The comprehensive review on 3D printing- pharmaceutical drug delivery and personalized food and nutrition

Three-dimensional printing is one of the emerging technologies that is gaining interest from the pharmaceutical industry as it provides an opportunity to customize drugs according to each patient's needs. Combining different active pharmaceutical ingredients, using different geometries, and providing sustained release enhances the effectiveness of medicine. One of the most innovative uses of 3D printing is producing fabrics, medical devices, medical implants, orthoses, and prostheses. This review summarizes the various 3D printing techniques such as stereolithography, inkjet printing, thermal inkjet printing, fused deposition modelling, extrusion printing, semi-solid extrusion printing, selective laser sintering, and hot-melt extrusion. Also, discusses the drug relies profile and its mechanisms, characteristics, and applications of the most common types of 3D printed API formulations and its recent development. Here, Authors also, summarizes the central flow of 3D food printing process and knowledge extension toward personalized nutrition.

Development of 3D-printed dual-release fixed-dose combination through double-melt extrusion

This study aimed to develop a 3D-printed fixed-dose combination tablet featuring differential release of two drugs using double-melt extrusion (DME). The hot-melt extrusion (HME) process was divided into two steps to manufacture a single filament containing the two drugs. In Step I, a sustained-release matrix of acetaminophen (AAP) was obtained through HME at 190 °C using Eudragit® S100, a pH-dependent polymer with a high glass transition temperature. In Step II, a filament containing both sustained-release AAP from Step I and solubilized ibuprofen (IBF) was fabricated via HME at 110 °C using a mixture of hydroxy propyl cellulose (HPC-LF) and Eudragit® EPO, whose glass transition temperatures make them suitable for use in a 3D printer. A filament manufactured using DME was used to produce a cylindrical 3D-printed fixed-dose combination tablet with a diameter and height of 9 mm. To evaluate the release characteristics of the manufactured filament and 3D-printed tablet, dissolution tests were conducted for 10 h under simulated gastrointestinal tract conditions using the pH jump method with the United States Pharmacopeia apparatus II paddle method at 37 ± 0.5 °C and 50 rpm. Dissolution tests confirmed that both the sustained-release and solubilized forms of AAP and IBF within the filament and 3D-printed tablet exhibited distinct drug-release behaviors. The physicochemical properties of the filament and 3D-printed tablet were confirmed by thermogravimetric analysis, differential scanning calorimetry, powder X-ray diffraction, and Fourier-transform infrared spectroscopy. HME transforms crystalline drugs into amorphous forms, demonstrating their physicochemical stability. Scanning electron microscopy and confocal laser scanning microscopy indicated the presence of sustained AAP granules within the filament, confirming that the drugs were independently separated within the filament and 3D-printed tablets. Finally, sustained-release AAP and solubilized IBF were independently incorporated into the filaments using DME technology. Therefore, a dual-release 3D-printed fixed-dose combination was prepared using the proposed filament.

Preparation, Characterization and Evaluation of Nintedanib Amorphous Solid Dispersions with Enhanced Oral Bioavailability

The dissolution and bioavailability challenges posed by poorly water-soluble drugs continue to drive innovation in pharmaceutical formulation design. Nintedanib (NDNB) is a typical BCS class II drug that has been utilized to treat idiopathic pulmonary fibrosis (IPF). Due to the low solubility, its oral bioavailability is relatively low, limiting its therapeutical effectiveness. It is crucial to enhance the dissolution and the oral bioavailability of NDNB. In this study, we focused on the preparation of amorphous solid dispersions (ASD) using hot melt extrusion (HME). The formulation employed Kollidon® VA64 (VA64) as the polymer matrix, blended with the NDNB at a ratio of 9:1. HME was conducted at temperatures ranging from 80 °C to 220 °C. The successful preparation of ASD was confirmed through various tests including polarized light microscopy (PLM), X-ray powder diffraction (XRPD), differential scanning calorimetry (DSC), Fourier-transform infrared spectroscopy (FT-IR), and thermogravimetric analysis (TGA). The in-vitro cumulative release of NDNB-ASD in 2 h in a pH 6.8 medium was 8.3-fold higher than that of NDNB (p < 0.0001). In a pH 7.4 medium, it was 10 times higher (p < 0.0001). In the in-vivo pharmacokinetic experiments, the area under curve (AUC) of NDNB-ASD was 5.3-fold higher than that of NDNB and 2.2 times higher than that of commercially available soft capsules (Ofev®) (p < 0.0001). There was no recrystallization after 6 months under accelarated storage test. Our study indicated that NDNB-ASD can enhance the absorption of NDNB, thus providing a promising method to improve NDNB bioavailability in oral dosages.

Fabrication and evaluation of stable amorphous polymer-drug composite particles via a nozzle-free ultrasonic nebulizer

We present a promising method for producing amorphous drug particles using a nozzle-free ultrasonic nebulizer with polymers, specifically polyvinylpyrrolidone (PVP), poly(acrylic acid) (PAA), and Eudragit® S 100 (EUD). Model crystalline phase drugs-Empagliflozin, Furosemide, and Ilaprazole-are selected. This technique efficiently produces spherical polymer-drug composite particles and demonstrates enhanced stability against humidity and thermal conditions, compared to the drug-only amorphous particles. The composite particles exhibit improved water dissolution compared to the original crystalline drugs, indicating potential bioavailability enhancements. While there are challenges, including the need for continuous water supply for ultrasonic component cooling, dependency on the solubility of polymers and drugs in volatile organic solvents, and mildly elevated temperatures for solvent evaporation, our method offers significant advantages over traditional approaches. It provides a straightforward, flexible process adaptable to various drug-polymer combinations and consistently yields spherical amorphous solid dispersion (ASD) particles with a narrow size distribution. These attributes make our method a valuable advancement in pharmaceutical drug formulation and delivery.

Development of multiple structured extended release tablets via hot melt extrusion and dual-nozzle fused deposition modeling 3D printing

The study aims to fabricate extended release (ER) tablets using a dual-nozzle fused deposition modeling (FDM) three-dimensional (3D) printing technology based on hot melt extrusion (HME), using caffeine as the model compound. Three different ER tablets were developed, which obtained "delayed-release", "rapid-sustained release", and "release-lag-release" properties. Each type of tablet was printed with two different formulations. A novel printing method was employed in this study, which is to push the HME filament from behind with polylactic acid (PLA) to prevent sample damage by gears during the printing process. Powder X-ray diffractometry (PXRD) and differential scanning calorimetry (DSC) results showed that caffeine was predominately amorphous in the final tablets. The dissolution of 3D printed tablets was assessed using a USP-II dissolution apparatus. ER tablets containing PVA dissolved faster than those developed with Kollicoat IR. Overall, this study revealed that ER tablets were successfully manufactured through HME paired with dual-nozzle FDM 3D printing and demonstrated the power of 3D printing in developing multi-layer tablets with complex structures.

