Systematic screening of pharmaceutical polymers for hot melt extrusion processing: a comprehensive review

Bioadhesive Polymeric Films Containing Rhamnolipids, An Innovative Antimicrobial Topical Formulation

Acne affects most of the world's population, causing an impact on the self-esteem of adolescents and young adults. One of the causes is the presence of the bacteria Cutibacterium acnes which are part of the natural microbiota of the skin. Topical treatments consist of anti-inflammatory and antibiotics, which could select resistant strains. Alternatives to the antibiotic are biocomposites that have antimicrobial activity like biosurfactants which are produced by bacteria. An innovative way of applying these compounds is bioadhesive polymeric films that adhere to the skin and release the active principle topically. Rhamnolipids have great potential to be used in the treatment of acne because they present antimicrobial activity against C. acnes in low and safe concentrations (MIC of 15.62 µg/mL, CBM of 31.25 µg/mL and CC50 of 181.93 µg/mL). Four films with different rhamnolipids concentrations (0.0; 0.1; 0.2; and 0.3%, w/w) were obtained as to visual appearance, mass variation, thickness, density, solubility, pH, water vapor transmission, mechanical properties (folding endurance, bioadhesion strength, tensile strength, elongation at break and Young's modulus), scanning electron microscopy and infrared. The results show that these formulations had a homogeneous appearance; elastic mechanical properties; pH similar to human skin and bioadhesive. The polymeric films containing rhamnolipids were effective against C. acnes, in the in vitro test, at the three concentrations tested, the film with the highest concentration (0.3%, w/w) being the most promising for presenting the highest antimicrobial activity. Thus, the polymeric film containing rhamnolipids has the potential to be used in the treatment of acne.

Enhanced Dissolution and Bioavailability of Curcumin Nanocrystals Prepared by Hot Melt Extrusion Technology

Purpose

Curcumin nanocrystals (Cur-NCs) were prepared by hot melt extrusion (HME) technology to improve the dissolution and bioavailability of curcumin (Cur).

Methods

Cur-NCs with different drug-carrier ratios were prepared by one-step extrusion process with Eudragit® EPO (EEP) as the carrier. The dispersed size and solid state of Cur in extruded samples were characterized by dynamic light scattering (DLS), scanning electron microscope (SEM), differential scanning calorimetry (DSC), and X-ray diffraction (XRD). The thermal stability of Cur was analyzed by thermogravimetric analysis (TGA) and high performance liquid chromatography (HPLC). Dissolution and pharmacokinetics were studied to evaluate the improvement of dissolution and absorption of Cur by nano-preparation.

Results

Cur-NCs with particle sizes in the range of 50~150 nm were successfully prepared by using drug-carrier ratios of 1:1, 2:1 and 4:1, and the crystal form of Cur was Form 1 both before and after HME. The extrudate powders showed very efficient dissolution with the cumulative dissolution percentage of 80% in less than 2 min, and the intrinsic dissolution rates of them were 13.68 ± 1.20 mg/min/cm2, 11.78 ± 0.57 mg/min/cm2 and 4.35 ± 0.20 mg/min/cm2, respectively, whereas that of pure Cur was only 0.04 ± 0.00 mg/min/cm2. The TGA data demonstrated that the degradation temperature of Cur was about 250 °C, while the HPLC results showed Cur was degraded when extruded at the temperature over 150 °C. Pharmacokinetic experiment showed a significant improvement in the absorption of Cur. The Cmax of Cur in the Cur-NC group was 1.68 times that of pure Cur group, and the Cmax and area under the curve (AUC0-∞) of metabolites were 2.79 and 4.07 times compared with pure Cur group.

Conclusion

Cur-NCs can be prepared by HME technology in one step, which significantly improves the dissolution and bioavailability of Cur. Such a novel method for preparing insoluble drug nanocrystals has broad application prospects.

Formulation Development and Evaluation of Cannabidiol Hot-Melt Extruded Solid Self-Emulsifying Drug Delivery System for Oral Applications

Cannabidiol (CBD) is a highly lipophilic compound with poor oral bioavailability, due to poor aqueous solubility and extensive pre-systemic metabolism. The aim of this study was to explore the potential of employing Hot Melt Extrusion (HME) technology for the continuous production of Self Emulsifying Drug Delivery Systems (SEDDS) to improve the solubility and in vitro dissolution performance of CBD. Accordingly, different placebos were processed through HME in order to obtain a lead CBD loaded solid SEDDS. Two SEDDS were prepared with sesame oil, Poloxamer 188, Gelucire®59/14, PEO N80 and Soluplus®. Moreover, Vitamin E was added as an antioxidant. The SEDDS formulations demonstrated emulsification times of 9.19 and 9.30 min for F1 and F2 respectively. The formed emulsions showed smaller droplet size ranging from 150-400 nm that could improve lymphatic uptake of CBD and reduce first pass metabolism. Both formulations showed significantly faster in vitro dissolution rate (90% for F1 and 83% for F2) compared to 14% for the pure CBD within the first hour, giving an enhanced release profile. The formulations were tested for stability over a 60-day time period at 4°C, 25°C, and 40°C. Formulation F1 was stable over the 60-day time-period at 4°C. Therefore, the continuous HME technology could replace conventional methods for processing SEDDS and improve the oral delivery of CBD for better therapeutic outcomes.

Amorphous solid dispersion of a binary formulation with felodipine and HPMC for 3D printed floating tablets

This study focuses on the combination of three-dimensional printing (3DP) and amorphous solid dispersion (ASD) technologies for the manufacturing of gastroretentive floating tablets. Employing hot melt extrusion (HME) and fused deposition modeling (FDM), the study investigates the development of drug-loaded filaments and 3D printed (3DP) tablets containing felodipine as model drug and hydroxypropyl methylcellulose (HPMC) as the polymeric carrier. Prior to fabrication, solubility parameter estimation and molecular dynamics simulations were applied to predict drug-polymer interactions, which are crucial for ASD formation. Physical bulk and surface characterization complemented the quality control of both drug-loaded filaments and 3DP tablets. The analysis confirmed a successful amorphous dispersion of felodipine within the polymeric matrix. Furthermore, the low infill percentage and enclosed design of the 3DP tablet allowed for obtaining low-density systems. This structure resulted in buoyancy during the entire drug release process until a complete dissolution of the 3DP tablets (more than 8 h) was attained. The particular design made it possible for a single polymer to achieve a zero-order controlled release of the drug, which is considered the ideal kinetics for a gastroretentive system. Accordingly, this study can be seen as an advancement in ASD formulation for 3DP technology within pharmaceutics.

