Interparticle van der Waals force in powder flowability and compactibility

Assessment of microwave drying for rapid and convenient analysis of medicinal plants for quality assurance

INTRODUCTION

The safety and quality of many medicinally important herbs are compromised since farmers and small organizations are involved in the cultivation, aggregation, and primary processing of these herbs. Such organizations often lack adequate quality control facilities. To improve the safety and quality of herbal products, simple, rapid, and affordable quality control systems are required.

OBJECTIVES

The aim of this study was to assess the suitability of microwave oven-drying for moisture content (MC) determination and sample preparation of herbs in small organizations.

METHODS

Microwave oven-drying (720 W) and convective oven-drying at 105°C for MC determination were compared. The effects of three different drying methods (microwave oven-drying, low-temperature convective drying, and freeze-drying) on in vitro antioxidant and polyphenol oxidase (PPO) activity were determined, similarity analysis was conducted using HPLC signature spectra, and validation was performed with LC-MS focusing on one herb.

RESULTS

Microwave oven-drying at 720 W significantly reduced the drying time (from hours to minutes), whereas the spatial variation of temperature in convective ovens set at 105°C can cause about 10% underestimation of MC. Microwave oven-drying showed similar macro-properties like freeze-drying and higher extractability (10%-20%) and in vitro antioxidant capacity (33%-66%) and lower PPO activity compared to low-temperature convective drying. HPLC signature spectra revealed strong similarity of soluble components between freeze-dried and microwave oven-dried herbs. LC-MS analysis demonstrated more common compounds between freeze-dried and microwave oven-dried Centella asiatica extracts, whereas convective tray-dried samples had fewer compounds common with samples obtained by freeze-drying or microwave oven-drying.

CONCLUSIONS

Microwave oven-drying is rapid (tens of min) and shows small batch-to-batch variation compared to oven-drying at 105°C. The in vitro antioxidant assays and signature spectra can be used for assessing the source and purity or quality of a specific herb variety.

Enhancing Quality Control: Image-Based Quantification of Carbides and Defect Remediation in Binder Jetting Additive Manufacturing

While binder jetting (BJ) additive manufacturing (AM) holds considerable promise for industrial applications, defects often compromise part quality. This study addresses these challenges by investigating binding mechanisms and analyzing common defects, proposing tailored solutions to mitigate them. Emphasizing defect identification for effective quality control in BJ-AM, this research offers strategies for in-process rectification and post-process evaluation to elevate part quality. It shows how to successfully process metallic parts with complex geometries while maintaining consistent material properties. Furthermore, the paper explores the microstructure of AISI M2 tool steel, utilizing advanced image processing techniques like digital image analysis and SEM images to evaluate carbide distribution. The results show that M2 tool steel has a high proportion of M6C carbides, with furnace-cooled samples ranging from ~2.4% to 7.1% and MC carbides from ~0.4% to 9.4%. M6C carbides ranged from ~2.6% to 3.8% in air-cooled samples, while water-cooled samples peaked at ~8.52%. Sintering conditions also affected shrinkage, with furnace-cooled samples showing the lowest rates (1.7 ± 0.4% to 5 ± 0.4%) and water-cooled samples showing the highest (2 ± 0.4% to 14.1 ± 0.4%). The study recommends real-time defect detection systems with autonomous corrective capabilities to improve the quality and performance of BJ-AM components.

