Pharmaceutical Applications of Hot-Melt Extrusion: Part I
TL;DR: The pharmaceutical applications of hot-melt extrusion, including equipment, principles of operation, and process technology, are reviewed and the physicochemical properties of the resultant dosage forms are described.
Abstract: Interest in hot-melt extrusion techniques for pharmaceutical applications is growing rapidly with well over 100 papers published in the pharmaceutical scientific literature in the last 12 years. Hot-melt extrusion (HME) has been a widely applied technique in the plastics industry and has been demonstrated recently to be a viable method to prepare several types of dosage forms and drug delivery systems. Hot-melt extruded dosage forms are complex mixtures of active medicaments, functional excipients, and processing aids. HME also offers several advantages over traditional pharmaceutical processing techniques including the absence of solvents, few processing steps, continuous operation, and the possibility of the formation of solid dispersions and improved bioavailability. This article, Part I, reviews the pharmaceutical applications of hot-melt extrusion, including equipment, principles of operation, and process technology. The raw materials processed using this technique are also detailed and the physicochemical properties of the resultant dosage forms are described. Part II of this review will focus on various applications of HME in drug delivery such as granules, pellets, immediate and modified release tablets, transmucosal and transdermal systems, and implants.
Citations
More filters
TL;DR: The article provides an integrated and contemporary discussion of current approaches to solubility and dissolution enhancement but has been deliberately structured as a series of stand-alone sections to allow also directed access to a specific technology where required.
Abstract: Drugs with low water solubility are predisposed to low and variable oral bioavailability and, therefore, to variability in clinical response. Despite significant efforts to "design in" acceptable developability properties (including aqueous solubility) during lead optimization, approximately 40% of currently marketed compounds and most current drug development candidates remain poorly water-soluble. The fact that so many drug candidates of this type are advanced into development and clinical assessment is testament to an increasingly sophisticated understanding of the approaches that can be taken to promote apparent solubility in the gastrointestinal tract and to support drug exposure after oral administration. Here we provide a detailed commentary on the major challenges to the progression of a poorly water-soluble lead or development candidate and review the approaches and strategies that can be taken to facilitate compound progression. In particular, we address the fundamental principles that underpin the use of strategies, including pH adjustment and salt-form selection, polymorphs, cocrystals, cosolvents, surfactants, cyclodextrins, particle size reduction, amorphous solid dispersions, and lipid-based formulations. In each case, the theoretical basis for utility is described along with a detailed review of recent advances in the field. The article provides an integrated and contemporary discussion of current approaches to solubility and dissolution enhancement but has been deliberately structured as a series of stand-alone sections to allow also directed access to a specific technology (e.g., solid dispersions, lipid-based formulations, or salt forms) where required.
1,201 citations
Cites background from "Pharmaceutical Applications of Hot-..."
...The mixture is subsequently forced through a die to produce an extrudate of uniform shape (Crowley et al., 2007)....
[...]
...More recently, hot-melt extrusion (HME) has grown in popularity as it appears to address many of the limitations of simple fusion methods (Breitenbach, 2002; Crowley et al., 2007; Repka et al., 2007)....
[...]
TL;DR: Critical aspects and recent advances in formulation, preparation and characterization of solid dispersions as well as in-depth pharmaceutical solutions to overcome some problems and issues that limit the development and marketability of solid dispersion products are reviewed.
Abstract: Over 40% of active pharmaceutical ingredients (API) in development pipelines are poorly water-soluble drugs which limit formulation approaches, clinical application and marketability because of their low dissolution and bioavailability. Solid dispersion has been considered one of the major advancements in overcoming these issues with several successfully marketed products. A number of key references that describe state-of-the-art technologies have been collected in this review, which addresses various pharmaceutical strategies and future visions for the solubilization of poorly water-soluble drugs according to the four generations of solid dispersions. This article reviews critical aspects and recent advances in formulation, preparation and characterization of solid dispersions as well as in-depth pharmaceutical solutions to overcome some problems and issues that limit the development and marketability of solid dispersion products.
510 citations
TL;DR: This work has demonstrated the potential of 3DP to manufacture tablet shapes of different geometries, many of which would be challenging to manufacture by powder compaction.
