Silver in healthcare : its antimicrobial efficacy and safety in use

275 Pages·2010·2.668 MB·English

by  A B G Lansdown

Issues in Toxicology
Alan B G Lansdown
Silver in Healthcare
Its Antimicrobial Efficacy and Safety in Use
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Silver in Healthcare
Its Antimicrobial Efficacy and Safety in Use
Issues in Toxicology
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Silver in Healthcare
Its Antimicrobial Efficacy and Safety in Use
Alan B. G. Lansdown
CharingCrossHospitalandImperialCollege,FacultyofMedicine,London,UK
IssuesinToxicologyNo.6
ISBN: 978-1-84973-006-8
ISSN: 1757-7179
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rAlanB.G.Lansdown2010
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Foreword
Silver—is it a wolf in sheep’s clothing? Or is it another case of the Emperor’s
new clothes?
Many people have their own views on this old, but recently rediscovered
agent,thoughtheirviewsmaybecolouredbyanumberoffactors.Forthefirst
time, as far as I am aware, Alan Lansdown has provided us with a focused,
academically sound and balanced view of this important and increasingly
valuable metal.
As a clinician I want to know before I treat my patients: is a product both
safeandeffective?However,myabilitytomakeaninformedjudgementcan,if
I am not careful, be influenced by laboratory research results which may have
limitedtranslationtotheclinicalsettingandthe‘‘smokeandmirrors’’oftenseen
when commercial concerns become involved in developing new products with
an ability to cure all ills. I am sure the number of papers and citations about
silver have increased enormously over the past decade, but how balanced are
these papers? The analogies I drew at the beginning are very true in this
situation and we all risk being ‘‘duped’’ into sitting one side of the fence or
other. This book provides a comprehensive review of silver in a way that
I believe will allow clinicians, academics, product developers and decision-
makers who control the availability of silver-containing products to make an
informed decision.
The chapters provide a logical analysis of the current situation and under-
standing of this element’s use in healthcare. Understanding the chemistry of
silver,itsuptake,metabolismandtoxicologyanditsuseinmedicaldevicesare
all scene setters for the main body of this work, which focuses on silver as an
antimicrobial agent in wounds.
Infection causes great concerns in clinical practice. The simple question
of—is this wound infected?—can not be answered simply in all cases. As a
consequence,theappropriateselectionofantimicrobialagentsandmeasuresof
theirefficacyarefraughtwithdifficulty.Foravarietyofreasonstherehasbeen
anexplosionofinterestinsilverasanantimicrobialagentinwoundhealingin
recent years. Discussions and debates on its value are still ongoing and the
limited amount of high quality evidence published in the peer reviewed litera-
ture all make for a confusing picture at the present time. The interest and
v
vi Foreword
apparentsuccessofmanynewwoundtreatmentscontainingsilvershouldmean
that new data and consensus will eventually emerge.
Silver is an old element. The resurgence of interest in its use clinically has
sparkedconsiderablediscussion.Alan’sbookshouldbeseenassomethingthat
helps provide an informed balanced view of this element’s use in clinical
practice.Thepotentialforfurtherinnovationsandusesareconsiderablebut,in
keepingwiththecommentsmadeatthebeginningofthispiece,weshouldnot
‘‘wanttothrowthebabyoutwiththebathwater’’.Thisworkhelpsusallresolve
questionsandconcernswemayhaveand,assuch,Iwouldrecommendallwho
are involved in this area to read it.
Professor Keith Harding
Head of Department of Dermatology and
Wound Healing Academic
Director of Innovation & Engagement
School of Medicine, Cardiff University,
Upper Ground Floor, Room 18, Heath Park, Cardiff, UK
Preface
This book owes much to my initial training and guidance in experimental
pathology and toxicology by Professor Paul Grasso and his team in the
British Industrial Biological Research Association. At different times, I can
look back on the fruitful discussions that I have held with Paul and other col-
leagues in industry and academia. I acknowledge the support that I have
received from companies within the pharmaceutical and healthcare industries;
this has enabled me enrich my knowledge, to pursue research, and to travel
and lecture in Britain and overseas. It is noteworthy that my first research
with silver was as a collaborative project with Dr Pisamai Laupattarakasem
and Dr Auranut Vuttivirojana of the Faculty of Medicine, Khon Kaen
University (Thailand), who visited my laboratory in Britain with support
from the British Council. Their interest and enthusiasm is greatly appreciated.
This publication is the fruit of many years of experimental study on the
action and interaction of metals in biological systems fostered by discussion
and collaboration with clinical and academic colleagues at Charing Cross
Hospital and the former Charing Cross and Westminster Medical School.
IappreciatetheclosecollaborationandfriendshipofBarrySampson whohas
taught me much about the analysis of metals in body tissues and fluids, and
fostered my interest in zinc and metal-carrier proteins as essential modulators
in all living systems. Angela Williams in the Department of Vascular Surgery
has been a good friend and teacher in the clinical evaluation of silver-con-
taining wound therapies. Her nursing experience and devotion to patient care
has been highly beneficial in aiding my understanding patterns of clinical
woundhealing.Inwoundcare, asmuchdependsuponthebedsidemanner,as
upon treatment of the wound with appropriate silver therapy.
I should like to acknowledge with sincere thanks the constant support and
tolerancethatmywifeVeronicahasgivenmeovermanyyears.Herinvaluable
adviceandhelpfulcriticismhasencouragedmetopresentmyideasonasubject
thatispresentlytopicalandofwide-reachingimplicationinhumanhealthand
welfare.
IssuesinToxicologyNo.6
SilverinHealthcare:ItsAntimicrobialEfficacyandSafetyinUse
ByAlanB.G.Lansdown
rAlanB.G.Lansdown2010
PublishedbytheRoyalSocietyofChemistry,www.rsc.org
vii
viii Preface
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Contents
Acknowledgements xii
Chapter 1 Silver in Health and Disease 1
References 6
Chapter 2 Silver and its Compounds, Chemistry and Biological
Interactions 9
2.1 Silver: the Essentials 9
2.2 Silver in the Environment and Ecosystem 14
2.3 Analysis of Silver in Biological Materials 15
2.4 Nanotechnology 22
2.5 SilverCompoundsinAntibioticTherapyandMedical
Devices 24
References 33
Chapter 3 Uptake and Metabolism of Silver in the Human Body 43
3.1 Introduction 43
3.2 Oral Exposure 46
3.3 Dermal Contact and Percutaneous Absorption 49
3.4 Inhalation and Absorption of Silver through the
Respiratory Tract 53
3.5 MiscellaneousRoutesofSilverExposureandSystemic
Absorption 56
3.6 Silver in Textiles 58
3.7 Metabolism of Silver in the Human Body 59
References 61
IssuesinToxicologyNo.6
SilverinHealthcare:ItsAntimicrobialEfficacyandSafetyinUse
ByAlanB.G.Lansdown
rAlanB.G.Lansdown2010
PublishedbytheRoyalSocietyofChemistry,www.rsc.org
ix