3D printing of modified-release aminosalicylate (4-ASA and 5-ASA) tablets

3D-Printing of Functional Biomedical Microdevices via Light- and Extrusion-Based Approaches

3D-printing is a powerful additive manufacturing tool, one that enables fabrication of biomedical devices and systems that would otherwise be challenging to create with more traditional methods such as machining or molding. Many different classes of 3D-printing technologies exist, most notably extrusion-based and light-based 3D-printers, which are popular in consumer markets, with advantages and limitations for each modality. The focus here is primarily on showcasing the ability of these 3D-printing platforms to create different types of functional biomedical microdevices-their advantages and limitations are covered with respect to other classes of 3D-printing, as well as the past, recent, and future efforts to advance the functional microdevice domain. In particular, the fabrication of micromachines/robotics, drug-delivery devices, biosensors, and microfluidics is addressed. The current challenges associated with 3D-printing of functional microdevices are also addressed, as well as future directions to improve both the printing techniques and the performance of the printed products.

Formulation development and process analysis of drug-loaded filaments manufactured via hot-melt extrusion for 3D-printing of medicines

Three dimensional(3D)-printing via fused deposition modeling (FDM) allows the production of individualized solid dosage forms. However, for bringing this benefit to the patient, active pharmaceutical ingredient (API)-loaded filaments of pharmaceutical grade excipients are necessary as feedstock and have to be produced industrially. As large-scale production of API-loaded filaments has not been described in literature, this study presents a development of 3D-printable filaments, which can continuously be produced via hot-melt extrusion. Further, a combination of testing methods for mechanical resilience of filaments was applied to improve the prediction of their printability. Eudragit RL was chosen as a sustained release polymer and theophylline (30%) as thermally stable model drug. Stearic acid (7%) and polyethylene glycol 4000 (10%), were evaluated as suitable plasticizers for producing 3D-printable filaments. The two formulations were printed into solid dosage forms and analyzed regarding their dissolution profiles. This revealed that stearic acid maintained sustained release properties of the matrix whereas polyethylene glycol 4000 did not. Analysis of the continuous extrusion process was done using a design of experiments. It showed that powder feed rate and speed of the stretching device used after extrusion predominantly determine the diameter of the filament and thereby the mechanical resilience of a filament.

3D extrusion printing of high drug loading immediate release paracetamol tablets

The manufacture of immediate release high drug loading paracetamol oral tablets was achieved using an extrusion based 3D printer from a premixed water based paste formulation. The 3D printed tablets demonstrate that a very high drug (paracetamol) loading formulation (80% w/w) can be printed as an acceptable tablet using a method suitable for personalisation and distributed manufacture. Paracetamol is an example of a drug whose physical form can present challenges to traditional powder compression tableting. Printing avoids these issues and facilitates the relatively high drug loading. The 3D printed tablets were evaluated for physical and mechanical properties including weight variation, friability, breaking force, disintegration time, and dimensions and were within acceptable range as defined by the international standards stated in the United States Pharmacopoeia (USP). X-ray Powder Diffraction (XRPD) was used to identify the physical form of the active. Additionally, XRPD, Attenuated Total Reflectance Fourier Transform Infrared spectroscopy (ATR-FTIR) and differential scanning calorimetry (DSC) were used to assess possible drug-excipient interactions. The 3D printed tablets were evaluated for drug release using a USP dissolution testing type I apparatus. The tablets showed a profile characteristic of the immediate release profile as intended based upon the active/excipient ratio used with disintegration in less than 60 s and release of most of the drug within 5 min. The results demonstrate the capability of 3D extrusion based printing to produce acceptable high-drug loading tablets from approved materials that comply with current USP standards.

3D Printed "Starmix" Drug Loaded Dosage Forms for Paediatric Applications

PURPOSE

Three- dimensional (3D) printing has received significant attention as a manufacturing process for pharmaceutical dosage forms. In this study, we used Fusion Deposition Modelling (FDM) in order to print "candy - like" formulations by imitating Starmix® sweets to prepare paediatric medicines with enhanced palatability.