Fused Deposition Modelling 3D printing and solubility improvement of BCS II and IV active ingredients - A narrative review

In the field of pharmaceutical research and development, Fused Deposition Modelling (FDM) 3D printing (3DP) has aroused growing interest within the last ten years. The use of thermoplastic polymers, combined with the melting process of the raw materials, offers the possibility of manufacturing amorphous solid dispersions (ASDs). In the pharmaceutical industry, the formulation of an ASD is a widely used strategy to improve the solubility of poorly soluble drugs (classified by the Biopharmaceutical Classification System (BCS) as class II and IV). In this review, an analysis of studies that have developed a FDM printed form containing a BCS class II or IV active substance was performed. The focus has been placed on the evaluation of the solid state of the active molecules (crystalline or amorphous) and on the study of their dissolution profile. Thus, the aim of this work is to highlight the interest of FDM 3DP to induce the amorphisation phenomenon of Class II and IV active substances by forming an ASD, and as result improving their solubility.

Highly protein-loaded melt extrudates produced by small-scale ram and twin-screw extrusion - evaluation of extrusion process design on protein stability by experimental and numerical approaches

Understanding of generation, extent and location of thermomechanical stress in small-scale (< 3 g) ram and twin-screw melt-extrusion is crucial for mechanistic correlations to the stability of protein particles (lysozyme and BSA) in PEG-matrices. The aim of the study was to apply and correlate experimental and numerical approaches (1D and 3D) for the evaluation of extrusion process design on protein stability. The simulation of thermomechanical stress during extrusion raised the expectation of protein degradation and protein particle grinding during extrusion, especially when TSE was used. This was confirmed by experimental data on protein stability. Ram extrusion had the lowest impact on protein unfolding temperatures, whereas TSE showed significantly reduced unfolding temperatures, especially in combination with kneading elements containing screws. In TSE, the mechanical stress in the screws always exceeded the shear stress in the die, while mechanical stress within ram extrusion was generated in the die, only. As both extruder designs revealed homogeneously distributed protein particles over the cross section of the extrudates for all protein-loads (20-60%), the dispersive power of TSE revealed not to be decisive. Consequently, the ram extruder would be favored for the production of stable protein-loaded extrudates in small scale.

Strategies to improve the stability of amorphous solid dispersions in view of the hot melt extrusion (HME) method

Oral administration of drugs is preferred over other routes for several reasons: it is non-invasive, easy to administer, and easy to store. However, drug formulation for oral administration is often hindered by the drug's poor solubility, which limits its bioavailability and reduces its commercial value. As a solution, amorphous solid dispersion (ASD) was introduced as a drug formulation method that improves drug solubility by changing the molecular structure of the drugs from crystalline to amorphous. The hot melt extrusion (HME) method is emerging in the pharmaceutical industry as an alternative to manufacture ASD. However, despite solving solubility issues, ASD also exposes the drug to a high risk of crystallisation, either during processing or storage. Formulating a successful oral administration drug using ASD requires optimisation of the formulation, polymers, and HME manufacturing processes applied. This review presents some important considerations in ASD formulation, including strategies to improve the stability of the final product using HME to allow more new drugs to be formulated using this method.

Preformulation study for the selection of a suitable polymer for the development of ellagic acid-based solid dispersion using hot-melt extrusion

Ellagic acid is one of the most studied polyphenolic compounds due to its numerous promising therapeutic properties. However, this therapeutic potential remains difficult to exploit owing to its low solubility and low permeability, resulting in low oral bioavailability. In order to allow an effective therapeutic application of EA, it is therefore necessary to develop strategies that sufficiently enhance its solubility, dissolution rate and bioavailability. For this purpose, solid dispersions based on pre-selected polymers such as Eudragit® EPO, Soluplus® and Kollidon® VA 64, with 5% w/w ellagic acid loading were prepared by hot extrusion and characterized by X-ray diffraction, FTIR spectroscopy and in vitro dissolution tests in order to select the most suitable polymer for future investigations. The results showed that Eudragit® EPO was the most promising polymer for ellagic acid solid dispersions development because its extrudates allowed to obtain a solution supersaturated in ellagic acid that was stable for at least 90 min. Moreover, the resulting apparent solubility was 20 times higher than the actual solubility of ellagic acid. The extrudates also showed a high dissolution rate of ellagic acid (96.25% in 15 min), compared to the corresponding physical mixture (6.52% in 15 min) or the pure drug (1.56% in 15 min). Furthermore, increasing the loading rate of ellagic acid up to 12% in extrudates based on this polymer did not negatively influence its release profile through dissolution tests.

Development of multifunctional drug delivery system via hot-melt extrusion paired with fused deposition modeling 3D printing techniques

The model of core-shell structured tablets is gaining increased interest due to its advantages in controlled-release and combinational drug delivery. Through the encapsulation of the drug by the outer shell, this model exhibits huge potential for reduced administration frequency, improved taste-masking, and personalized medication strategy. Although different types of core-shell tablets have been recently developed, most of them focused on the embedding of the solid tablets. Therefore there is still a need to investigate an optimized model in which multiple dosage forms can be loaded. This work uses hot-melt extrusion and fused deposition modeling 3D printing (FDM 3DP) techniques to develop a multifunctional core-shell model for controlled drug delivery. Acetaminophen (APAP) was used as the model drug. Hydroxypropyl cellulose (HPC) and hydroxypropyl methylcellulose (HPMC) was used as the matrix materials. Polyethylene oxide (PEO) and Eudragit RS PO (E RSPO) were used to adjust the printability while the E RSPO was expected to act as an extended-release agent due to its hydrophobicity. Liquid, semi-solid and solid dosage forms could be successfully loaded into the produced shells. The formulations were characterized by scanning electron microscopy, three point-bend tests, differential scanning calorimetry, and dissolution studies. The dissolution results suggested the modified-release character of the designed model. Overall, the designed core-shell model could be successfully produced via hot-melt extrusion paired with FDM 3DP techniques and could be utilized for the delivery of distinct dosage forms which improve the on-demand formulation development for patient-centered medication.

