Development of a Biodegradable Subcutaneous Implant for Prolonged Drug Delivery Using 3D Printing

An alternative filament fabrication method as the basis for 3D-printing personalized implants from elastic ethylene vinyl acetate copolymer

In this work, a novel tool for small-scale filament production is presented. Unlike traditional methods such as hot melt extrusion (HME), the device (i) allows filament manufacturing from small material amounts as low as three grams, (ii) ensures high diameter stability almost independent of the viscoelastic behavior of the polymer melt, and (iii) enables processing of materials with rheological profiles specifically tailored toward fused filament fabrication (FFF). Hence, novel materials, previously difficult to process due to HME limitations, become easily accessible for FFF for the first time. Here, we showcase the production of highly flexible drug-free, and drug-loaded filaments based on ethylene-vinyl acetate polymers with a vinyl acetate content of 28 w% (EVA28) and unprecedented high melt flow rates of up to 400 g/10 min. Owing to their low viscosity, FFF with low print nozzle sizes of 250 μm was achieved for the first time for EVA28. These small nozzle diameters facilitate 3D-printing of high-resolution structures in small-dimensional dosage forms such as subcutaneous implantable drug delivery systems, which can later be used for personalization. Consequently, the material portfolio for FFF is tremendously broadened, allowing material and formulation optimization toward FFF, independent of a preliminary extrusion process.

Current trends in 3D printed gastroretentive floating drug delivery systems: A comprehensive review

Gastrointestinal (GI) environment is influenced by several factors (gender, genetics, sex, disease state, food) leading to oral drug absorption variability or to low bioavailability. In this scenario, gastroretentive drug delivery systems (GRDDS) have been developed in order to solve absorption problems, to lead to a more effective local therapy or to allow sustained drug release during a longer time period than the typical oral sustained release dosage forms. Among all GRDDS, floating systems seem to provide a promising and practical approach for achieving a long intra-gastric residence time and sustained release profile. In the last years, a novel technique is being used to manufacture this kind of systems: three-dimensional (3D) printing technology. This technique provides a versatile and easy process to manufacture personalized drug delivery systems. This work presents a systematic review of the main 3D printing based designs proposed up to date to manufacture floating systems. We have also summarized the most important parameters involved in buoyancy and sustained release of the systems, in order to facilitate the scale up of this technology to industrial level. Finally, a section discussing about the influence of materials in drug release, their biocompatibility and safety considerations have been included.

Impacts of post-operation loading and fixation implant on the healing process of fractured tibia

Healing of tibia demonstrates a complex mechanobiological process as it is stimulated by the major factor of strains applied by body weight. The effect of screw heads and bodies as well as their pressure distribution is often overlooked. Hence, effective mechanical conditions of the healing process of tibia can be categorized into the material of the plate and screws, post-operation loadings, and screw type and pressure. In this paper, a mathematical biodegradation model was used to simulate the PGF/PLA plate-screw device over 8 weeks. The effect of different post-operation loading patterns was studied for both locking and non-locking screws. The aim was to reach the best configuration for the most achievable healing using FEA by computing the healing pattern, trend, and efficiency with the mechano-regulation theory based on deviatoric strain. The biodegradation process of the plate and screws resulted in 82% molecular weight loss and 1.05 GPa decrease in Young's modulus during 8 weeks. The healing efficiency of the cases ranged from 4.72% to 14.75% in the first week and 18.64% to 63.05% in the eighth week. Finally, an optimal case was achieved by considering the prevention of muscle erosion, bone density reduction, and nonunion, according to the obtained results.

Evaluating the efficacy of Rose Bengal-PVA combinations within PCL/PLA implants for sustained cancer treatment

The current investigation aims to address the limitations of conventional cancer therapy by developing an advanced, long-term drug delivery system using biocompatible Rose Bengal (RB)-loaded polyvinyl alcohol (PVA) matrices incorporated into 3D printed polycaprolactone (PCL) and polylactic acid (PLA) implants. The anticancer drug RB's high solubility and low lipophilicity require frequent and painful administration to the tumour site, limiting its clinical application. In this study, RB was encapsulated in a PVA (RB@PVA) matrix to overcome these challenges and achieve a localised and sustained drug release system within a biodegradable implant designed to be implanted near the tumour site. The RB@PVA matrix demonstrated an RB loading efficiency of 77.34 ± 1.53%, with complete RB release within 30 min. However, when integrated into implants, the system provided a sustained RB release of 75.84 ± 8.75% over 90 days. Cytotoxicity assays on PC-3 prostate cancer cells indicated an IC50 value of 1.19 µM for RB@PVA compared to 2.49 µM for free RB, effectively inhibiting cancer cell proliferation. This innovative drug delivery system, which incorporates a polymer matrix within an implantable device, represents a significant advancement in the sustained release of hydrosoluble drugs. It holds promise for reducing the frequency of drug administration, thereby improving patient compliance and translating experimental research into practical therapeutic applications.

Ultra-Long-Term Delivery of Hydrophilic Drugs Using Injectable In Situ Cross-Linked Depots

Achieving ultra-long-term release of hydrophilic drugs over several months remains a significant challenge for existing long-acting injectables (LAIs). Existing platforms, such as in situ forming implants (ISFI), exhibit high burst release due to solvent efflux and microsphere-based approaches lead to rapid drug diffusion due to significant water exchange and large pores. Addressing these challenges, we have developed an injectable platform that, for the first time, achieves ultra-long-term release of hydrophilic drugs for over six months. This system employs a methacrylated ultra-low molecular weight pre-polymer (polycaprolactone) to create in situ cross-linked depots (ISCD). The ISCD's solvent-free design and dense mesh network, both attributed to the ultra-low molecular weight of the pre-polymer, effectively minimizes burst release and water influx/efflux. In vivo studies in rats demonstrate that ISCD outperforms ISFI by achieving lower burst release and prolonged drug release. We demonstrated the versatility of ISCD by showcasing ultra-long-term delivery of several hydrophilic drugs, including antiretrovirals (tenofovir alafenamide, emtricitabine, abacavir, and lamivudine), antibiotics (vancomycin and amoxicillin) and an opioid antagonist naltrexone. Additionally, ISCD achieved ultra-long-term release of the hydrophobic drug tacrolimus and enabled co-delivery of hydrophilic drug combinations encapsulated in a single depot. We also identified design parameters to tailor the polymer network, tuning drug release kinetics and ISCD degradation. Pharmacokinetic modeling predicted over six months of drug release in humans, significantly surpassing the one-month standard achievable for hydrophilic drugs with existing LAIs. The platform's biodegradability, retrievability, and biocompatibility further underscore its potential for improving treatment adherence in chronic conditions.

Recent advances in implantable sensors and electronics using printable materials for advanced healthcare

This review article focuses on the recent printing technological progress in healthcare, underscoring the significant potential of implantable devices across diverse applications. Printing technologies have widespread use in developing health monitoring devices, diagnostic systems, and surgical devices. Recent years have witnessed remarkable progress in fabricating low-profile implantable devices, driven by advancements in printing technologies and nanomaterials. The importance of implantable biosensors and bioelectronics is highlighted, specifically exploring printing tools using bio-printable inks for practical applications, including a detailed examination of fabrication processes and essential parameters. This review also justifies the need for mechanical and electrical compatibility between bioelectronics and biological tissues. In addition to technological aspects, this article delves into the importance of appropriate packaging methods to enhance implantable devices' performance, compatibility, and longevity, which are made possible by integrating cutting-edge printing technology. Collectively, we aim to shed light on the holistic landscape of implantable biosensors and bioelectronics, showcasing their evolving role in advancing healthcare through innovative printing technologies.