METHODS

Hot melt extrusion processing (HME) was coupled with FDM to prepare extruded filaments of indomethacin (IND), hypromellose acetate succinate (HPMCAS) and polyethylene glycol (PEG) formulations and subsequently feed them in the 3D printer. The shapes of the Starmix® objects were printed in the form of a heart, ring, bottle, ring, bear and lion. Differential scanning calorimetry (DSC), X-ray powder diffraction (XRPD), Fourier Transform Infra-red Spectroscopy (FT-IR) and confocal Raman analysis were used to assess the drug - excipient interactions and the content uniformity.

RESULTS

Physicochemical analysis showed the presence of molecularly dispersed IND in the printed tablets. In vivo taste masking evaluation demonstrated excellent masking of the drug bitterness. The printed forms were evaluated for drug dissolution and showed immediate IND release independently of the printed shape, within 60 min.

CONCLUSIONS

3D printing was used successfully to process drug loaded filaments for the development of paediatric printed tablets in the form of Starmix® designs.

FDM 3D printing of modified drug-delivery systems using hot melt extrusion: a new approach for individualized therapy

The production process of 3D-printed drugs offers unique advantages such as the possibility of individualizing the drug therapy and easily associating different drugs and release technologies in the same pharmaceutical unit. Fused deposition modeling, a 3D printing technique, seems especially interesting for pharmaceutical applications, due to its low cost, precise and reproducible control of the printed structures, and versatility for industrial and laboratory scale. This technique combined with another technology already adapted for the pharmaceutical industry, the hot melt extrusion, is able to incorporate various mechanisms of modified drug release. This special report aims to bring together data of the experimental progress achieved using the fused deposition modeling 3D printing combined with hot melt extrusion technique and its potential in drug delivery.

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3D printing for drug manufacturing: A perspective on the future of pharmaceuticals

Since a three-dimensional (3D) printed drug was first approved by the Food and Drug Administration in 2015, there has been a growing interest in 3D printing for drug manufacturing. There are multiple 3D printing methods - including selective laser sintering, binder deposition, stereolithography, inkjet printing, extrusion-based printing, and fused deposition modeling - which are compatible with printing drug products, in addition to both polymer filaments and hydrogels as materials for drug carriers. We see the adaptability of 3D printing as a revolutionary force in the pharmaceutical industry. Release characteristics of drugs may be controlled by complex 3D printed geometries and architectures. Precise and unique doses can be engineered and fabricated via 3D printing according to individual prescriptions. On-demand printing of drug products can be implemented for drugs with limited shelf life or for patient-specific medications, offering an alternative to traditional compounding pharmacies. For these reasons, 3D printing for drug manufacturing is the future of pharmaceuticals, making personalized medicine possible while also transforming pharmacies.

Polymers for 3D Printing and Customized Additive Manufacturing

Additive manufacturing (AM) alias 3D printing translates computer-aided design (CAD) virtual 3D models into physical objects. By digital slicing of CAD, 3D scan, or tomography data, AM builds objects layer by layer without the need for molds or machining. AM enables decentralized fabrication of customized objects on demand by exploiting digital information storage and retrieval via the Internet. The ongoing transition from rapid prototyping to rapid manufacturing prompts new challenges for mechanical engineers and materials scientists alike. Because polymers are by far the most utilized class of materials for AM, this Review focuses on polymer processing and the development of polymers and advanced polymer systems specifically for AM. AM techniques covered include vat photopolymerization (stereolithography), powder bed fusion (SLS), material and binder jetting (inkjet and aerosol 3D printing), sheet lamination (LOM), extrusion (FDM, 3D dispensing, 3D fiber deposition, and 3D plotting), and 3D bioprinting. The range of polymers used in AM encompasses thermoplastics, thermosets, elastomers, hydrogels, functional polymers, polymer blends, composites, and biological systems. Aspects of polymer design, additives, and processing parameters as they relate to enhancing build speed and improving accuracy, functionality, surface finish, stability, mechanical properties, and porosity are addressed. Selected applications demonstrate how polymer-based AM is being exploited in lightweight engineering, architecture, food processing, optics, energy technology, dentistry, drug delivery, and personalized medicine. Unparalleled by metals and ceramics, polymer-based AM plays a key role in the emerging AM of advanced multifunctional and multimaterial systems including living biological systems as well as life-like synthetic systems.

