34 – MEDICAL DISPOSABLE GLOVES: STRUCTURAL MATERIALS DIFFERENT FROM LATEX

Luca Martinelli

Medical disposable gloves: structural materials different from latex

Publication nr. 34 – 18th December 2013

1. FOREWORD

In the last few years we have observed a sudden rise of irritant allergic and not allergic reactions, due to the use of latex gloves.

Those are caused by the proteins that constitute latex and by chemical additives.

Generalizing, latex allergies can be listed as follows: contact dermatitis eczema, allergic urticaria, generalized urticaria, angioneurotic edema, edema of the glottis, anaphylactic shock.

To latex another cause of allergy is added: the powder used as lubricant.

It was in fact demonstrated that the powder added into the gloves to fit them easily, can cause conjunctivitis, rhinitis and bronchial asthma because it work as an aeroallergen: means of transport of causative agent to respiratory tract.

Deproteinization, dust delete and all the other solutions adopted have considerably helped to decrease the percentage of the allergic reaction cases but the problem hasn’t been finally solved yet.

For this reason in time it has developed the search of alternative materials which could permit the manufacturing of not in latex gloves but with barrier performance and functional characteristics that would come close as much as possible to the latex one.

1.1 Medical disposable gloves standards

Technical standards that give requirements to manufacture correctly gloves are UNI EN seria 455 “Medical disposable gloves”.

UNI EN 455 part 1 (455-1) specifies the requirements and gives the method to test the  medical disposable gloves to determinate the absence of holes;

UNI EN 455 part 2 (455-2) specifies the requirements and gives method to test the physical characteristics of medical disposable gloves, to guarantee an adequate  protection level for the patient and for the user from mutual contamination, during their use.

UNI EN 455 part 3 (455-3) specifies the requirements for the assessment of biologic safety of medical disposable gloves and gives requirements for label and packaging of gloves. It gives also requirements on disclosure of info related to test method used;

UNI EN 455 part 4 (455-4) specifies requirements for medical disposable gloves shelf life and specifies also requirements on disclosure of info related to test method used.

As we know, technical standards are requirements of voluntary alignment that eventually become technical requirements if expressly indicated in lows or regulations and that give the presumption of conformity to statutory and regulatory requirements.

Apart from technical standards, that, as we have seen, are voluntary alignment requirements, the medical disposable gloves are medical devices. As such, they have to be compliant to minimum security requirements prescribed by the law. This means that they have to satisfy the applicable provisions of DL 24th February 1997, nr. 46. Implementation of the 93/42/CEE Directive about medical devices, as amended by 25th January 2010 DL, n. 37, Implementation of 2007/47/CE Directive.

We recollect that when transposing a European Directive to national, every member of a State could apply some more restrictive requirements than the same Directive. For this reason, for conformity, the referement law is always the national law of recepiments, not only the European Directive.

Done this technical standards foreword, when we buy a medical device put on the market with CE standards (which is a conformity declaration), we take for granted that the disposal is compliant and we don’t care about all the reference technical standards; what we mostly care is the use that we have to do, the price and, todays more than ever, the material with which the gloves are made. 

2. THE MEDICAL DISPOSABLE GLOVE: DEFINITIONS

Before analyzing the materials alternative to latex, we recollect what is a medical disposable glove.

2.1 Medical disposable glove

Medical disposable gloves are gloves for use in medical field to protect the patient and the user from crossed contamination.

2.2 Surgical gloves

Surgical gloves are sterilized medical gloves with anatomic shape with the thumb placed in front of the palmar surface of the index finger, instead of being flat, for use in invasive surgery.

2.3 Examination/procedure gloves

Examination/procedure gloves are sterilized or not sterilized. They can have or not have anatomic shape, they can be used to make medical visits, diagnostic procedures and therapeutic and to manipulate medical contaminated materials.

2.4 Medical gloves long

We can find two types of medical gloves long:

a) surgical gloves with a minimum overall length of 300 mm;

b) examination/procedure gloves with a minimum overall length of 270 mm.

2.5 Medical welded gloves; welded gloves

The medical welded gloves are made with flat films of material, joint by welding or by other assembly techniques.