Toward high-resolution 3D-printing of pharmaceutical implants - A holistic analysis of relevant material properties and process parameters

In this work, filament-based 3D-printing, the most widely used sub-category of material extrusion additive manufacturing (MEAM), is presented as a promising manufacturing platform for the production of subcutaneous implants. Print nozzle diameters as small as 100 µm were utilized demonstrating MEAM of advanced porous internal structures at the given cylindrical implant geometry of 2 mm × 40 mm. The bottlenecks related to high-resolution MEAM of subcutaneous implants are systematically analyzed and the print process is optimized accordingly. Custom synthesized biodegradable phase-separated poly(ether ester) multiblock copolymers exhibiting appropriate melt viscosity at comparatively low printing temperatures of 135 °C and 165 °C were utilized as 3D-printing feedstock. The print process was optimized to minimize thermomechanical polymer degradation by employing print speeds of 30 mm∙s-1 in combination with a nozzle diameter of 150 µm at layer heights of 110 µm. These results portray the basis for further development of subcutaneous implantable drug delivery systems where drug release profiles can be tailored through the adaption of the internal implant structure, which cannot be achieved using existing manufacturing techniques.

Tailoring drug release from long-acting contraceptive levonorgestrel intrauterine systems

The wide array of polydimethylsiloxane (PDMS) variants available on the market, coupled with the intricate combination of additives in silicone polymers, and the incomplete understanding of drug release behavior make formulation development of levonorgestrel intrauterine systems (LNG-IUSs) formidable. Accordingly, the objectives of this work were to investigate the impact of excipients on formulation attributes and in vitro performance of LNG-IUSs, elucidate drug release mechanisms, and thereby improve product understanding. LNG-IUSs with a wide range of additives and fillers were prepared, and in vitro drug release testing was conducted for up to 12 months. Incorporating various additives and/or fillers (silica, silicone resins, silicone oil, PEG, etc.) altered the crystallization kinetics of the crosslinked polymer, the viscosity, and the microstructure. In addition, drug-excipient interactions can occur. Interestingly, additives which increased matrix hydrophobicity and hindered PDMS crystallization facilitated dissolution and permeation of the lipophilic LNG. The influence of additives and lubricants on the mechanical properties of LNG-IUSs were also evaluated. PDMS chemical substitution and molecular weight were deemed to be most critical polymer attributes to the in vitro performance of LNG-IUSs. Drugs with varying physicochemical characteristics were used to prepare IUSs, modeling of the release kinetics was performed, and correlations between release properties and the various physicochemical attributes of the model drugs were established. Strong correlations between first order release rate constants and both drug solubility and Log P underpin the partition and diffusion-based release mechanisms in LNG-IUSs. This is the first comprehensive report to provide a mechanistic understanding of material-property-performance relationships for IUSs. This work offers an evidence-based approach to rational excipient selection and tailoring of drug release to achieve target daily release rates in vivo. The novel insights gained through this research could be helpful for supporting development of brand and generic IUS products as well as their regulatory assessment.

A Novel Intrauterine Device for the Spatio-Temporal Release of Norethindrone Acetate as a Counter-Estrogenic Intervention in the Genitourinary Syndrome of Menopause

The genitourinary syndrome of menopause (GSM) is a widely occurring condition affecting millions of women worldwide. The current treatment of GSM involves the use of orally or vaginally administered estrogens, often with the risk of endometrial hyperplasia. The utilization of progestogens offers a means to counteract the effects of estrogen on the endometrial tissue, decreasing unwanted side effects and improving therapeutic outcomes. In this study, a norethindrone acetate (NETA)-loaded, hollow, cylindrical, and sustained release platform has been designed, fabricated, and optimized for implantation in the uterine cavity as a counter-estrogenic intervention in the treatment of GSM. The developed system, which comprises ethyl cellulose (EC) and polycaprolactone (PCL), has been statistically optimized using a two-factor, two-level factorial design, with the mechanical properties, degradation, swelling, and in vitro drug release of NETA from the device evaluated. The morphological characteristics of the platform were further investigated through scanning electron microscopy in addition to cytocompatibility studies using NIH/3T3 cells. Results from the statistical design highlighted the platform with the highest NETA load and the EC-to-PCL ratio that exhibited favorable release and weight loss profiles. The drug release data for the optimal formulation were best fitted with the Peppas-Sahlin model, implicating both diffusion and polymer relaxation in the release mechanism, with cell viability results noting that the prepared platform demonstrated favorable cytocompatibility. The significant findings of this study firmly establish the developed platform as a promising candidate for the sustained release of NETA within the uterine cavity. This functionality serves as a counter-estrogenic intervention in the treatment of GSM, with the platform holding potential for further advanced biomedical applications.

Formulating biopharmaceuticals using three-dimensional printing

Additive manufacturing, commonly referred to as three-dimensional (3D) printing, has the potential to initiate a paradigm shift in the field of medicine and drug delivery. Ever since the advent of the first-ever United States Food and Drug Administration (US FDA)-approved 3D printed tablet, there has been an increased interest in the application of this technology in drug delivery and biomedical applications. 3D printing brings us one step closer to personalized medicine, hence rendering the "one size fits all" concept in drug dosing obsolete. In this review article, we focus on the recent developments in the field of modified drug delivery systems in which various types of additive manufacturing technologies are applied.

Design and preparation of an electromechanical implant prototype for an on-demand drug delivery

INTRODUCTION

A bio-implant is a drug-delivery system that is implanted in the human body for a period of more than 30 days. Electromechanical systems are one type of bio-implant that has recently been introduced as a new generation of targeted drug delivery methods. The overarching goal of utilizing these systems is to integrate electrical and mechanical features in order to benefit from the numerous applications of these two systems when used together. The current study aimed to design a prototype of an electromechanical system using Fused Deposition Modeling (FDM), Selective Laser Sintering (SLS), and MultiJet Fusion (MJF) techniques for drug delivery that can release a specific drug dosage in the patient's body by connecting to a sensor or under the control of a signal sent by the physician.

METHODS

Initially, the implant chambers were created in the form of a hollow cylinder, closed at one end, using three different types of 3D printers: FDM, SLS, and MJF. Each implant was then filled with a model drug (pentoxifylline) and sealed with a thin gold membrane. To achieve the lowest voltage required to melt the gold membrane, an electric circuit with controllable DC voltage generator was designed. Finally, the mechanical resistance, drug release rate, and surface morphology of the designed implants were evaluated.