Preparation of tofacitinib sustained-release tablets using hot melt extrusion technology

This study aimed to develop a tablet that shows a drug release profile similar to the tofacitinib sustained-release tablet (Xeljanz XR®; OROS™) using hot melt extrusion technology. Tofacitinib citrate was selected as the drug. HPMCAS, HPMCP, and Kollidon VA64 were used as thermoplastic polymers to prepare a hot-melt extrudate. The extrudate was obtained from a twin screw extruder and pelletizer. The granules were compressed using a single punch press machine and then coated. TGA, DSC, XRD, FT-IR, and SEM were performed on the hot melt extrudate to understand its physicochemical properties. Dissolution tests were performed using the paddle method (USP Apparatus II). The results showed that the crystallinity state of tofacitinib changed to amorphous after the hot melt extrusion process; however, no chemical change was observed. The drug release profile was similar to that of Xeljanz XR®, which has an initial lag time owing to its OROS™ formulation; a coating process was performed to obtain a similar drug release profile. The lag time was controlled by adjusting the thickness of the coating layer. Moreover, the extrudate size and compression force during tableting did not significantly affect drug release. In conclusion, the new tofacitinib sustained-release tablet prepared using hot melt extrusion showed a drug release behavior similar to that of Xeljanz XR®.

Hot-Melt Extrusion: from Theory to Application in Pharmaceutical Formulation-Where Are We Now?

Hot-melt extrusion (HME) is a globally recognized, robust, effective technology that enhances the bioavailability of poorly soluble active pharmaceutical ingredients and offers an efficient continuous manufacturing process. The twin-screw extruder (TSE) offers an extremely resourceful customizable mixer that is used for continuous compounding and granulation by using different combinations of conveying elements, kneading elements (forward and reverse configuration), and distributive mixing elements. TSE is thus efficiently utilized for dry, wet, or melt granulation not only to manufacture dosage forms such as tablets, capsules, or granule-filled sachets, but also for designing novel formulations such as dry powder inhalers, drying units for granules, nanoextrusion, 3D printing, complexation, and amorphous solid dispersions. Over the past decades, combined academic and pharmaceutical industry collaborations have driven novel innovations for HME technology, which has resulted in a substantial increase in published articles and patents. This article summarizes the challenges and models for executing HME scale-up. Additionally, it covers the benefits of continuous manufacturing, process analytical technology (PAT) considerations, and regulatory requirements. In summary, this well-designed review builds upon our earlier publication, probing deeper into the potential of twin-screw extruders (TSE) for various new applications.

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

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

Material-Sparing Feasibility Screening for Hot Melt Extrusion

Hot melt extrusion (HME) offers a high-throughput process to manufacture amorphous solid dispersions. A variety of experimental and model-based approaches exist to predict API solubility in polymer melts, but these methods are typically aimed at determining the thermodynamic solubility and do not take into account kinetics of dissolution or the associated degradation of the API during thermal processing, both of which are critical considerations in generating a successful amorphous solid dispersion by HME. This work aims to develop a material-sparing approach for screening manufacturability of a given pharmaceutical API by HME using physically relevant time, temperature, and shear. Piroxicam, ritonavir, and phenytoin were used as model APIs with PVP VA64 as the dispersion polymer. We present a screening flowchart, aided by a simple custom device, that allows rapid formulation screening to predict both achievable API loadings and expected degradation from an HME process. This method has good correlation to processing with a micro compounder, a common HME screening industry standard, but only requires 200 mg of API or less.

Impact of polymer chemistry on critical quality attributes of selective laser sintering 3D printed solid oral dosage forms

The aim of this study is to investigate the influence of polymer chemistry on the properties of oral dosage forms produced using selective laser sintering (SLS). The dosage forms were printed using different grades of polyvinyl alcohol or copovidone in combination with indomethacin as the active pharmaceutical ingredient. The properties of the printed structures were assessed according to European Pharmacopoeia guidelines at different printing temperatures and laser scanning speeds in order to determine the suitable printing parameters. The results of the study indicate that the chemical properties of the polymers, such as dynamic viscosity, degree of hydrolyzation, and molecular weight, have significant impact on drug release and kinetics. Drug release rate and supersaturation can be modulated by selecting the appropriate polymer type. Furthermore, the physical properties of the dosage forms printed under the same settings are influenced by the selected polymer type, which determines the ideal manufacturing settings. This study demonstrates how the chemical properties of the polymer can determine the appropriate choice of manufacturing settings and the final properties of oral dosage forms produced using SLS.

Preparation of Hot-Melt-Extruded Solid Dispersion Based on Pre-Formulation Strategies and Its Enhanced Therapeutic Efficacy

In this study, an amorphous solid dispersion containing the poorly water-soluble drug, bisacodyl, was prepared by hot-melt extrusion to enhance its therapeutic efficacy. First, the miscibility and interaction between the drug and polymer were investigated as pre-formulation strategies using various analytical approaches to obtain information for selecting a suitable polymer. Based on the calculation of the Hansen solubility parameter and the identification of the single glass transition temperature (Tg), the miscibility between bisacodyl and all the investigated polymers was confirmed. Additionally, the drug-polymer molecular interaction was identified based on the comprehensive results of dynamic vapor sorption (DVS), Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy, and a comparison of the predicted and experimental values of Tg. In particular, the hydroxypropyl methylcellulose (HPMC)-based solid dispersions, which exhibited large deviation between the calculated and experimental values of Tg and superior physical stability after DVS experiments, were selected as the most appropriate solubilized bisacodyl formulations due to the excellent inhibitory effects on precipitation based on the results of the non-sink dissolution test. Furthermore, it was shown that the enteric-coated tablets containing HPMC-bisacodyl at a 1:4 ratio (w/w) had significantly improved in vivo therapeutic laxative efficacy compared to preparations containing un-solubilized raw bisacodyl in constipation-induced rabbits. Therefore, it was concluded that the pre-formulation strategy, using several analyses and approaches, was successfully applied in this study to investigate the miscibility and interaction of drug-polymer systems, hence resulting in the manufacture of favorable solid dispersions with favorable in vitro and in vivo performances using hot-melt extrusion processes.

Mechanical Anisotropy of Injection-Molded PP/PS Polymer Blends and Correlation with Morphology

The molecular orientation formed by melt-forming processes depends strongly on the flow direction. Quantifying this anisotropy, which is more pronounced in polymer blends, is important for assessing the mechanical properties of thermoplastic molded products. For injection-molded polymer blends, this study used short-beam shear testing to evaluate the mechanical anisotropy as a stress concentration factor, and clarified the correlation between the evaluation results and the phase structure. Furthermore, because only shear yielding occurs with short-beam shear testing, the yielding conditions related to uniaxial tensile loading were identified by comparing the results with those of three-point bending tests. For continuous-phase PP, the phase structure formed a sea-island structure. The yield condition under uniaxial tensile loading was interface debonding. For continuous-phase PS, the phase structure was dispersed and elongated in the flow direction. The addition of styrene-ethylene-butadiene-styrene (SEBS) altered this structure. The yielding condition under uniaxial tensile loading was shear yielding. The aspect ratio of the dispersed phase was found to correlate with the stress concentration factor. When the PP forming the sea-island structure was of continuous phase, the log-complex law was sufficient to explain the shear yield initiation stress without consideration of the interfacial interaction stress.

