Biomaterials 23 (2002) 3913–3915

Book reviews

Microspheres, microcapsules and liposomes, Vol. 1:
preparation and chemical applications, Vol. 2: medical
and biotechnology applications
R. Arshady; Citus,1999,ISBN Vol. 1,0 9532187 1 6,
Vol. 2,0 9532187 2 4,Vol. 1,576+xxiii,Vol. 2,695+xi

A series of volumes have been planned to deal with

the topics of microspheres,microcapsules and liposomes
and these two volumes,covering preparation and
chemical applications,and medical and biotechnology
applications are the first to be published. These are both
multi-authored volumes with around 35 invited con-
tributions.

The subject matter of these volumes refers to three

closely related classes of material structures that have
extensive applications across a range of industries,
including the pharmaceutical and medical device sectors.
It is interesting to note that there is some general
confusion as to the meanings of these terms,and
certainly the words microspheres and microcapsules
are often used interchangeably. As the introduction to
the first volume states,microspheres are broadly defined
as spherical particles in the size range between 20 nm
and 2000 mm which are composed of one or more
polymeric materials,whilst microcapsules are outwardly
similar but have a core of an active ingredient and an
outer polymer shell or matrix. With this in mind it is
easy to see the pharmaceutical and biotechnological
potential for such objects.

The first volume covers the manufacturing and

polymer chemistry aspects of these structures,these
contributions being largely of a generic nature without
specific reference to the biological applications. They are
highly relevant,nevertheless,with good discussions
about a range of techniques including micronisation of
solids,manufacturing methodologies for microspheres
and microcapsules,emulsion immobilised enzymes and
methods of liposome preparation. Volume 2,as its title
implies,gets more interesting from the biomaterial point
of view,with reviews of the uses of functional micro-
spheres in medicine,microspheres in diagnostics,micro-
particles in haemoperfusion and extracorporeal therapy,
microparticulate drug delivery systems,stealth lipo-
somes and so on. These chapters take us from the very
straightforward and rather dated applications of micro-
encapsulated activated carbon for haemoperfusion to

the more recent applications of liposomes for gene
transfection.

There is a great deal of information packed into these

extensive volumes,which are generally well organised
and edited. Volume 1 provides good background
information and may well be of value as a reference
source to researchers involved in the medical applica-
tions of these products. Volume 2 will be of more value,
and provides both an in-depth understanding of the
rationale of the medical and biotechnological applica-
tions and extensive practical details. It is particularly
recommended for biomaterials scientists working in the
micro and nano-domains.

D.F. Williams

University of Liverpool, Liverpool, UK

PII: S 0 1 4 2 - 9 6 1 2 ( 0 2 ) 0 0 1 1 0 - 2

Titanium in medicine
D.M. Brunette,P. Tengvall,M. Textor,P. Thomsen;
Springer,Berlin,2001,pp. 11019+xii,ISBN 3-540-
66936-1

Titanium is a metal that has been used in various and

varied

medical

applications

for

about

40

years.

Although many biomaterials have come and gone
during this period,titanium is one of the few that has
seen its uses and reputation enhanced over the years and
it is both welcome and useful to see these experiences
drawn together in one volume. A total of 28 individual
contributions have been compiled into this volume,with
sections on the introduction,the metallurgy and
fabrication,surface engineering,biological performance
and clinical applications. There is also a collection of
factual appendices.

It has to be said that this is a truly excellent book,

both with respect to its organisation and the quality of
the individual contributions. It is difficult to think of
any relevant subject that has been left out and there is
very little in the book that is irrelevant or superfluous. It
is invidious to pick out any individual chapters for
special praise but the temptation cannot be resisted with

respect to the contributions on the nature of the oxide
films on titanium and its alloys (Chapter 7) and on the
titanium bone interface in vivo (Chapter 18). The
success of titanium in medical devices has largely been
attributed to the combination of the corrosion resistance
and the relatively benign biological activity of any
released metal ions,but there has always been some
uncertainty over the precise nature of the oxide film
which gives rise to the excellent corrosion resistance,and
the circumstances under which this can be disrupted.
Chapter 7 provides a thorough,and much needed,
review of the nature of this surface oxide film and
features such as repassivation and the formation of
calcium carbonate–phosphate layers on the oxide sur-
face. Similarly,we have seen the success of implantable
medical devices made of titanium in direct contact with
bone,and Chapter 18 provides a good review of the
nature of the interface which is established.