Fused Deposition Modelling of Polymer Composite: A Progress

Additive manufacturing (AM) highlights developing complex and efficient parts for various uses. Fused deposition modelling (FDM) is the most frequent fabrication procedure used to make polymer products. Although it is widely used, due to its low characteristics, such as weak mechanical properties and poor surface, the types of polymer material that may be produced are limited, affecting the structural applications of FDM. Therefore, the FDM process utilises the polymer composition to produce a better physical product. The review's objective is to systematically document all critical information on FDMed-polymer composite processing, specifically for part fabrication. The review covers the published works on the FDMed-polymer composite from 2011 to 2021 based on our systematic literature review of more than 150 high-impact related research articles. The base and filler material used, and the process parameters including layer height, nozzle temperature, bed temperature, and screw type are also discussed in this review. FDM is utilised in various biomedical, automotive, and other manufacturing industries. This study is expected to be one of the essential pit-stops for future related works in the FDMed-polymeric composite study.

Polymeric Biomaterials for Topical Drug Delivery in the Oral Cavity: Advances on Devices and Manufacturing Technologies

There are several routes of drug administration, and each one has advantages and limitations. In the case of the topical application in the oral cavity, comprising the buccal, sublingual, palatal, and gingival regions, the advantage is that it is painless, non-invasive, allows easy application of the formulation, and it is capable of avoiding the need of drug swallowing by the patient, a matter of relevance for children and the elderly. Another advantage is the high permeability of the oral mucosa, which may deliver very high amounts of medication rapidly to the bloodstream without significant damage to the stomach. This route also allows the local treatment of lesions that affect the oral cavity, as an alternative to systemic approaches involving injection-based methods and oral medications that require drug swallowing. Thus, this drug delivery route has been arousing great interest in the pharmaceutical industry. This review aims to condense information on the types of biomaterials and polymers used for this functionality, as well as on production methods and market perspectives of this topical drug delivery route.

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.

Solid Lipid Nanoparticles Administering Antioxidant Grape Seed-Derived Polyphenol Compounds: A Potential Application in Aquaculture

The supply of nutrients, such as antioxidant agents, to fish cells still represents a challenge in aquaculture. In this context, we investigated solid lipid nanoparticles (SLN) composed of a combination of Gelucire^® 50/13 and Precirol^® ATO5 to administer a grape seed extract (GSE) mixture containing several antioxidant compounds. The combination of the two lipids for the SLN formation resulted in colloids exhibiting mean particle sizes in the range 139–283 nm and zeta potential values in the range +25.6–43.4 mV. Raman spectra and X-ray diffraction evidenced structural differences between the free GSE and GSE-loaded SLN, leading to the conclusion that GSE alters the structure of the lipid nanocarriers. From a biological viewpoint, cell lines from gilthead seabream and European sea bass were exposed to different concentrations of GSE-SLN for 24 h. In general, at appropriate concentrations, GSE-SLN increased the viability of the fish cells. Furthermore, regarding the gene expression in those cells, the expression of antioxidant genes was upregulated, whereas the expression of hsp70 and other genes related to the cytoskeleton was downregulated. Hence, an SLN formulation containing Gelucire^® 50/13/Precirol^® ATO5 and GSE may represent a compelling platform for improving the viability and antioxidant properties of fish cells.

High-Drug-Loading Amorphous Solid Dispersions via In Situ Thermal Cross-Linking: Unraveling the Mechanisms of Stabilization

This article takes a step forward in understanding the mechanisms involved during the preparation and performance of cross-linked high-drug-loading (HDL) amorphous solid dispersions (ASDs). Specifically, ASDs, having 90 wt % poorly water-soluble drug indomethacin (IND), were prepared via in situ thermal cross-linking of poly(acrylic acid) (PAA) and poly(vinyl alcohol) (PVA) and thoroughly evaluated in terms of physical stability and in vitro supersaturation. Results showed that HDL ASDs having excellent active pharmaceutical ingredient (API) amorphous stability and prolonged in vitro supersaturation were prepared by fine tuning the cross-linking procedure. Unraveling of the processes involved during ASD's formation shed light on the significant role of the cross-linking conditions (i.e., temperature and time), the physicochemical properties of the API, and the hydrolysis level of the cross-linker as key factors in modulating ASD's stability. In-depth analysis of the prepared systems revealed the (1) reduction of API's molecular motions within the cross-linked polymeric networks (through API's strong spatial confinement), (2) the structural changes in the prepared cross-linked matrices (induced by the high API drug loading), and (3) the tuning of the cross-linking density via utilization of low-hydrolyzed PVA as the major mechanisms responsible for ASD's exceptional performance. Complementary analysis by means of molecular dynamics simulations also highlighted the vital role of strong drug-polymer intermolecular interactions evolving among the ASD components. Overall, the impression of the complexity of in situ cross-linked ASDs has been reinforced with the excessive variation of parameters investigated in the current study, offering thus insights up to the submolecular level to lay the groundwork and foundations for the comprehensive assessment of a new emerging class of HDL amorphous API formulations.

Pharmaceutical amorphous solid dispersion: A review of manufacturing strategies

Amorphous solid dispersions (ASDs) are popular for enhancing the solubility and bioavailability of poorly water-soluble drugs. Various approaches have been employed to produce ASDs and novel techniques are emerging. This review provides an updated overview of manufacturing techniques for preparing ASDs. As physical stability is a critical quality attribute for ASD, the impact of formulation, equipment, and process variables, together with the downstream processing on physical stability of ASDs have been discussed. Selection strategies are proposed to identify suitable manufacturing methods, which may aid in the development of ASDs with satisfactory physical stability.

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.

Hot-Melt Extrusion: a Roadmap for Product Development

Hot-melt extrusion has found extensive application as a feasible pharmaceutical technological option over recent years. HME applications include solubility enhancement, taste masking, and sustained drug release. As bioavailability enhancement is a hot topic of today's science, one of the main applications of HME is centered on amorphous solid dispersions. This review describes the most significant aspects of HME technology and its use to prepare solid dispersions as a drug formulation strategy to enhance the solubility of poorly soluble drugs. It also addresses molecular and thermodynamic features critical for the physicochemical properties of these systems, mainly in what concerns miscibility and physical stability. Moreover, the importance of applying the Quality by Design philosophy in drug development is also discussed, as well as process analytical technologies in pharmaceutical HME monitoring, under the current standards of product development and regulatory guidance. Graphical Abstract.

