted to varying degrees through the skin by healthy individuals. Some illnesses and the use of specific medications may also result in glove staining. Gloves with color additives may mask much of the discoloration.

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