Inflammatory-Targeted Lipid Carrier as a New Nanomaterial to Formulate an Inhaled Drug Delivery System

There is a pressing need for efficacious therapies in the field of respiratory diseases and infections. Lipid nanocarriers, administered through aerosols, represent a promising tool for maximizing therapeutic concentration in targeted cells and minimizing systemic exposure. However, this approach requires the application of efficient and safe nanomaterials. Palmitoylethanolamide (PEA), an endocannabinoid-like endogenous lipid, plays a crucial role in providing protective mechanisms during inflammation, making it an interesting material for preparing inhalable lipid nanoparticles (LNPs). This report aims to preliminarily explore the in vitro behavior of LNPs prepared with PEA (PEA-LNPs), a new inhalable inflammatory-targeted nanoparticulate drug carrier. PEA-LNPs exhibited a size of about 250 nm, a rounded shape, and an marked improvement in PEA solubility in comparison to naked PEA, indicative of easily disassembled nanoparticles. A twin glass impinger instrument was used to screen the aerosol performance of PEA-LNP powders, obtained via freeze-drying in the presence of two quantities of mannose as a cryoprotectant. Results indicated that a higher amount of mannose improved the emitted dose (ED), and in particular, the fine particle fraction (FPF). A cytotoxicity assay was performed and indicated that PEA-LNPs are not toxic towards the MH-S alveolar macrophage cell line up to concentrations of 0.64 mg/mL, and using coumarin-6 labelled particles, a rapid internalization into the macrophage was confirmed. This study demonstrates that PEA could represent a suitable material for preparing inhalable lipid nanocarrier-based dry powders, which signify a promising tool for the transport of drugs employed to treat respiratory diseases and infections.

Investigations on Compaction Behavior of Kollidon®SR-Based Multi-component Directly Compressed Tablets for Preparation of Controlled Release Diclofenac Sodium

The physics of tablets mixtures has gained much attention lately. The purpose of this work is to evaluate the compaction properties of Kollidon® SR (KSR) in the presence of different excipients such as Microcrystalline cellulose (MCC), Monohydrous lactose (MH Lactose), Poly (vinyl acetate) (PVA100), and a water-soluble drug Diclofenac sodium (DNa) to prepare once daily formulation. Tablets were prepared using direct compression and were compressed into flat-faced tablets using hydraulic press at various pressures. The combination of MCC and KSR in the tablets showed reduced porosity, and almost constant low Py values as KSR levels increased; also, KSR-DNa tablets had higher percentage porosity and crushing strength values than KSR-MH Lactose tablets. The crushing strengths of KSR-MCC tablets were larger than those of KSR-DNa tablets. Ternary mixture tablets comprised of KSR-MCC-DNa showed decreased porosities and low Py values as the percentage of KSR increased especially at high compression pressures but had higher crushing strengths compared to KSR-DNa or MCC-DNa binary tablets. KSR-MH Lactose-DNa ternary tablets experienced lower porosities and crushing strengths compared to KSR-MCC-DNa tablets. Quaternary tablets of KSR-PVA100-MCC-DNa showed lower porosity and Py values than quaternary tablets obtained using similar proportion of MH Lactose instead of MCC. In conclusion, optimum quaternary tablets were obtained with optimum crushing strengths, relatively low Py, and moderate percentage porosities among all prepared quaternary tablets. The drug release of the optimum quaternary tablets demonstrated similar in vitro release profile compared to that of the marketed product with a mechanism of release that follows Korsmeyer-Peppas model.

Material Evaluation and Dynamic Powder Deposition Modeling of PEEK/CF Composite for Laser Powder Bed Fusion Process

Polymeric composites such as Poly-ether-ether-ketone (PEEK)/carbon fiber (CF) have been widely utilized due to outstanding performances such as high specific strength and specific modulus. The PEEK/CF components via powder bed fusion additive manufacturing usually show brittle fracture behaviors induced by their poor interfacial affinity and inner voids. These defects are strongly associated with powder packing quality upon deposition. The particle dynamic model has been widely employed to study the interactions of particle motions. Powder property, bulk material property, and interfacial features of composite powders are key factors in the particle dynamic model. In this work, an efficient and systematic material evaluation is developed for composite powders to investigate their deposition mechanism. The discrete element method is utilized to simulate the dynamic behaviors of PEEK/CF composite powders. The powder properties, bulk material properties, and interfacial features of powders are calibrated and justified by experimental measurement, numerical simulation, and design of experiments. The particle dynamic model can explain the powder flow behaviors and interactions. The experimental and simulation AOR results show a maximal deviation of 4.89%. It reveals that the addition of short CF particles can assist the flow of PEEK powders and improve the packing quality of the composite powders. The results show an experimental improvement of 31.3% and 55.2% for PEEK/CF_30wt% and PEEK/CF_50wt%, with a simulated improvement of 27.4% and 50.2% for corresponding composite powders.