Corroborating various material-sparing techniques with hot melt extrusion for the preparation of triclabendazole amorphous solid dispersions

Amorphous solid dispersions (ASD) are one of the most adopted technologies for improving the solubility of novel molecules. Formulation of ASDs using solvent free methods such as hot melt extrusion (HME) has been in the spotlight off-lately. However, early-stage formulation development is tricky and a difficult bridge to pass due to limited drug availability. Material-sparing techniques (theoretical & practical) have been used for selecting suitable polymeric carriers for formulating ASDs. However, these techniques have limitations in predicting the effect of process parameters. The objective of this study is to use both theoretical and practical material-sparing techniques to optimize a polymer for the developing Triclabendazole (TBZ) ASDs. Initial screening by theoretical approaches suggested that TBZ is highly miscible with Kollidon®VA64 (VA64) and poorly miscible with Parteck®MXP (PVA). However, results from ASDs prepared using SCFe were opposite to these predictions. ASDs prepared using either technique and both VA64 and PVA showed >200x increase in solubility. Each formulation released >85% of drug in less than 15 mins. Although the thermodynamic phase diagram suggested that VA64 was the ideal polymer for TBZ-ASDs, it has certain limitations in factoring the different elements during melt-processing and hence, practical approaches like SCFe could help in predicting the drug-polymer miscibility for HME processing.

Influence of Poloxamer on the Dissolution and Stability of Hot-Melt Extrusion-Based Amorphous Solid Dispersions Using Design of Experiments

The current study aimed to see the effects of poloxamer P407 on the dissolution performance of hydroxypropyl methylcellulose acetate succinate (AquaSolve™ HPMC-AS HG)-based amorphous solid dispersions (ASD). A weakly acidic, poorly water-soluble active pharmaceutical ingredient (API), mefenamic acid (MA), was selected as a model drug. Thermal investigations, including thermogravimetry (TG) and differential scanning calorimetry (DSC), were conducted for raw materials and physical mixtures as a part of the pre-formulation studies and later to characterize the extruded filaments. The API was blended with the polymers using a twin shell V-blender for 10 min and then extruded using an 11-mm twin-screw co-rotating extruder. Scanning electron microscopy (SEM) was used to study the morphology of the extruded filaments. Furthermore, Fourier-transform infrared spectroscopy (FT-IR) was performed to check the intermolecular interactions of the components. Finally, to assess the in vitro drug release of the ASDs, dissolution testing was conducted in phosphate buffer (0.1 M, pH 7.4) and hydrochloric acid-potassium chloride (HCl-KCl) buffer (0.1 M, pH 1.2). The DSC studies confirmed the formation of the ASDs, and the drug content of the extruded filaments was observed to be within an acceptable range. Furthermore, the study concluded that the formulations containing poloxamer P407 exhibited a significant increase in dissolution performance compared to the filaments with only HPMC-AS HG (at pH 7.4). In addition, the optimized formulation, F3, was stable for over 3 months when exposed to accelerated stability studies.

Veering to a Continuous Platform of Fused Deposition Modeling Based 3D Printing for Pharmaceutical Dosage Forms: Understanding the Effect of Layer Orientation on Formulation Performance

Three-dimensional (3D) printing of pharmaceuticals has been centered around the idea of personalized patient-based 'on-demand' medication. Fused deposition modeling (FDM)-based 3D printing processes provide the capability to create complex geometrical dosage forms. However, the current FDM-based processes are associated with printing lag time and manual interventions. The current study tried to resolve this issue by utilizing the dynamic z-axis to continuously print drug-loaded printlets. Fenofibrate (FNB) was formulated with hydroxypropyl methylcellulose (HPMC AS LG) into an amorphous solid dispersion using the hot-melt extrusion (HME) process. Thermal and solid-state analyses were used to confirm the amorphous state of the drug in both polymeric filaments and printlets. Printlets with a 25, 50, and 75% infill density were printed using the two printing systems, i.e., continuous, and conventional batch FDM printing methods. Differences between the two methods were observed in the breaking force required to break the printlets, and these differences reduced as the infill density went up. The effect on in vitro release was significant at lower infill densities but reduced at higher infill densities. The results obtained from this study can be used to understand the formulation and process control strategies when switching from conventional FDM to the continuous printing of 3D-printed dosage forms.

Buccal delivery of small molecules and biologics: Of mucoadhesive polymers, films, and nanoparticles - An update

Buccal delivery of small and large molecules is an attractive route of administration that has been studied extensively over the past few decades. This route bypasses first-pass metabolism and can be used to deliver therapeutics directly to systemic circulation. Moreover, buccal films are efficient dosage forms for drug delivery due to their simplicity, portability, and patient comfort. Films have traditionally been formulated using conventional techniques, including hot-melt extrusion and solvent casting. However, newer methods are now being exploited to improve the delivery of small molecules and biologics. This review discusses recent advances in buccal film manufacturing, using the latest technologies, such as 2D and 3D printing, electrospraying, and electrospinning. This review also focuses on the excipients used in the preparation of these films, with emphasis on mucoadhesive polymers and plasticizers. Along with advances in manufacturing technology, newer analytical tools have also been used for the assessment of permeation of the active agents across the buccal mucosa, the most critical biological barrier and limiting factor of this route. Additionally, preclinical and clinical trial challenges are discussed, and some small molecule products already on the market are explored.

3D-Printed Fast-Dissolving Oral Dosage Forms via Fused Deposition Modeling Based on Sugar Alcohol and Poly(Vinyl Alcohol)-Preparation, Drug Release Studies and In Vivo Oral Absorption

Three-dimensional printing technology holds marked promise for the pharmaceutical industry and is now under intense investigation. Most research is aimed at a greater efficiency in printing oral dosage forms using powder bed printing or fused deposition modeling (FDM). Oral dosage forms printed by FDM tend to be hard objects, which reduce the risk of cracking and chipping. However, one challenge in printing oral dosage forms via FDM is achieving rapid drug release, because the materials for FDM are basically thermoplastic polymers with slow drug release properties. In this study, we investigated printing a fast-dissolving oral dosage form by adding sugar alcohol to a poly(vinyl alcohol)-based formulation for FDM. Filaments which contain sugar alcohol were successfully prepared, and objects were printed with them as oral dosage forms by FDM. On drug release testing, a printed oral dosage form in a ring shape which contained 55% maltitol showed a more than 85% drug release in 15 min. In vivo oral absorption of this printed oral dosage form in dogs was comparable to that of a conventional fast-dissolving tablet. Of particular interest, the drug release profile and drug amount of the oral dosage forms can be easily controlled by a change in shape using 3D Computer Aided Design. These characteristics will encourage the prevalence of FDM by the pharmaceutical industry, and contribute to the promotion of personalized medicine.