Current and emerging applications of 3D printing in medicine

Three-dimensional (3D) printing enables the production of anatomically matched and patient-specific devices and constructs with high tunability and complexity. It also allows on-demand fabrication with high productivity in a cost-effective manner. As a result, 3D printing has become a leading manufacturing technique in healthcare and medicine for a wide range of applications including dentistry, tissue engineering and regenerative medicine, engineered tissue models, medical devices, anatomical models and drug formulation. Today, 3D printing is widely adopted by the healthcare industry and academia. It provides commercially available medical products and a platform for emerging research areas including tissue and organ printing. In this review, our goal is to discuss the current and emerging applications of 3D printing in medicine. A brief summary on additive manufacturing technologies and available printable materials is also given. The technological and regulatory barriers that are slowing down the full implementation of 3D printing in the medical field are also discussed.

Fused Deposition Modeling (FDM) 3D Printed Tablets for Intragastric Floating Delivery of Domperidone

The aim of this study was to explore the feasibility of fused deposition modeling (FDM) 3D printing to prepare intragastric floating sustained release (FSR) tablets. Domperidone (DOM), an insoluble weak base, was chosen as a model drug to investigate the potential of FSR in increasing its oral bioavailability and reducing its administration frequency. DOM was successfully loaded into hydroxypropyl cellulose (HPC) filaments using hot melt extrusion (HME). The filaments were then printed into hollow structured tablets through changing the shell numbers and the infill percentages. Physical characterization results indicated that the majority of DOM gradually turned into the amorphous form during the fabrication process. The optimized formulation (contain 10% DOM, with 2 shells and 0% infill) exhibited the sustained release characteristic and was able to float for about 10 h in vitro. Radiographic images showed that the BaSO₄-labeled tablets were retained in the stomach of rabbits for more than 8 h. Furthermore, pharmacokinetic studies showed the relative bioavailability of the FSR tablets compared with reference commercial tablets was 222.49 ± 62.85%. All the results showed that FDM based 3D printing might be a promising way to fabricate hollow tablets for the purpose of intragastric floating drug delivery.

Patient-specific 3D scanned and 3D printed antimicrobial polycaprolactone wound dressings

The increasing prevalence of wound infections caused by antibiotic resistant bacteria is an urgent challenge facing modern medicine. To address this issue the expedient use of antimicrobial metals such as zinc, copper and silver were incorporated into an FDA-approved polymer (polycaprolactone - PCL) to produce filaments for 3D printing. These metals have broad-spectrum antimicrobial properties, and moreover, copper and zinc can enhance the wound healing process. 3D scanning was used to construct 3D models of a nose and ear to provide the opportunity to customize shape and size of a wound dressing to an individual patient. Hot melt extrusion was used to extrude pellets obtained by vacuum-drying of solutions of PCL and the different metals in order to manufacture metal-homogeneously-loaded filaments. Wound dressings with different shapes were produced with the filaments containing different concentrations of metals. Release of the metals from the dressings was determined by inductively coupled plasma atomic emission spectroscopy. All the different metal dressings show fast release (up to 24h) followed by slow release (up to 72h). The antibacterial efficacy of the wound dressings was tested using a thermal activity monitor system, revealing that silver and copper wound dressings had the most potent bactericidal properties. This study shows that 3D scanning and 3D printing, which are becoming simpler and more affordable, have the potential to offer solutions to produce personalised wound dressings.