Comprehensive powder flow characterization with reduced testing

Powder flow is a critical attribute of pharmaceutical blends to ensure tablet weight uniformity and production of tablets with consistent and reproducible properties. This study aims at characterizing different powder blends with a number of different rheologic techniques, in order to understand how particles' attributes and interaction between components within the formulation generate different responses when analysed by different rheological tests. Furthermore, this study intends on reducing the number of tests in early development phases, by selecting the ones that provide the best information about the flowability attributes of the pharmaceutical blends. This work considered two cohesive powders - spray-dried hydroxypropyl cellulose (SD HPMC) and micronized indomethacin (IND) - formulated with other four commonly used excipients [(lactose monohydrated (LAC), microcrystalline cellulose (MCC), magnesium stearate (MgSt) and colloidal silica (CS)]. The experimental results showed that powder flowability may be affected by materials particles' size, bulk density, morphology, and interactions with lubricant. In detail, parameters, such as angle of repose (AoR), compressibility percentage (CPS), and flow function coefficient (ff_c) have shown to be highly affected by the particle size of the materials present in the blends. On the other hand, the Specific Energy (SE) and the effective angle of internal friction (φe) showed to be more related with particle morphology and materials interaction with the lubricant. Since both ff_c and φe parameters are generated from the yield locus test, data suggest that a number of different powder flow features may be understood only by applying this test, avoiding redundant powder flow characterization, as well as extensive time and material spent in early development formulation stages.

Reviewing the Impact of Powder Cohesion on Continuous Direct Compression (CDC) Performance

The pharmaceutical industry is undergoing a paradigm shift towards continuous processing from batch, where continuous direct compression (CDC) is considered to offer the most straightforward implementation amongst powder processes due to the relatively low number of unit operations or handling steps. Due to the nature of continuous processing, the bulk properties of the formulation will require sufficient flowability and tabletability in order to be processed and transported effectively to and from each unit operation. Powder cohesion presents one of the greatest obstacles to the CDC process as it inhibits powder flow. As a result, there have been many studies investigating potential manners in which to overcome the effects of cohesion with, to date, little consideration of how these controls may affect downstream unit operations. The aim of this literature review is to explore and consolidate this literature, considering the impact of powder cohesion and cohesion control measures on the three-unit operations of the CDC process (feeding, mixing, and tabletting). This review will also cover the consequences of implementing such control measures whilst highlighting subject matter which could be of value for future research to better understand how to manage cohesive powders for CDC manufacture.

Particle Agglomeration and Properties of Pregelatinized Potato Starch Powder

Pregelatinized starches are used as thickeners in many instant food products. The unique properties of pregelatinized starches, such as their dispersibility in water and high viscosity, are generally desirable for instant food products. However, powdered starches cannot be easily dispersed in cold water due to clumping. The most reliable method to solve this problem is particle size enlargement by an agglomeration technique that causes a structural change in the starch. In this study, pregelatinized potato starch powder (PPSP) was agglomerated in a fluidized bed agglomerator, after which the physical, structural, and rheological properties of the PPSP agglomerated with different maltodextrin (MD) binder concentrations were investigated. The powder solubility and flowability (CI and HR) of all the agglomerated PPSPs were improved, and the particle size (D₅₀) tended to increase as the MD concentration increased, except for the control (0% MD) and the 40% MD. The changes in the particle size of the agglomerated PPSPs were consistent with the SEM image analysis. The magnitudes of the gel strength and viscoelastic moduli (G' and G″) of the agglomerated PPSPs with 10% MD were higher than those of the control due to the more stable structure formed by better intermolecular interaction in the starch and MD during the agglomeration process. Therefore, our results indicated that the fluidized bed agglomeration process and the MD addition as a binder solution greatly influence the physical, structural, and rheological properties of PPSP.