Formulation development and in Vitro-Ex vivo characterization of hot-melt extruded ciprofloxacin hydrochloride inserts for ocular applications: Part I

This study developed, optimized, characterized, and evaluated bioadhesive, hot-melt extruded (HME), extended-release ocular inserts containing ciprofloxacin hydrochloride (CIP-HCL) to improve the therapeutic outcomes of ocular bacterial infections. The inserts were fabricated with FDA-approved biocompatible, biodegradable, and bioadhesive polymers that were tuned in different ratios to achieve a sustained release profile. The results revealed an inverse relationship between the Klucel™ hydroxypropyl cellulose (HPC, 140,000 Da) concentration and drug release and extended-release profile over 24 h. The CIP-HCL-HME inserts presented stable drug content, thermal behavior, surface pH, and release profiles over three months of room-temperature storage and demonstrated adequate mucoadhesive strength. SEM micrographs revealed a smooth surface. Bacterial growth was not observed on the samples during the in vitro release experiment (0.5-24 h), indicating that a minimum inhibitory concentration (MIC) of 90 against Pseudomonas aeruginosa was achieved. Ex vivo transcorneal permeation studies using excised rabbit corneas revealed that the prepared ocular inserts prolonged the transcorneal flux of the drug compared to commercial eye drops and immediate-release inserts and could reduce the administration frequency to once daily. Therefore, the inserts could increase patient compliance and exhibited prolonged antibacterial activity and thus could provide better therapeutic outcomes against ocular bacterial infections.

Compatibility Study between Fenbendazole and Polymeric Excipients Used in Pharmaceutical Dosage Forms Using Thermal and Non-Thermal Analytical Techniques

The body of work described in this research paper evaluates the compatibility between Fenbendazole (Fen), which is a broad-spectrum anthelmintic with promising antitumor activity, and three polymeric excipients commonly applied in pharmaceutical dosage forms. The assessment of binary mixtures was performed by differential scanning calorimetry and thermogravimetric analysis/derivative thermogravimetry to predict physical and/or chemical interactions, followed by X-ray diffraction spectroscopy (XRD), Fourier transform infrared spectroscopy (FTIR), and high-performance liquid chromatography (HPLC) to confirm or exclude any interactions. Thermal studies suggested the presence of interactions between Fen and P 407, PCL, and PLA. To validate these data, XRD showed that Fen is compatible with PCL and PLA, suggesting some interaction with P 407. FTIR demonstrated that PCL and PLA can establish physical interactions with Fen; moreover, it suggested that P 407 interacts not only physically but also chemically, which was later proved by HPLC to be only new intermolecular interactions. This work supports the further application of P 407, PCL, and PLA for the development of new medicinal and veterinary formulations containing Fen, since they do not affect the physical and chemical characteristics of the active ingredient and consequently its bioavailability and therapeutic efficacy.

SEDEX-Self-Emulsifying Delivery Via Hot Melt Extrusion: A Continuous Pilot-Scale Feasibility Study

The aim of this study was to develop a continuous pilot-scale solidification and characterization of self-emulsifying drug delivery systems (SEDDSs) via hot melt extrusion (HME) using Soluplus^® and Kollidon^® VA-64. First, an oil-binding capacity study was performed to estimate the maximal amount of SEDDSs that the polymers could bind. Then, HME was conducted using a Coperion 18 mm ZSK18 pilot plant-scale extruder with split-feeding of polymer and SEDDS in 10, 20, and 30% w/w SEDDSs was conducted. The prepared extrudates were characterized depending on appearance, differential scanning calorimetry, wide-angle X-ray scattering, emulsification time, droplet size, polydispersity index, and cloud point. The oil-binding studies showed that the polymers were able to bind up to 50% w/w of liquid SEDDSs. The polymers were processed via HME in a temperature range between 110 and 160 °C, where a plasticizing effect of the SEDDSs was observed. The extrudates were found to be stable in the amorphous state and self-emulsified in demineralized water at 37 °C with mean droplet sizes between 50 and 300 nm. A cloud point and phase inversion were evident in the Soluplus^® samples. In conclusion, processing SEDDSs with HME could be considered a promising alternative to the established solidification techniques as well as classic amorphous solid dispersions for drug delivery.

The Effect of Hot-Melt Extrusion of Mulberry Leaf on the Number of Active Compounds and Antioxidant Activity

The aim of this study is to compare the functions of the physiologically active compounds of three types of mulberry leaf by cultivar, and to confirm the changes using hot-melt extrusion (HME-ML). The active components of mulberry leaf were analyzed using the HPLC system, and total phenolic content (TPC), total flavonoid content (TFC), and antioxidant activity were measured. Among the three varieties, the highest contents of rutin and isoquercetin were detected in Cheongil, of TPC in Cheongol, and of TFC in Cheongil. It was confirmed that this bio-accessibility was increased in HME-ML compared with the control. The DPPH radical scavenging activity of Cheongol showed greater antioxidant properties, and HME showed improvement in the antioxidant properties of all mulberry leaves. These results suggest that the application of HME technology can improve the biological activities of mulberry leaf.

Formulation and Evaluation of Fenbendazole Extended-Release Extrudes Processed by Hot-Melt Extrusion

This study aimed to demonstrate the feasibility of hot-melt extrusion in the development of extended-release formulations of Fenbendazole (Fen) dispersed in PEO/PCL blend-based matrices. Their thermal, physical, chemical and viscosity properties were assessed by differential scanning calorimetry, thermogravimetric analysis/derivative thermogravimetry, Fourier transform infrared spectroscopy, X-ray diffraction spectroscopy, and melt flow index. Drug dispersion was analyzed by scanning electron microscopy with electron dispersive X-ray spectroscopy, and drug release was evaluated by ultraviolet-visible spectroscopy. A thermal analysis indicated the conversion of the drug to its amorphous state. FTIR analysis endorsed the thermal studies pointing to a decrease in the drug's crystallinity with the establishment of intermolecular interactions. XRD analysis confirmed the amorphous nature of Fen. MFI test revealed that PCL acts as a plasticizer when melt-processed with PEO. SEM images displayed irregular surfaces with voids and pores, while EDX spectra demonstrated a homogeneous drug distribution throughout the polymeric carrier. Dissolution testing revealed that PCL retards the drug release proportionally to the content of such polymer incorporated. These melt-extruded matrices showed that the drug release rate in a PEO/PCL blend can easily be tailored by altering the ratio of PCL to address the issues related to the multiple-dosing regimen of Fen in ruminants.

Exploiting Polymeric Films as a Multipurpose Drug Delivery System: a Review

Polymeric films are drug delivery systems that maintain contact with the delivery tissue and sustain a controlled release of therapeutic molecules. These systems allow a longer time of drug contact with the target site in the case of topical treatments and allow the controlled administration of drugs. They can be manufactured by various methods such as solvent casting, hot melt extrusion, electrospinning, and 3D bioprinting. Furthermore, they can employ various polymers, for example PVP, PVA, cellulose derivatives, chitosan, gelling gum, pectin, and alginate. Its versatility is also applicable to different routes of administration, as it can be administered to the skin, oral mucosa, vaginal canal, and eyeballs. All these factors allow numerous combinations to obtain a better treatment. This review focuses on exploring some possible ways to develop them and some particularities and advantages/disadvantages in each case. It also aims to show the versatility of these systems and the advantages and disadvantages in each case, as they bring the opportunity to develop different medicines to facilitate therapies for the most diverse purposes .