Most of the other chapters are of equal value,

providing a mass of factual data and interpretations of
properties and behaviour. Surprisingly,for such a varied
collection of authors there is a strong uniform style and
good quality graphics and bibliographies. Since titanium
and its alloys will be with us for many years yet,this
book will be essential reading matter for anyone
concerned with implantable medical devices for the
foreseeable future.

D.F. Williams

University of Liverpool, Liverpool, UK

PII: S 0 1 4 2 - 9 6 1 2 ( 0 2 ) 0 0 1 1 1 - 4

Chitin: fulfilling a biomaterials promise
E. Khor; Elsevier,Amsterdam,2001,pp. 136+xi,ISBN
0 08 044018 5

Chitin and its derivative chitosan are fascinating

materials that have played a minor role around the
periphery of biomaterials,wound care and pharmaceu-
tical products for many years. They are based upon
natural products and appear to have some interesting
biological properties but so far have never quite made it
to the higher echelons of any list of preferred materials
for any application. This equivocal position that chitin
and chitosan are in forms the subject of a very concise,
neat and well-written monograph of Eugene Khor,a
biomaterials scientist at the National University of
Singapore.

The book starts with a short historical perspective and

then moves into its longest chapter with a review of the
real and putative biomedical applications of chitin. This
concentrates on the areas of wound dressings,blood

contacting devices,bone substitutes,drug delivery and
tissue engineering. In each case the potential for the
material in terms of its attractive properties is discussed
but then examples are shown where the material has not
quite lived up to the potential. With wound dressings
there are many patents and some products involving
chitin powders and its incorporation into fibres,gauzes
and multi-layered dressings but the ideal chitin-based
dressing is still to emerge. In terms of blood contacting
devices,the uncertainty over the role of the material is
seen from the attempts to use chitin as an anticoagulant
(not surprising in view of its similarity to heparin) and as
a haemostatic agent. The widest uses of chitin and its
derivatives are in the drug delivery arena and examples
are given of patents,processes and products.

The remainder of the book covers the sources and

production of chitin,the chemistry and structural
properties and biocompatibility issues. The order in
which these items are covered is a little strange,and the
style of writing is unusual,but there is a great deal of
information,an easily understood analysis of the main
features and a good bibliography. Overall a book well
worth consulting if chitin and chitosan play,or could
play,any role in a readers medical technology interests.

D.F. Williams

University of Liverpool, Liverpool, UK

PII: S 0 1 4 2 - 9 6 1 2 ( 0 2 ) 0 0 1 1 2 - 6

Bone engineering
J.E. Davies; Em Squared Inc.,pp. 656+xiv,ISBN 0
9686980-0-X

This book is the product of the second workshop

organised by J.E. Davies to discuss bone in the context
of current issues in biomaterials and tissue engineering.
Apart from its size,the book is unlike most workshop
proceedings in that there has been a significant effort by
each contributor,assisted by the editor,to present and
discuss a topic in an instructive and very thorough
manner. It is not a ‘pick up and read’ type of book and
is a lot more than a record of what when on at the
December 1999 workshop in Toronto. Most chapters
could,and should,be read individually. Of course,
cross-referencing can be done throughout the book,but
reading the book from front to back cover would reveal
much repetition—this is inevitable in a multi-authored
book of this nature and is not necessarily a bad thing,
but the value lies in the quality of the individual
contributions.

Inevitably the long-term value of the book is as a

reference tool. The selection of topics is excellent and the

Book reviews / Biomaterials 23 (2002) 3913–3915

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