RESULTS

The MJF 3D printer, overally, had higher printing precision and repeatability than other printers; however, the implants printed by the FDM 3D printer were more accurate than other techniques (P value < 0.001), similar to the dimensions of the designed file. The mechanical resistance of the implants was also evaluated, and the polylactic acid implants printed by FDM had the highest value of Young's modulus in both the standard samples and the designed implants. During the 3-month drug leakage study, FDM 3D printed implant had a greater ability to store the desired drug load (P value < 0.001), Furthermore, the SEM micrographs revealed that the polylactic acid implants printed by FDM had minimal porosity in their structure and the layers were well adhered together. The gold membrane with a middle diameter of 2 mm required the lowest voltage of 6 V. As a result, the final electrical circuit was designed with smaller dimensions in order to achieve the voltage required to melt the gold membrane.

CONCLUSION

Due to the lack of drug leakage and other mechanical studies, the electromechanical implant produced by the FDM 3D printer was chosen as the optimal electromechanical implant in this study. Along with the designed small circuit, this implant can release a drug dosage in the patient's body at the physician's demand.

An isocratic RP-HPLC-UV method for simultaneous quantification of tizanidine and lidocaine: application to in vitro release studies of a subcutaneous implant

Implantable devices have been widely investigated to improve the treatment of multiple diseases. Even with low drug loadings, these devices can achieve effective delivery and increase patient compliance by minimizing potential side effects, consequently enhancing the quality of life of the patients. Moreover, multi-drug products are emerging in the pharmaceutical field, capable of treating more than one ailment concurrently. Therefore, a simple analytical method is essential for detecting and quantifying different analytes used in formulation development and evaluation. Here, we present, for the first time, an isocratic method for tizanidine hydrochloride (TZ) and lidocaine (LD) loaded into a subcutaneous implant, utilizing reversed-phase high-performance liquid chromatography (RP-HPLC) coupled with a UV detector. These implants have the potential to treat muscular spasticity while providing pain relief for several days after implantation. Chromatographic separation of the two drugs was accomplished using a C18 column, with a mobile phase consisting of 0.1% TFA in water and MeOH in a 58 : 42 ratio, flowing at 0.7 ml min-1. The method exhibited specificity and robustness, providing accurate and precise results. It displayed linearity within the range of 0.79 to 100 μg ml-1, with an R2 value of 1 for the simultaneous analysis of TZ and LD. The developed method demonstrated selectivity, offering limits of detection and quantification of 0.16 and 0.49 μg ml-1 for TZ, and 0.30 and 0.93 μg ml-1 for LD, respectively. Furthermore, the solution containing both TZ and LD proved stable under various storage conditions. While this study applied the method to assess an implant device, it has broader applicability for analysing and quantifying the in vitro drug release of TZ and LD from diverse dosage forms in preclinical settings.

Exploring the vast potentials and probable limitations of novel and nanostructured implantable drug delivery systems for cancer treatment

Conventional cancer chemotherapy regimens, albeit successful to some extent, suffer from some significant drawbacks, such as high-dose requirements, limited bioavailability, low therapeutic indices, emergence of multiple drug resistance, off-target distribution, and adverse effects. The main goal of developing implantable drug delivery systems (IDDS) is to address these challenges and maintain anti-cancer drugs directly at the intended sites of therapeutic action while minimizing inevitable side effects. IDDS possess numerous advantages over conventional drug delivery, including controlled drug release patterns, one-time drug administration, as well as loading and stabilizing poorly water-soluble chemotherapy drugs. Here, we summarized conventional and novel (three-dimensional (3D) printing and microfluidic) preparation techniques of different IDDS, including nanofibers, films, hydrogels, wafers, sponges, and osmotic pumps. These systems could be designed with high biocompatibility and biodegradability features using a wide variety of natural and synthetic polymers. We also reviewed the published data on these systems in cancer therapy with a particular focus on their release behavior. Various release profiles could be attained in IDDS, which enable predictable, adjustable, and sustained drug releases. Furthermore, multi-step or stimuli-responsive drug release could be obtained in these systems. The studies mentioned in this article have proven the effectiveness of IDDS for treating different cancer types with high prevalence, including breast cancer, and aggressive cancer types, such as glioblastoma and liver cancer. Additionally, the challenges in applying IDDS for efficacious cancer therapy and their potential future developments are also discussed. Considering the high potential of IDDS for further advancements, such as programmable release and degradation features, further clinical trials are needed to ensure their efficiency. The overall goal of this review is to expand our understanding of the behavior of commonly investigated IDDS and to identify the barriers that should be addressed in the pursuit of more efficient therapies for cancer. See also the graphical abstract(Fig. 1).

Development of Subdermal Implants Using Direct Powder Extrusion 3D Printing and Hot-Melt Extrusion Technologies

Implants are drug delivery platforms that consist of a drug-polymer matrix with the ability of providing a localized and efficient controlled release of the drug with minimal side effects and achievement of the desired therapeutic outcomes with low drug loadings. Direct powder extrusion (DPE) 3D printing technology involves the extrusion of material through a nozzle of the printer in the form of pellets or powder. The present study aimed at investigating the use of the CELLINK BIO X™ bioprinter using DPE 3D printing technique to fabricate and evaluate the impact of different shapes (cuboid, cylinder, and tube) of raloxifene hydrochloride (RFH)-loaded subdermal implants on the release of RFH from the implants. This study further evaluated the impact of different processing techniques, viz., hot-melt extrusion (HME) technology vs. DPE 3D printing technique, on the release of RFH from the implants fabricated by each processing technique. All the fabricated implants were characterized by XRD, DSC, SEM, and FTIR, and evaluated for their water uptake, mass loss, and in vitro RFH release. The current study successfully demonstrated a great opportunity of controlling and/or tuning the release of RFH from the subdermal implants by altering the implant shape, and hence surface area, and could be a great contribution and/or addition to the personalization of medicines and improvement of patient compliance.

Enhancing antioxidant delivery through 3D printing: a pathway to advanced therapeutic strategies

The rapid advancement of 3D printing has transformed industries, including medicine and pharmaceuticals. Integrating antioxidants into 3D-printed structures offers promising therapeutic strategies for enhanced antioxidant delivery. This review explores the synergistic relationship between 3D printing and antioxidants, focusing on the design and fabrication of antioxidant-loaded constructs. Incorporating antioxidants into 3D-printed matrices enables controlled release and localized delivery, improving efficacy while minimizing side effects. Customization of physical and chemical properties allows tailoring of antioxidant release kinetics, distribution, and degradation profiles. Encapsulation techniques such as direct mixing, coating, and encapsulation are discussed. Material selection, printing parameters, and post-processing methods significantly influence antioxidant release kinetics and stability. Applications include wound healing, tissue regeneration, drug delivery, and personalized medicine. This comprehensive review aims to provide insights into 3D printing-assisted antioxidant delivery systems, facilitating advancements in medicine and improved patient outcomes for oxidative stress-related disorders.

Long-acting microneedle formulations

The minimally-invasive and painless nature of microneedle (MN) application has enabled the technology to obviate many issues with injectable drug delivery. MNs not only administer therapeutics directly into the dermal and ocular space, but they can also control the release profile of the active compound over a desired period. To enable prolonged delivery of payloads, various MN types have been proposed and evaluated, including dissolving MNs, polymeric MNs loaded or coated with nanoparticles, fast-separable MNs hollow MNs, and hydrogel MNs. These intricate yet intelligent delivery platforms provide an attractive approach to decrease side effects and administration frequency, thus offer the potential to increase patient compliance. In this review, MN formulations that are loaded with various therapeutics for long-acting delivery to address the clinical needs of a myriad of diseases are discussed. We also highlight the design aspects, such as polymer selection and MN geometry, in addition to computational and mathematical modeling of MNs that are necessary to help streamline and develop MNs with high translational value and clinical impact. Finally, up-scale manufacturing and regulatory hurdles along with potential avenues that require further research to bring MN technology to the market are carefully considered. It is hoped that this review will provide insight to formulators and clinicians that the judicious selection of materials in tandem with refined design may offer an elegant approach to achieve sustained delivery of payloads through the simple and painless application of a MN patch.