Development and Pharmacokinetics of a Novel Acetylsalicylic Acid Dry Powder for Pulmonary Administration

Aspirin is an historic blockbuster product, and it has been proposed in a wide range of formulas. Due to exacerbation risks, the pulmonary route has been seldom considered as an alternative to conventional treatments. Only recently, owing to overt advantages, inhalable acetylsalicylic acid dry powders (ASA DPI) began to be considered as an option. In this work, we developed a novel highly performing inhalable ASA DPI using a nano spray-drying technique and leucine as an excipient and evaluated its pharmacokinetics compared with oral administration. The formulation obtained showed remarkable respirability and quality features. Serum and lung ASA DPI profiles showed faster presentation in blood and higher retention compared with oral administration. The dry powder was superior to the DPI suspension. The relative bioavailability in serum and lungs claimed superiority of ASA DPI over oral administration, notwithstanding a fourfold lower pulmonary dose. The obtained ASA DPI formulation shows promising features for the treatment of inflammatory and infectious lung pathologies.

Assessing the Interrelationship of Microstructure, Properties, Drug Release Performance, and Preparation Process for Amorphous Solid Dispersions Via Noninvasive Imaging Analytics and Material Characterization

PURPOSE

The purpose of this work is to evaluate the interrelationship of microstructure, properties, and dissolution performance for amorphous solid dispersions (ASDs) prepared using different methods.

METHODS

ASD of GDC-0810 (50% w/w) with HPMC-AS was prepared using methods of spray drying and co-precipitation via resonant acoustic mixing. Microstructure, particulate and bulk powder properties, and dissolution performance were characterized for GDC-0810 ASDs. In addition to application of typical physical characterization tools, we have applied X-Ray Microscopy (XRM) to assess the contribution of microstructure to the characteristics of ASDs and obtain additional quantification and understanding of the drug product intermediates and tablets.

RESULTS

Both methods of spray drying and co-precipitation produced single-phase ASDs. Distinct differences in microstructure, particle size distribution, specific surface area, bulk and tapped density, were observed between GDC-0810 spray dried dispersion (SDD) and co-precipitated amorphous dispersion (cPAD) materials. The cPAD powders prepared by the resonant acoustic mixing process demonstrated superior compactibility compared to the SDD, while the compressibility of the ASDs were comparable. Both SDD powder and tablets showed higher in vitro dissolution than those of cPAD powders. XRM calculated total solid external surface area (S_A) normalized by calculated total solid volume (S_V) shows a strong correlation with micro dissolution data.

CONCLUSION

Strong interrelationship of microstructure, physical properties, and dissolution performance was observed for GDC-0810 ASDs. XRM image-based analysis is a powerful tool to assess the contribution of microstructure to the characteristics of ASDs and provide mechanistic understanding of the interrelationship.

The Application and Challenge of Binder Jet 3D Printing Technology in Pharmaceutical Manufacturing

Three-dimensional (3D) printing is an additive manufacturing technique that creates objects under computer control. Owing to the rapid advancement of science and technology, 3D printing technology has been widely utilized in processing and manufacturing but rarely used in the pharmaceutical field. The first commercial form of Spritam® immediate-release tablet was approved by FDA in 2015, which promoted the advancement of 3D printing technology in pharmaceutical development. Three-dimensional printing technology is able to meet individual treatment demands with customized size, shape, and release rate, which overcomes the difficulties of traditional pharmaceutical technology. This paper intends to discuss the critical process parameters of binder jet 3D printing technology, list its application in pharmaceutical manufacturing in recent years, summarize the still-open questions, and demonstrate its great potential in the pharmaceutical industry.