Lipid-based solubilization technology via hot melt extrusion: promises and challenges

INTRODUCTION

Self-emulsifying drug delivery systems (SEDDS) are a promising strategy to improve the oral bioavailability of poorly water-soluble drugs (PWSD). The excipients of SEDDS enable permeation through the mucus and gastro-intestinal barrier, inhibiting efflux transporters (e.g. P-glycoprotein) of drugs. Poor drug loading capacity and formulation instability are the main setbacks of traditional SEDDS. The use of polymeric precipitation inhibitors was shown to create supersaturable SEDDS with increased drug payload, and their solidification can help to overcome the instability challenge. As an alternative to several existing SEDDS solidification technologies, hot melt extrusion (HME) holds the potential for lean and continuous manufacturing of supersaturable solid-SEDDS. Despite being ubiquitously applied in solid lipid and polymeric processing, HME has not yet been widely considered for the preparation of SEDDS.

AREAS COVERED

The review begins with the rationale why SEDDS as the preferred lipid-based delivery systems (LBDS) is suitable for the oral delivery of PWSD and discusses the common barriers to oral administration. The potential of LBDS to surmount them is discussed. SEDDS as the flagship of LBDS for PWSD is proposed with a special emphasis on solid-SEDDS. Finally, the opportunities and challenges of HME from the lipid-based excipient (LBE) processing and product performance standpoint are highlighted.

EXPERT OPINION

HME can be a continuous, solvent-free, cost-effective, and scalable technology for manufacturing solid supersaturable SEDDS. Several critical formulations and process parameters in successfully preparing SEDDS via HME are identified.

A systematic and robust assessment of hot-melt extrusion-based amorphous solid dispersions: Theoretical prediction to practical implementation

Amorphous solid dispersions (ASDs) have gained attention as a formulation strategy in recent years, with the potential to improve the apparent solubility and, hence, the oral bioavailability of poorly soluble drugs. The process of formulating ASDs is commonly faced with challenges owing to the intrinsic physical and chemical instability of the initial amorphous form and the long-term physical stability of drug formulations. Numerous research publications on hot-melt extrusion (HME) technology have demonstrated that it is the most efficient approach for manufacturing reasonably stable ASDs. The HME technique has been established as a faster scale-up production strategy for formulation evaluation and has the potential to minimize the time to market. Thermodynamic evaluation and theoretical predictions of drug-polymer solubility and miscibility may assist to reduce the product development cost by HME. This review article highlights robust and established prediction theories and experimental approaches for the selection of polymeric carriers for the development of hot melt extrusion based stable amorphous solid dispersions (ASDs). In addition, this review makes a significant contribution to the literature as a pilot guide for ASD assessment, as well as to confirm the drug-polymer compatibility and physical stability of HME-based formulations.

Modified Release Kinetics in Dual Filament 3D Printed Individualized Oral Dosage Forms

On demand production of totally customizable combinative preparations is a central goal of a patient-centric pharmaceutical supply chain. Additive manufacturing techniques like fused deposition modeling (FDM) could be key technologies towards such individualized dosage forms. As so far only a limited number of studies on 3D printed combinative preparations applying FDM have been reported, a core-shell dosage form was the focus of the present study. Dosage forms with an initial and a sustained release part with theophylline as model API were successfully produced applying a dual nozzle FDM 3D printer. Investigations identified microstructural defects at the interface between the two formulations by means of µCT analysis. Dissolution testing proved the achievement of the intended release profile. In combination with additionally characterized release profile of single material prints of different shapes, the combinative release profiles could be predicted by developing model equations and taking into account the geometric composition. As these model approaches can accordingly facilitate the prediction of API release from 3D printed combinative preparations with only data from single material release. This is a first step towards a truly individualized and reliable patient-centric pharmaceutical supply via 3D printing.

Three-Dimensional Printing of a Container Tablet: A New Paradigm for Multi-Drug-Containing Bioactive Self-Nanoemulsifying Drug-Delivery Systems (Bio-SNEDDSs)

This research demonstrates the use of fused deposition modeling (FDM) 3D printing to control the delivery of multiple drugs containing bioactive self-nano emulsifying drug-delivery systems (SNEDDSs). Around two-thirds of the new chemical entities being introduced in the market are associated with some inherent issues, such as poor solubility and high lipophilicity. SNEDDSs provide for an innovative and easy way to develop a delivery platform for such drugs. Combining this platform with FDM 3D printing would further aid in developing new strategies for delivering poorly soluble drugs and personalized drug-delivery systems with added therapeutic benefits. This study evaluates the performance of a 3D-printed container system containing curcumin (CUR)- and lansoprazole (LNS)-loaded SNEDDS. The SNEDDS showed 50% antioxidant activity (IC₅₀) at concentrations of around 330.1 µg/mL and 393.3 µg/mL in the DPPH and ABTS radical scavenging assay, respectively. These SNEDDSs were loaded with no degradation and leakage from the 3D-printed container. We were able to delay the release of the SNEDDS from the hollow prints while controlling the print wall thickness to achieve lag phases of 30 min and 60 min before the release from the 0.4 mm and 1 mm wall thicknesses, respectively. Combining these two innovative drug-delivery strategies demonstrates a novel option for tackling the problems associated with multi-drug delivery and delivery of drugs susceptible to degradation in, i.e., gastric pH for targeting disease conditions throughout the gastrointestinal tract (GIT). It is also envisaged that such delivery systems reported herein can be an ideal solution to deliver many challenging molecules, such as biologics, orally or near the target site in the future, thus opening a new paradigm for multi-drug-delivery systems.

Quality aspects in the development of pelletized dosage forms

The aim of this work was to identify and collate the major common challenges that arise during pellet development. These challenges focus on aspects right from raw material properties until the final drying process of the pelletization. The challenges associated with the particle size of drug and excipients, physicochemical properties, drug excipient interaction and the effect of type/grade and amount of raw material on the pellet properties are covered in this review. Technological and process related challenges within the commonly used pelletization techniques such as extrusion-spheronization, hot-melt extrusion and layering techniques are also emphasized. The paper likewise gives an insight to the possible ways of addressing the quality of pellets during development.

Preparation of Azithromycin Amorphous Solid Dispersion by Hot-Melt Extrusion: An Advantageous Technology with Taste Masking and Solubilization Effects

Azithromycin (AZI) is one of the most commonly used macrolide antibiotics in children, but has the disadvantages of a heavy bitter taste and poor solubility. In order to solve these problems, hot-melt extrusion (HME) was used to prepare azithromycin amorphous solid dispersion. Preliminary selection of a polymer for HME was conducted by calculating Hansen solubility parameter to predict the miscibility of the drug and polymer. Eudragit^® RL PO was chosen as the polymer due to its combination of taste-masking effect and dissolution. Moreover, the solubility was improved with this polymer. Design of experiments (DoE) was used to optimize the formulation and process, with screw speed, extrusion temperature, and drug percentage as independent variables, and content, dissolution, and extrudates diameter as dependent variables. The optimal extrusion parameters were obtained as follows: temperature-150 °C; screw speed-75 rpm; and drug percentage-25%. Differential scanning calorimetry (DSC) and Powder X-ray Diffraction (PXRD) studies of the powdered solid dispersions showed that the crystalline AZI transformed into the amorphous form. Fourier transform infrared spectroscopy (FTIR) results indicated that the formation of a hydrogen bond between AZI and the polymer led to the stabilization of AZI in its amorphous form. In conclusion, this work illustrated the importance of HME for the preparation of amorphous solid dispersion of AZI, which can solve the problems of bitterness and low solubility. It is also of great significance for the development of compliant pediatric AZI preparation.