Customizable 3D Printed Implants Containing Triamcinolone Acetonide: Development, Analysis, Modification, and Modeling of Drug Release

Three-dimensional-printed customizable drug-loaded implants provide promising opportunities to improve the current therapy options. In this study, we present a modular implant in which shape, dosage, and drug release can be individualized independently of each other to patient characteristics to improve parenteral therapy with triamcinolone acetonide (TA) over three months. This study focused on the examination of release modification via fused deposition modeling and subsequent prediction. The filaments for printing consisted of TA, ethyl cellulose, hypromellose, and triethyl citrate. Two-compartment implants were successfully developed, consisting of a shape-adaptable shell and an embedded drug-loaded network. For the network, different strand widths and pore size combinations were printed and analyzed in long-term dissolution studies to evaluate their impact on the release performance. TA release varied between 8.58 ± 1.38 mg and 21.93 mg ± 1.31 mg over three months depending on the network structure and the resulting specific surface area. Two different approaches were employed to predict the TA release over time. Because of the varying release characteristics, applicability was limited, but successful in several cases. Using a simple Higuchi-based approach, good release predictions could be made for a release time of 90 days from the release data of the initial 15 days (RMSEP ≤ 3.15%), reducing the analytical effort and simplifying quality control. These findings are important to establish customizable implants and to optimize the therapy with TA for specific intra-articular diseases.

Solid implantable devices for sustained drug delivery

Implantable drug delivery systems (IDDS) are an attractive alternative to conventional drug administration routes. Oral and injectable drug administration are the most common routes for drug delivery providing peaks of drug concentrations in blood after administration followed by concentration decay after a few hours. Therefore, constant drug administration is required to keep drug levels within the therapeutic window of the drug. Moreover, oral drug delivery presents alternative challenges due to drug degradation within the gastrointestinal tract or first pass metabolism. IDDS can be used to provide sustained drug delivery for prolonged periods of time. The use of this type of systems is especially interesting for the treatment of chronic conditions where patient adherence to conventional treatments can be challenging. These systems are normally used for systemic drug delivery. However, IDDS can be used for localised administration to maximise the amount of drug delivered within the active site while reducing systemic exposure. This review will cover current applications of IDDS focusing on the materials used to prepare this type of systems and the main therapeutic areas of application.

Engineering 3D-Printed Advanced Healthcare Materials for Periprosthetic Joint Infections

The use of additive manufacturing or 3D printing in biomedicine has experienced fast growth in the last few years, becoming a promising tool in pharmaceutical development and manufacturing, especially in parenteral formulations and implantable drug delivery systems (IDDSs). Periprosthetic joint infections (PJIs) are a common complication in arthroplasties, with a prevalence of over 4%. There is still no treatment that fully covers the need for preventing and treating biofilm formation. However, 3D printing plays a major role in the development of novel therapies for PJIs. This review will provide a deep understanding of the different approaches based on 3D-printing techniques for the current management and prophylaxis of PJIs. The two main strategies are focused on IDDSs that are loaded or coated with antimicrobials, commonly in combination with bone regeneration agents and 3D-printed orthopedic implants with modified surfaces and antimicrobial properties. The wide variety of printing methods and materials have allowed for the manufacture of IDDSs that are perfectly adjusted to patients' physiognomy, with different drug release profiles, geometries, and inner and outer architectures, and are fully individualized, targeting specific pathogens. Although these novel treatments are demonstrating promising results, in vivo studies and clinical trials are required for their translation from the bench to the market.

Practical Application of 3D Printing for Pharmaceuticals in Hospitals and Pharmacies

Three-dimensional (3D) printing is an unrivaled technique that uses computer-aided design and programming to create 3D products by stacking materials on a substrate. Today, 3D printing technology is used in the whole drug development process, from preclinical research to clinical trials to frontline medical treatment. From 2009 to 2020, the number of research articles on 3D printing in healthcare applications surged from around 10 to 2000. Three-dimensional printing technology has been applied to several kinds of drug delivery systems, such as oral controlled release systems, micropills, microchips, implants, microneedles, rapid dissolving tablets, and multiphase release dosage forms. Compared with conventional manufacturing methods of pharmaceutical products, 3D printing has many advantages, including high production rates due to the flexible operating systems and high drug loading with the desired precision and accuracy for potent drugs administered in small doses. The cost of production via 3D printing can be decreased by reducing material wastage, and the process can be adapted to multiple classes of pharmaceutically active ingredients, including those with poor solubility. Although several studies have addressed the benefits of 3D printing technology, hospitals and pharmacies have only implemented this process for a small number of practical applications. This article discusses recent 3D printing applications in hospitals and pharmacies for medicinal preparation. The article also covers the potential future applications of 3D printing in pharmaceuticals.

Recent patent-based review on the role of three-dimensional printing technology in pharmaceutical and biomedical applications

Three-dimensional printing (3DP) is emerging as an innovative manufacturing technology for biomedical and pharmaceutical applications, since the US FDA approval of Spritam as a 3D-printed drug. In the present review, we have highlighted the potential benefits of 3DP technology in healthcare, such as the ability to create patient-specific medical devices and implants, as well as the possibility of on-demand production of drugs and personalized dosage forms. We have further discussed future research to optimize 3DP processes and materials for pharmaceutical and biomedical applications. Cohesively, we have put forward the current state of active patents and applications related to 3DP technology in the healthcare and pharmaceutical industries including hearing aids, prostheses, medical devices and drug-delivery systems.

3D and 4D Bioprinting Technologies: A Game Changer for the Biomedical Sector?

Bioprinting is an innovative and emerging technology of additive manufacturing (AM) and has revolutionized the biomedical sector by printing three-dimensional (3D) cell-laden constructs in a precise and controlled manner for numerous clinical applications. This approach uses biomaterials and varying types of cells to print constructs for tissue regeneration, e.g., cardiac, bone, corneal, cartilage, neural, and skin. Furthermore, bioprinting technology helps to develop drug delivery and wound healing systems, bio-actuators, bio-robotics, and bio-sensors. More recently, the development of four-dimensional (4D) bioprinting technology and stimuli-responsive materials has transformed the biomedical sector with numerous innovations and revolutions. This issue also leads to the exponential growth of the bioprinting market, with a value over billions of dollars. The present study reviews the concepts and developments of 3D and 4D bioprinting technologies, surveys the applications of these technologies in the biomedical sector, and discusses their potential research topics for future works. It is also urged that collaborative and valiant efforts from clinicians, engineers, scientists, and regulatory bodies are needed for translating this technology into the biomedical, pharmaceutical, and healthcare systems.

