The aim of this book is to provide a brief but comprehensive overview on the issue of biodegradable polymers. The introduction chapter is followed by a description of the general characteristics of biodegradable polymers and pathways of their degradation in the human body. Particular pitfalls and specifics of their various biomedical and pharmaceutical applications, especially in the field of pharmaceutical technology, are described in order to define the ideal carrier polymer system for specific types of therapy. Finally, the work presents the classification of these polymers based on the type of degradation mechanism. This section also includes the chemical structure of particular polymer molecules, their chemical or bio-synthesis and the description of their uses in specific biomedical and pharmaceutical applications.
The book could be used as a textbook for students of medical and pharmaceutical sciences as well as by researchers in this field or industrial area.
In the past few decades, biodegradable polymers have reached significant importance in fields of biomedical and pharmaceutical applications. They have become preferred candidates for the manufacture of therapeutic forms, for instance, orthopaedics devices, temporary bone screws and spins, three-dimensional scaffolds for tissue engineering or drug delivery systems for sustained and targeted release. Each of these applications requires material with specific physical, biological, and chemical properties, as well as specific degradation profile. These polymers (natural or synthetic) undergo hydrolytic or enzymatic degradation, which both have some advantages and disadvantages. Most widely used polymer materials in biomedical applications are listed, including their structure and degradation pathways.
Table of Contents
1. INTRODUCTION AND GOAL
2. GENERAL TERMS
2.1 Biodegradable polymers
2.2 Properties of biodegradable polymers
2.3 Changes in physical and chemical properties in the course of biodegradation
2.3.1 Crystallinity
2.3.2 Molecular weight
2.3.3 Mechanic properties
2.3.4 Changes in dimensions and morphology
2.3.5 Chemical composition of the surface
2.3.6 Absorption of water and weight loss
2.4 Biodegradation
2.4.1 Principles of hydrolytic degradation
2.4.2 Principles of enzymatic biodegradation
3. BIODEGRADABLE POLYMERS – EXAMPLES OF USE
3.1 Scaffold constructions in tissue engineering and sutures
3.2 Advantages of biodegradable bone fillings, prosthetics, and fixations in orthopaedics
3.3 Biodegradable polymers in drug delivery systems
3.3.1 Polymeric delivery systems
3.3.2 Challenges in inhalation therapy
3.3.3 Targeted administration, local and topical administration, implants
4. BIODEGRADABLE POLYMERS
4.1 Polymers degradable by hydrolysis
4.1.1 Poly(α-ester)s
4.1.2 Chemically synthesised aliphatic polyesters
4.1.3 Polyglycolide (PGA)
4.1.4 Polylactide (PLA)
4.1.5 Lactide glycolide copolymer (PLGA)
4.1.6 Polycaprolactone (PCL)
4.1.7 Polydioxanone (PDS)
4.1.8 Poly(trimethylene carbonate) (PTMC)
4.1.9 Polyhydroxyalkanoates (PHA)
4.1.10 Polyesters containing aromatic groups in their structure
4.1.11 Polyurethanes (PUR)
4.1.12 Poly(ester amides) (PEA)
4.1.13 Poly(ortho esters) (POE)
4.1.14 Polyanhydrides (PA)
4.1.15 Poly(phosphoester)s (PPE)
4.2 Polymers degradable by enzymes
4.2.1 Polysaccharides
4.2.2 Polysaccharides occurring in humans
4.2.3 Hyaluronic acid (HA)
4.2.4 Chondroitin sulphate
4.2.5 Polysaccharides not occurring in humans
4.2.6 Chitin and chitosan
4.2.7 Alginic acid and alginate
4.2.8 Cellulose derivatives and their mixtures
4.2.9 Proteins and poly(amino acids)
4.2.10 Collagen
4.2.11 Gelatine
4.2.12 Natural poly(amino acids)
4.2.13 Poly(γ-glutamic acid) (γ-PGA)
4.2.14 Poly-ε-L-lysine (EPL)
4.2.15 Cyanophycin
4.2.16 Poly(aspartic acid) (PAA)
4.2.17 Fibrin
4.2.18 Elastin and similar peptides
4.2.19 Albumin
5. CONCLUSION
Objectives and Research Themes
This book aims to provide a comprehensive overview of biodegradable polymers, focusing on their classification, chemical structures, biodegradation mechanisms, and practical applications in the biomedical and pharmaceutical fields. The research seeks to define the ideal carrier systems for controlled and targeted drug delivery and tissue engineering while analyzing the specific properties required for effective therapeutic performance.
- Mechanisms of hydrolytic and enzymatic degradation in polymers.
- Characterization of physical and chemical properties during the biodegradation process.
- Applications of synthetic and natural polymers in orthopaedics and drug delivery.
- Synthesis and production techniques of various biodegradable polymer materials.
- Assessment of biocompatibility and therapeutic potential in clinical practice.