Relating Crystal Structure to Surface Properties: A Study on Quercetin Solid Forms

The surface energy and surface chemistry of a crystal are of great importance when designing particles for a specific application, as these will impact both downstream manufacturing processes as well as final product quality. In this work, the surface properties of two different quercetin solvates (quercetin dihydrate and quercetin DMSO solvate) were studied using molecular (synthonic) modeling and experimental techniques, including inverse gas chromatography (IGC) and contact angle measurements, to establish a relationship between crystal structure and surface properties. The attachment energy model was used to predict morphologies and calculate surface properties through the study of their growth synthons. The modeling results confirmed the surface chemistry anisotropy for the two forms. For quercetin dihydrate, the {010} facets were found to grow mainly by nonpolar offset quercetin-quercetin stacking interactions, thus being hydrophobic, while the {100} facets were expected to be hydrophilic, growing by a polar quercetin-water hydrogen bond. For QDMSO, the dominant facet {002} grows by a strong polar quercetin-quercetin hydrogen bonding interaction, while the second most dominant facet {011} grows by nonpolar π-π stacking interactions. Water contact angle measurements and IGC confirmed a greater overall surface hydrophilicity for QDMSO compared to QDH and demonstrated surface energy heterogeneity for both structures. This work shows how synthonic modeling can help in the prediction of the surface nature of crystalline particles and guide the choice of parameters that will determine the optimal crystal form and final morphology for targeted surface properties, for example, the choice of crystallization conditions, choice of solvent, or presence of additives or impurities, which can direct the crystallization of a specific crystal form or crystal shape.

Trends in small molecule drug properties: A developability molecule assessment perspective

Developability molecule assessment is a key interfacial capability across the biopharmaceutical industry, screening and staging molecules discovered by medicinal chemists for successful chemistry manufacturing controls (CMC) development and launch. The breadth of responsibility and expertise such teams possess puts them in a unique position to understand the impact of the physicochemical properties of a drug during its initial discovery and subsequent development. However, most of the publications describing trends in physicochemical properties are written from a medicinal chemistry perspective with the aim to identify molecules with better ADMET profiles that are either lead-like or drug-like, failing to describe the impact these properties have on CMC development. To systematically uncover knowledge obtained from recent trends in physicochemical properties and the corresponding impact on CMC development, a comprehensive analysis was conducted on molecules in the drug repurposing hub dataset. The only physicochemical property that seems to have been preserved in FDA-approved oral molecules over the decades (1900-2020) is a constant H-bond donor count, highlighting the importance this property has on cell permeability and lattice energy. Pharmaceutical attrition analysis suggests that partition-distribution coefficient, H-bond acceptors, polar surface area and the fraction of sp³ carbons are properties that are associated with compound attrition. Looking at pharmaceutical attrition asynchronously with the temporal analysis of FDA-approved oral molecules highlights the opposing trends, risks and diminishing effects some of these physiochemical properties (cLogP, cLogD and Fsp3) have on describing compound attrition during the past decade. Trellising the dataset by target class suggests that certain formulation and drug delivery strategies can be anticipated or put into place based on target class of a molecule. For example, molecules binding to nuclear hormone receptors are amenable to lipid-based drug delivery systems with proven commercial success. Although the poor solubility of kinase inhibitors is a combination of hydrophobicity (due to aromaticity) required to bind to its target and high lattice energy (melting point), they are a challenging target class to formulate. The influence of drug targets on physicochemical properties and the temporal nature of these properties is highlighted when comparing molecules in the drug repurposing dataset to those developed at Amgen. An improved understanding of the impact of molecular properties on performance attributes can accelerate decisions and facilitate risk assessments during candidate selection and development.