Quality of FDM 3D Printed Medicines for Pediatrics: Considerations for Formulation Development, Filament Extrusion, Printing Process and Printer Design

3d printing is capable of providing dose individualization for pediatric medicines and translating the precision medicine approach into practical application. In pediatrics, dose individualization and preparation of small dosage forms is a requirement for successful therapy, which is frequently not possible due to the lack of suitable dosage forms. For precision medicine, individual characteristics of patients are considered for the selection of the best possible API in the most suitable dose with the most effective release profile to improve therapeutic outcome. 3d printing is inherently suitable for manufacturing of individualized medicines with varying dosages, sizes, release profiles and drug combinations in small batch sizes, which cannot be manufactured with traditional technologies. However, understanding of critical quality attributes and process parameters still needs to be significantly improved for this new technology. To ensure health and safety of patients, cleaning and process validation needs to be established. Additionally, adequate analytical methods for the in-process control of intermediates, regarding their printability as well as control of the final 3d printed tablets considering any risk of this new technology will be required. The PolyPrint consortium is actively working on developing novel polymers for fused deposition modeling (FDM) 3d printing, filament formulation and manufacturing development as well as optimization of the printing process, and the design of a GMP-capable FDM 3d printer. In this manuscript, the consortium shares its views on quality aspects and measures for 3d printing from drug-loaded filaments, including formulation development, the printing process, and the printed dosage forms. Additionally, engineering approaches for quality assurance during the printing process and for the final dosage form will be presented together with considerations for a GMP-capable printer design.

Amorphous solid dispersions of cyclosporine A with improved bioavailability prepared via hot melt extrusion: Formulation, physicochemical characterization, and in vivo evaluation

In this study, the amorphous solid dispersions of cyclosporine A (CsA-ASDs) were prepared by hot melt extrusion (HME) with PVP K12 as carrier to improve the oral bioavailability of CsA. The polymers were screened by solubilization and recrystallization inhibition experiments, then the CsA-ASDs were prepared with optimized technological parameters and characterized on thermodynamics and morphology. The results showed that CsA was dispersed among PVP K12 as amorphous form in CsA-ASDs, and the infrared spectrum testified that there was possible hydrogen bond interaction between CsA and PVP K12. The in vivo pharmacokinetics of CsA formulations in rats were analyzed via LC-MS. The AUC of CsA-ASD tablets increased by 7.3 times compared to CsA bulk powder and 3.1 times in contrast to CsA-PM tablets, respectively. The experiment proved that CsA-ASD tablets significantly improved the dissolution and absorption of the drug. This study had a reference value for the bioavailability improvement of oral CsA preparations.

Selective Laser Sintering of a Photosensitive Drug: Impact of Processing and Formulation Parameters on Degradation, Solid State, and Quality of 3D-Printed Dosage Forms

This research study utilized a light-sensitive drug, nifedipine (NFD), to understand the impact of processing parameters and formulation composition on drug degradation, crystallinity, and quality attributes (dimensions, hardness, disintegration time) of selective laser sintering (SLS)-based three-dimensional (3D)-printed dosage forms. Visible lasers with a wavelength around 455 nm are one of the laser sources used for selective laser sintering (SLS) processes, and some drugs such as nifedipine tend to absorb radiation at varying intensities around this wavelength. This phenomenon may lead to chemical degradation and solid-state transformation, which was assessed for nifedipine in formulations with varying amounts of vinyl pyrrolidone-vinyl acetate copolymer (Kollidon VA 64) and potassium aluminum silicate-based pearlescent pigment (Candurin) processed under different SLS conditions in the presented work. After preliminary screening, Candurin, surface temperature (ST), and laser speed (LS) were identified as the significant independent variables. Further, using the identified independent variables, a 17-run, randomized, Box-Behnken design was developed to understand the correlation trends and quantify the impact on degradation (%), crystallinity, and quality attributes (dimensions, hardness, disintegration time) employing qualitative and quantitative analytical tools. The design of experiments (DoEs) and statistical analysis observed that LS and Candurin (wt %) had a strong negative correlation on drug degradation, hardness, and weight, whereas ST had a strong positive correlation with drug degradation, amorphous conversion, and hardness of the 3D-printed dosage form. From this study, it can be concluded that formulation and processing parameters have a critical impact on stability and performance; hence, these parameters should be evaluated and optimized before exposing light-sensitive drugs to the SLS processes.

Development and Evaluation of Amorphous Oral Thin Films Using Solvent-Free Processes: Comparison between 3D Printing and Hot-Melt Extrusion Technologies

Conventional oral dosage forms may not always be optimal especially for those patients suffering from dysphasia or difficulty swallowing. Development of suitable oral thin films (OTFs), therefore, can be an excellent alternative to conventional dosage forms for these patient groups. Hence, the main objective of the current investigation is to develop oral thin film (OTF) formulations using novel solvent-free approaches, including additive manufacturing (AM), hot-melt extrusion, and melt casting. AM, popularly recognized as 3D printing, has been widely utilized for on-demand and personalized formulation development in the pharmaceutical industry. Additionally, in general active pharmaceutical ingredients (APIs) are dissolved or dispersed in polymeric matrices to form amorphous solid dispersions (ASDs). In this study, acetaminophen (APAP) was selected as the model drug, and Klucel™ hydroxypropyl cellulose (HPC) E5 and Soluplus^® were used as carrier matrices to form the OTFs. Amorphous OTFs were successfully manufactured by hot-melt extrusion and 3D printing technologies followed by comprehensive studies on the physico-chemical properties of the drug and developed OTFs. Advanced physico-chemical characterizations revealed the presence of amorphous drug in both HME and 3D printed films whereas some crystalline traces were visible in solvent and melt cast films. Moreover, advanced surface analysis conducted by Raman mapping confirmed a more homogenous distribution of amorphous drugs in 3D printed films compared to those prepared by other methods. A series of mathematical models were also used to describe drug release mechanisms from the developed OTFs. Moreover, the in vitro dissolution studies of the 3D printed films demonstrated an improved drug release performance compared to the melt cast or extruded films. This study suggested that HME combined with 3D printing can potentially improve the physical properties of formulations and produce OTFs with preferred qualities such as faster dissolution rate of drugs.