3. CONSTRUCTION MATERIALS ALTERNATIVE TO LATEX

The most used materials used for manufacturing gloves alternative to latex are: nitrile, vinyl, neoprene and last in order of arrival but first for performance, the synthetic polyisoprene, which maintains all the characteristics of latex, although in a slightly lower, but it misses all the problems related to the latex one because it doesn’t contain latex

3.1 Latex

Latex (NRL - Natural Rubber Latex) is the most elastic natural material today known. It’s a substance extracted by “Hevea Brasiliensis” (also called rubber tree). This tree is mostly cultivated in Asia in sountries like Malaysia, Thailand, Indonesia, that not by chance are the major producers of latex gloves.

Latex, simplifying, is made by water 65%, polyisoprene 33%, resins 2% and by protein 1,8%.

Its elastic capacity, its capacity to return into original shape after subjected to pressure or elongation, its adaptability to shape, in this case of the hand, are the main characteristics for which latex has always been the favorite material to make gloves.

Unfortunately the numerous advantages coexist with the phenomena of sensibilization and the allergies that the protein of latex cause to man.

3.1.2 Advantages and disadvantages of latex

As we have told before, one of the most advantage of latex is its elasticity and capacity to adapt to shape. It has a high tear strenght, good waterproof, bio-degradability so sustainable.

Among the disadvantages the most is its potential to cause allergic reactions and irritations; we add also a poor resistance to chemicals.

3.2 Nitril

Nitril (NBR - Nitril Butadiene Rubber) is a synthetic material obtained by polimerization of è un materiale sintetico ottenuto dalla polymerizzazione of Acrylonitril and Butadiene.

It’s wrongly called also synthetic rubber for its capacity to imitate the elasticity of natural rubber and also because the raw material, necessary to its manufacture, is in the liquid state.

They are widely used because they permit to obviate the latex problems but even because they have characteristics that make them resistent both to chemicals and mechanical stress.

They are more resistant to perforation compared to latex and to other materials. They are also more resistant to elongation.

Nitril gloves have chemical and mechanical resistance characteristics and are suitable for contacts with acids, greases and for food contacts, peculiarity that latex and vinil gloves don’t have.

3.2.1 Advantages and disadvantages of nitril

The most appreciable advantage of nitrili s its capacity to reply the latex characteristics, surely with a good resistance to mechanical stress, a good chemicals resistance and eligibility to contact with food (in the case of dental is of little relevance).

Among the disadvantages we find a limited sensitivity capability, this means that they don’t permit to act with the same skill as a latex glove, causing also a certain fatigue in hand.

However we underline that after a few minutes that you wear a nitril glove, the glove tends to conform to the anatomy of the hand.

Certainly less important for the salitary aspect are its not bio-degradability and then poor eco sustainability.

  

3.3 Neoprene

Neoprene gloves are made with a chloroprene polymer (2-chlorine-1, 3-butadene). They offer a protection/barrier similar to the latex one, thanks to a crosslinked film petroleum based.

This material permits a resistance to perforation almost double than the latex one.

Neoprene has got a good resistance to the most chemical solvents and acids, alcohols, caustics, detergents and ketones.

Its form, which means the force to stretch the glove, is quite similar to the latex one. Its degree of elasticity gives al excellent wearability.

The comfort level is significantly above Il livello di comfort è notevolmente superiore al nitrile e vinile.

3.3.1 Advantages and disadvantages of Neoprene

Excellence resistance to chemicals, in particular oils, fats, alkalis, chlorinated hydrocarbons and fluorinate acids.

Excellent tactile qualities and improved resistance to aging, exposure to sunlight, ozone and weather.

In contrast, compared to other materials, we have a low abrasion resistance to cutting and perforation and a poor resistance to aromatic and axygentated solvents.

3.4 Vinyl

Vinyl gloves have wide distribution because represent a good budget option.

They are made with PVC (Poly Vinyl Chloride), the same material as saliva ejectors, with the addition of plasticisers (mainly phthalates) needed to make them soft and moldable.

The mechanical strength of these gloves, in comparison with latex, neoprene, nitril and polyisoprene gloves, is significantly lower due to the low molecular cohesion of PVC (plasticizers don’t chemically bind with PVC). Then the glove is less elastic and more prone to breakage (also micro breakage) and then definitely less suitable for running biohazard procedures.