Development of extra-fine particles containing nanosized meloxicam for deep pulmonary delivery: in vitro aerodynamic and cell line measurements

Pulmonary drug administration provides a platform for the effective local treatment of various respiratory diseases. Application of nano-sized active ingredients results in higher bioavailability because of their large specific surface area. Extra-fine dry powder inhalers reach the smaller airways, further improving therapeutic efficiency. Poorly water-soluble meloxicam was the selected active ingredient. We aimed to decrease the particle size into the nano range by wet milling and producing extra-fine inhalable particles via nano spray-drying. The diameter of the drug was reduced to 138 nm. The particle size of the dry products was between 1.1-1.5 µm, and the dispersed diameter was between 500-800 nm. Owing to the excipients (poly-vinyl-alcohol, leucine), the spray-dried particles presented nearly spherical morphology. The drug became partially amorphous. Thanks to the improved surface area, the solubility and the released and the diffused amount of the meloxicam increased in artificial lung media. The in vitro aerodynamic measurements showed that the leucine-containing formulations had outstanding fine particle fraction (FPF) deposition with 1.3 µm mass median aerodynamic diameter (MMAD). The aerodynamic particle counter test also proved the extra-fine aerodynamic particle size. The in vitro cell line experiments revealed the non-cytotoxicity of the products and the suppression of the interleukin concentration. Overall, the powders are suitable for deep pulmonary delivery and the local treatment of lung inflammations.

Cleaving Method for Molecular Crystals and Its Application to Calculation of the Surface Free Energy of Crystalline β-d-Mannitol at Room Temperature

Calculation of the surface free energy (SFE) is an important application of the thermodynamic integration (TI) methodology, which was mainly employed for atomic crystals (such as Lennard–Jones or metals). In this work, we present the calculation of the SFE of a molecular crystal using the cleaving technique which we implemented in the LAMMPS molecular dynamics package. We apply this methodology to a crystal of β-d-mannitol at room temperature and report the results for two types of force fields belonging to the GROMOS family: all atoms and united atoms. The results show strong dependence on the type of force field used, highlighting the need for the development of better force fields to model the surface properties of molecular crystals. In particular, we observe that the united-atoms force field, despite its higher degree of coarse graining compared to the all-atoms force field, produces SFE results in better agreement with the experimental results from inverse gas chromatography measurements.

Computational Modeling of Fluidized Beds with a Focus on Pharmaceutical Applications: A Review

The fluidized bed is an essential and standard equipment in the field of process development. It has a wide application in various areas and has been extensively studied. This review paper aims to discuss computational modeling of a fluidized bed with a focus on pharmaceutical applications. Eulerian, Lagrangian, and combined Eulerian-Lagrangian models have been studied for fluid bed applications with the rise of modeling capabilities. Such models assist in optimizing the process parameters and expedite the process development cycle. This paper discusses the background of modeling and then summarizes research papers relevant to pharmaceutical unit operations.

Development of an Age-Appropriate Mini Orally Disintegrating Carvedilol Tablet with Paediatric Biopharmaceutical Considerations

Owing to considerable differences observed in anatomy and physiology between paediatric subsets, it has been well established that children respond to drugs differently compared to adults. Furthermore, from a formulation perspective, there is a distinct challenge to develop a dosage form that is capable of safely, accurately, and reliably delivering the dose across the whole paediatric population. Orally disintegrating mini-tablets (ODMT) have widely been considered as an age-appropriate formulation option that possess the ability for adequate dose flexibility, avoids swallowing difficulties, and exhibits superior stability due to its solid state. Within this study, two strengths (0.5 mg and 2 mg) of carvedilol ODMT formulations were developed using an excipient composition and load that is appropriate for paediatric use. The formulations demonstrated adequate mechanical strength (>20 N) and fast disintegration times (<30 s). Dissolution profiles observed were robust and comparable to the marketed conventional tablet formulation across various parts of the gastrointestinal (GI) tract in both the fed and fasted state, signifying appropriate efficacy, quality, and performance. As such, the formulations developed in this study show potential to address the need of an 'age-appropriate' formulation of carvedilol, as highlighted by the European Medicines Agency (EMA) Inventory of the Needs for Paediatric Medicine.