Novel Rhinological Application of Polylactic Acid-An In Vitro Study

A novel approach to the treatment of sinusitis is the use of nasal stents. The stent is loaded with a corticosteroid, which prevents complications in the wound-healing process. The design is such that it will prevent the sinus from closing again. The stent is 3D printed using a fused deposition modeling printer, which enhances the customization. The polymer utilized for the purpose of 3D printing is polylactic acid (PLA). The compatibility between the drugs and polymers is confirmed by FT-IR and DSC. The drug is loaded onto the polymer by soaking the stent in the drug's solvent, known as the solvent casting method. Using this method, approximately 68% of drug loading is found to be achieved onto the PLA filaments, and a total of 72.8% of drug loading is obtained in terms of the 3D-printed stent. Drug loading is confirmed by the morphological characteristics of the stent by SEM, where the loaded drug is clearly visible as white specks on the surface of the stent. Drug release characterization is conducted by dissolution studies, which also confirm drug loading. The dissolution studies show that the release of drugs from the stent is constant and not erratic. Biodegradation studies were conducted after increasing the rate of degradation of PLA by soaking it in PBS for a predetermined duration of time. The mechanical properties of the stent, such as stress factor and maximum displacement, are discussed. The stent has a hairpin-like mechanism for opening inside the nasal cavity.

Therapeutic Agent-Loaded Fibrous Scaffolds for Biomedical Applications

Tissue engineering is a sophisticated field that involves the integration of various disciplines, such as clinical medicine, material science, and life science, to repair or regenerate damaged tissues and organs. To achieve the successful regeneration of damaged or diseased tissues, it is necessary to fabricate biomimetic scaffolds that provide structural support to the surrounding cells and tissues. Fibrous scaffolds loaded with therapeutic agents have shown considerable potential in tissue engineering. In this comprehensive review, we examine various methods for fabricating bioactive molecule-loaded fibrous scaffolds, including preparation methods for fibrous scaffolds and drug-loading techniques. Additionally, we delved into the recent biomedical applications of these scaffolds, such as tissue regeneration, inhibition of tumor recurrence, and immunomodulation. The aim of this review is to discuss the latest research trends in fibrous scaffold manufacturing methods, materials, drug-loading methods with parameter information, and therapeutic applications with the goal of contributing to the development of new technologies or improvements to existing ones.

3D printed implantable drug delivery devices for women's health: Formulation challenges and regulatory perspective

Modern pharmaceutical interventions are shifting from traditional "one-size-fits-all" approaches toward tailored therapies. Following the regulatory approval of Spritam®, the first marketed drug manufactured using three-dimensional printing (3DP) technologies, there is a precedence set for the use of 3DP in the manufacture of pharmaceutical products. The involvement of 3DP technologies in pharmaceutical research has demonstrated its capabilities in enabling the customisation of characteristics such as drug dosing, release characteristics and product designs on an individualised basis. Nonetheless, research into 3DP implantable drug delivery devices lags behind that for oral devices, cell-based therapies and tissue engineering applications. The recent efforts and initiatives to address the disparity in women's health is overdue but should provide a drive for more research into this area, especially using new and emerging technologies as 3DP. Therefore, the focus of this review has been placed on the unique opportunity of formulating personalised implantable drug delivery systems using 3DP for women's health applications, particularly passive implants. An evaluation of the current landscape and key formulation challenges for achieving this is provided supplemented with critical insight into the current global regulatory status and its outlook.

Aloe vera and ofloxacin incorporated chitosan hydrogels show antibacterial activity, stimulate angiogenesis and accelerate wound healing in full thickness rat model

Burns are potentially fatal and physically debilitating injuries, causing psychological and physical scars and result in chronic disabilities. A well vascularized wound bed is required to achieve complete and scar free wound closure. For many centuries, a variety of herbal plants have been used for wound healing, among these aloe vera (AV) has been found to be very effective in wound healing. Secondly, the main reason for delayed wound healing is bacterial infections. Ofloxacin (OX) has been reported as an active antibacterial drug for topical infections and it is effective against both positive and negative bacterial strains. In current research three different concentrations of OX (0.5, 2.5, and 5 mg) were loaded into chitosan (CS)/AV based hydrogels prepared by freeze gelation. The surface morphology of prepared CS/AV based OX loaded hydrogels were evaluated by scanning electron microscopy (SEM). In drug release analysis, 0.5 mg OX loaded hydrogel showed a sustained drug release behavior over 3 days period. An effective dose dependent antibacterial activity was exhibited by OX loaded hydrogels. Alamar Blue cells viability assay revealed that 0.5 mg OX hydrogel (CA 0.5 OX) showed comparatively better 3 T3 fibroblast cells proliferation as compared to CA 2.5 OX (2.5 mg OX) and CA 5 OX hydrogel (5 mg OX). Moreover, all OX loaded hydrogels showed good angiogenic activity in CAM bioassay while higher angiogenic potential was observed from CA 0.5 OX containing comparatively lower concentration of OX. These OX incorporated CS/AV based hydrogels are promising wound dressings for future clinical use.

Influence of Process Parameters on the Characteristics of Additively Manufactured Parts Made from Advanced Biopolymers

Over the past few decades, additive manufacturing (AM) has become a reliable tool for prototyping and low-volume production. In recent years, the market share of such products has increased rapidly as these manufacturing concepts allow for greater part complexity compared to conventional manufacturing technologies. Furthermore, as recyclability and biocompatibility have become more important in material selection, biopolymers have also become widely used in AM. This article provides an overview of AM with advanced biopolymers in fields from medicine to food packaging. Various AM technologies are presented, focusing on the biopolymers used, selected part fabrication strategies, and influential parameters of the technologies presented. It should be emphasized that inkjet bioprinting, stereolithography, selective laser sintering, fused deposition modeling, extrusion-based bioprinting, and scaffold-free printing are the most commonly used AM technologies for the production of parts from advanced biopolymers. Achievable part complexity will be discussed with emphasis on manufacturable features, layer thickness, production accuracy, materials applied, and part strength in correlation with key AM technologies and their parameters crucial for producing representative examples, anatomical models, specialized medical instruments, medical implants, time-dependent prosthetic features, etc. Future trends of advanced biopolymers focused on establishing target-time-dependent part properties through 4D additive manufacturing are also discussed.

Development of 3D-printed subcutaneous implants using concentrated polymer/drug solutions

Implantable drug-eluting devices that provide therapeutic cover over an extended period of time following a single administration have potential to improve the treatment of chronic conditions. These devices eliminate the requirement for regular and frequent drug administration, thus reducing the pill burden experienced by patients. Furthermore, the use of modern technologies, such as 3D printing, during implant development and manufacture renders this approach well-suited for the production of highly tuneable devices that can deliver treatment regimens which are personalised for the individual. The objective of this work was to formulate subcutaneous implants loaded with a model hydrophobic compound, olanzapine (OLZ) using robocasting - a 3D-printing technique. The formulated cylindrical implants were prepared from blends composed of OLZ mixed with either poly(caprolactone) (PCL) or a combination of PCL and poly(ethylene)glycol (PEG). Implants were characterised using scanning electron microscopy (SEM), thermal analysis, infrared spectroscopy, and X-ray diffraction and the crystallinity of OLZ in the formulated devices was confirmed. In vitro release studies demonstrated that all the formulations were capable of maintaining sustained drug release over a period of 200 days, with the maximum percentage drug release observed to be c.a. 60 % in the same period.