Fused-filament 3D printing of drug products: Microstructure analysis and drug release characteristics of PVA-based caplets

Fused deposition modeling (FDM) 3-Dimensional (3D) printing is becoming an increasingly important technology in the pharmaceutical sciences, since it allows the manufacture of personalized oral dosage forms by deposition of thin layers of material. Here, a filament extruder was used to obtain filaments of polyvinyl alcohol (PVA) containing paracetamol or caffeine appropriate for 3D printing. The filaments were used to manufacture caplets for oral administration by FDM 3D printing, with the aim of evaluating the effect of the internal structure (micropore volume), drug loading and composition on drug dissolution behaviour. Micropore volume of the caplets was primarily determined by the presence of large pores due to gaps in the printed layers/net while printing, and the porosity of the caplets was 10 fold higher than the porosity of the extruded filament. Dynamic dissolution drug release tests on the caplets in biorelevant bicarbonate media revealed distinctive release profiles, which were dependent on drug solubility and drug loading. Porosity of the caplets did not help to predict the different drug release profiles. This study confirms the potential of 3D printing to fabricate caplets and helps to elucidate which factors influence drug release from this type of new dosage form.

Preparation and investigation of controlled-release glipizide novel oral device with three-dimensional printing

The purpose of this study was to explore the feasibility of combining fused deposition modeling (FDM) 3D printing technology with hot melt extrusion (HME) to fabricate a novel controlled-release drug delivery device. Glipizide used in the treatment of diabetes was selected as model drug, and was successfully loaded into commercial polyvinyl alcohol (PVA) filaments by HME method. The drug-loaded filaments were printed through a dual-nozzle 3D printer, and finally formed a double-chamber device composed by a tablet embedded within a larger tablet (DuoTablet), each chamber contains different contents of glipizide. The drug-loaded 3D printed device was evaluated for drug release under in vitro dissolution condition, and we found the release profile fit Korsmeyer-Peppas release kinetics. With the double-chamber design, it is feasible to design either controlled drug release or delayed drug release behavior by reasonably arranging the concentration distribution of the drug in the device. The characteristics of the external layer performed main influence on the release profile of the internal compartment such as lag-time or rate of release. The results of this study suggest the potential of 3D printing to fabricate controlled-release drug delivery system containing multiple drug concentration distributions via hot melt extrusion method and specialized design configurations.

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

Orally administered solid dosage forms currently dominate over all other dosage forms and routes of administrations. However, human gastrointestinal tract (GIT) poses a number of obstacles to delivery of the drugs to the site of interest and absorption in the GIT. Pharmaceutical scientists worldwide have been interested in colon drug delivery for several decades, not only for the delivery of the drugs for the treatment of colonic diseases such as ulcerative colitis and colon cancer but also for delivery of therapeutic proteins and peptides for systemic absorption. Despite extensive research in the area of colon targeted drug delivery, we have not been able to come up with an effective way of delivering drugs to the colon. The current tablets designed for colon drug release depend on either pH-dependent or time-delayed release formulations. During ulcerative colitis the gastric transit time and colon pH-levels is constantly changing depending on whether the patient is having a relapse or under remission. Hence, the current drug delivery system to the colon is based on one-size-fits-all. Fails to effectively deliver the drugs locally to the colon for colonic diseases and delivery of therapeutic proteins and peptides for systemic absorption from the colon. Hence, to overcome the current issues associated with colon drug delivery, we need to provide the patients with personalized tablets which are specifically designed to match the individual's gastric transit time depending on the disease state. Three-dimensional (3D) printing (3DP) technology is getting cheaper by the day and bespoke manufacturing of 3D-printed tablets could provide the solutions in the form of personalized colon drug delivery system. This review provides a bird's eye view of applications and current advances in pharmaceutical 3DP with emphasis on the development of colon targeted drug delivery systems.

