Engineering Advances in Spray Drying for Pharmaceuticals

Drying kinetics and energy efficiency of soot ash of smelting silicon manganese alloys under microwave heating

When smelting silicon manganese alloy in an industrial electric furnace, it will produce smoke and dust waste gas, which can be utilized again back to the furnace and improve the utilization rate of raw materials after a particular trapping device and collection treatment. However, at higher moisture levels, they are prone to explode. Effects of various initial masses, initial moisture contents, and microwave output powers on the soot ash of smelting silicon manganese alloy were studies. The findings indicate that the microwave drying rate increases with all three variables. The time for complete microwave drying is directly proportional to the sample's initial moisture content and the sample's initial mass, and the time for complete microwave drying is inversely proportional to the microwave output power. The results demonstrate that the Modified Page model can accurately describe the microwave drying process. The experimental data were fitted experimentally by drying kinetic models. Microscopic characterization of soot ash from refining silico‑manganese alloys before and after drying was carried out using FTIR and SEM. Through FTIR characterization, the peak value of the -OH absorption peak decreases upon drying, and SEM results in no agglomeration caused by microwave drying and better dispersion of the soot ash of the dried smelted silica‑manganese alloys, all of which proved that microwaves could effectively remove water. It was discovered that the diffusion coefficient increased gradually with increasing power when it was computed using Fick's second law. The diffusion coefficient increases and then decreases as the moisture content increases. The diffusion coefficient decreases as the initial mass increases. Activation energy of microwave drying of soot ash from the refining of silicomanganese alloys was calculated to be -1.4467 W/g. Its purpose is to offer a detailed guide for the industrial drying of soot ash from silicomanganese alloy refinement using microwave drying technology.

Spray-drying of PEI-/PPI-based nanoparticles for DNA or siRNA delivery

Spray-drying of nucleic acid-based drugs designed for gene therapy or gene knockdown is associated with many advantages including storage stability and handling as well as the possibility of pulmonary application. The encapsulation of nucleic acids in nanoparticles prior to spray-drying is one strategy for obtaining efficient formulations. This, however, strongly relies on the definition of optimal nanoparticles, excipients and spray-drying conditions. Among polymeric nanoparticles, polyethylenimine (PEI)-based complexes with or without chemical modifications have been described previously as very efficient for gene or oligonucleotide delivery. The tyrosine-modification of linear or branched low molecular weight PEIs, or of polypropylenimine (PPI) dendrimers, has led to high complex stability, improved cell uptake and transfection efficacy as well as high biocompatibility. In this study, we identify optimal spray-drying conditions for PEI-based nanoparticles containing large plasmid DNA or small siRNAs, and further explore the spray-drying of nanoparticles containing chemically modified polymers. Poly(vinyl alcohol) (PVA), but not trehalose or lactose, is particularly well-suited as excipient, retaining or even enhancing transfection efficacies compared to fresh complexes. A big mesh size is critically important as well, while the variation of the spray-drying temperature plays a minor role. Upon spray-drying, microparticles in a ∼ 3.3 - 8.5 µm size range (laser granulometry) are obtained, dependent on the polymers. Upon their release from the spray-dried material, the nanoparticles show increased sizes and markedly altered zeta potentials as compared to their fresh counterparts. This may contribute to their high efficacy that is seen also after prolonged storage of the spray-dried material. We conclude that these spray-dried systems offer a great potential for the preparation of nucleic acid drug storage forms with facile reconstitution, as well as for their direct pulmonary application as dry powder.

Research advances in Zein-based nano-delivery systems

Zein is the main vegetable protein from maize. In recent years, Zein has been widely used in pharmaceutical, agriculture, food, environmental protection, and other fields because it has excellent biocompatibility and biosafety. However, there is still a lack of systematic review and research on Zein-based nano-delivery systems. This paper systematically reviews preparation and modification methods of Zein-based nano-delivery systems, based on the basic properties of Zein. It discusses the preparation of Zein nanoparticles and the influencing factors in detail, as well as analyzing the advantages and disadvantages of different preparation methods and summarizing modification methods of Zein nanoparticles. This study provides a new idea for the research of Zein-based nano-delivery system and promotes its application.