Abstract: The aim of this work was to explore the feasibility of combining hot melt extrusion (HME) with 3D printing (3DP) technology, with a view to producing different shaped tablets which would be otherwise difficult to produce using traditional methods. A filament extruder was used to obtain approx. 4% paracetamol loaded filaments of polyvinyl alcohol with characteristics suitable for use in fused-deposition modelling 3DP. Five different tablet geometries were successfully 3D-printed-cube, pyramid, cylinder, sphere and torus. The printing process did not affect the stability of the drug. Drug release from the tablets was not dependent on the surface area but instead on surface area to volume ratio, indicating the influence that geometrical shape has on drug release. An erosion-mediated process controlled drug release. This work has demonstrated the potential of 3DP to manufacture tablet shapes of different geometries, many of which would be challenging to manufacture by powder compaction.
494 citations
Cites methods from "Pharmaceutical Applications of Hot-..."
...Several research groups have demonstrated HME processes as a viable method to prepare a wide range of accepted pharmaceutical drug delivery systems, including granules, pellets, transdermal patches, transmucosal films systems and implants (Breitenbach, 2002; Crowley et al., 2007; Fonteyne et al., 2013)....
[...]
TL;DR: This review will consider the literature that describes the manufacture and characterization of mucoadhesive buccal films and hot-melt extrusion has been explored as an alternative manufacturing process and has yielded promising results.
Abstract: The buccal route of administration has a number of advantages including bypassing the gastrointestinal tract and the hepatic first pass effect. Mucoadhesive films are retentive dosage forms and release drug directly into a biological substrate. Furthermore, films have improved patient compliance due to their small size and reduced thickness, compared for example to lozenges and tablets. The development of mucoadhesive buccal films has increased dramatically over the past decade because it is a promising delivery alternative to various therapeutic classes including peptides, vaccines, and nanoparticles. The "film casting process" involves casting of aqueous solutions and/or organic solvents to yield films suitable for this administration route. Over the last decade, hot-melt extrusion has been explored as an alternative manufacturing process and has yielded promising results. Characterization of critical properties such as the mucoadhesive strength, drug content uniformity, and permeation rate represent the major research areas in the design of buccal films. This review will consider the literature that describes the manufacture and characterization of mucoadhesive buccal films.
381 citations
Cites methods from "Pharmaceutical Applications of Hot-..."
...Hot-melt extrusion has been used for the manufacture of controlled-release matrix tablets, pellets, and granules [84], as well as orally disintegrating films [85]....
[...]
TL;DR: The study confirms the potential of 3D printing to fabricate multiple-drug containing devices with specialized design configurations and unique drug release characteristics, which would not otherwise be possible using conventional manufacturing methods.
Abstract: Three dimensional printing (3D printing) was used to fabricate novel oral drug delivery devices with specialized design configurations. Each device was loaded with multiple actives, with the intent of applying this process to the production of personalized medicines tailored at the point of dispensing or use. A filament extruder was used to obtain drug-loaded--paracetamol (acetaminophen) or caffeine--filaments of poly(vinyl alcohol) with characteristics suitable for use in fused-deposition modeling 3D printing. A multinozzle 3D printer enabled fabrication of capsule-shaped solid devices containing the drug with different internal structures. The design configurations included a multilayer device, with each layer containing drug, whose identity was different to the drug in the adjacent layers, and a two-compartment device comprising a caplet embedded within a larger caplet (DuoCaplet), with each compartment containing a different drug. Raman spectroscopy was used to collect 2-dimensional hyper spectral arrays across the entire surface of the devices. Processing of the arrays using direct classical least-squares component matching to produce false color representations of distribution of the drugs was used. This clearly showed a definitive separation between the drug layers of paracetamol and caffeine. Drug release tests in biorelevant bicarbonate media showed unique drug release profiles dependent on the macrostructure of the devices. In the case of the multilayer devices, release of both paracetamol and caffeine was simultaneous and independent of drug solubility. With the DuoCaplet design, it was possible to engineer either rapid drug release or delayed release by selecting the site of incorporation of the drug in the device; the lag-time for release from the internal compartment was dependent on the characteristics of the external layer. The study confirms the potential of 3D printing to fabricate multiple-drug containing devices with specialized design configurations and unique drug release characteristics, which would not otherwise be possible using conventional manufacturing methods.
359 citations
References
More filters
1,883 citations
Book•
01 Jan 1995
TL;DR: The authors provided the basic building blocks of polymer science and engineering by coverage of fundamental polymer chemistry and materials topics given in Chapters 1 through 7 and provided information on the exciting new materialsnow available and the emerging areas of technological growth that could motivate a new generation of scientists and engineers.