Three-Dimensional Printing of Medicinal Products and the Challenge of Personalized Therapy

By 3-dimensional (3D) printing, solid objects of any shape are fabricated through layer-by-layer addition of materials based on a digital model. At present, such a technique is broadly exploited in many industrial fields because of major advantages in terms of reduced times and costs of development and production. In the biomedical and pharmaceutical domains, the interest in 3D printing is growing in step with the needs of personalized medicine. Printed scaffolds and prostheses have partly replaced medical devices produced by more established techniques, and more recently, 3D printing has been proposed for the manufacturing of drug products. Notably, the availability of patient-tailored pharmaceuticals would be of utmost importance for children, elderly subjects, poor and high metabolizers, and individuals undergoing multiple drug treatments. 3D printing encompasses a range of differing techniques, each involving advantages and open issues. Particularly, solidification of powder, extrusion, and stereolithography have been applied to the manufacturing of drug products. The main challenge to their exploitation for personalized pharmacologic therapy is likely to be related to the regulatory issues involved and to implementation of production models that may allow to efficiently turn the therapeutic needs of individual patients into small batches of appropriate drug products meeting preset quality requirements.

On drug-base incompatibilities during extrudate manufacture and fused deposition 3D printing

Aim: 3D printing can be applied for point-of-care personalized treatment. This study aimed to determine the manufacturability and characteristics of 3D printed, drug-loaded implants for alcohol misuse. Materials & methods: Disulfiram was the drug substance used and polylactic acid (PLA) the base material. Implantable devices were designed in silico. Drug and PLA were placed into the extruder to produce a 5% blend at 1.75-mm diameter. Material characterization included differential scanning calorimetry, thermogravimetric analysis plus inverse GC-surface energy analyzer. Results: Implantable constructs from the PLA feedstock were acquired. The extrusion processes had a detrimental effect on the active pharmaceutical ingredient-base blend. differential scanning calorimetry and thermogravimetric analysis analysis indicated drug–base interactions. Thermal history was found to influence inverse GC probe interaction. Conclusion: Drug-base incompatibilities must be considered during 3D printing.

Controlled and Sequential Delivery of Fluorophores from 3D Printed Alginate-PLGA Tubes

Controlled drug delivery systems, that include sequential and/or sustained drug delivery, have been utilized to enhance the therapeutic effects of many current drugs by effectively delivering drugs in a time-dependent and repeatable manner. In this study, with the aid of 3D printing technology, a novel drug delivery device was fabricated and tested to evaluate sequential delivery functionality. With an alginate shell and a poly(lactic-co-glycolic acid) (PLGA) core, the fabricated tubes displayed sequential release of distinct fluorescent dyes and showed no cytotoxicity when incubated with the human embryonic kidney (HEK293) cell line or bone marrow stromal stem cells (BMSC). The controlled differential release of drugs or proteins through such a delivery system has the potential to be used in a wide variety of biomedical applications from treating cancer to regenerative medicine.

A new chapter in pharmaceutical manufacturing: 3D-printed drug products

FDA recently approved a 3D-printed drug product in August 2015, which is indicative of a new chapter for pharmaceutical manufacturing. This review article summarizes progress with 3D printed drug products and discusses process development for solid oral dosage forms. 3D printing is a layer-by-layer process capable of producing 3D drug products from digital designs. Traditional pharmaceutical processes, such as tablet compression, have been used for decades with established regulatory pathways. These processes are well understood, but antiquated in terms of process capability and manufacturing flexibility. 3D printing, as a platform technology, has competitive advantages for complex products, personalized products, and products made on-demand. These advantages create opportunities for improving the safety, efficacy, and accessibility of medicines. Although 3D printing differs from traditional manufacturing processes for solid oral dosage forms, risk-based process development is feasible. This review highlights how product and process understanding can facilitate the development of a control strategy for different 3D printing methods. Overall, the authors believe that the recent approval of a 3D printed drug product will stimulate continual innovation in pharmaceutical manufacturing technology. FDA encourages the development of advanced manufacturing technologies, including 3D-printing, using science- and risk-based approaches.