Pullulan-Based Spray-Dried Mucoadhesive Microparticles for Sustained Oromucosal Drug Delivery

Mucoadhesive microparticles for oromucosal drug delivery offer several advantages, including intimate contact with the mucosa, delivery to less accessible regions, extended residence time, sustained drug release, reduced irritation, and improved patient compliance. In this study, pullulan was used to prepare mucoadhesive spray-dried microparticles for delivering benzydamine hydrochloride (BZH) to oral mucosa. The BZH-pullulan spray-dried microparticles had a mean size of <25 μm with an angle of repose values between 25.8-36.6°. Pullulan markedly extended drug-release time to >180 min, ~9 times greater than the duration (i.e., 20 min) reportedly achieved by chitosan. Kinetic analysis showed the drug-release rate was concentration dependent and jointly controlled by drug diffusion and polymer chain relaxation. Further, pullulan was mucoadhesive and was able to retain up to 78.8% w/w of microencapsulated gold nanoparticle probes at the mucosal membrane. These data strongly suggest that BZH-pullulan microparticles have great potential for oromucosal drug delivery, by providing elongated residence time in situ and sustained drug release for the treatment of local diseases.

Rapid screening of ternary amorphous formulations by a spray drying robot

Spray drying is commonly used for producing amorphous solid dispersions to improve drug solubility. The development of such formulations typically relies on comprehensive excipient and composition screening, which requires the preparation of many spray-dried powder samples. This is both labour-intensive and time-consuming when carried out manually. In the present work, the formulation screening task was automated by coupling a laboratory spray dryer operated in a semi-continuous mode with custom-made add-ons, allowing for rapid, computer-controlled production of formulation samples with systematically varying composition. The practical use of the spray drying robot in formulation development was demonstrated on a case study of poorly water-soluble model drugs simvastatin and ezetimibe. Six different polymers and several drug:polymer ratios were screened for the enhancement of dissolution properties. From a pool of 28 spray-dried samples, ternary compositions containing Eudragit L100-55 were identified as the most suitable ones for further processing and characterisation. The ability to populate the formulation design space rapidly and automatically made it possible to construct maps of physico-chemical properties such as glass transition temperature or dissolution rate. The spray drying robot thus enables the acceleration of early formulation development and a deeper understanding of composition-property relationships for multi-component spray dried powders.

In Vitro and In Vivo testing of 3D-Printed Amorphous Lopinavir Printlets by Selective Laser Sinitering: Improved Bioavailability of a Poorly Soluble Drug

The aim of this paper was to investigate the effects of formulation parameters on the physicochemical and pharmacokinetic (PK) behavior of amorphous printlets of lopinavir (LPV) manufactured by selective laser sintering 3D printing method (SLS). The formulation variables investigated were disintegrants (magnesium aluminum silicate at 5-10%, microcrystalline cellulose at 10-20%) and the polymer (Kollicoat® IR at 42-57%), while keeping printing parameters constant. Differential scanning calorimetry, X-ray powder diffraction, and Fourier-transform infrared analysis confirmed the transformation of the crystalline drug into an amorphous form. A direct correlation was found between the disintegrant concentration and dissolution. The dissolved drug ranged from 71.1 ± 5.7% to 99.3 ± 2.7% within 120 min. A comparative PK study in rabbits showed significant differences in the rate and extent of absorption between printlets and compressed tablets. The values for Tmax, Cmax, and AUC were 4 times faster, and 2.5 and 1.7 times higher in the printlets compared to the compressed tablets, respectively. In conclusion, the SLS printing method can be used to create an amorphous delivery system through a single continuous process.

Solidification and oral delivery of biologics to the colon- A review

The oral delivery of biologics such as therapeutic proteins, peptides and oligonucleotides for the treatment of colon related diseases has been the focus of increasing attention over the last years. However, the major disadvantage of these macromolecules is their degradation propensity in liquid state which can lead to the undesirable and complete loss of function. Therefore, to increase the stability of the biologic and reduce their degradation propensity, formulation techniques such as solidification can be performed to obtain a stable solid dosage form for oral administration. Due to their fragility, stress exerted on the biologic during solidification has to be reduced with the incorporation of stabilizing excipients into the formulation. This review focuses on the state-of-the-art solidification techniques required to obtain a solid dosage form for the oral delivery of biologics to the colon and the use of suitable excipients for adequate stabilization upon solidification. The solidifying processes discussed within this review are spray drying, freeze drying, bead coating and also other techniques such as spray freeze drying, electro spraying, vacuum- and supercritical fluid drying. Further, the colon as site of absorption in both healthy and diseased state is critically reviewed and possible oral delivery systems for biologics are discussed.

