Self-microemulsifying drug delivery systems (SMEDDS) containing volatile phytotherapeutics such as thymol (T), carvacrol (C), and eugenol (E) present significant formulation challenges, even when solidified. Their instability and interactions with coatings often hinder intestinal delivery. To address these limitations, we developed solid SMEDDS consisting of pellets (microcrystalline cellulose/magnesium aluminometasilicate/chitosan) and enteric capsules (CEC) for enhanced intestinal delivery. Based on solubility and pseudo-ternary phase diagrams, SMEDDS formulations (SES1-3) differing in component ratios (glycerol monooleate/caprylocaproyl macrogol-8 glycerides/diethylene glycol monoethyl ether) with 5% w/w of each drug were identified, demonstrating nano-scale droplet sizes (PDI <0.4) and showing no phase separation over 6 months. Thermodynamic stability and liquid-state NMR revealed particle size variations with preserved structural integrity. The lead formulation SES1 exhibited superior ex-vivo intestinal permeation (T-SES1). CECs filled with T-, C-, and E-loaded SES1 pellets, respectively, prepared via extrusion/spheronization, exhibited in-vitro gastro-resistant release, and achieved > 85% drug release within 120 min after a pH change to 6.8 during a one-year stability study (25 °C; 60% RH). FTIR-ATR analysis of the CEC internal surface confirmed the temperature-dependent restructuring of hypromellose and E sorption, a phenomenon not observed with C or T, which is likely attributable to physicochemical distinctions. Oral administration of CEC with T-SES1-pellets (0.5 mg/kg) in piglets demonstrated a delayed peak plasma concentration (Cmax 11.67 ng/mL at 9 h) and sustained systemic exposure (AUC 119.8 ng·h/mL). These in-vivo findings substantiate the gastro-protective effect and enhanced intestinal absorption, positioning the pellet/CEC system as a promising strategy for the application of volatile phytotherapeutics in current pharmacotherapy.

Orodispersible films (ODFs) are increasingly employed for individualized drug delivery due to their ease of administration and precise dosing. However, their drug loading capacity is often limited by the need to maintain thin, flexible structures, posing a particular challenge for incorporating poorly soluble drugs. This study aimed to develop and characterize porous ODF matrices optimized for 3D printing of medicated inks. The primary objective was to investigate the impact of macroporosity on the dissolution kinetics of both poorly soluble and readily soluble drugs, with a focus on enhancing the release of the poorly soluble dexamethasone. Porous ODFs were fabricated via solvent casting using silica- and silicate-based porogens, then loaded with caffeine or dexamethasone through 3D printing. The films were comprehensively characterized using structural (micro-CT, BET), mechanical, and solid-state techniques (SEM, Raman microscopy, FTIR, XRD) to assess porosity, drug crystallization behavior, and drug-matrix compatibility. Drug release was evaluated through dissolution studies. Silica-based porogens yielded films with tunable macroporosity, supporting high drug loads (up to 3–5 times the ink volume). Dexamethasone printed on the SY2 substrate exhibited markedly enhanced dissolution (79.2 ± 1.8%) compared to its powdered form (29.9 ± 11.5%), achieving 61.5% release within 20 min. In contrast, caffeine (readily soluble) showed a transient reduction in dissolution rate during the initial two minutes, attributed to increased particle size and delayed film disintegration. Overall, integrating porous matrix design with 3D printing significantly improved the dissolution of poorly soluble dexamethasone without inducing drug-matrix interactions, confirming that structural modifications drive the enhanced release. Graphical Abstract

Alginate gels are outstanding biomaterials widely applicable in food and pharmaceutical industries. This contribution provides comprehensive insight into the design of advanced hybrid alginate/pectin co-networks double crosslinked by Ca2+/Zn2+ ions encapsulating self-emulsifying systems (SES). The tunable mucoadhesive properties, structural stability, integrity, dissolution profiles, and enhanced in-vivo bioavailability make the synthesized hybrid systems ideal vehicles for the delivery of lipophilic phytotherapeutics, allowing the long-term site-specific treatment of intestinal inflammation. This work also provides a thorough understanding of the structure-property relationships of alginate-pectin gels at the atomic resolution level. It was found out that SES molecules form well-distributed, phase-separated microparticles that interact with the polysaccharide matrix through a well-defined interface. The hybrid alginate-pectin gel is highly cross-linked, with both types of polysaccharides participating in the network formation. The observed surface interactions of SES droplets increase the intrinsic mobility of the network. The plasticizing effect can be regulated by the amount of pectin macromolecules, whose interaction with alginate chains enables a strengthening of the polysaccharide network. Overall, the domain-like architecture of hybrid alginate-pectin gels synthesized by external ionic gelation is revealed; the key structural motifs responsible for their properties are discovered; and the pathways allowing their regulation are identified. Biological in-vivo tests then confirmed positive effects of the synthesized systems in living organisms. The strategy presented thus offers a new perspective for the rational design of alginate-based materials for the microencapsulation of bioactive compounds for advanced orally administered delivery systems or controlled-release decontaminators applicable in the food and nutraceutical processing industries.