Abstract: From the Book:
PREFACE: At least dozens of good introductory textbooks on polymer science and engineering are now available. Why then has yet another book been written?
The decision was based on my belief that none of the available texts fully addresses the needs of students in chemical engineering. It is not that chemical engineers are a rare breed, but rather that they have special training in areas of thermodynamics and transport phenomena that is seldom challenged by texts designed primarily for students of chemistry or materials science. This has been a frustration of mine and of many of my students for the past 15 years during which I have taught an introductory course, Polymer Technology, to some 350 chemical engineering seniors. In response to this perceived need, I had written nine review articles that appeared in the SPE publication Plastics Engineering from 1982 to 1984. These served as hard copy for my students to supplement their classroom notes but fell short of a complete solution.
In writing this text, it was my objective to first provide the basic building blocks of polymer science and engineering by coverage of fundamental polymer chemistry and materials topics given in Chapters 1 through 7.
As a supplement to the traditional coverage of polymer thermodynamics, extensive discussion of phase equilibria, equation-of- state theories, and UNIFAC has been included in Chapter 3. Coverage of rheology, including the use of constitutive equations and the modeling of simple flow geometries, and the fundamentals of polymer processing operations are given in Chapter 11.
Finally, I wanted to provide information on the exciting new materialsnowavailable and the emerging areas of technological growth that could motivate a new generation of scientists and engineers. For this reason, engineering and specialty polymers are surveyed in Chapter 10 and important new applications for polymers in separations (membrane separations), electronics (conducting polymers), biotechnology (controlled drug release), and other specialized areas of engineering are given in Chapter 12. In all, this has been an ambitious undertaking and I hope that I have succeeded in at least some of these goals.
Although the intended audience for this text is advanced undergraduates and graduate students in chemical engineering, the coverage of polymer science fundamentals (Chapters 1 through 7) should be suitable for a semester course in a materials science or chemistry curriculum.
Chapters 8 through 10 intended as survey chapters of the principal categories of polymers commodity thermoplastics and fibers, network polymers (elastomers and thermosets), and engineering and specialty polymers may be included to supplement and reinforce the material presented in the chapters on fundamentals and should serve as a useful reference source for the practicing scientist or engineer in the plastics industry.
981 citations
TL;DR: A comparison of the carbonyl stretching region of γ indomethacin, known to form carboxylic acid dimers, with that of amorphous indometHacin indicated that the amorphously phase exists predominantly as dimers.
Abstract: Purpose. To study the molecular structure of indomethacin-PVP amorphous solid dispersions and identify any specific interactions between the components using vibrational spectroscopy.
904 citations
Book•
01 Jan 1988
TL;DR: In this article, the elastic properties of polymeric solids and their properties of rubber are discussed. But they focus on the structure of the molecule rather than the properties of the solids.
Abstract: Introduction. 1: Structure of the molecule. 2: Structure of polymeric solids. 3: The elastic properties of rubber. 4: Viscoelasticity. 5: Yield and fracture. 6: Reinforced polymers. 7: Forming. 8: Design. Further reading, Answers, Index
790 citations
TL;DR: Improved bioavailability was achieved again demonstrating the value of the technology as a drug delivery tool, with particular advantages over solvent processes like co-precipitation.
Abstract: Starting from the plastic industry, today melt extrusion has found its place in the array of pharmaceutical manufacturing operations. This article reviews the process technology with regard to the set up and specific elements of the extruder as well as its application. Melt extrusion processes are currently applied in the pharmaceutical field for the manufacture of a variety of dosage forms and formulations such as granules, pellets, tablets, suppositories, implants, stents, transdermal systems and ophthalmic inserts. As a specific area the manufacture of solid dispersions, in particular, solid molecular dispersions using the melt extrusion process is reviewed. Melt extrusion is considered to be an efficient technology in this field with particular advantages over solvent processes like co-precipitation. Potential drawbacks like the influence of heat stress and shear forces on the drug active have been overcome in a number of examples with drugs of different chemical structure. Examples of suitable excipients and recent findings like self-emulsifying preparations are presented. The article concludes with a number of published examples of melt extrudates applying the principle of solid molecular dispersions. Improved bioavailability was achieved again demonstrating the value of the technology as a drug delivery tool.
790 citations