3D printed spherical mini-tablets: Geometry versus composition effects in controlling dissolution from personalised solid dosage forms

Oral dosage forms are by far the most common prescription and over-the-counter pharmaceutical dosage forms used worldwide. However, many patients suffer from adverse effects caused by their use of "one-size fits all" mass produced commercially available solid dosage forms, whereby they do not receive dedicated medication or dosage adjusted to their specific needs. The development of 3D printing paves the way for personalised medicine. This work focuses on personalised therapies for hypertensive patients using nifedipine as the model drug. 3D printed full solid and channelled spherical mini-tablets with enhanced surface area (1.6-fold higher) were printed using modified PVA commercial filaments loaded by passive diffusion (PD), and Kollidon VA64 (KVA) and ethylcellulose (EC) based filaments prepared by hot-melt extrusion (HME). Drug loading ranged from 3.7% to 60% based on the employed technique, with a 13-fold higher drug loading achieved with the HME compared to PD. Composition was found to have a more significant impact on drug dissolution than geometry and surface area. Both KVA and EC-based formulations exhibited a biphasic zero-order drug-release profile. Physicochemical characterization revealed that nifedipine was in the amorphous form in the KVA-based end-products which led to a greater dissolution control over a 24 h period compared to the EC-based formulations that exhibited low levels of crystallinity by PXRD. The proposed 3D printed spherical mini-tablets provide a versatile technology for personalised solid dosage forms with high drug loading and dissolution control, easily adaptable to patient and disease needs.

Quaternary enteric solid dispersion prepared by hot-melt extrusion to mask the bitter taste and enhance drug stability

To mask the bitterness of drug is profoundly important especially in children's medication. This study designed and investigated a quaternary enteric solid dispersion (QESD) by secondary hot-melt-extrusion. Erythromycin (EM) was chosen as a model drug. The optimal QESD contained enteric polymer HPMCP-55, plasticizer and water-soluble polymer copovidone VA64. Raman and Atomic force microscope has exploited that majority EM was distributed in VA64 matrix, nanometer-sized EM-VA64 system was entrapped within enteric continuous phase to form a solid emulsion-like structure. For the prepared QESD, EM released concentration was far less than bitterness threshold (7 μg/mL to 20 μg/mL) in artificial saliva within the first 30 s. And dissolution rate was increased by 10% in article intestine fluid, which dominated by water-soluble VA64. Stress testing after two months at high-humidity (75% RH) and high-temperature (60 °C) revealed, compared with traditional enteric SDs, the chemical degradation of EM was slowed down in QESD. Furthermore, hydrogen and salt bonds were respectively formed between EM and VA64 and between leaking EM and HPMCP-55, which increasing the system stability and taste-masking. The effect of masking bitter taste can be satisfied as well as enhance drug dissolution rate in the intestine, and formulation physicochemical stability during storage.

Hot Melt Extrusion and its Application in 3D Printing of Pharmaceuticals

Hot Melt Extrusion (HME) is a continuous pharmaceutical manufacturing process that has been extensively investigated for solubility improvement and taste masking of active pharmaceutical ingredients. Recently, it is being explored for its application in 3D printing. 3D printing of pharmaceuticals allows flexibility of dosage form design, customization of dosage form for personalized therapy and the possibility of complex designs with the inclusion of multiple actives in a single unit dosage form. Fused Deposition Modeling (FDM) is a 3D printing technique with a variety of applications in pharmaceutical dosage form development. FDM process requires a polymer filament as the starting material that can be obtained by hot melt extrusion. Recent reports suggest enormous applications of a combination of hot melt extrusion and FDM technology in 3D printing of pharmaceuticals and need to be investigated further. This review in detail describes the HME process, along with its application in 3D printing. The review also summarizes the published reports on the application of HME coupled with 3D printing technology in drug delivery.

Innovations in Thermal Processing: Hot-Melt Extrusion and KinetiSol® Dispersing

Thermal processing has gained much interest in the pharmaceutical industry, particularly for the enhancement of solubility, bioavailability, and dissolution of active pharmaceutical ingredients (APIs) with poor aqueous solubility. Formulation scientists have developed various techniques which may include physical and chemical modifications to achieve solubility enhancement. One of the most commonly used methods for solubility enhancement is through the use of amorphous solid dispersions (ASDs). Examples of commercialized ASDs include Kaletra®, Kalydeco®, and Onmel®. Various technologies produce ASDs; some of the approaches, such as spray-drying, solvent evaporation, and lyophilization, involve the use of solvents, whereas thermal approaches often do not require solvents. Processes that do not require solvents are usually preferred, as some solvents may induce toxicity due to residual solvents and are often considered to be damaging to the environment. The purpose of this review is to provide an update on recent innovations reported for using hot-melt extrusion and KinetiSol® Dispersing technologies to formulate poorly water-soluble APIs in amorphous solid dispersions. We will address development challenges for poorly water-soluble APIs and how these two processes meet these challenges.

The optimization of process analytical technology for the inline quantification of multiple drugs in fixed dose combinations during continuous processing

Complications associated with uncontrolled hypertension are considered the major cause of premature death worldwide. Fixed-dose combinations (FDCs) offer an alternative approach to polypharmacy with the aim to improve patient compliance. Process Analytical Technology (PAT) is gaining momentum as a non-invasive, predictive tool to control the quality of drugs during continuous processing. PAT offers real-time quality control that can be built into the production line. However, the vast majority of studies reported in the literature have focused on quantifying a single drug during continuous processing. The aim of this study was to develop non-destructive, predictive inline PAT tools allowing for the simultaneous quantification of two antihypertensive drugs, Hydrochlorothiazide (HCTZ) and Ramipril (RMP), during the continuous manufacture of FDCs. A calibration set composed of HCTZ and RMP at concentration ranges of 6.5 to 40 and 2.5-15 (% w/w), respectively, were manufactured using hot melt extrusion. The extrudates were analysed during the process using inline Raman spectroscopy. Optimum wavenumber regions were observed at 200-400 and 630-730 cm^-1 for HCTZ, and 980-1100 cm^-1 for RMP using principal component analysis. Partial least squares (PLS) regression was performed to establish the predictive calibration models. The PLS developed models showed excellent linearity (R2 = 0.986 and 0.974), selectivity (PC1 = 98.6% and 91.9%) and accuracy (RMSEcv = 1.586 and 0.645%) for HCTZ and RMP, respectively. Additionally, RMSEP values were reported as 1.237 and 1.007% for HCTZ and RMP, respectively, depicting good predictability for drug content in the validation set. The output of this study demonstrated that utilisation of the full potential of chemometrics, Raman spectroscopy can be used for the simultaneous inline quantification of multiple drugs in complex formulations. This facilitates the in-process quality control of FDCs and other multicomponent systems during continuous pharmaceutical production.