Multifunctional, Hybrid Materials Design via Spray-Drying: Much more than Just Drying

Spray-drying is a popular and well-known "drying tool" for engineers. This perspective highlights that, beyond this application, spray-drying is a very interesting and powerful tool for materials chemists to enable the design of multifunctional and hybrid materials. Upon spray-drying, the confined space of a liquid droplet is narrowed down, and its ingredients are forced together upon "falling dry." As  detailed in this article, this enables the following material formation strategies either individually or even in combination: nanoparticles and/or molecules can be assembled; precipitation reactions as well as chemical syntheses can be performed; and templated materials can be designed. Beyond this, fragile moieties can be processed, or "precursor materials" be prepared. Post-treatment of spray-dried objects eventually enables the next level in the design of complex materials. Using spray-drying to design (particulate) materials comes with many advantages-but also with many challenges-all of which are outlined here. It is believed that multifunctional, hybrid materials, made via spray-drying, enable very unique property combinations that are particularly highly promising in myriad applications-of which catalysis, diagnostics, purification, storage, and information are highlighted.

Inhalation powder development without carrier: How to engineer ultra-flying microparticles?

Particle engineering technologies have led to the commercialization of new inhaled powders like PulmoSolTM or PulmoSphereTM. Such platforms are produced by spray drying, a well-known process popular for its versatility, thanks to wide-ranging working parameters. Whereas these powders contain a high drug-loading, we have studied a low-dose case, in optimizing the production of powders with two anti-asthmatic drugs, budesonide and formoterol. Using a Design of Experiments approach, 27 powders were produced, with varying excipient mixes (cyclodextrins, raffinose and maltodextrins), solution concentrations, and spray drying parameters in order to maximize deep lung deposition, measured through fine particle fraction (next generation impactor). Based on statistical analysis, two powders made of hydropropyl-β-cyclodextrin alone or mixed with raffinose and L-leucine were selected. Indeed, the two powders demonstrated very high fine particle fraction (>55%), considerably better than commercially available products. Deep lung deposition has been correlated to very fine particle size and lower microparticles interactions shown by laser diffraction assays at different working pressures, and particle morphometry. Moreover, the two drugs would be predicted to deposit homogeneously into the lung according to impaction studies. Uniform delivery is fundamental to control symptoms of asthma. In this study, we develop carrier-free inhalation powders promoting very efficient lung deposition and demonstrate the high impact of inter-particular interactions intensity on their aerosolization behaviour.

Driving Spray Drying towards Better Yield: Tackling a Problem That Sticks Around

Powder deposition and accumulation on walls of spray drying chamber has been known to impact spray drying processes, resulting in lower yield, frequent shutdowns, and downtimes. Critical factors that impact the extent and rate of wall deposition have been studied extensively in the chemical and food industry. In this paper, we present an atypical process yield issue wherein acceptable yield is obtained during the first batch of spray drying but undergoes significant yield loss in consecutive batches. Through understanding the interplay of the process, material properties, and equipment, we identify key mechanisms that are playing a role in causing the process yield issue. These mechanisms include surface roughness of the inner wall of the spray dryer, variation in gas flow due to the introduction of process analytical technology, start-up and shutdown operating parameters that expose the wall deposited powder from the prior batch to temperatures close to the onset of glass transition temperature and cause depression of its glass transition temperature. These factors result in more wall accumulation and impact the yield in subsequent batches. By correcting for most of these factors, the yield reduction issue was mitigated, and processing efficiency was improved.

Contemporary Aspects of Designing Marine Polysaccharide Microparticles as Drug Carriers for Biomedical Application

The main goal of modern pharmaceutical technology is to create new drug formulations that are safer and more effective. These formulations should allow targeted drug delivery, improved drug stability and bioavailability, fewer side effects, and reduced drug toxicity. One successful approach for achieving these objectives is using polymer microcarriers for drug delivery. They are effective for treating various diseases through different administration routes. When creating pharmaceutical systems, choosing the right drug carrier is crucial. Biomaterials have become increasingly popular over the past few decades due to their lack of toxicity, renewable sources, and affordability. Marine polysaccharides, in particular, have been widely used as substitutes for synthetic polymers in drug carrier applications. Their inherent properties, such as biodegradability and biocompatibility, make marine polysaccharide-based microcarriers a prospective platform for developing drug delivery systems. This review paper explores the principles of microparticle design using marine polysaccharides as drug carriers. By reviewing the current literature, the paper highlights the challenges of formulating polymer microparticles, and proposes various technological solutions. It also outlines future perspectives for developing marine polysaccharides as drug microcarriers.