Coupling 3D printing with hot-melt extrusion to produce controlled-release tablets

The main objective of this work was to explore the potential of coupling fused deposition modeling in three-dimensional (3D) printing with hot-melt extrusion (HME) technology to facilitate additive manufacturing, in order to fabricate tablets with enhanced extended release properties. Acetaminophen was used as the model drug and different grades and ratios of polymers were used to formulate tablets. Three-point bending and hardness tests were performed to determine the mechanical properties of the filaments and tablets. 3D-printed tablets, directly compressed mill-extruded tablets, and tablets prepared from a physical mixture were evaluated for drug release rates using a USP-II dissolution apparatus. The surface and cross-sectional morphology of the 3D-printed tablets were assessed by scanning electron microscopy. Differential scanning calorimetry and thermogravimetric analysis were used to characterize the crystal states and thermal properties of materials, respectively. The 3D-printed tablets had smooth surfaces and tight structures; therefore, they showed better extended drug release rates than the directly compressed tablets did. Further, this study clearly demonstrated the feasibility of coupling HME with 3D printing technology, which allows for the formulation of drug delivery systems using different grades and ratios of pharmaceutical polymers. In addition, formulations can be made based on the personal needs of patients.

Fabricating a Shell-Core Delayed Release Tablet Using Dual FDM 3D Printing for Patient-Centred Therapy

PURPOSE

Individualizing gastric-resistant tablets is associated with major challenges for clinical staff in hospitals and healthcare centres. This work aims to fabricate gastric-resistant 3D printed tablets using dual FDM 3D printing.

METHODS

The gastric-resistant tablets were engineered by employing a range of shell-core designs using polyvinylpyrrolidone (PVP) and methacrylic acid co-polymer for core and shell structures respectively. Filaments for both core and shell were compounded using a twin-screw hot-melt extruder (HME). CAD software was utilized to design a capsule-shaped core with a complementary shell of increasing thicknesses (0.17, 0.35, 0.52, 0.70 or 0.87 mm). The physical form of the drug and its integrity following an FDM 3D printing were assessed using x-ray powder diffractometry (XRPD), thermal analysis and HPLC.

RESULTS

A shell thickness ≥0.52 mm was deemed necessary in order to achieve sufficient core protection in the acid medium. The technology proved viable for incorporating different drug candidates; theophylline, budesonide and diclofenac sodium. XRPD indicated the presence of theophylline crystals whilst budesonide and diclofenac sodium remained amorphous in the PVP matrix of the filaments and 3D printed tablets. Fabricated tablets demonstrated gastric resistant properties and a pH responsive drug release pattern in both phosphate and bicarbonate buffers.

CONCLUSIONS

Despite its relatively limited resolution, FDM 3D printing proved to be a suitable platform for a single-process fabrication of delayed release tablets. This work reveals the potential of dual FDM 3D printing as a unique platform for personalising delayed release tablets to suit an individual patient's needs.

An investigation into the use of polymer blends to improve the printability of and regulate drug release from pharmaceutical solid dispersions prepared via fused deposition modeling (FDM) 3D printing

FDM 3D printing has been recently attracted increasing research efforts towards the production of personalized solid oral formulations. However, commercially available FDM printers are extremely limited with regards to the materials that can be processed to few types of thermoplastic polymers, which often may not be pharmaceutically approved materials nor ideal for optimizing dosage form performance of poor soluble compounds. This study explored the use of polymer blends as a formulation strategy to overcome this processability issue and to provide adjustable drug release rates from the printed dispersions. Solid dispersions of felodipine, the model drug, were successfully fabricated using FDM 3D printing with polymer blends of PEG, PEO and Tween 80 with either Eudragit E PO or Soluplus. As PVA is one of most widely used polymers in FDM 3D printing, a PVA based solid dispersion was used as a benchmark to compare the polymer blend systems to in terms of processability. The polymer blends exhibited excellent printability and were suitable for processing using a commercially available FDM 3D printer. With 10% drug loading, all characterization data indicated that the model drug was molecularly dispersed in the matrices. During in vitro dissolution testing, it was clear that the disintegration behavior of the formulations significantly influenced the rates of drug release. Eudragit EPO based blend dispersions showed bulk disintegration; whereas the Soluplus based blends showed the 'peeling' style disintegration of strip-by-strip. The results indicated that interplay of the miscibility between excipients in the blends, the solubility of the materials in the dissolution media and the degree of fusion between the printed strips during FDM process can be used to manipulate the drug release rate of the dispersions. This brings new insight into the design principles of controlled release formulations using FDM 3D printing.