Impact of Hot-Melt-Extrusion on Solid-State Properties of Pharmaceutical Polymers and Classification Using Hierarchical Cluster Analysis

The impact of hot-melt extrusion (HME) on the solid-state properties of four methacrylic (Eudragit® L100-55, Eudragit® EPO, Eudragit® RSPO, Eudragit® RLPO) and four polyvinyl (Kollidon® VA64, Kollicoat® IR, Kollidon® SR, and Soluplus®) polymers was studied. Overall, HME decreased Tg but increased electrostatic charge and surface free energy. Packing density decreased with electrostatic charge, whereas Carr’s and Hausner indices showed a peak curve dependency. Overall, HME reduced work of compaction (Wc), deformability (expressed as Heckel PY and Kawakita 1/b model parameters and as slope S′ of derivative force/displacement curve), and tablet strength (TS) but increased elastic recovery (ER). TS showed a better correlation with S′ than PY and 1/b. Principal component analysis (PCA) organized the data of neat and extruded polymers into three principal components explaining 72.45% of the variance. The first included Wc, S′ and TS with positive loadings expressing compaction, and ER with negative loading opposing compaction; the second included PY, 1/b, and surface free energy expressing interactivity with positive loadings opposing tap density or close packing. Hierarchical cluster analysis (HCA) assembled polymers of similar solid-state properties regardless of HME treatment into a major cluster with rescaled distance Cluster Combine Index (CCI) < 5 and several other weaker clusters. Polymers in the major cluster were: neat and extruded Eudragit® RSPO, Kollicoat® IR, Kollidon® SR, Soluplus®, and extruded Eudragit® L100-55. It is suggested that PCA may be used to distinguish variables having similar or dissimilar activity, whereas HCA can be used to cluster polymers based on solid-state properties and pick exchangeable ones (e.g., for sustain release or dissolution improvement) when the need arises.

Design of pressure-sensitive adhesive suitable for the preparation of transdermal patches by hot-melt printing

This work aimed to design low-melting pressure sensitive adhesives and to demonstrate the feasibility of the preparation of (trans)dermal patches by hot-melt ram extrusion printing. This approach allows defining both the geometry of (trans)dermal patch and the drug strength easily according to patient needs. The preparation steps are the mixing of a poly-ammonium methacrylate polymer (i.e. Eudragit RL and RS) with a suitable amount of plasticizer (triacetin or tributyl citrate) and drug (ketoprofen or nicotine), the melting in the ram extruder, and the printing on the backing layer foil. The formulations were characterized in terms of rheological and adhesive properties, in vitro drug release and skin permeation profiles. The (trans)dermal patches made of Eudragit RL or Eudragit RS plasticized with the 40% triacetin could be printed at 90 °C giving formulations with suitable adhesive properties and without cold flow after 1 month of storage at 40 °C. Furthermore, the overall results showed that the performances of printed (trans)dermal patches overlapped those made by solvent casting, suggesting that the proposed solvent-free technology can be useful to treat cutaneous pathologies when the availability of (trans)dermal patches with size and shape that perfectly fit with the skin area affected by the disease improves the safety of the pharmacological treatment.

Nicotinamide extrudates as novel anti-aging and collagen promoting platform: a comparative cosmeceutical study versus the gel form

The objective of the study was to explore the potential of a novel nicotinamide extrudate as an anti-aging platform compared to the conventional gel. Nicotinamide extrudates were prepared by hot melt extrusion and characterized pharmaceutically for their thermal behavior, mositure uptake, skin adhesion, and deposition in different skin layers. The pharmacological potential of the extrudates was explored in terms of induction of skin amino acids, cellular energy estimation, 8-hydroxy-2-deoxyguanosine content, Nitrate + nitrite content and histological chacaterization of collagen area percent. Results revealed that the extrusion technique managed to amorphize nicotinamide and enhance its skin deposition (46%) compared to the gel form which only showed about 10% deposition, owing to the mucoadhesive nature of the former. Extrudates were also found superior to the gel form as demonstrated by the increased amino acids level (glycine, proline, hydroxyproline), increased cellular energy, decreased oxidative stress and increased collagen formation. Nictotinamide extrudates were proven to be a scalable promising anti-aging platform which are worthy of entering the cosmeceutical market as products.

Characterization of Orodispersible Films: An Overview of Methods and Introduction to a New Disintegration Test Apparatus Using LDR - LED Sensors

Orodispersible Film (ODF) is a promising and progressive dosage form that offers exceptional drug delivery benefits to patients. Indeed, they are the most transformational alternatives to traditional/conventional dosage forms such as tablets and capsules. ODFs are portable and highly comfortable for self-administration by patients with swallowing problems. The key to gain end-user acceptance is to have an ODF with outstanding quality. Poor quality may lead to choking or spitting, accordingly leading to a lack of compliance. It is vital to employ suitable experimental methodologies that facilitate characterization or determination of the quality of ODF. Nonetheless, there are no standard techniques prescribed in official compendia of any country. But, there is a consensus in the thin-film research community about the characterization techniques that one relies on deciding the quality of an ODF. We review various experimental techniques and highlight its importance in determining the performance and quality of an ODF. We provide a relatively novel and inventive disintegration test apparatus, which works using 'Light Dependent Resistor (LDR) and Light Emitting Diode (LED) sensors' for clear and accurate determination of start and end disintegration time of an ODF.

Quality by design thinking in the development of long-acting injectable PLGA/PLA-based microspheres for peptide and protein drug delivery

Adopting the Quality by Design (QbD) approach in the drug development process has transformed from "nice-to-do" into a crucial and required part of the development, ensuring the quality of pharmaceutical products throughout their whole life cycles. This review is discussing the implementation of the QbD thinking into the production of long-acting injectable (LAI) PLGA/PLA-based microspheres for the therapeutic peptide and protein drug delivery. Various key elements of the QbD approaches are initially elaborated using Bydureon®, a commercial product of LAI PLGA/PLA-based microspheres, as a classical example. Subsequently, the factors influencing the release patterns and the stability of the peptide and protein drugs are discussed. This is followed by a summary of the state-of-the-art of manufacturing LAI PLGA/PLA-based microspheres and the related critical process parameters (CPPs). Finally, a landscape of generic product development of LAI PLGA/PLA-based microspheres is reviewed including some major challenges in the field.