Recent Advances in Amorphous Solid Dispersions: Preformulation, Formulation Strategies, Technological Advancements and Characterization

Amorphous solid dispersions (ASDs) are among the most popular and widely studied solubility enhancement techniques. Since their inception in the early 1960s, the formulation development of ASDs has undergone tremendous progress. For instance, the method of preparing ASDs evolved from solvent-based approaches to solvent-free methods such as hot melt extrusion and Kinetisol^®. The formulation approaches have advanced from employing a single polymeric carrier to multiple carriers with plasticizers to improve the stability and performance of ASDs. Major excipient manufacturers recognized the potential of ASDs and began introducing specialty excipients ideal for formulating ASDs. In addition to traditional techniques such as differential scanning calorimeter (DSC) and X-ray crystallography, recent innovations such as nano-tomography, transmission electron microscopy (TEM), atomic force microscopy (AFM), and X-ray microscopy support a better understanding of the microstructure of ASDs. The purpose of this review is to highlight the recent advancements in the field of ASDs with respect to formulation approaches, methods of preparation, and advanced characterization techniques.

Characteristics of Probiotic Preparations and Their Applications

The probiotics market is one of the fastest growing segments of the food industry as there is growing scientific evidence of the positive health effects of probiotics on consumers. Currently, there are various forms of probiotic products and they can be categorized according to dosage form and the site of action. To increase the effectiveness of probiotic preparations, they need to be specifically designed so they can target different sites, such as the oral, upper respiratory or gastrointestinal tracts. Here we review the characteristics of different dosage forms of probiotics and discuss methods to improve their bioavailability in detail, in the hope that this article will provide a reference for the development of probiotic products.

Synthesis of Celecoxib-Eutectic Mixture Particles via Supercritical CO2 Process and Celecoxib Immediate Release Tablet Formulation by Quality by Design Approach

Significant improvements in the wettability and dissolution rate of celecoxib (CEL), a poorly soluble selective cyclooxygenase-2 (COX-2) inhibitor, have been shown by Huyn et al., 2019 by combining the binary pharmaceutical compositions including CEL and one of the two co-formers, adipic acid (ADI) and saccharin (SAC), into eutectic mixtures (EM). Purpose: In this study, we developed a therapeutic eutectic system for CEL which is a promising approach for oral delivery to enhance bioavailability. CEL EM were synthesized by novel techniques including supercritical CO₂ techniques and new tablet formulations were purposed. Methods: CEL EM were synthesized by evaporation crystallization method, spray drying, supercritical fluid (SCF) techniques. The CEL EM particles were then characterized by differential scanning calorimetry, powder X-ray diffraction, Fourier-transform infrared spectroscopy, scanning electron microscope, and particle size analysis. Dissolution studies were carried out. With a quality by design approach, a statistical method through design of experiment and data analysis by JMP^® (SAS institute) was applied to CEL EM immediate release tablet formulation development. Results: CEL EM produced by spray drying technique, supercritical fluid (SCF) techniques were identified and characterized. The enhancement of dissolution was observed for SCF processed samples. The design space for CEL-ADI EM IR tablet and control limits for individual parameters were determined.

Simultaneous Spray Drying for Combination Dry Powder Inhaler Formulations

Spray drying is a particle engineering technique used to manufacture respirable pharmaceutical powders that are suitable for delivery to the deep lung. It is amenable to processing both small molecules and biologic actives, including proteins. In this work, a simultaneous spray-drying process, termed simul-spray, is described; the process involves two different active pharmaceutical ingredient (API) solutions that are simultaneously atomized through separate nozzles into a single-spray dryer. Collected by a single cyclone, simul-spray produces a uniform mixture of two different active particles in a single-unit operation. While combination therapies for dry powder inhalers containing milled small molecule API are commercially approved, limited options exist for preparing combination treatments that contain both small molecule APIs and biotherapeutic molecules. Simul-spray drying is also ideal for actives which cannot withstand a milling-based particle engineering process, or which require a high dose that is incompatible with a carrier-based formulation. Three combination case studies are demonstrated here, in which bevacizumab is paired with erlotinib, cisplatin, or paclitaxel in a dry powder inhaler formulation. These model systems were chosen for their potential relevance to the local treatment of lung cancer. The resulting formulations preserved the biologic activity of the antibody, achieved target drug concentration, and had aerosol properties suitable for pulmonary delivery.

Solid-State and Particle Size Control of Pharmaceutical Cocrystals using Atomization-Based Techniques

Poor bioavailability and aqueous solubility represent a major constraint during the development of new API molecules and can influence the impact of new medicines or halt their approval to the market. Cocrystals offer a novel and competitive advantage over other conventional methods with respect towards the substantial improvement in solubility profiles relative to the single-API crystals. Furthermore, the production of such cocrystals through atomization-based methods allow for greater control, with respect to particle size reduction, to further increase the solubility of the API. Such atomization-based methods include supercritical fluid methods, conventional spray drying and electrohydrodynamic atomization/electrospraying. The influence of process parameters such as solution flow rates, pressure and solution concentration, in controlling the solid-state and final particle size are discussed in this review with respect to atomization-based methods. For the last decade, literature has been attempting to catch-up with new regulatory rulings regarding the classification of cocrystals, due in part to data sparsity. In recent years, there has been an increase in cocrystal publications, specifically employing atomization-based methods. This review considers the benefits to employing atomization-based methods for the generation of pharmaceutical cocrystals, examines the most recent regulatory changes regarding cocrystals and provides an outlook towards the future of this field.

