Application of three-dimensional printing for colon targeted drug delivery systems

Design strategies, advances and future perspectives of colon-targeted delivery systems for the treatment of inflammatory bowel disease

Inflammatory bowel diseases (IBD) significantly contribute to high mortality globally and negatively affect patients' qualifications of life. The gastrointestinal tract has unique anatomical characteristics and physiological environment limitations. Moreover, certain natural or synthetic anti-inflammatory drugs are associated with poor targeting, low drug accumulation at the lesion site, and other side effects, hindering them from exerting their therapeutic effects. Colon-targeted drug delivery systems represent attractive alternatives as novel carriers for IBD treatment. This review mainly discusses the treatment status of IBD, obstacles to drug delivery, design strategies of colon-targeted delivery systems, and perspectives on the existing complementary therapies. Moreover, based on recent reports, we summarized the therapeutic mechanism of colon-targeted drug delivery. Finally, we addressed the challenges and future directions to facilitate the exploitation of advanced nanomedicine for IBD therapy.

Status of Polymer Fused Deposition Modeling (FDM)-Based Three-Dimensional Printing (3DP) in the Pharmaceutical Industry

Additive manufacturing (AM) or 3D printing (3DP) is arguably a versatile and more efficient way for the production of solid dosage forms such as tablets. Of the various 3DP technologies currently available, fused deposition modeling (FDM) includes unique characteristics that offer a range of options in the production of various types of tablets. For example, amorphous solid dispersions (ASDs), enteric-coated tablets or poly pills can be produced using an appropriate drug/polymer combination during FDM 3DP. The technology offers the possibility of evolving personalized medicines into cost-effective production schemes at pharmacies and hospital dispensaries. In this review, we highlight key FDM features that may be exploited for the production of tablets and improvement of therapy, with emphasis on gastrointestinal delivery. We also highlight current constraints that must be surmounted to visualize the deployment of this technology in the pharmaceutical and healthcare industries.

3D Printed Personalized Colon-targeted Tablets: A Novel Approach in Ulcerative Colitis Management

Ulcerative colitis (UC) and Crohn's disease (CD) are two types of idiopathic inflammatory bowel disease (IBD) that are increasing in frequency and incidence worldwide, particularly in highly industrialized countries. Conventional tablets struggle to effectively deliver anti-inflammatory drugs since the inflammation is localized in different areas of the colon in each patient. The goal of 3D printing technology in pharmaceutics is to create personalized drug delivery systems (DDS) that are tailored to each individual's specific needs. This review provides an overview of existing 3D printing processes, with a focus on extrusion-based technologies, which have received the most attention. Personalized pharmaceutical products offer numerous benefits to patients worldwide, and 3D printing technology is becoming more affordable every day. Custom manufacturing of 3D printed tablets provides innovative ideas for developing a tailored colon DDS. In the future, 3D printing could be used to manufacture personalized tablets for UC patients based on the location of inflammation in the colon, resulting in improved therapeutic outcomes and a better quality of life.

3D printed pH-responsive tablets containing N-acetylglucosamine-loaded methylcellulose hydrogel for colon drug delivery applications

The pH-responsive drug release approach in combination with three-dimensional (3D) printing for colon-specific oral drug administration can address the limitations of current treatments such as orally administered solid tablets. Such existing treatments fail to effectively deliver the right drug dosage to the colon. In order to achieve targeted drug release profiles, this work aimed at designing and producing 3D printed tablet shells using Eudragit® FS100 and polylactic acid (PLA) where the core was filled with 100 µl of N-acetylglucosamine (GlcNAc)-loaded methyl cellulose (MC) hydrogel. To meet the requirements of such tablets, the effects of polymer blending ratios and MC concentrations on physical, thermal, and material properties of various components of the tablets and most importantly in vitro drug release kinetics were investigated. The tablets with 80/20 wt% of Eudragit® FS100/PLA and the drug-loaded hydrogel with 30 mg/ml GlcNAc and 3% w/v MC showed the most promising results having the best printability, processability, and drug release kinetics besides being non-cytotoxic. Manufacturing of these tablets will be the first milestone in shifting from the conventional "one size fits all" approach to personalized medicine where different dosages and various combinations of drugs can be effectively delivered to the inflammation site.