Roughly Spherical: Tailored PMMA-SiO2 Composite Supraparticles with Optimized Powder Flowability for Additive Manufacturing

Particulate materials with well-engineered properties are of key importance for many aspects in our daily life. Polymer powders with high flowability, for example, play a crucial role in the emerging field of powder-based additive manufacturing processes. However, the polymer- and composite material selection for these technologies is still limited. Here, we demonstrate the design of spherical polymethyl methacrylate (PMMA) and PMMA-SiO₂ composite supraparticle powders with excellent powder flowability and tailored composition for powder-based additive manufacturing. Our process assembles these powders from the bottom up and affords a precise control over surface roughness and internal morphology via the choice of colloidal primary particles. We establish process-structure-property relationships connecting external spray-drying parameters and primary particle sizes with the resulting supraparticle roughness and, subsequently, with the macroscopic powder flowability and powder bed density. In a second step, we demonstrate the control of composition and internal morphology of PMMA-SiO₂ composite supraparticles based on different mass mixings and diameter ratios of the two primary particle dispersions. Finally, we successfully apply the prepared supraparticle powders in powder bed additive manufacturing. The optimized flowability of the composite powders allows the production of two-layered square specimens with fusion between the individual layers and a uniform and tunable distribution of nanoscale SiO₂ additives without requiring the addition of any flowing aids.

The influence of particle size on the application of compression and compaction models for tableting

The physical characteristics of raw materials determine powder compression and compaction performance as relevant in pharmaceutical processes. For instance, the influence of initial particle size on powder compression and the resulting strength of specimen are highly complex and are still not sufficiently understood. Existing studies are often limited to materials with well-defined deformation behaviour, such as purely brittle or ductile. However, the deformation behaviour of active pharmaceutical ingredients (APIs) is often more complex. In this study, the influence of initial particle size on powder compressibility and compactibility is systematically characterized by consideration of in-die compressibility, specific energies, quick elastic recovery, tablet porosity and, tensile strength for the binder microcrystalline cellulose and three APIs. The decrease of particle size leads to an increase of the resistance against compression by trend and probably to a different contribution of the acting deformation mechanisms. The compactibility is increased with decreasing particle size because of the increasing number of bonds in a cross-sectional area of the tablet, as found by the application of the model of Rumpf. Furthermore, it is found that the model of Rumpf combined with the JKR model provides a meaningful property function to estimate tablet tensile strength.

Pinto J, Paudel A. Understanding Carrier Performance in Low-Dose Dry Powder Inhalation: An In Vitro-In Silico Approach

The use of physiologically based pharmacokinetic (PBPK) models to support drug product development has become increasingly popular. The in vitro characterization of the materials of the formulation provides valuable descriptors for the in silico prediction of the drug’s pharmacokinetic profile. Thus, the application of an in vitro–in silico framework can be decisive towards the prediction of the in vivo performance of a new medicine. By applying such an approach, this work aimed to derive mechanistic based insights into the potential impact of carrier particles and powder bulk properties on the in vivo performance of a lactose-based dry powder inhaler (DPI). For this, a PBPK model was developed using salbutamol sulphate (SS) as a model drug and the in vitro performance of its low-dose blends (2% w/w) with different types of lactose particles was investigated using different DPI types (capsule versus reservoir) at distinct airflows. Likewise, the influence of various carrier’s particle and bulk properties, device type and airflow were investigated in silico. Results showed that for the capsule-based device, low-dose blends of SS had a better performance, when smaller carrier particles (Dv_0.5 ≈ 50 μm) with about 10% of fines were used. This resulted in a better predicted bioavailability of the drug for all the tested airflows. For the reservoir type DPI, the mean particle size (Dv_0.5) was identified as the critical parameter impacting performance. Shear cell and air permeability or compressibility measurements, particle size distribution by pressure titration and the tensile strength of the selected lactose carrier powders were found useful to generate descriptors that could anticipate the potential in vivo performance of the tested DPI blends.