Fabrication and Characterisation of 3D-Printed Triamcinolone Acetonide-Loaded Polycaprolactone-Based Ocular Implants

Triamcinolone acetonide (TA) is a corticosteroid that has been used to treat posterior segment eye diseases. TA is injected intravitreally in the management of neovascular disorders; however, frequent intravitreal injections result in many potential side effects and poor patient compliance. In this work, a 3D bioprinter was used to prepare polycaprolactone (PCL) implants loaded with TA. Implants were manufactured with different shapes (filament-, rectangular-, and circle-shaped) and drug loadings (5, 10, and 20%). The characterisation results showed that TA was successfully mixed and incorporated within the PCL matrix without using solvents, and drug content reached almost 100% for all formulations. The drug release data demonstrate that the filament-shaped implants (SA/V ratio~7.3) showed the highest cumulative drug release amongst all implant shapes over 180 days, followed by rectangular- (SA/V ratio~3.7) and circle-shaped implants (SA/V ratio~2.80). Most implant drug release data best fit the Korsmeyer−Peppas model, indicating that diffusion was the prominent release mechanism. Additionally, a biocompatibility study was performed; the results showed >90% cell viability, thus proving that the TA-loaded PCL implants were safe for ocular application.

User-designed device with programmable release profile for localized treatment

Three-dimensional printing enables precise and on-demand manufacture of customizable drug delivery systems to advance healthcare toward the goal of personalized medicine. However, major challenges remain in realizing personalized drug delivery that fits a patient-specific drug dosing schedule using local drug delivery systems. In this study, a user-designed device is developed as implantable therapeutics that can realize personalized drug release kinetics by programming the inner structural design on the microscale. The drug release kinetics required for various treatments, including dose-dense therapy and combination therapy, can be implemented by controlling the dosage and combination of drugs along with the rate, duration, initiation time, and time interval of drug release according to the device layer design. After implantation of the capsular device in mice, the in vitro-in vivo and pharmacokinetic evaluation of the device is performed, and the therapeutic effect of the developed device is achieved through the local release of doxorubicin. The developed user-designed device provides a novel platform for developing next-generation drug delivery systems for personalized and localized therapy.

Customised 3D printed multi-drug systems: An effective and efficient approach to polypharmacy

INTRODUCTION

Combination therapies continue to improve therapeutic outcomes as currently achieved by polypharmacy. Since the introduction of the polypill, there has been a significant improvement in adherence and patient outcomes. However, the mass production of polypills presents a number of technical, formulation, and clinical challenges. The current one-size-fits-all approach ignores the unique clinical demands of patients, necessitating the adoption of a more versatile tool. That will be the novel, but not so novel, 3D printing.

AREAS COVERED

: The present review investigates this promising paradigm shift from one medication for all, to customised medicines, providing an overview of the current state of 3D-printed multi-active pharmaceutical forms, techniques applied and printing materials. Details on cost implications, as well as potential limitations and challenges are also elaborated.

EXPERT OPINION

: 3D printing of multi-active systems, is not only beneficial but also essential. With growing interest in this field, a shift in manufacturing, prescribing, and administration patterns is at this point, unavoidable. Addressing limitations and challenges, as well as data presentation on clinical trial results, will aid in the acceleration of this technology's implementation. However, it is clear that 3D printing is not the end of it, as evidenced by the emerging 4D printing technology.

Polylactide Perspectives in Biomedicine: From Novel Synthesis to the Application Performance

The incessant developments in the pharmaceutical and biomedical fields, particularly, customised solutions for specific diseases with targeted therapeutic treatments, require the design of multicomponent materials with multifunctional capabilities. Biodegradable polymers offer a variety of tailored physicochemical properties minimising health adverse side effects at a low price and weight, which are ideal to design matrices for hybrid materials. PLAs emerge as an ideal candidate to develop novel materials as are endowed withcombined ambivalent performance parameters. The state-of-the-art of use of PLA-based materials aimed at pharmaceutical and biomedical applications is reviewed, with an emphasis on the correlation between the synthesis and the processing conditions that define the nanostructure generated, with the final performance studies typically conducted with either therapeutic agents by in vitro and/or in vivo experiments or biomedical devices.

3D-printed reservoir-type implants containing poly(lactic acid)/poly(caprolactone) porous membranes for sustained drug delivery

Implantable drug delivery systems are an interesting alternative to conventional drug delivery systems to achieve local or systemic drug delivery. In this work, we investigated the potential of fused-deposition modelling to prepare reservoir-type implantable devices for sustained drug delivery. An antibiotic was chosen as a model molecule to evaluate the potential of this type of technology to prepare implants on-demand to provide prophylactic antimicrobial treatment after surgery. The first step was to prepare and characterize biodegradable rate-controlling porous membranes based on poly(lactic acid) (PLA) and poly(caprolactone) (PCL). These membranes were prepared using a solvent casting method. The resulting materials contained different PLA/PCL ratios. Cylindrical implants were 3D-printed vertically on top of the membranes. Tetracycline (TC) was loaded inside the implants and drug release was evaluated. The results suggested that membranes containing a PLA/PCL ratio of 50/50 provided drug release over periods of up to 25 days. On the other hand, membranes containing lower PCL content did not show a porous structure and accordingly the drug could not permeate to the same extent. The influence of different parameters on drug release was evaluated. It was established that film thickness, drug content and implant size are critical parameters as they have a direct influence on drug release kinetics. In all cases the implants were capable of providing drug release for at least 25 days. The antimicrobial properties of the implants were evaluated against E. coli and S. aureus. The resulting implants showed antimicrobial properties at day 0 and even after 21 days against both type of microorganisms. Finally, the biocompatibility of the implants was evaluated using endothelial cells. Cells exposed to implants were compared with a control group. There were no differences between both groups in terms of cell proliferation and morphology.

Recent advances in 3D-printed polylactide and polycaprolactone-based biomaterials for tissue engineering applications

The three-dimensional printing (3DP) also known as the additive manufacturing (AM), a novel and futuristic technology that facilitates the printing of multiscale, biomimetic, intricate cytoarchitecture, function-structure hierarchy, multi-cellular tissues in the complicated micro-environment, patient-specific scaffolds, and medical devices. There is an increasing demand for developing 3D-printed products that can be utilized for organ transplantations due to the organ shortage. Nowadays, the 3DP has gained considerable interest in the tissue engineering (TE) field. Polylactide (PLA) and polycaprolactone (PCL) are exemplary biomaterials with excellent physicochemical properties and biocompatibility, which have drawn notable attraction in tissue regeneration. Herein, the recent advancements in the PLA and PCL biodegradable polymer-based composites as well as their reinforcement with hydrogels and bio-ceramics scaffolds manufactured through 3DP are systematically summarized and the applications of bone, cardiac, neural, vascularized and skin tissue regeneration are thoroughly elucidated. The interaction between implanted biodegradable polymers, in-vivo and in-vitro testing models for possible evaluation of degradation and biological properties are also illustrated. The final section of this review incorporates the current challenges and future opportunities in the 3DP of PCL- and PLA-based composites that will prove helpful for biomedical engineers to fulfill the demands of the clinical field.