Spray-dried Pneumococcal Membrane Vesicles are Promising Candidates for Pulmonary Immunization

Pneumococcal infections represent a global health threat, which requires novel vaccine developments. Extracellular vesicles are secreted from most cells, including prokaryotes, and harbor virulence factors and antigens. Hence, bacterial membrane vesicles (MVs) may induce a protective immune response. For the first time, we formulate spray-dried gram-positive pneumococcal MVs-loaded vaccine microparticles using lactose/leucine as inert carriers to enhance their stability and delivery for pulmonary immunization. The optimized vaccine microparticles showed a mean particle size of 1-2µm, corrugated surface, and nanocrystalline nature. Their aerodynamic diameter of 2.34µm, average percentage emitted dose of 88.8%, and fine powder fraction 79.7%, demonstrated optimal flow properties for deep alveolar delivery using a next-generation impactor. Furthermore, confocal microscopy confirmed the successful encapsulation of pneumococcal MVs within the prepared microparticles. Human macrophage-like THP-1 cells displayed excellent viability, negligible cytotoxicity, and a rapid uptake around 60% of fluorescently labeled MVs after incubation with vaccine microparticles. Moreover, vaccine microparticles increased the release of pro-inflammatory cytokines tumor necrosis factor and interleukin-6 from primary human peripheral blood mononuclear cells. Vaccine microparticles exhibited excellent properties as promising vaccine candidates for pulmonary immunization and are optimal for further animal testing, scale-up and clinical translation.

Acetic Acid as Processing Aid Dramatically Improves Organic Solvent Solubility of Weakly Basic Drugs for Spray Dried Dispersion Manufacture

Many active pharmaceutical ingredients (APIs) in the pharmaceutical pipeline require bioavailability enhancing formulations due to very low aqueous solubility. Although spray dried dispersions (SDDs) have demonstrated broad utility in enhancing the bioavailability of such APIs by trapping them in a high-energy amorphous form, many new chemical entities (NCEs) are poorly soluble not just in water, but in preferred organic spray drying solvents, e.g., methanol (MeOH) and acetone. Spraying poorly solvent soluble APIs from dilute solutions leads to low process throughput and small particles that challenge downstream processing. For APIs with basic pKa values, spray solvent solubility can be dramatically increased by using an acid to ionize the API. Specifically, we show that acetic acid can increase API solubility in MeOH:H2O by 10-fold for a weakly basic drug, gefitinib (GEF, pKa 7.2), by ionizing GEF to form the transient acetate salt. The acetic acid is removed during drying, resulting in a SDD of the original GEF free base having performance similar to SDDs sprayed from solvents without acetic acid. The increase in solvent solubility enables large scale manufacturing for these challenging APIs by significantly increasing the throughput and reducing the amount of solvent required.

Optimization of Spray-Drying Process Parameters to Study Anti-Sticking Effect of Hydroxypropyl Methyl Cellulose-VLV on Corni fructus Extracts

To prevent the sticking of Corni fructus extract (CFE) during spray drying, the anti-sticking effects of different excipients were compared. Hydroxypropyl methylcellulose (HPMC)-VLV showed a higher powder yield at a lower dosage (8% of total solids), and a lower solution viscosity, compared with HPMC-E5. Therefore, HPMC-VLV is a more effective excipient for reducing CFE sticking during spray drying. The spray-drying process parameters were optimized by central composite rotatable design/response surface methodology, and spray drying was conducted under the following conditions: Inlet air temperature, 126 °C; atomization pressure, 1.05 bar; pump speed, 7.7 mL/min. Scanning electron microscopy showed that the powder comprised shrunken spherical particles with particle sizes in the range of 2-30 μm. Analysis of dynamic surface tension and chemical elements on the powder surface showed that HPMC-VLV rapidly moved to the droplet surface owing to its surface activity. HPMC covered the droplet surface and reduced surface tension, achieving an anti-sticking effect. In conclusion, HPMC-VLV at a solid content of 8% significantly improved the spray drying and reduced sticking of CFE. The spray-drying process parameters were nonlinearly related to the dry product yield. Graphical Abstract.