Formulation and In Vitro and In Silico Characterization of "Nano-in-Micro" Dry Powder Inhalers Containing Meloxicam

Pulmonary delivery has high bioavailability, a large surface area for absorption, and limited drug degradation. Particle engineering is important to develop inhalable formulations to improve the therapeutic effect. In our work, the poorly water-soluble meloxicam (MX) was used as an active ingredient, which could be useful for the treatment of non-small cell lung cancer, cystic fibrosis, and chronic obstructive pulmonary disease. We aimed to produce inhalable “nano-in-micro” dry powder inhalers (DPIs) containing MX and additives (poly-vinyl-alcohol, leucine). We targeted the respiratory zone with the microcomposites and reached a higher drug concentration with the nanonized active ingredient. We did the following investigations: particle size analysis, morphology, density, interparticular interactions, crystallinity, in vitro dissolution, in vitro permeability, in vitro aerodynamics (Andersen cascade impactor), and in silico aerodynamics (stochastic lung model). We worked out a preparation method by combining wet milling and spray-drying. We produced spherical, 3–4 µm sized particles built up by MX nanoparticles. The increased surface area and amorphization improved the dissolution and diffusion of the MX. The formulations showed appropriate aerodynamical properties: 1.5–2.4 µm MMAD and 72–76% fine particle fraction (FPF) values. The in silico measurements proved the deposition in the deeper airways. The samples were suitable for the treatment of local lung diseases.

A Bilayer Vaginal Tablet for the Localized Delivery of Disulfiram and 5-Fluorouracil to the Cervix

This study was performed to develop an adjuvant therapy in the form of a self-administered vaginal tablet regimen for the localized delivery of chemotherapeutic drugs. This therapy will help to reduce relapse by eradicating cancerous cells in the margin of cervical tumors. The vaginal tablet is a very common formulation that is easy to manufacture, easy to place in the vagina, and has a low cost of manufacture, making them ideal for use in developing countries. A combination of disulfiram and 5-fluorouracil, which are both off-patent drugs and provide different modes of action, were evaluated. The tablets developed were evaluated for weight variation, thickness, hardness, friability, swelling index, differential scanning calorimetry (DSC), particle morphology, in vitro drug release, and cytotoxicity on Ca-Ski cells. Both layers were designed to release both drugs concurrently for a synergistic effect. The polymer–polymer interaction between the layers was able to reduce the loss of formulation due to chitosan. While the bilayer tablet had satisfactory performance in the physicochemical tests, in vitro cell culture with Ca-Ski also showed a synergistic effect using a combination of drugs at a low dose. However, the formulation only had 24-h dose release before degradation. Further drug combinations should be evaluated in subsequent studies.

Bottom-Up Design of Composite Supraparticles for Powder-Based Additive Manufacturing

Additive manufacturing promises high flexibility and customized product design. Powder bed fusion processes use a laser to melt a polymer powder at predefined locations and iterate the scheme to build 3D objects. The design of flowable powders is a critical parameter for a successful fabrication process that currently limits the choice of available materials. Here, a bottom-up process is introduced to fabricate tailored polymer- and composite supraparticles for powder-based additive manufacturing processes by controlled aggregation of colloidal primary particles. These supraparticles exhibit a near-spherical shape and tailored composition, morphology, and surface roughness. These parameters can be precisely controlled by the mixing and size ratio of the primary particles. Polystyrene/silica composite particles are chosen as a model system to establish structure-property relations connecting shape, morphology, and surface roughness to the adhesion within the powder, which is accessed by tensile strength measurements. The adhesive properties are then connected to powder flowability and it is shown that the resulting powders allow the formation of dense powder films with uniform coverage. Finally, successful powder bed fusion is demonstrated by producing macroscopic single layer specimens with uniform distribution of nanoscale silica additives.