A 3D Printed Bone Tissue Engineering Scaffold Composed of Alginate Dialdehyde-Gelatine Reinforced by Lysozyme Loaded Cerium Doped Mesoporous Silica-Calcia Nanoparticles

A novel biomaterial comprising alginate dialdehyde-gelatine (ADA-GEL) hydrogel augmented by lysozyme loaded mesoporous cerium doped silica-calcia nanoparticles (Lys-Ce-MSNs) was 3D printed to create bioactive scaffolds. Lys-Ce-MSNs raised the mechanical stiffness of the hydrogel composite scaffold and induced surface apatite mineralization, when the scaffold was immersed in simulated body fluid (SBF). Moreover, the scaffolds could co-deliver bone healing (Ca and Si) and antioxidant ions (Ce), and Lys to achieve antibacterial (and potentially anticancer) properties. The nanocomposite hydrogel scaffolds could hold and deliver Lys steadily. Based on the in vitro results, the hydrogel nanocomposite containing Lys assured improved pre-osteoblast cell (MC3T3-E1) proliferation, adhesion, and differentiation, thanks to the biocompatibility of ADA-GEL, bioactivity of Ce-MSNs, and the stabilizing effect of Lys on the scaffold structure. On the other hand, the proliferation level of MG63 osteosarcoma cells decreased, likely due to the anticancer effect of Lys. Last but not least, cooperatively, alongside gentamicin (GEN), Lys brought about a proper antibacterial efficiency to the hydrogel nanocomposite scaffold against gram-positive and gram-negative bacteria. Taken together, ADA-GEL/Lys-Ce-MSN nanocomposite holds great promise for 3D printing of multifunctional hydrogel BTE scaffolds, able to induce bone regeneration, address infection, and potentially inhibit tumor formation and growth. This article is protected by copyright. All rights reserved.

Controlled release starch-lipid implant for the therapy of severe malaria

Parenteral depot systems can provide a constant release of drugs over a few days to months. Poly-(lactic acid) (PLA) and Poly-(lactide-co-glycolide) (PLGA) are the most commonly used polymers in the production of these systems. Finding alternatives to these polymers is of great importance to avoid certain drawbacks of these polymers (e.g. microacidity) and to increase the selection possibilities. In this study, different types of starch in combination with glycerol monostearate (GMS) were developed and investigated for their physicochemical properties and release characteristics. The noninvasive method of electron paramagnetic resonance (EPR) was used to study the release kinetics and mechanisms of nitroxide model drugs. The studies demonstrated the general suitability of the system composed of high amylose starch and GMS to form a controlled release system. For further characterization of the prepared system, formulations with different proportions of starch and GMS, loaded with the antimalarial agents artesunate or artemether were prepared. The implants were characterized with X-ray powder diffraction (XRPD) and texture analysis. The in vitro release studies demonstrated the sustained release of artemether over 6 days from a starch-based implant which matches desired kinetic for the treatment of severe malaria. In summary, a starch-based implant with appropriate mechanical properties was produced that can be a potential candidate for the treatment of severe malaria.

The Role of 3D Printing Technology in Microengineering of Microneedles

Microneedles (MNs) are minimally invasive devices, which have gained extensive interest over the past decades in various fields including drug delivery, disease diagnosis, monitoring, and cosmetics. MN geometry and shape are key parameters that dictate performance and therapeutic efficacy, however, traditional fabrication methods, such as molding, may not be able to offer rapid design modifications. In this regard, the fabrication of MNs using 3D printing technology enables the rapid creation of complex MN prototypes with high accuracy and offers customizable MN devices with a desired shape and dimension. Moreover, 3D printing shows great potential in producing advanced transdermal drug delivery systems and medical devices by integrating MNs with a variety of technologies. This review aims to demonstrate the advantages of exploiting 3D printing technology as a new tool to microengineer MNs. Various 3D printing methods are introduced, and representative MNs manufactured by such approaches are highlighted in detail. The development of advanced MN devices is also included. Finally, clinical translation and future perspectives for the development of MNs using 3D printing are discussed.

Medical Applications of Porous Biomaterials: Features of Porosity and Tissue-Specific Implications for Biocompatibility

Porosity is an important material feature commonly employed in implants and tissue scaffolds. The presence of material voids permits the infiltration of cells, mechanical compliance, and outward diffusion of pharmaceutical agents. Various studies have confirmed that porosity indeed promotes favorable tissue responses, including minimal fibrous encapsulation during the foreign body reaction (FBR). However, increased biofilm formation and calcification is also described to arise due to biomaterial porosity. Additionally, the relevance of host responses like the FBR, infection, calcification, and thrombosis are dependent on tissue location and specific tissue microenvironment. In this review, the features of porous materials and the implications of porosity in the context of medical devices is discussed. Common methods to create porous materials are also discussed, as well as the parameters that are used to tune pore features. Responses toward porous biomaterials are also reviewed, including the various stages of the FBR, hemocompatibility, biofilm formation, and calcification. Finally, these host responses are considered in tissue specific locations including the subcutis, bone, cardiovascular system, brain, eye, and female reproductive tract. The effects of porosity across the various tissues of the body is highlighted and the need to consider the tissue context when engineering biomaterials is emphasized.

3D-printed implantable devices with biodegradable rate-controlling membrane for sustained delivery of hydrophobic drugs

Implantable drug delivery systems offer an alternative for the treatments of long-term conditions (i.e. schizophrenia, HIV, or Parkinson’s disease among many others). The objective of the present work was to formulate implantable devices loaded with the model hydrophobic drug olanzapine (OLZ) using robocasting 3D-printing combined with a pre-formed rate controlling membrane. OLZ was selected as a model molecule due to its hydrophobic nature and because is a good example of a molecule used to treat a chronic condition schizophrenia. The resulting implants consisted of a poly(ethylene oxide) (PEO) implant coated with a poly(caprolactone) (PCL)-based membrane. The implants were loaded with 50 and 80% (w/w) of OLZ. They were prepared using an extrusion-based 3D-printer from aqueous pastes containing 36–38% (w/w) of water. The printing process was carried out at room temperature. The resulting implants were characterized by using infrared spectroscopy, scanning electron microscopy, thermal analysis, and X-ray diffraction. Crystals of OLZ were present in the implant after the printing process. In vitro release studies showed that implants containing 50% and 80% (w/w) of OLZ were capable of providing drug release for up to 190 days. On the other hand, implants containing 80% (w/w) of OLZ presented a slower release kinetics. After 190 days, total drug release was ca. 77% and ca. 64% for implants containing 50% and 80% (w/w) of OLZ, respectively. The higher PEO content within implants containing 50% (w/w) of OLZ allows a faster release as this polymer acts as a co-solvent of the drug.