Biomedical applications of three-dimensional bioprinted craniofacial tissue engineering

Anatomical complications of the craniofacial regions often present considerable challenges to the surgical repair or replacement of the damaged tissues. Surgical repair has its own set of limitations, including scarcity of the donor tissues, immune rejection, use of immune suppressors followed by the surgery, and restriction in restoring the natural aesthetic appeal. Rapid advancement in the field of biomaterials, cell biology, and engineering has helped scientists to create cellularized skeletal muscle-like structures. However, the existing method still has limitations in building large, highly vascular tissue with clinical application. With the advance in the three-dimensional (3D) bioprinting technique, scientists and clinicians now can produce the functional implants of skeletal muscles and bones that are more patient-specific with the perfect match to the architecture of their craniofacial defects. Craniofacial tissue regeneration using 3D bioprinting can manage and eliminate the restrictions of the surgical transplant from the donor site. The concept of creating the new functional tissue, exactly mimicking the anatomical and physiological function of the damaged tissue, looks highly attractive. This is crucial to reduce the donor site morbidity and retain the esthetics. 3D bioprinting can integrate all three essential components of tissue engineering, that is, rehabilitation, reconstruction, and regeneration of the lost craniofacial tissues. Such integration essentially helps to develop the patient-specific treatment plans and damage site-driven creation of the functional implants for the craniofacial defects. This article is the bird's eye view on the latest development and application of 3D bioprinting in the regeneration of the skeletal muscle tissues and their application in restoring the functional abilities of the damaged craniofacial tissue. We also discussed current challenges in craniofacial bone vascularization and gave our view on the future direction, including establishing the interactions between tissue-engineered skeletal muscle and the peripheral nervous system.

3D Printed Fractal-like Structures with High Percentage of Drug for Zero-Order Colonic Release

Colonic drug delivery of drugs is an area of great interest due to the need to treat high prevalence colonic local diseases as well as systemic conditions that may benefit from the advantages associated to this route of drug administration. In the last decade, the use of 3D printing technologies has expanded, offering the possibility of preparing personalized medicines in small batches directly at the point of care. The aim of this work is to design a high drug loaded 3D printed system prepared by a combination of Fused Deposition Modelling (FDM) and Injection Volume Filling (IVF) techniques intended for zero-order colonic drug release. For this purpose, different batches of binary and ternary filaments based on the thermoplastic polyurethane Tecoflex EG-72D (TPU), theophylline anhydrous (AT) as model drug, and magnesium stearate as lubricant have been developed and characterized. Filaments with the highest drug load and the best rheological properties were selected for the manufacture of a printed fractal-like structure based on multiple toroids. This design was proposed to provide high surface area, leading to increased drug release and water uptake in the colonic region. This structure was 3D printed by FDM and then coated in a unique step by IVF technology using the enteric polymer DrugCoat S 12.5. This way, an additional coating process is avoided, reducing costs and production time. Studies of drug release confirmed the ability of the structures to provide a five-hour period of constant drug delivery in the colonic region.

Controlling drug release with additive manufacturing-based solutions

3D printing is an innovative manufacturing technology with great potential to revolutionise solid dosage forms. Novel features of 3D printing technology confer advantage over conventional solid dosage form manufacturing technologies, including rapid prototyping and an unparalleled capability to fabricate complex geometries with spatially separated conformations. Such a novel technology could transform the pharmaceutical industry, enabling the production of highly personalised dosage forms with well-defined release profiles. In this work, we review the current state of the art of using additive manufacturing for predicting and understanding drug release from 3D printed novel structures. Furthermore, we describe a wide spectrum of 3D printing technologies, materials, procedure, and processing parameters used to fabricate fundamentally different matrices with different drug releases. The different methods to manipulate drug release patterns including the surface area-to-mass ratio, infill pattern, geometry, and composition, are critically evaluated. Moreover, the drug release mechanisms and models that could aid exploiting the release profile are also covered. Finally, this review also covers the design opportunities alongside the technical and regulatory challenges that these rapidly evolving technologies present.

Inkjet printing of small molecules, biologics, and nanoparticles

During the last decades, inkjet printing has emerged as a novel technology and attracted the attention of the pharmaceutical industry, as a potential method for manufacturing personalized and customizable dosage forms to deliver drugs. Commonly, the desired drug is dissolved or dispersed within the ink and then dispensed in various dosage forms. Using this approach, several studies have been conducted to load hydrophilic or poorly water-soluble small molecules onto the surface of different solid substrates, including films, tablets, microneedles, and smart data-enriched edible pharmaceuticals, using two-dimensional and three-dimensional inkjet printing methods, with high dose accuracy and reproducibility. Furthermore, biological drugs, such as peptides, proteins, growth factors, and plasmids, have also been evaluated with positive results, eliciting the expected biological response; nonetheless, minor changes in the structure of these compounds with significant impaired activity cannot be dismissed. Another strategy using inkjet printing is to disperse drug-loaded nanoscale particles in the ink liquid, such as nanosuspension, nanocomplexes, or nanoparticles, which have been explored with promising results. Although these favorable outcomes, the proper selection of ink constituents and the inkjet printer, the correlation of printing cycles and effectively printed doses, the stability studies of drugs within the ink and the optimal analysis of samples before and after the printing process are the main challenges for inkjet printing, and therefore, this review analyzes these aspects to assess the body of current literature and help to guide future investigations on this field.