A Lower Temperature FDM 3D Printing for the Manufacture of Patient-Specific Immediate Release Tablets

PURPOSE

The fabrication of ready-to-use immediate release tablets via 3D printing provides a powerful tool to on-demand individualization of dosage form. This work aims to adapt a widely used pharmaceutical grade polymer, polyvinylpyrrolidone (PVP), for instant on-demand production of immediate release tablets via FDM 3D printing.

METHODS

Dipyridamole or theophylline loaded filaments were produced via processing a physical mixture of API (10%) and PVP in the presence of plasticizer through hot-melt extrusion (HME). Computer software was utilized to design a caplet-shaped tablet. The surface morphology of the printed tablet was assessed using scanning electron microscopy (SEM). The physical form of the drugs and its integrity following an FDM 3D printing were assessed using x-ray powder diffractometry (XRPD), thermal analysis and HPLC. In vitro drug release studies for all 3D printed tablets were conducted in a USP II dissolution apparatus.

RESULTS

Bridging 3D printing process with HME in the presence of a thermostable filler, talc, enabled the fabrication of immediate release tablets at temperatures as low as 110°C. The integrity of two model drugs was maintained following HME and FDM 3D printing. XRPD indicated that a portion of the loaded theophylline remained crystalline in the tablet. The fabricated tablets demonstrated excellent mechanical properties, acceptable in-batch variability and an immediate in vitro release pattern.

CONCLUSIONS

Combining the advantages of PVP as an impeding polymer with FDM 3D printing at low temperatures, this approach holds a potential in expanding the spectrum of drugs that could be used in FDM 3D printing for on demand manufacturing of individualised dosage forms.

Three-dimensional quick response code based on inkjet printing of upconversion fluorescent nanoparticles for drug anti-counterfeiting

Medicine counterfeiting is a serious issue worldwide, involving potentially devastating health repercussions. Advanced anti-counterfeit technology for drugs has therefore aroused intensive interest. However, existing anti-counterfeit technologies are associated with drawbacks such as the high cost, complex fabrication process, sophisticated operation and incapability in authenticating drug ingredients. In this contribution, we developed a smart phone recognition based upconversion fluorescent three-dimensional (3D) quick response (QR) code for tracking and anti-counterfeiting of drugs. We firstly formulated three colored inks incorporating upconversion nanoparticles with RGB (i.e., red, green and blue) emission colors. Using a modified inkjet printer, we printed a series of colors by precisely regulating the overlap of these three inks. Meanwhile, we developed a multilayer printing and splitting technology, which significantly increases the information storage capacity per unit area. As an example, we directly printed the upconversion fluorescent 3D QR code on the surface of drug capsules. The 3D QR code consisted of three different color layers with each layer encoded by information of different aspects of the drug. A smart phone APP was designed to decode the multicolor 3D QR code, providing the authenticity and related information of drugs. The developed technology possesses merits in terms of low cost, ease of operation, high throughput and high information capacity, thus holds great potential for drug anti-counterfeiting.