In fact, despite the plasticizers used in vinyl to give elasticity, and therefore a good fit, vinyl stretches with difficulty, presenting a low elasticity and wide wrists, resulting in barrier-integrity high risk and fit.

For this reason it would be appropriate to limit its use to short procedures in low biological risk situation, with no exposure to blood, body fluids and/or chemicals.

Finally we report some publications that highlight cases of skin reaction due to chemical additives used in manufacturing process.

Vinyl gloves are used for food, but with the exclusion of foods containing fats and alcohol, as they cause the dissolution, and transfer of plasticizers into the food. 

This poor resistance to degradation by chemicals, like alcohol used to clean work surfaces, makes them advised against, even for the cleanliness of areas to be decontaminated or to treat with aggressive substances.

3.4.1 Advantagesantaggi and disadvantages of vinyl

The best advantage is its good biocompatibility and its cost.

Disadvantages are very few. To the ones already anticipated, we add that applying the “simulation of use” method, the most of the studies shows that vinyl medical gloves have more problems of leak compared to nitril or latex exploration gloves.

It was even demonstrated that barrier/protection against microorganisms of vinyl exploration gloves is lower than the one guaranteed by the nitril and latex ones.

Moreover, vinyl gloves are to be avoided in case of handling chemiotherapy drugs.

They are not biodegradable and so not eco sustainable.

3.5 Polyethylene

Polyethylene (PE) is one of the most cheap and common plastic.

It is not largely used in medical practice because its use is hygienic: it prevents the direct contact between the hand and what is touched by it.

Polyethylene gloves are manufactured by dinking and heat sealing of the film.

It’s a plastic with excellent chemical stability. For this reason it is often used as insulating. It is produced in film intended for contact with food (bags and film).

High density polyethylene (HDPE) is more rigid and hard compared to low density. It is used for cheap gloves.

Low density polyethylene (LDPE) is a more ductile material. It is used for gloves that need a bigger sensitivity and soft welding, as for exaple in medical field.

3.5.1 Advantages and disadvantages of polyethylene

We can say that they are quick to wear, cheap and can be in contact with food. Against they have a poor resistance, they have welding and a very poor barrier.

3.6 Synthetic Polyisoprene (synthetic rubber)

This materiali s still little known. It is very suitable for medical use because it maintains all the latex glove characteristics with few degrees of inferiority in the corresponding properties, without having any track of latex.

Natural polyisoprene is the major component of natural rubber (latex). Synthetic polyisoprene is made by synthesis. It is a synthetic rubber manufactured imitating natural rubber, which is obtained, industrially, by catalysis.

Nowadays new synthesis process permits to have a degree of purity very similar to natural latex.

Polyisoprene gloves is the best one that can compete with latex glove.

3.6.1 Advantages and disadvantages of polyisoprene

The first advantage is surely the absence of latex allergenic properties. It ha salso a high elasticity and break resistance. Its elasticity permits a great manipulation. Practically, as already told before, it has the same characteristics of latex glove, with slightly lower performances.

The most sensitive disadvantage is the cost, which nowadays is quite considerable compared to the latex gloves.

4. QUICK REFERENCE COMPARATIVE TABEL

Quickly resuming the properties and characteristics of gloves manufactured with materials different from latex, we can see the following chart (Fig.1).

COMPARATIVE TABEL OF FUNCTIONAL CHARACTERISTICS AMONG THE MAIN MATERIALS USED TO MANUFACTURE MEDICAL GLOVES

(no polyethylene gloves are considered in this tabel)

CHARACTERISTICS	LATEX	NEOPRENE	NITRIL	POLYISOPRENE	VINYL
Protection barrier	Excellent	Very good	Excellent	Excellent	Enough for short term use
Strenght/duration	Excellent	Very good	Excellent	Excellent	Sufficient
Elasticity	Excellent	Very good	Very good	Excellent	From sufficient to poor
Resistance to perforation	Very good	Good	Excellent	Very good	From sufficient to poor
Fitting, tactility, comfort	Excellent	Very good	Very good	Excellent	Sufficient
Chemical resistance	Good	Very good	Excellent	Good	Poor

Fig.1

5. CONCLUSIONS

In the last few years many allergies to latex have been observed.