Drug Delivery Applications of Three-Dimensional Printed (3DP) Mesoporous Scaffolds

Mesoporous materials are structures characterized by a well-ordered large pore system with uniform porous dimensions ranging between 2 and 50 nm. Typical samples are zeolite, carbon molecular sieves, porous metal oxides, organic and inorganic porous hybrid and pillared materials, silica clathrate and clathrate hydrates compounds. Improvement in biochemistry and materials science led to the design and implementation of different types of porous materials ranging from rigid to soft two-dimensional (2D) and three-dimensional (3D) skeletons. The present review focuses on the use of three-dimensional printed (3DP) mesoporous scaffolds suitable for a wide range of drug delivery applications, due to their intrinsic high surface area and high pore volume. In the first part, the importance of the porosity of materials employed for drug delivery application was discussed focusing on mesoporous materials. At the end of the introduction, hard and soft templating synthesis for the realization of ordered 2D/3D mesostructured porous materials were described. In the second part, 3DP fabrication techniques, including fused deposition modelling, material jetting as inkjet printing, electron beam melting, selective laser sintering, stereolithography and digital light processing, electrospinning, and two-photon polymerization were described. In the last section, through recent bibliographic research, a wide number of 3D printed mesoporous materials, for in vitro and in vivo drug delivery applications, most of which relate to bone cells and tissues, were presented and summarized in a table in which all the technical and bibliographical details were reported. This review highlights, to a very cross-sectional audience, how the interdisciplinarity of certain branches of knowledge, as those of materials science and nano-microfabrication are, represent a growing valuable aid in the advanced forum for the science and technology of pharmaceutics and biopharmaceutics.

3D Printing Technologies: Recent Development and Emerging Applications in Various Drug Delivery Systems

The 3D printing is considered as an emerging digitized technology that could act as a key driving factor for the future advancement and precise manufacturing of personalized dosage forms, regenerative medicine, prosthesis and implantable medical devices. Tailoring the size, shape and drug release profile from various drug delivery systems can be beneficial for special populations such as paediatrics, pregnant women and geriatrics with unique or changing medical needs. This review summarizes various types of 3D printing technologies with advantages and limitations particularly in the area of pharmaceutical research. The applications of 3D printing in tablets, films, liquids, gastroretentive, colon, transdermal and intrauterine drug delivery systems as well as medical devices have been briefed. Due to the novelty and distinct features, 3D printing has the inherent capacity to solve many formulation and drug delivery challenges, which are frequently associated with poorly aqueous soluble drugs. Recent approval of Spritam® and publication of USFDA technical guidance on additive manufacturing related to medical devices has led to an extensive research in various field of drug delivery systems and bioengineering. The 3D printing technology could be successfully implemented from pre-clinical phase to first-in-human trials as well as on-site production of customized formulation at the point of care having excellent dose flexibility. Advent of innovative 3D printing machineries with built-in flexibility and quality with the introduction of new regulatory guidelines would rapidly integrate and revolutionize conventional pharmaceutical manufacturing sector.

Pharmaceutical Product Development Exploiting 3D Printing Technology: Conventional to Novel Drug Delivery System

Background:

3D printed pharmaceutical products are revolutionizing the pharmaceutical industry as a prospective mean to achieve a personalized method of treatments acquired to the specially designed need of each patient. It will depend upon age, weight, concomitants, pharmacogenetics and pharmacokinetic profile of the patient and thus transforming the current pharmaceutical market as a potential alternative to conventional medicine. 3D printing technology is getting more consideration in new medicine formulation development as a modern and better alternative to control many challenges associated with conventional medicinal products. There are many advantages of 3D printed medicines which create tremendous opportunities for improving the acceptance, accuracy and effectiveness of these medicines. In 2015, United State Food and Drug Administration has approved the first 3D printed tablet (Spritam®) and had shown the emerging importance of this technology.

Methods:

This review article summarizes as how in-depth knowledge of drugs and their manufacturing processes can assist to manage different strategies for various 3D printing methods. The principal goal of this review is to provide a brief introduction about the present techniques employed in tech -medicine evolution from conventional to a novel drug delivery system.

Results:

It is evidenced that through its unparalleled advantages of high-throughput, versatility, automation, precise spatial control and fabrication of hierarchical structures, the implementation of 3D printing for the expansion and delivery of controlled drugs acts as a pivotal role.

Conclusion:

3D printing technology has an extraordinary ability to provide elasticity in the manufacturing and designing of composite products that can be utilized in programmable and personalized medicine. Personalized medicine helps in improving drug safety and minimizes side effects such as toxicity to individual human being which is associated with unsuitable drug dose.