Injection-molded capsule bodies and caps based on polymer blends for controlled drug delivery

A variety of polymer:polymer blends was used to prepare hot melt extrudates and empty capsules (bodies and caps) by injection-molding using a benchtop extruder (Babyplast). KollidonSR:inulin and Carbothane:inulin blends were investigated. The impact of the blend ratio on the water uptake and dry mass loss kinetics upon exposure to 0.1 MHCl, phosphate buffer pH6.8 and culture medium optionally inoculated with fecal samples from Inflammatory Bowel Disease (IBD) patients were studied. Hot melt extrudates were loaded with up to 60% theophylline, capsules were filled with drug powder. Increasing the inulin content led to increased water uptake and dry mass loss rates, resulting in accelerated drug release from the dosage forms, irrespective of the type of polymer blend. This can be attributed to the higher hydrophilicity/water-solubility of this polymer compared to KollidonSR and Carbothane. Interestingly, the presence of fecal samples in culture medium increased the water uptake and dry mass loss of hot melt extrudates to a certain extent, suggesting partial system degradation by bacterial enzymes. However, these phenomena did not translate into any noteworthy impact of the presence of colonic bacteria on theophylline release from the investigated extrudates or capsules. Hence, drug release can be expected to be independent of the location "small intestine vs. colon" from these dosage forms, which can be advantageous for long term release throughout the entire gastro intestinal tract.

Harnessing artificial intelligence for the next generation of 3D printed medicines

Artificial intelligence (AI) is redefining how we exist in the world. In almost every sector of society, AI is performing tasks with super-human speed and intellect; from the prediction of stock market trends to driverless vehicles, diagnosis of disease, and robotic surgery. Despite this growing success, the pharmaceutical field is yet to truly harness AI. Development and manufacture of medicines remains largely in a 'one size fits all' paradigm, in which mass-produced, identical formulations are expected to meet individual patient needs. Recently, 3D printing (3DP) has illuminated a path for on-demand production of fully customisable medicines. Due to its flexibility, pharmaceutical 3DP presents innumerable options during formulation development that generally require expert navigation. Leveraging AI within pharmaceutical 3DP removes the need for human expertise, as optimal process parameters can be accurately predicted by machine learning. AI can also be incorporated into a pharmaceutical 3DP 'Internet of Things', moving the personalised production of medicines into an intelligent, streamlined, and autonomous pipeline. Supportive infrastructure, such as The Cloud and blockchain, will also play a vital role. Crucially, these technologies will expedite the use of pharmaceutical 3DP in clinical settings and drive the global movement towards personalised medicine and Industry 4.0.

Impact of Laser Speed and Drug Particle Size on Selective Laser Sintering 3D Printing of Amorphous Solid Dispersions

This research demonstrates the influence of laser speed and the drug particle size on the manufacturing of amorphous solid dispersions (ASD) and dosage forms thereof using selective laser sintering 3-dimensional (3D) printing. One-step manufacturing of ASD is possible using selective laser sintering 3D printing processes, however, the mechanism of ASD formation by this process is not completely understood and it requires further investigation. We hypothesize that the mechanism of ASD formation is the diffusion and dissolution of the drug in the polymeric carrier during the selective laser sintering (SLS) process and the drug particle size plays a critical role in the formation of said ASDs as there is no mixing involved in the sintering process. Herein, indomethacin was used as a model drug and introduced into the feedstock (Kollidon® VA64 and Candurin® blend) as either unprocessed drug crystals (particle size > 50 µm) or processed hot-melt extruded granules (DosePlus) with reduced drug particle size (<5 µm). These feedstocks were processed at 50, 75, and 100 mm/s scan speed using SLS 3D printing process. Characterization and performance testing were conducted on these tablets which revealed the amorphous conversion of the drug. Both MANOVA and ANOVA analyses depicted that the laser speed and drug particle size significantly impact the drug's apparent solubility and drug release. This significant difference in performance between formulations is attributed to the difference in the extent of dissolution of the drug in the polymeric matrix, leading to residual crystallinity, which is detrimental to ASD's performance. These results demonstrate the influence of drug particle size on solid-state and performance of 3D printed solid dispersions, and, hence, provide a better understanding of the mechanism and limitations of SLS 3D printing of ASDs and its dosage forms.

Continuous manufacture of hydroxychloroquine sulfate drug products via hot melt extrusion technology to meet increased demand during a global pandemic: From bench to pilot scale

During pandemics and global crises, drug shortages become critical as a result of increased demand, shortages in personnel and lockdown restrictions that disrupt the supply chain. The pharmaceutical industry is therefore moving towards continuous manufacturing instead of conventional batch manufacturing involving numerous steps, that normally occur at different sites. In order to validate the use of large-scale industrial processes, feasibility studies need to be performed using small-scale laboratory equipment. To that end, the scale-up of a continuous process and its effect on the critical quality attributes (CQAs) of the end product were investigated in this work. Hydroxychloroquine Sulphate (HCQS) was used as the model drug, Soluplus® as a model polymeric carrier and both horizontal and vertical twin screw extruders used to undertake this hot melt extrusion (HME) study. Seven formulations were processed using a small-scale horizontal extruder and a pilot-scale vertical extruder at various drug loadings, temperature profiles and screw speeds. When utilising a horizontal extruder, formulations with the highest drug load and processed at the lowest screw speed and temperature had the highest crystallinity with higher drug release rates. Upon scale-up to a vertical extruder, the crystallinity of the HCQS was significantly reduced, with less variation in both crystallinity and release profile across the different extrudates. This study demonstrates improved robustness with the pilot-scale vertical extruder compared to lab-scale horizontal extruder. The reduced variation with the vertical extruder will allow for short increases in production rate, with minimum impact on the CQAs of the final product enabling high-performance continuous manufacturing with minimum waste of raw materials. Finally, this research provides valuable information for the pharmaceutical industry in accessing continuous technologies for the manufacture of pharmaceutical products, allowing for efficient utilisation of resources upon scale-up and mass production during global pandemics and drug shortages.

Recent advances of oral film as platform for drug delivery

Orally drug delivery film has received extensive interest duo to a distinct set of its advantageous properties compared to the traditional orally administered dosages, including faster rate of drug absorption, higher bioavailability and better patient compliance for children and elders with swallowing deficiencies. In particular, its potential capacity of delivering proteins and peptides has further attracted great attention. Lately, tremendous advances have been made in designing and developing both novel mucoadhesive films and orodispersible films to fulfill specific accomplishments of drug delivery. This review aims to summarize those newly developed oral films, discussing their formulation strategies, manufacturing methods as well as advantages and limitations thereof. Conclusions and future perspectives are also provided in brief.

Development and optimization of hot-melt extruded moxifloxacin hydrochloride inserts, for ocular applications, using the design of experiments

The current study sought to formulate sustained-release hot-melt extruded (HME) ocular inserts of moxifloxacin hydrochloride (MOX; MOX-HME) for the treatment of bacterial keratitis. The concentration of Eudragit™ FS-100 (FS) and propylene glycol (PG) used as polymer and plasticizer, respectively, in the inserts were optimized using the central composite design (CCD) to achieve sustained release. The inserts were characterized for weight, thickness, surface characteristics, pH, and in vitro release profile. The crystalline characteristics of MOX and surface morphology of the inserts were evaluated using differential scanning calorimetry (DSC) and scanning electron microscopy (SEM). Furthermore, ex vivo permeation through rabbit cornea and stability of the optimized MOX-HME insert was investigated. The results demonstrate an inverse correlation between FS concentration and MOX release from the MOX-HME inserts, and a potential 24 h release. The optimized MOX-HME inserts were found to be stable at room temperature for four months, showing no significant change in drug content, pH and release profile. MOX converted into an amorphous form in the MOX-HME inserts and did not recrystallize during the study period. SEM analysis confirmed the smooth surface of the MOX-HME insert. The ex vivo studies revealed that the MOX-HME inserts provided a much prolonged transcorneal MOX flux as compared to the commercial ophthalmic solution and the immediate-release MOX-HME insert. The results indicate that MOX-HME inserts could potentially provide a once-a-day application, consequently reducing the dosing frequency and acting as an alternative delivery system in the management of bacterial infections.