Stilbenes in food and medicinal plants have been described as potent antiphlogistic and antioxidant compounds, and therefore, they present an interesting potential for the development of dietary supplements. Among them, macasiamenene F (MF) has recently been shown to be an effective anti-inflammatory and cytoprotective agent that dampens peripheral and CNS inflammation in vitro. Nevertheless, this promising molecule, like other stilbenes and a large percentage of drugs under development, faces poor water solubility, which results in trickier in vivo administration and low bioavailability. With the aim of improving MF solubility and developing a form optimized for in vivo administration, eight types of conventional liposomal nanocarriers and one type of PEGylated liposomes were formulated and characterized. In order to select the appropriate form of MF encapsulation, the safety of MF liposomal formulations was evaluated on THP-1 and THP-1-XBlue-MD2-CD14 monocytes, BV-2 microglia, and primary cortical neurons in culture. Furthermore, the cellular uptake of liposomes and the effect of encapsulation on MF anti-inflammatory effectiveness were evaluated on THP-1-XBlue-MD2-CD14 monocytes and BV-2 microglia. MF (5 mol %) encapsulated in PEGylated liposomes with an average size of 160 nm and polydispersity index of 0.122 was stable, safe, and the most promising form of MF encapsulation keeping its cytoprotective and anti-inflammatory properties.

Nanoparticles belong to a modern and developing group of drug delivery systems with great potential for further future use. To pharmacotherapy, it brings a number of advantages. The combination of their size, specific properties of used excipients and a suitable drug can result in a more targeted therapy for some serious diagnoses. However, potential adverse effects are also associated with the subcellular size of the pharmaceutical form, and although research is being conducted with countless excipients and types of nanoparticles, only a small proportion of them have made it into clinical practice. This brief overview discusses these classes, it presents the basic characteristics, classification, and possible clinical use. The article also includes an up-to-date overview of representatives of individual nanoparticle drug delivery classes currently registered in the Czech Republic.

The direct tailoring of the size, composition, or number of layers belongs to the advantages of 3D printing employment in producing orodispersible films (ODFs) compared to the frequently utilized solvent casting method. This study aimed to produce porous ODFs as a substrate for medicated ink deposited by a 2D printer. The innovative semi-solid extrusion 3D printing method was employed to produce multilayered ODFs, where the bottom layer assures the mechanical properties. In contrast, the top layer provides a porous structure for ink entrapment. Hydroxypropyl methylcellulose and polyvinyl alcohol were utilized as film-forming polymers, glycerol as a plasticizer, and sodium starch glycolate as a disintegrant in the bottom matrix. Several porogen agents (Aeroperl® 300, Fujisil®, Syloid® 244 FP, Syloid® XDP 3050, Neusilin® S2, Neusilin® US2, and Neusilin® UFL2) acted as porosity enhancers in the two types of top layer. ODFs with satisfactory disintegration time were prepared. The correlation between the porogen content and the mechanical properties was proved. A porous ODF structure was detected in most samples and linked to the porogen content. SSE 3D printing represents a promising preparation method for the production of porous ODFs as substrates for subsequent drug deposition by 2D printing, avoiding the difficulties arising in casting or printing medicated ODFs directly.

The growing need for processing natural lipophilic and often volatile substances such as thymol, a promising candidate for topical treatment of intestinal mucosa, led us to the utilization of solid-state nuclear magnetic resonance (ss-NMR) spectroscopy for the rational design of enteric pellets with a thymol self-emulsifying system (SES). The SES (triacylglycerol, Labrasol®, and propylene glycol) provided a stable o/w emulsion with particle size between 1 and 7 µm. The ex vivo experiment confirmed the SES mucosal permeation and thymol delivery to enterocytes. Pellets W90 (MCC, Neusilin®US2, chitosan) were prepared using distilled water (90 g) by the M1–M3 extrusion/spheronisation methods varying in steps number and/or cumulative time. The pellets (705–740 µm) showed mostly comparable properties—zero friability, low intraparticular porosity (0–0.71%), and relatively high density (1.43–1.45%). They exhibited similar thymol release for 6 h (burst effect in 15th min ca. 60%), but its content increased (30–39.6 mg/g) with a shorter process time. The M3-W90 fluid-bed coated pellets (Eudragit®L) prevented undesirable thymol release in stomach conditions (<10% for 3 h). A detailed, ss-NMR investigation revealed structural differences across samples prepared by M1–M3 methods concerning system stability and internal interactions. The suggested formulation and methodology are promising for other lipophilic volatiles in treating intestinal diseases.