Five-Stage Approach for a Systematic Screening and Development of Etravirine Amorphous Solid Dispersions by Hot-Melt Extrusion

The aim of this study was to develop a fast, effective, and material sparing screening method to design amorphous solid dispersions (ASDs) of etravirine to drive more effectively the development process, leading to improved bioavailability (BA) and stability. A systematic step-by-step approach was followed by combining theoretical calculations with high-throughput screening (HTS) and software-assisted multivariate statistical analysis. The thermodynamic miscibility and interaction of the drug in several polymers were predicted using Hansen solubility parameters (δ). The selected polymers were evaluated by HTS, using solvent evaporation. Binary compositions were evaluated by their solubilization capacity and physical stability over 2 months. JMP 14.0 was used for multivariate statistical analysis using principal components analysis. Extrusion was performed in Thermo Scientific HAAKE MiniLab II, and extrudates were characterized by assay, related substances, dissolution, and physical state (polarized light microscopy (PLM), Raman spectroscopy, and X-ray powder diffraction (XRPD)). A short stability study was performed where milled extrudates were exposed to 25 °C/60%RH and 40 °C/75%RH for 3 months. Through thermodynamic predictions, five main polymers were selected. The HTS enabled the evaluation of 42 formulations for solubilization capacity and physical stability. The three most promising compositions were selected for hot-melt extrusion (HME) tests. In general, a good correlation was found among the results of theoretical predictions, HTS, and HME. Poly(vinylpyrrolidone) (PVP)-based formulations were shown to be easily extrudable, with low degradation and complete amorphicity, whereas in Soluplus, the drug was not miscible, leading to a high crystalline content. The drug release rate was improved more than two times with PVP, and the manufactured ASD was demonstrated to be stable physically and chemically. A fast and effective screening technique to develop stable ASDs for a poorly soluble drug was successfully developed as applied to etravirine. The given method is easy to use, requires a low amount of drug, and is fairly accurate in predicting the amorphization of the drug when formulated. The success of HME formulation development of etravirine was undoubtedly enhanced with this high-throughput tool, which led to the identification of extrudates with improved biopharmaceutical properties. The structural characterization performed by PLM, XRPD, and Raman spectroscopy demonstrated that the HME prototype was essentially amorphous. The unexpected stability at 40 °C/75%RH was correlated with the presence of molecular interaction characterized by Raman spectroscopy.

Stable amorphous solid dispersions of fenofibrate using hot melt extrusion technology: Effect of formulation and process parameters for a low glass transition temperature drug

Development of stable amorphous solid dispersions (ASDs) for a low glass transition temperature (Tg) drug is a challenging task. The physico-chemical properties of the drug and excipients play a critical role in developing stable ASDs. In this study, ASDs of poorly soluble fenofibrate, a drug with a low Tg, were formulated using hydroxy propyl methylcellulose acetate succinate (HPMCAS) via hot melt extrusion (HME). The feasible processing conditions were established at varying drug loads and processing temperatures. The prepared ASDs were characterized for crystallinity using differential scanning calorimetry (DSC) and powder X-ray diffraction (PXRD). Fourier transform-infrared spectroscopy was performed to study the potential interactions. DSC and PXRD studies confirmed the amorphous state of fenofibrate in the prepared ASDs. A discriminative in vitro dissolution method was established to study the impact of HPMCAS grades on dissolution profile. The dissolution parameters such as dissolution efficiency, initial dissolution rate and mean dissolution rate, suggested improved dissolution characteristics compared to pure fenofibrate. Accelerated stability studies at 40 °C/75% RH showed preservation of the amorphous nature of fenofibrate in formulations with 15% drug load and in vitro drug release studies indicated similar release profiles (f2 >50). This study provides an insight into the formulation and processing of ASDs for poorly soluble drugs with low Tg.

Scale-Up of pharmaceutical Hot-Melt-Extrusion: Process optimization and transfer

Hot-Melt-Extrusion on Twin-Screw-Extruders has been established as a standard processing technique for pharmaceutical products. A major challenge is the transfer from a lab to a production level, since the combination of several unit operations within one apparatus leads to complex conditions for such a continuous manufacturing process. Here the residence time distribution is a crucial measure, which reflects the different mechanisms, e.g. dissolution, mixing or degradation, during processing. In the first part of a Scale-Up study, a methodology for the optimization of an extrusion process with respect to the load and throughput is presented. The developed concept was applied for different extruder scales in order to compare the identified processing windows. A deviation of the dominant material heating mechanisms was observed for the different scales, while the constraints for the transfer of a process to a different scale by the developed optimization concept is demonstrated. Finally, a sufficient operating point on a reference extruder is identified and in the second part of this study, different concepts from literature are applied for the transfer of this Hot-Melt-Extrusion process to two larger scales. The focus of the investigations was on the impact of the different approaches on the residence time distribution and the comparison. The determined results revealed a change of the most sufficient approach for the two different extruder sizes. The impact on the location in the time domain and form of the distribution are discussed and additionally evaluated by the fit to a RTD-model. In conclusion, the ratio of the applied energy for transport to mixing is identified as valuable addition in this context.

A Comparative Solubility Enhancement Study of Cefixime Trihydrate Using Different Dispersion Techniques

This study aimed to investigate the effect of different polymers (polyethylene glycol 4000 and 6000 and Soluplus®) on the enhancement of solubility, dissolution, and stability of cefixime trihydrate as a selected class II model drug. Different solid dispersions have been prepared using conventional methods and supercritical fluid technology. The effect of co-solvent incorporation in supercritical fluid technology was also studied. Physicochemical properties for solid dispersions were investigated using Fourier transform infrared analysis, differential scanning calorimetry, thermogravimetric analysis, powder X-ray diffraction, and scanning electron microscopy. The solubility of the prepared solid dispersions increased except for those prepared with Soluplus® using supercritical fluid technology without co-solvent. The best enhancement in the release profile was recorded by Soluplus®-based solid dispersions prepared using a conventional method. The conventional methods of preparation and the presence of co-solvent in supercritical fluid technology converted cefixime into its amorphous form.

Approaches to increase mechanistic understanding and aid in the selection of precipitation inhibitors for supersaturating formulations – a PEARRL review

Objectives

Supersaturating formulations hold great promise for delivery of poorly soluble active pharmaceutical ingredients (APIs). To profit from supersaturating formulations, precipitation is hindered with precipitation inhibitors (PIs), maintaining drug concentrations for as long as possible. This review provides a brief overview of supersaturation and precipitation, focusing on precipitation inhibition. Trial-and-error PI selection will be examined alongside established PI screening techniques. Primarily, however, this review will focus on recent advances that utilise advanced analytical techniques to increase mechanistic understanding of PI action and systematic PI selection.

Key findings

Advances in mechanistic understanding have been made possible by the use of analytical tools such as spectroscopy, microscopy and mathematical and molecular modelling, which have been reviewed herein. Using these techniques, PI selection can be guided by molecular rationale. However, more work is required to see widespread application of such an approach for PI selection.

Summary

Precipitation inhibitors are becoming increasingly important in enabling formulations. Trial-and-error approaches have seen success thus far. However, it is essential to learn more about the mode of action of PIs if the most optimal formulations are to be realised. Robust analytical tools, and the knowledge of where and how they can be applied, will be essential in this endeavour.

