Resistance of gloves to permeation by chemotherapy drugs

How gloves intended to be worn when handling chemotherapy drugs can be assessed at SATRA’s chemistry laboratory.

Skin contact with chemotherapy drugs can pose a significant health risk to medical professionals. Therefore, protective examination gloves must be worn when handling these drugs. In order for the gloves to be considered fit for purpose, it is important that they are assessed by evaluating their resistance to permeation by chemotherapy drugs. Due to the specialist nature of this testing, only a handful of laboratories are able to offer this service. SATRA has developed its own internal standard operating procedure to offer testing in accordance with ASTM D6978-05 (2019).

Chemical permeation

‘Permeation’ is the process by which a challenge chemical passes through any barrier at a molecular level – in this case, the glove material. In many instances, the process of permeation does not cause any physical change to the glove, so when the glove has not changed visually after contact with the challenge chemical it does not necessarily mean there has been no permeation.

To test the permeation resistance, a representative specimen of the glove is clamped between two halves of a permeation cell, with the diluted chemotherapy drug on one side and the collection medium on the other. This results in the outer surface of the test specimen being in continuous contact with the chemotherapy drug.

The concentration of the chemotherapy drug in the collection medium is monitored over the test duration. The resistance of the gloves to permeation by chemotherapy drugs is then determined by measuring the time taken for the maximum permitted permeation rate to be achieved – also called the ‘breakthrough time’. The permeation rate is defined as the amount (in μg) of challenge chemical per surface area (in cm²) of the test specimen detected per minute.

Choice of chemotherapy drugs

The test method that is viewed as the industry standard to assess chemotherapy drug permeation is the American standard ASTM D6978. Gloves to be tested in accordance with this standard require assessment against at least nine chemotherapy drugs. These nine drugs comprise of seven compulsory drugs and a minimum of two drugs from a list of additional chemotherapy drugs (see tables 1 and 2). The full list of 24 drugs given in ASTM D6978 was selected to include the four common methods by which chemotherapy drugs affect cancer cells, these being: i) by damaging the DNA of the cancer cells, ii) by replacing some sections of the cancer cell DNA, iii) by damaging the enzymes within the cancer cells and iv) by preventing the cancer cells from duplicating.

Table 1: Compulsory chemotherapy drugs in ASTM D6978
Drug	Concentration (mg/ml)
Carmustine	3.3
Cyclophosphamide	20.0
Doxorubicin hydrochloride (Adriamycin)	2.0
Etoposide	20.0
Fluorouracil (Adrucil)	50.0
Paclitaxel (Taxol)	6.0
ThioTEPA	10.0

Table 2: Additional chemotherapy drugs in ASTM D6978 (minimum of two required)
Drug	Concentration (mg/ml)
Bleomycin sulphate	15.0
Carboplatin	10.0
Cisplatin	1.0
Cytarabine hydrochloride	100.0
Dacarbazine	10.0
Daunorubicin hydrochloride	5.0
Docetaxel	10.0
Gemcitabine	38.0
Idarubicin	1.0
Ifosfamide	50.0
Irinotecan	20.0
Mechlorethamine hydrochloride	1.0
Melphalan	5.0
Methotrexate	25.0
Mitomycin	0.5
Mitoxantrone	2.0
Vincristine sulphate	1.0

Methods of analysis

There are several international test methods for measuring the resistance to permeation by chemicals. To assess suitability for working with chemotherapy drugs, the most established method for the determination of a time that gloves provide protection against a drug is ASTM D6978. When testing in accordance with this standard, the test is performed at 35 ±2°C for a maximum of four hours, with the maximum permeation rate before breakthrough being 0.01 μg of the specific drug, per cm² of glove surface area per minute of the test (0.01 μg/cm²/minute).

It is possible to use alternative test methods for this analysis, primarily EN 16523-1:2015+A1:2018, where the test is performed at 23 ±1°C over a maximum of an eight-hour time period. Here, the permeation rate considered as the breakthrough time is 1 μg/cm²/minute. These major differences between ASTM D6978 and EN 16523-1 mean that it is not possible to directly compare a glove material’s performance between the two methods.

Testing at SATRA

SATRA offers testing against the seven compulsory chemotherapy drugs and a limited number from the list of optional drugs. Further work is underway to develop internal procedures to eventually be able to test against most of the additional drugs. Due to the low concentrations of the drugs that must be detected in order to quantify them at the 0.01 μg/cm²/minute breakthrough rate, SATRA is using discrete sampling where an aliquot is taken from the collection medium at several times throughout the four-hour duration of the test.

Analysis of the aliquots is performed using High Performance Liquid Chromatography (HPLC) with either a diode array detector (DAD) for those drugs with a strong absorbance in the UV spectra, or tandem mass spectrometry (MS/MS). These techniques have very low quantification limits for the permeation drugs and are highly sophisticated analytical instruments, hence their suitability for testing to this application.

In addition to ASTM D6978, SATRA can assess the permeation rates of other hazardous chemicals by performing testing in accordance with EN 16523-1. A wide variety of challenge chemicals can be tested, including acids, alkalis, organic solvents, disinfectants and cleaning solutions. SATRA’s range of detection techniques include conductivity, gas chromatography (GC) with either flame ionisation (FID) or photo ionisation (PID) detectors, ultraviolet/visible (UV/Vis) spectrophotometry, ion chromatography (IC) and high-performance liquid chromatography (HPLC).

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