Polyvinyl Alcohol-Based 3D Printed Tablets: Novel Insight into the Influence of Polymer Particle Size on Filament Preparation and Drug Release Performance

Three-dimensional printing (3DP) by fused deposition modeling (FDM) has gained momentum as a promising pharmaceutical manufacturing method due to encouraging forward-looking perspectives in personalized medicine preparation. The current challenges the technology has for applicability in the fabrication of solid dosage forms include the limited range of suitable pharmaceutical grade thermoplastic materials. Hence, it is important to investigate the implications of variable properties of the polymeric carrier on the preparation steps and the final output, as versatile products could be obtained by using the same material. In this study, we highlighted the influence of polyvinyl alcohol (PVA) particle size on the residence time of the mixtures in the extruder during the drug-loaded filament preparation step and the consequent impact on drug release from the 3D printed dosage form. We enhanced filament printability by exploiting the plasticizing potential of the active pharmaceutical ingredient (API) and we explored a channeled tablet model as a design strategy for dissolution facilitating purposes. Our findings disclosed a new perspective regarding material considerations for the preparation of PVA-based solid dosage forms by coupling hot melt extrusion (HME) and FDM-3DP.

Fused deposition modelling for the development of drug loaded cardiovascular prosthesis

Cardiovascular diseases constitute a number of conditions which are the leading cause of death globally. To combat these diseases and improve the quality and duration of life, several cardiac implants have been developed, including stents, vascular grafts and valvular prostheses. The implantation of these vascular prosthesis has associated risks such as infection or blood clot formation. In order to overcome these limitations medicated vascular prosthesis have been previously used. The present paper describes a 3D printing method to develop medicated vascular prosthesis using fused deposition modelling (FDM) technology. For this purpose, rifampicin (RIF) was selected as a model molecule as it can be used to prevent vascular graft prosthesis infection. Thermoplastic polyurethane (TPU) and RIF were combined using hot melt extrusion (HME) to obtain filaments containing RIF concentrations ranging between 0 and 1% (w/w). These materials are capable of providing RIF release for periods ranging between 30 and 80 days. Moreover, TPU-based materials containing RIF were capable of inhibiting the growth of Staphylococcus aureus. This behaviour was observed even for TPU-based materials containing RIF concentrations of 0.1% (w/w). TPU containing 1% (w/w) of RIF showed antimicrobial properties even after 30 days of RIF release. Alternatively, these methods were used to prepare dipyridamole containing TPU filaments. Finally, using a dual extrusion 3D printer vascular grafts containing both drugs were prepared.

Amorphous Solid Dispersions and the Contribution of Nanoparticles to In Vitro Dissolution and In Vivo Testing: Niclosamide as a Case Study

We developed an amorphous solid dispersion (ASD) of the poorly water-soluble molecule niclosamide that achieved a more than two-fold increase in bioavailability. Notably, this niclosamide ASD formulation increased the apparent drug solubility about 60-fold relative to the crystalline material due to the generation of nanoparticles. Niclosamide is a weakly acidic drug, Biopharmaceutics Classification System (BCS) class II, and a poor glass former with low bioavailability in vivo. Hot-melt extrusion is a high-throughput manufacturing method commonly used in the development of ASDs for increasing the apparent solubility and bioavailability of poorly water-soluble compounds. We utilized the polymer poly(1-vinylpyrrolidone-co-vinyl acetate) (PVP–VA) to manufacture niclosamide ASDs by extrusion. Samples were analyzed based on their microscopic and macroscopic behavior and their intermolecular interactions, using differential scanning calorimetry (DSC), X-ray diffraction (XRD), nuclear magnetic resonance (NMR), Fourier-transform infrared (FTIR), and dynamic light scattering (DLS). The niclosamide ASD generated nanoparticles with a mean particle size of about 100 nm in FaSSIF media. In a side-by-side diffusion test, these nanoparticles produced a four-fold increase in niclosamide diffusion. We successfully manufactured amorphous extrudates of the poor glass former niclosamide that showed remarkable in vitro dissolution and diffusion performance. These in vitro tests were translated to a rat model that also showed an increase in oral bioavailability.

Mechanistic study of preparation of drug/polymer/surfactant ternary hot extrudates to obtain small and stable drug nanocrystal suspensions

We studied optimized conditions for preparing ternary hot extrudates (HEs) of glibenclamide (GLB)/polyvinylpyrrolidone (PVP)/sodium dodecyl sulfate to generate stable nanocrystal suspensions following aqueous dispersion. Raman and solid-state NMR measurements of ternary HEs prepared by altering HE conditions revealed that GLB crystallinity in HEs reduced with increased extrusion temperature and count and decreased screw speed. Aqueous dispersions of all HEs temporarily formed GLB nanoparticles with a diameter of 75-420 nm. The suspension from the HEs with the low GLB crystallinity (<22%) precipitated after 4-h storage, while the HEs with the high GLB crystallinity (>22%) formed stable nanocrystal suspension. Interestingly, the number of GLB nanoparticles <150  nm was different despite aqueous dispersion of HEs with similar GLB crystallinity, reflecting the different GLB crystalline size in those HEs. Although both the crushing by shear force and GLB dissolution into PVP reduced GLB crystalline size, the crushing GLB crystal by the shear force has a relatively high ability to decrease GLB crystalline size without excess amorphization of GLB. Performing the hot extrusion at a low temperature, a high screw speed, and maximizing extrusion count with GLB crystallinity >22% led to formation of small and stable nanocrystal suspensions.

Development of Porous Polyurethane Implants Manufactured via Hot-Melt Extrusion

Implantable drug delivery systems (IDDSs) offer good patient compliance and allow the controlled delivery of drugs over prolonged times. However, their application is limited due to the scarce material selection and the limited technological possibilities to achieve extended drug release. Porous structures are an alternative strategy that can overcome these shortcomings. The present work focuses on the development of porous IDDS based on hydrophilic (HPL) and hydrophobic (HPB) polyurethanes and chemical pore formers (PFs) manufactured by hot-melt extrusion. Different PF types and concentrations were investigated to gain a sound understanding in terms of extrudate density, porosity, compressive behavior, pore morphology and liquid uptake. Based on the rheological analyses, a stable extrusion process guaranteed porosities of up to 40% using NaHCO3 as PF. The average pore diameter was between 140 and 600 µm and was indirectly proportional to the concentration of PF. The liquid uptake of HPB was determined by the open pores, while for HPL both open and closed pores influenced the uptake. In summary, through the rational selection of the polymer type, the PF type and concentration, porous carrier systems can be produced continuously via extrusion, whose properties can be adapted to the respective application site.