3D Printing: Applications in Tissue Engineering, Medical Devices, and Drug Delivery

The gemstone of 3-dimensional (3D) printing shines up from the pyramid of additive manufacturing. Three-dimensional bioprinting technology has been predicted to be a game-changing breakthrough in the pharmaceutical industry since the last decade. It is fast evolving and finds its seats in a variety of domains, including aviation, defense, automobiles, replacement components, architecture, movies, musical instruments, forensic, dentistry, audiology, prosthetics, surgery, food, and fashion industry. In recent years, this miraculous manufacturing technology has become increasingly relevant for pharmaceutical purposes. Computer-aided drug (CAD) model will be developed by computer software and fed into bioprinters. Based on material inputs, the printers will recognize and produce the model scaffold. Techniques including stereolithography, selective laser sintering, selective laser melting, material extrusion, material jetting, inkjet-based, fused deposition modelling, binder deposition, and bioprinting expedite the printing process. Distinct advantages are rapid prototyping, flexible design, print on demand, light and strong parts, fast and cost-effective, and environment friendly. The present review gives a brief description of the conceptional 3-dimensional printing, followed by various techniques involved. A short note was explained about the fabricating materials in the pharmaceutical sector. The beam of light is thrown on the various applications in the pharma and medical arena.

Proof of concept of a predictive model of drug release from long-acting implants obtained by fused-deposition modeling

In the pharmaceutical field, there is a growing interest in manufacturing of drug delivery dosage forms adapted to the needs of a large variety of patients. 3D printing has proven to be a powerful tool allowing the adaptation of immediate drug delivery dosage forms. However, there are still few studies focusing on the adaptation of long-acting dosage forms for patient suffering of neurological diseases. In this study, paliperidone palmitate (PP) was chosen as a model drug in combination with different polymers adapted for fused-deposition modeling (FDM). The impact of different printing parameters on the release of PP were investigated. The layer thickness and the infill percentage were studied using a quality by design approach. Indeed, by defining the critical quality attributes (CQA), a proof of concept of a prediction system, and a quality control system were studied through designs of experiments (DoE). The first part of this study was dedicated to the release of PP from a fix geometry. In the second part, the prediction system was developed to require only surface and surface to volume ratio. From that point, it was possible to get rid of a fix geometry and predict the amount of PP released from complex architectures.

A New and Sensitive HPLC-UV Method for Rapid and Simultaneous Quantification of Curcumin and D-Panthenol: Application to In Vitro Release Studies of Wound Dressings

Curcumin (CUR) and D-panthenol (DPA) have been widely investigated for wound-healing treatment. In order to analyse these two compounds from a dosage form, such as polymer-based wound dressings or creams, an analytical method that allows the quantification of both drugs simultaneously should be developed. Here, we report for the first time a validated high-performance liquid chromatographic (HPLC) method coupled with UV detection to quantify CUR and DPA based on the standards set by the International Council on Harmonization (ICH) guidelines. The separation of the analytes was performed using a C₁₈ column that utilised a mobile phase consisting of 0.001% v/v phosphoric acid and methanol using a gradient method with a run time of 15 min. The method is linear for drug concentrations within the range of 0.39–12.5 μg mL⁻¹ (R² = 0.9999) for CUR and 0.39–25 μg mL⁻¹ for DPA (R² = 1). The validated method was found to be precise and accurate. Moreover, the CUR and DPA solution was found to be stable under specific storage conditions. We, therefore, suggest that the HPLC-UV method developed in this study may be very useful in screening formulations for CUR and DPA within a preclinical setting through in vitro release studies.

Recent progress in three-dimensionally-printed dosage forms from a pharmacist perspective

OBJECTIVE

Additive manufacturing (AM), commonly known as 3D printing (3DP), has opened new frontiers in pharmaceutical applications. This review is aimed to summarise the recent development of 3D-printed dosage forms, from a pharmacists' perspective.

METHODS

Keywords including additive manufacturing, 3D printing and drug delivery were used for literature search in PubMed, Excerpta Medica Database (EMBASE) and Web of Science, to identify articles published in the year 2020.

RESULTS

For each 3DP study, the active pharmaceutical ingredients, 3D printers and materials used for the printing were tabulated and discussed. 3DP has found its applications in various dosage forms for oral delivery, transdermal delivery, rectal delivery, vaginal delivery, implant and bone scaffolding. Several topics were discussed in detail, namely patient-specific dosing, customisable drug administration, multidrug approach, varying drug release, compounding pharmacy, regulatory progress and future perspectives. AM is expected to become a common tool in compounding pharmacies to make polypills and personalised medications.

CONCLUSION

3DP is an enabling tool to fabricate dosage forms with intricate structure designs, tailored dosing, drug combinations and controlled release, all of which lend it to be highly conducive to personalisation, thereby revolutionising the future of pharmacy practice.

Differential Drug Release Kinetics from Paclitaxel-Loaded Polydioxanone Membranes and Capsules

BACKGROUND

Drug laden implantable systems can provide drug release over several hours to years, which eventually aid in the therapy of both acute and chronic diseases. The present study focuses on a fundamental evaluation of the influence of implant properties such as morphology, architecture, porosity, surface area, and wettability in regulating the drug release kinetics from drug-loaded polymeric matrices.

METHODS

For this, Polydioxanone (PDS) was selected as the polymer and Paclitaxel (Ptx) as the model drug. Two different forms of the matrix implants, viz., reservoir type capsules developed by dip coating and matrix type membranes fabricated by phase inversion and electrospinning, were utilized for the study. Drug release from all the four different matrices prepared by simple techniques was evaluated in vitro in PBS and ex vivo in peritoneal wash fluid for ~4 weeks. The drug release profiles were thereafter correlated with the physicochemical parameters of the polymeric implants.

RESULTS

Reservoir-type capsules followed a slow and steady zero-order kinetics, while matrix-type electrospun and phase inversion membranes displayed typical biphasic kinetics.

CONCLUSION

It was inferred that the slow degradation rate of PDS polymer as well as the implant properties like porosity and wettability play an important role in controlling the drug release rates.

3D printing of alginate dialdehyde-gelatin (ADA-GEL) hydrogels incorporating phytotherapeutic icariin loaded mesoporous SiO2-CaO nanoparticles for bone tissue engineering

3D printing enables a better control over the microstructure of bone restoring constructs, addresses the challenges seen in the preparation of patient-specific bone scaffolds, and overcomes the bottlenecks that can appear in delivering drugs/growth factors promoting bone regeneration. Here, 3D printing is employed for the fabrication of an osteogenic construct made of hydrogel nanocomposites. Alginate dialdehyde-gelatin (ADA-GEL) hydrogel is reinforced by the incorporation of bioactive glass nanoparticles, i.e. mesoporous silica-calcia nanoparticles (MSNs), in two types of drug (icariin) loading. The composites hydrogel is printed as superhydrated composite constructs in a grid structure. The MSNs not only improve the mechanical stiffness of the constructs but also induce formation of an apatite layer when the construct is immersed in simulated body fluid (SBF), thereby promoting cell adhesion and proliferation. The nanocomposite constructs can hold and deliver icariin efficiently, regardless of its incorporation mode, either as loaded into the MSNs or freely distributed within the hydrogel. Biocompatibility tests showed that the hydrogel nanocomposites assure enhanced osteoblast proliferation, adhesion, and differentiation. Such optimum biological properties stem from the superior biocompatibility of ADA-GEL, the bioactivity of the MSNs, and the supportive effect of icariin in relation to cell proliferation and differentiation. Taken together, given the achieved structural and biological properties and effective drug delivery capability, the hydrogel nanocomposites show promising potential for bone tissue engineering.