Abstract Porcine circovirus type 2 is the main causative agent of post-weaning multisystemic wasting syndrome, which affects the immune system of swine and causes widespread epidemics in livestock farms resulting in significant piglet mortality and economic losses every year. Although several commercial vaccines were developed, the efficiency and safety need to be improved. Therefore, we have engineered the chimeric complex containing PCV2bCap protein based on virus like particles (VLPs) and the mouse polyomavirus (MPyV) as VLPs represent modern and safe alternative of classical vaccine with high B cells stimulating activity. The ability of this complex to induce an immune response in both mouse and pig models in vivo were evaluated. Firstly, experimental mice were divided into 4 groups and immunized with sterile buffer and VP1-PCV2bCap with different adjuvants, the immune response was monitored for 10 weeks. Robust immune response was detected after the first immunization and gradually increased after the second and third dose, especially in mice immunized by recombinant protein with Emulsigen (10%) as an adjuvant. Subsequently, to confirm the vaccine efficacy in a target organism, 8-week-old piglets were immunized with VP1-PCV2bCap protein with Emulsigen (10%). The levels of anti-PCV2b specific IgG antibodies were significantly increased in piglets after the second immunization. Finally, strong neutralizing activity of these antibodies was confirmed in PK-15 cells infected with PCV2 Stoon 1010. VP1-PCV2bCap protein complex appears as a promising candidate vaccine for preventing disease associated with PCV2 infection in pigs.

Allergen immunotherapy (AIT) is the only currently available medical intervention that can limit the natural course of allergic rhinitis and lead to long-term disease modification [1]. Although the subcutaneous route of immunization has previously been considered a reference for AIT, it is now well established that sublingual immunotherapy (SLIT) is an effective and safer alternative and has recently been explored in food allergy with promising results [2]. The excellent safety profile of SLIT can be explained by the fact that oral tissues constitute an immune-privileged gateway containing few proinflammatory cells and exhibiting an allergen-tolerogenic phenotype prone to orient immune responses toward a Th1/Treg-cell profile [3].

Microparticles are widely used in myriad fields such as pharmaceuticals, foods, cosmetics, and other industrial fields. Compared with traditional methods for synthesizing microparticles, microfluidic techniques provide very powerful platforms for creating highly controllable emulsion droplets as templates for fabricating uniform microparticles with advanced structures and functions. Microfluidic techniques can generate emulsion droplets with precisely controlled size, shape, and composition. A more precise preparation process brings an effective tool to control the release profile of the drug and introduces an easily accessible reproducibility. The paper gives information about basic droplet-based set-ups and examples of attainable microparticle types preparable by this method.

Successful mucosal administration and delivery of drugs still pose a great challenge.However, the possibility to deliver not only small drug molecules but also macromolecular drugs and nanoparticles via mucosal surfaces represents a great opportunity.Rapid onset of drug action, avoidance of first-pass metabolism, and high immunocompetence of mucosa are some of the important features for mucosal drug and vaccine delivery.The use of mucoadhesive drug delivery systems, systems with fast dissolving properties, and nanomaterials with mucus penetration properties are examples of successful strategies to achieve effective mucosal drug and vaccine delivery.Non-keratinized mucosa of the oral cavity, the nasal and vaginal mucosa represent favorable sites of drug administration.Polymer nanofibers have attracted much attention because of remarkable characteristics such as a large surface area to volume ratio and high porosity.Nanofibers have been extensively used for different biomedical applications including wound dressing, tissue engineering, and drug delivery.Among their fabrication methods, the introduction of electrospinning technique was an important step toward achieving the goal of large scale industrial production of nanofiber-based drug delivery systems used in mucosal applications.This chapter provides an overview on all aspects of mucosal drug and vaccine delivery using nanofibers.