The reactions after the use of latex gloves can be summarized as follows:

-allergy to latex protein;

-allergy mainly to latex chemical additives;

-not allergic reactions that can become a way to allergic reaction.

This phenomena moved the research of alternative to latex materials.

Those materials are different one another with barrier, fit and tactile sensitivity characteristics.

Thinking about a merely personal list we can say that just after latex, the best material to use are the polyisoprene gloves and then the neoprene and nitril ones.

The use of vinil gloves must be carefully checked: it is supposed to be chosen when it is not necessary a sure biologic barrier and for short term use only.

6. Bibliography

-Norma UNI EN 455-1:2002;

-Norma UNI EN 455-2:2013;

-Norma UNI EN 455-3:2007;

-Norma UNI EN 455-4:2009;  

-DL 24 febbraio 1997, n. 46. Attuazione della Direttiva 93/42/CEE, concernente i dispositivi medici;

-Dlgs 25 gennaio 2010, n. 37, Attuazione della direttiva 2007/47/CE;

-Direttiva 93/42/cee del consiglio del 14 giugno 1993 concernente i dispositivi medici;

-Direttiva 2007/47/ce del parlamento europeo e del consiglio del 5 settembre 2007 che modifica la direttiva 90/385/CEE del Consiglio per il ravvicinamento delle legislazioni degli Stati membri relative ai dispositivi medici impiantabili attivi, la direttiva 93/42/CEE del Consiglio concernente i dispositivi medici, e la direttiva 98/8/CE relativa all’immissione sul mercato dei biocidi;

-Massimo Gola. Dermatologia allergologica nel bambino e nell’adolescente.

Spinger-Verlag Italia 2007;

-C. Cangemi, C. Monti, G.Tomei. Caratteristiche dei diversi tipi di guanti usati in ambito sanitario. Giornate Romane di medicina del Lavoro “Antonello Spinazzole” – Sezione Regionale Laziale-Abruzzese della S.I.M.L.I.I. – Scuola di Specializzazione in Medicina del Lavoro – Università degli Studi di Roma “La Sapienza” – Marzo 2005;

-Korniewicz DM, El-Masri MM, Broyles JM, Martin CD, O’Connell KP. A laboratory-based study to assess the performance of surgical gloves. AORN J. 2003 Apr;

-Opinion of the Scientific Committee on Medical Products and Medical Devices on ‘The protection offered by natural rubber latex devices (medical gloves and condoms) against transmissible diseases’. European Commission. Health & Consumer Protection Directorate-General. October 2003.

-Yip ES. Comments to the Maine legislature on proposed prohibition of sale of non-sterile gloves. 2003.

-Susman E. AAAAI: Latex sensitivity infrequent in health care workers. In: Doctor’s guide global edition. 2003.

-Sussman G. The effects of interventions and glove changes in healthcare workers with latex allergy. Ann Allergy Asthma Immunol. 2003;

-Osborne, S. Occupational exposures: balancing the costs of prevention vs treatment in operating theatres, with particular focus on double gloving practices. ACORN. 2001, Winter.

-MacDonald M and Ryan G. Monitoring occupational exposure to blood borne viruses in health care workers in Australia. Australian HIV Surveillance Report. 1999, April, vol 15(2):1-6. In: Osborne, S. Occupational exposures: balancing the costs of prevention vs treatment in operating theatres, with particular focus on double gloving practices. ACORN. 2001.

-U.S. Department of Labor Occupational Safety & Health Administration (OSHA). (1999). Technical Manual (OTM) TED 01-00-015. www.osha.gov

-Korniewicz DM. Intelligently selecting gloves. Surgical Services Management. 1997, vol. 3 number 2;

-Evangelisto M. Latex allergy: The downside of Standard Precautions. Todays Surg Nurse. 1997. Sep/Oct.

-NIOSH: Preventing allergic reactions to natural rubber latex in the Workplace – NOISH 1997;

-Alessio A., Pisati R., Campana C. e al.: Patologie allergiche e irritative da guanti in ambiente sanitario e loro prevenzione. Documento di consenso. Med Lav 1996.