Natural Korean Medicine Dang-Gui: Biosynthesis, Effective Extraction and Formulations of Major Active Pyranocoumarins, Their Molecular Action Mechanism in Cancer, and Other Biological Activities

Angelica gigas Nakai (AGN) is a crucial oriental medicinal herb that grows especially in Korea and the Far-East countries. It contains chemically active compounds like pyranocoumarins, polyacetylenes and essential oils, which might be useful for treatment of several chronic diseases. It has been used for centuries as a traditional medicine in Southeast Asia, but in Western countries is used as a functional food and a major ingredient of several herbal products. The genus Angelica is also known as ‘female ginseng’ due to its critical therapeutic role in female afflictions, such as gynecological problems. However, it is well-documented that the AGN pyranocoumarins may play vital beneficial roles against cancer, neurodisorders, inflammation, osteoporosis, amnesia, allergies, depression, fungi, diabetes, ischemia, dermatitis, reactive oxygen species (ROS) and androgen. Though numerous studies revealed the role of AGN pyranocoumarins as therapeutic agents, none of the reviews have published their molecular mechanism of action. To the best of our knowledge, this would be the first review that aims to appraise the biosynthesis of AGN’s major active pyranocoumarins, discuss effective extraction and formulation methods, and detail the molecular action mechanism of decursin (D), decursinol angelate (DA) and decursinol (DOH) in chronic diseases, which would further help extension of research in this area.

Melt extrusion with poorly soluble drugs - An integrated review

Over the last few decades, hot melt extrusion (HME) has emerged as a successful technology for a broad spectrum of applications in the pharmaceutical industry. As indicated by multiple publications and patents, HME is mainly used for the enhancement of solubility and bioavailability of poorly soluble drugs. This review is focused on the recent reports on the solubility enhancement via HME and provides an update for the manufacturing/scaling up aspects of melt extrusion. In addition, drug characterization methods and dissolution studies are discussed. The application of process analytical technology (PAT) tools and use of HME as a continuous manufacturing process may shorten the drug development process; as a result, the latter is becoming the most widely utilized technique in the pharmaceutical industry. The advantages, disadvantages, and practical applications of various PAT tools such as near and mid-infrared, ultraviolet/visible, fluorescence, and Raman spectroscopies are summarized, and the characteristics of other techniques are briefly discussed. Overall, this review also provides an outline for the currently marketed products and analyzes the strengths, weaknesses, opportunities and threats of HME application in the pharmaceutical industry.

Diblock Terpolymers Are Tunable and pH Responsive Vehicles To Increase Hydrophobic Drug Solubility for Oral Administration

Synthetic polymers offer tunable platforms to create new oral drug delivery vehicles (excipients) to increase solubility, supersaturation maintenance, and bioavailability of poorly aqueous soluble pharmaceutical candidates. Five well-defined diblock terpolymers were synthesized via reversible addition-fragmentation chain transfer polymerization (RAFT) and consist of a first block of either poly(ethylene-alt-propylene) (PEP), poly(N-isopropylacrylamide) (PNIPAm), or poly(N,N-diethylaminoethyl methacrylate) (PDEAEMA) and a second hydrophilic block consisting of a gradient copolymer of N,N-dimethylacrylamide (DMA) and 2-methacrylamidotrehalose (MAT). This family of diblock terpolymers offers hydrophobic, hydrophilic, or H-bonding functionalities to serve as noncovalent sites of drug binding. Drug-polymer spray dried dispersions (SDDs) were created with a model drug, probucol, and characterized by differential scanning calorimetry (DSC). These studies revealed that probucol crystallinity decreased with increasing H-bonding sites available in the polymer. The PNIPAm-b-P(DMA-grad-MAT) systems revealed the best performance at pH 6.5, where immediate probucol release and effective maintenance of 100% supersaturation was found, which is important for facilitating drug solubility in more neutral conditions (intestinal environment). However, the PDEAEMA-b-P(DMA-grad-MAT) system revealed poor probucol dissolution at pH 6.5 and 5.1. Alternatively, at an acidic pH of 3.1, a rapid and high dissolution profile and effective supersaturation maintenance of up to 90% of the drug was found, which could be useful for triggering drug release in acidic environments (stomach). The PEP-b-P(DMA-grad-MAT) system showed poor performance (only ∼20% of drug solubility at pH 6.5), which was attributed to the low solubility of the polymers in the dissolution media. This work demonstrates the utility of diblock terpolymers as a potential new excipient platform to optimize design parameters for triggered release and solubilizing hydrophobic drug candidates for oral delivery.

Milling solid proteins to enhance activity after melt-encapsulation

Polymeric systems for the immobilization and delivery of proteins have been extensively used for therapeutic and catalytic applications. While most devices have been created via solution based methods, hot melt extrusion (HME) has emerged as an alternative due to the high encapsulation efficiencies and solvent-free nature of the process. HME requires high temperatures and mechanical stresses that can result in protein aggregation and denaturation, but additives and chemical modifications have been explored to mitigate these effects. This study explores the use of solid-state ball milling to decrease protein particle size before encapsulation within poly(lactic-co-glycolic acid) (PLGA) via HME. The impact of milling on particle dispersion, retained enzymatic activity, secondary structure stability, and release was explored for lysozyme, glucose oxidase, and the virus-like particle derived from Qβ to fully understand the impact of milling on protein systems with different sizes and complexities. The results of this study describe the utility of milling to further increase the stability of protein/polymer systems prepared via HME.

Bioactive Potential of 3D-Printed Oleo-Gum-Resin Disks: B. papyrifera, C. myrrha, and S. benzoin Loading Nanooxides-TiO2, P25, Cu2O, and MoO3

This experimental study investigates the bioactive potential of filaments produced via hot melt extrusion (HME) and intended for fused deposition modeling (FDM) 3D printing purposes. The oleo-gum-resins from benzoin, myrrha, and olibanum in pure state and also charged with 10% of metal oxide nanoparticles, TiO₂, P25, Cu₂O, and MoO₃, were characterized by ultraviolet-visible (UV-Vis) and Fourier transform infrared (FTIR) spectroscopy, energy-dispersive X-ray microanalysis (EDXMA), scanning electron microscopy (SEM), and differential scanning calorimetry (DSC). Disks were 3D-printed into model geometries (10 × 5 mm) and the disk-diffusion methodology was used for the evaluation of antimicrobial and antifungal activity of materials in study against the clinical isolates: Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, and Candida albicans. Due to their intrinsic properties, disks containing resins in pure state mostly prevent surface-associated growth; meanwhile, disks loaded with 10% oxides prevent planktonic growth of microorganisms in the susceptibility assay. The microscopy analysis showed that part of nanoparticles was encapsulated by the biopolymeric matrix of resins, in most cases remaining disorderly dispersed over the surface of resins. Thermal analysis shows that plant resins have peculiar characteristics, with a thermal behavior similar to commercial available semicrystalline polymers, although their structure consists of a mix of organic compounds.