Excerpt from the Book
INTRODUCTION AND GOAL
In recent decades, there has been significant progress in the development of biologically degradable polymer materials. Because of their biocompatibility and ability to decompose to non-toxic monomer units, these degradable polymers (both of natural and purely artificial origin) are preferred in the development of new and modern therapeutic systems. They are sought after in various fields of medicine – as elementary scaffold in tissue engineering, sutures (without subsequent need to extract stitches), or bone replacement as well as of pharmaceutics – their suitable properties play key role as carrier materials in the production of modern dosage forms with controlled or targeted release of drug in the organism. Any of these applications demands material with specific physical, chemical, biological, biochemical, and degradation properties that are essential for the therapy to be effective (1). The synthesis and design of new polymer combinations is a trend showing significant future potential, widening the range of perspective locations where new systems can deliver the drug in the organism (2).
The earliest proven application of biodegradable polymers for therapeutic purposes can be traced to Egypt, 3500 BC. The Egyptians used natural polymers – treated animal guts – to stitch wounds; these can be considered to be the earliest versions of surgical sutures based on collagen (3).
Polymers based on polyesters were the first synthetic biodegradable polymers to have properties suitable for biomedical application. At the beginning of 1930s, DuPont company manufactured high-molecular linear poly(lactide)s using ring-opening polymerization. Since 1960, as the result of subsequent oil crises, biotechnological procedures for polymer materials as poly(hydroxy alcanoate)s have been developed to be independent of petrochemical procedures to manufacture plastics and polymers. Shortly afterwards, at the beginning of 1970s, first co-polyesters were used in matrices for controlled release drugs or as sutures in surgery (4).
Summary of Chapters
INTRODUCTION AND GOAL: This chapter introduces the development and significance of biodegradable polymers in modern medicine and pharmaceutics, highlighting their role in tissue engineering and drug delivery systems.
GENERAL TERMS: This section covers the fundamental definitions of biodegradable polymers, their classification into natural and synthetic categories, and the physical/chemical properties that dictate their behavior during degradation.
BIODEGRADABLE POLYMERS – EXAMPLES OF USE: This chapter details the practical application of polymers in orthopaedic fixations, tissue engineering scaffolds, and drug delivery systems, emphasizing the need for materials tailored to specific clinical requirements.
BIODEGRADABLE POLYMERS: This comprehensive section provides an in-depth analysis of specific polymers categorized by their degradation mechanism, covering their synthesis, chemical structure, and concrete medical use cases.
CONCLUSION: The concluding chapter summarizes the importance of biocompatibility in polymer research and highlights the future potential of natural and synthetic polymers in therapeutic systems.
Keywords
polymer, biodegradation, hydrolytic degradation, enzymatic degradation, biomaterial, drug delivery system, tissue engineering, biocompatibility, synthesis, orthopaedics, scaffold, polyester, polysaccharide, protein, implant.
Frequently Asked Questions
What is the primary focus of this publication?
The work provides a concise but comprehensive overview of biodegradable polymers, covering their classification, chemical structure, principles of degradation, and their various biomedical and pharmaceutical applications.
What are the central themes covered in the text?
The central themes include the mechanism of polymer degradation (both hydrolytic and enzymatic), the properties required for biocompatibility, and the design of polymer-based delivery systems and tissue engineering scaffolds.
What is the primary research objective?
The aim is to identify and describe the ideal carrier polymer systems for specific therapeutic interventions, ensuring that materials meet precise physical, chemical, and biological requirements for effectiveness.
Which scientific methods are discussed for analyzing polymer degradation?
The book discusses various analytical methods, including surface analysis techniques like infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and contact angle measurement, as well as bulk analysis methods like gel permeation chromatography (GPC) and texture analysis.
What content is included in the main section?
The main part focuses on the classification of polymers into those degradable by hydrolysis (e.g., polyesters, polyurethanes) and those degradable by enzymes (e.g., polysaccharides, proteins), detailing their synthesis, degradation pathways, and clinical applications.
Which keywords best characterize this work?
The work is characterized by terms such as polymer, biodegradation, hydrolytic degradation, enzymatic degradation, biomaterial, drug delivery system, tissue engineering, and biocompatibility.
How does the degradation of polyesters typically occur?
Polyesters primarily degrade through the mechanism of bulk erosion, where water diffuses into the polymer matrix, leading to the hydrolysis of ester bonds throughout the entire material.
What role do enzymes play in the biodegradation process?
Enzymes act as catalysts for the breakdown of polymers, primarily at the surface of the material (surface erosion), which is especially important for highly crystalline or hydrophobic polymers that are inaccessible to water molecules alone.
Why are natural polymers sometimes preferred over synthetic ones?
Natural polymers are often preferred for their inherent biological activity, such as the ability to act as ligands, and their natural presence in the human body, which can improve tissue regeneration and biocompatibility.
- Citar trabajo
- Jan Gajdziok (Autor), Roman Goněc (Autor), David Vetchý (Autor), 2016, Biodegradable Polymers in Pharmacy and Medicine. Classification, Chemical Structure, Principles of Biodegradation and Use, Múnich, GRIN Verlag, https://www.grin.com/document/340033