Hot-melt extruded filaments based on pharmaceutical grade polymers for 3D printing by fused deposition modeling

Fused deposition modeling (FDM) is a 3D printing technique based on the deposition of successive layers of thermoplastic materials following their softening/melting. Such a technique holds huge potential for the manufacturing of pharmaceutical products and is currently under extensive investigation. Challenges in this field are mainly related to the paucity of adequate filaments composed of pharmaceutical grade materials, which are needed for feeding the FDM equipment. Accordingly, a number of polymers of common use in pharmaceutical formulation were evaluated as starting materials for fabrication via hot melt extrusion of filaments suitable for FDM processes. By using a twin-screw extruder, filaments based on insoluble (ethylcellulose, Eudragit(®) RL), promptly soluble (polyethylene oxide, Kollicoat(®) IR), enteric soluble (Eudragit(®) L, hydroxypropyl methylcellulose acetate succinate) and swellable/erodible (hydrophilic cellulose derivatives, polyvinyl alcohol, Soluplus(®)) polymers were successfully produced, and the possibility of employing them for printing 600μm thick disks was demonstrated. The behavior of disks as barriers when in contact with aqueous fluids was shown consistent with the functional application of the relevant polymeric components. The produced filaments were thus considered potentially suitable for printing capsules and coating layers for immediate or modified release, and, when loaded with active ingredients, any type of dosage forms.

Recent developments in micro- and nanofabrication techniques for the preparation of amorphous pharmaceutical dosage forms

Nano- and microfabrication techniques have been widely explored in the textile, polymer and biomedical arenas, although more recently these systems have attracted considerable interest as drug delivery vehicles with concomitant considerations of physical characterization, scalability, stability and drug release. In this review, the current thinking with regards to the manufacture of solid amorphous pharmaceutical materials using electrohydrodynamic and gyration-based approaches, melt-spinning approaches, thermal moulding, inkjet printing and 3D printing will be examined in the context of their potential and actual viability as dosage forms. A series of practical examples will be discussed as to how these approaches have been used as means of producing drug delivery systems for a range of delivery systems and treatments.

Modifying release characteristics from 3D printed drug-eluting products

This work describes an approach to modify the release of active compound from a 3D printed model drug product geometry intended for flexible dosing and precision medication. The production of novel polylactic acid and hydroxypropyl methylcellulose based feed materials containing nitrofurantoin for 3D printing purposes is demonstrated. Nitrofurantoin, Metolose® and polylactic acid were successfully co-extruded with up to 40% Metolose® content, and subsequently 3D printed into model disk geometries (ø10mm, h=2mm). Thermal analysis with differential scanning calorimetry and solid phase identification with Raman spectroscopy showed that nitrofurantoin remained in its original solid form during both hot-melt extrusion and subsequent 3D printing. Rheological measurements of the different compositions showed that the flow properties were sensitive to the amount of undissolved particles present in the formulation. Release of nitrofurantoin from the disks was dependent on Metolose® loading, with higher accumulated release observed for higher Metolose® loads. This work shows the potential of custom-made, drug loaded feed materials for 3D printing of precision drug products with tailored drug release characteristics.

Stereolithographic (SLA) 3D printing of oral modified-release dosage forms

The aim of this work was to evaluate the suitability of stereolithography (SLA) to fabricate drug-loaded tablets with modified-release characteristics. The SLA printer creates solid objects by using a laser beam to photopolymerise monomers. In this work polyethylene glycol diacrylate (PEGDA) was used as a monomer and diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide was used as a photo-initiator. 4-aminosalicylic acid (4-ASA) and paracetamol (acetaminophen) were selected as model drugs. Tablets were successfully printed and formulations with different properties were fabricated by adding polyethylene glycol 300 (PEG 300) to the printing solution. The loading of paracetamol and 4-ASA in the printed tablets was 5.69% and 5.40% respectively. In a realistic dynamic dissolution simulation of the gastrointestinal tract, drug release from the tablets was dependent on the composition of the formulations, but independent of dissolution pH. In conclusion SLA 3DP technology allows the manufacture of drug loaded tablets with specific extended-release profiles. In the future this technology could become a manufacturing technology for the elaboration of oral dosage forms, for industrial production or even for personalised dose.