Solid state characterisation and taste masking efficiency evaluation of polymer based extrudates of isoniazid for paediatric administration

Hot melt extrusion has gained considerable attention as a novel technique for taste masking of bitter APIs. The aim of this study was to investigate whether hot melt extrusion could be used to develop taste masked formulations of isoniazid and also to evaluate and correlate different taste assessment methods Two polymers with different physico-chemical properties, Soluplus and Eudragit E-PO were chosen as carriers for the drug. Eudragit E-PO has already been widely used for taste masking due to its selective release properties, while Soluplus has not been studied in this regard but provides a useful comparator of a polymer that should release the drug reasonably efficiently. Polymeric formulations of isoniazid were produced with drug loadings of 20% and 30% w/w. The solid state characteristics of the formulations were assessed by differential scanning calorimetry and powder X-ray diffraction. The taste of isoniazid was assessed using the rodent Brief Access Taste Aversion (BATA) model, while formulations were assessed using the electronic tongue and dissolution under simulated oral conditions. Investigation into the drug loading effect with these two polymers showed that all Soluplus based extrudates with drug loading up to 30% w/w were fully amorphous while Eudragit E-PO based extrudates contained crystalline drug as demonstrated by both DSC and PXRD, dependent on loading. BATA testing of isoniazid gave an IC₅₀ value, i.e. the dose of drug which inhibits 50% of licks, of 11.1mg/mL. Taste assessment of the formulations using both simulated oral drug release and the electronic tongue demonstrated that Eudragit E-PO based formulations had a better taste masking efficiency than Soluplus. This is due to the fact that significantly less isoniazid is released from the Eudragit E-PO based formulations under oral conditions.

Antitumor and Immunomodulatory Effect of Gastrodia elata on Colon Cancer In Vitro and In Vivo

Gastrodia elata Blume (GE) is a well-known kind of herb that has been used in traditional medicine for thousands of years. The extrusion of raw materials from it could improve flavor and enhance bioavailability in food and drug development. The purpose of this study is to investigate antitumor and immune boosting effects of extruded GE in human colon carcinoma cells, splenocytes, and mice-bearing CT26 colon carcinoma cell. Treatment with 100[Formula: see text][Formula: see text]g/mL of extruded GE decreased cell viability and induced the expression of Caspase-3 and Bax in HT29 cells ([Formula: see text]). When we performed DAPI staining, apoptotic bodies with condensed chromatin and fragmented nuclei, known as indicative of apoptotic morphology, increased 24[Formula: see text]h after treatment with 100[Formula: see text][Formula: see text]g/mL of extruded GE. Treatments with extruded GE significantly promoted splenocyte proliferation and IL-2 or IFN-[Formula: see text] secretion, compared with that of control cells ([Formula: see text]). The administration of extruded GE of 200 mg/kg/day decreased tumor growth and Ki-67 or [Formula: see text]-catenin expression in mice ([Formula: see text]). Additionally, we investigated the contents of compounds in extruded GE extracts using ultra performance liquid chromatography. The contents of p-hydroxylbenzyl alcohol and p-hydroxybenzaldehyde in extruded GE were 2.97[Formula: see text]mg/g and 0.04[Formula: see text]mg/g, respectively. It was supposed that antitumor and immunomodulatory effects of extruded GE might exert by the p-hydroxylbenzyl alcohol and p-hydroxybenzaldehyde of many compositions analyzed from extruded GE. These results suggest that extruded GE have the potential to be developed into a natural pharmaceutical and functional food as a cancer chemopreventive agent.

Engineering hot-melt extruded solid dispersion for controlled release of hydrophilic drugs

It is often challenging to precisely manipulate the release behavior of hydrophilic drugs that is believed to be crucial for a satisfactory therapeutic outcome. The aim of this work was to regulate the dissolution of hydrophilic drug from hot-melt extruded solid dispersion via rational screening of the pore-forming agents. Venlafaxine hydrochloride and Compritol® 888 ATO was selected as the model drug and carrier excipient, respectively. Hydrophilic polyethylene glycol (PEG 6000) and polyvinylpyrolidone (PVP K30) were chosen as the transient pore-forming agents. The X-ray diffraction and thermal analysis showed that both drug and carrier existed in the crystalline form. Both types of polymers could generate pores upon dissolution test and the drug release rate was proportionally correlated to the pore-forming agent content. The mathematical modelling showed that the Ritger-Peppas model gave the best fit to the release curves, which demonstrates a diffusion-dominant release mechanism. The scanning electron microscopy and mercury intrusion porosimetry analysis proved that PVP K30 could generate large pores with low porosity, but PEG 6000 produced smaller pores with relatively high porosity. The in vivo pharmacokinetics study in rat revealed that solid dispersions containing either PEG 6000 or PVP K30 (both at 2.5%, w/w) exhibited an elevated bioavailability compared to the commercial product, Effexor® XR. The current work implied that rational screening of transient pore-forming polymer in solid dispersion could be a robust approach for controlling hydrophilic drug release.

Hot Melt Extrusion for Sustained Protein Release: Matrix Erosion and In Vitro Release of PLGA-Based Implants

The design of biodegradable implants for sustained release of proteins is a complex challenge optimizing protein polymer interaction in combination with a mini-scale process which is predictive for production. The process of hot melt extrusion (HME) was therefore conducted on 5- and 9-mm mini-scale twin screw extruders. Poly(lactic-co-glycolic acid) (PLGA) implants were characterized for their erosion properties and the in vitro release of the embedded protein (bovine serum albumin, BSA). The release of acidic monomers as well as other parameters (pH value, mass loss) during 16 weeks indicated a delayed onset of matrix erosion in week 3. BSA-loaded implants released 17.0% glycolic and 5.9% lactic acid after a 2-week lag time. Following a low burst release (3.7% BSA), sustained protein release started in week 4. Storage under stress conditions (30°C, 75% rH) revealed a shift of erosion onset of 1 week (BSA-loaded implants: 26.9% glycolic and 9.3% lactic acid). Coherent with the changed erosion profiles, an influence on the protein release was observed. Confocal laser scanning and Raman microscopy showed a homogenous protein distribution throughout the matrix after extrusion and during release studies. Raman spectra indicated a conformational change of the protein structure which could be one reason for incomplete protein release. The study underlined the suitability of the HME process to obtain a solid dispersion of protein inside a polymeric matrix providing sustained protein release. However, the incomplete protein release and the impact by storage conditions require thorough characterization and understanding of erosion and release mechanisms.