Hydroxypropylmethylcellulose (HPMC), also known as Hypromellose, is a traditional pharmaceutical excipient widely exploited in oral sustained drug release matrix systems. The choice of numerous viscosity grades and molecular weights available from different manufacturers provides a great variability in its physical-chemical properties and is a basis for its broad successful application in pharmaceutical research, development, and manufacturing. The excellent mucoadhesive properties of HPMC predetermine its use in oromucosal delivery systems including mucoadhesive tablets and films. HPMC also possesses desirable properties for formulating amorphous solid dispersions increasing the oral bioavailability of poorly soluble drugs. Printability and electrospinnability of HPMC are promising features for its application in 3D printed drug products and nanofiber-based drug delivery systems. Nanoparticle-based formulations are extensively explored as antigen and protein carriers for the formulation of oral vaccines, and oral delivery of biologicals including insulin, respectively. HPMC, being a traditional pharmaceutical excipient, has an irreplaceable role in the development of new pharmaceutical technologies, and new drug products leading to continuous manufacturing processes, and personalized medicine. This review firstly provides information on the physical-chemical properties of HPMC and a comprehensive overview of its application in traditional oral drug formulations. Secondly, this review focuses on the application of HPMC in modern pharmaceutical technologies including spray drying, hot-melt extrusion, 3D printing, nanoprecipitation and electrospinning leading to the formulation of printlets, nanoparticle-, microparticle-, and nanofiber-based delivery systems for oral and oromucosal application. Hypromellose is an excellent excipient for formulation of classical dosage forms and advanced drug delivery systems. New methods of hypromellose processing include spray draying, hot-melt extrusion, 3D printing, and electrospinning.

Hydroxypropylmethylcellulose (HPMC), also known as Hypromellose, is a traditional pharmaceutical excipient widely exploited in oral sustained drug release matrix systems. The choice of numerous viscosity grades and molecular weights available from different manufacturers provides a great variability in its physical-chemical properties and is a basis for its broad successful application in pharmaceutical research, development, and manufacturing. The excellent mucoadhesive properties of HPMC predetermine its use in oromucosal delivery systems including mucoadhesive tablets and films. HPMC also possesses desirable properties for formulating amorphous solid dispersions increasing the oral bioavailability of poorly soluble drugs. Printability and electrospinnability of HPMC are promising features for its application in 3D printed drug products and nanofiber-based drug delivery systems. Nanoparticle-based formulations are extensively explored as antigen and protein carriers for the formulation of oral vaccines, and oral delivery of biologicals including insulin, respectively. HPMC, being a traditional pharmaceutical excipient, has an irreplaceable role in the development of new pharmaceutical technologies, and new drug products leading to continuous manufacturing processes, and personalized medicine. This review firstly provides information on the physical-chemical properties of HPMC and a comprehensive overview of its application in traditional oral drug formulations. Secondly, this review focuses on the application of HPMC in modern pharmaceutical technologies including spray drying, hot-melt extrusion, 3D printing, nanoprecipitation and electrospinning leading to the formulation of printlets, nanoparticle-, microparticle-, and nanofiber-based delivery systems for oral and oromucosal application.

Hypromellose, a semi-synthetic derivative of cellulose, is by far the most commonly used hydrophilic polymer for the development of oral controlled release dosage forms. Modulation of drug release can be achieved by combination of different viscosity grades of hypromellose or combination with other polymers including water insoluble, non-ionic or ionic polymers. These combinations of excipients are widely used in the formulation of standard and also modem dosage forms including matrix tablets, multilayer tablets, minitablets, floating gastroretentive system, mucoadhesive dosage forms, micro- and nanopartides, 3D printed dosage forms, and nanofiber-based drug delivery systems.

Currently, the method of external ionic gelation for the preparation of alginate particles is successfully used not only in the field of pharmacy and medicine, but also especially in the field of biotechnology. Therefore, the preparation of alginate particles and their subsequent evaluation using principal component analysis was the key task of our experiment. To optimize this method, we focused on the evaluation of the effect of formulation (the polymer concentration, the hardening solution concentration) and process parameters (the outer diameter of the injection needle) on the properties of the resulting beads (yield, sphericity factor, equivalent diameter and swelling capacity at pH 6). Using multivariate data analysis, the major influence on the resulting properties of the prepared particles was confirmed only in sodium alginate concentration. Obtained results verified the reliable and safe potential of the external ionic gelation for preparation alginate-based particulate dosage forms.

The aim of the present study was to investigate the suitability of insoluble Eudragit® water dispersions (NE, NM, RL, and RS) for direct high-shear granulation of very soluble levetiracetam in order to decrease its burst effect from HPMC K100M matrices. The process characteristics, ss-NMR analysis, in vitro dissolution behavior, drug release mechanism and kinetics, texture profile analysis of the gel layer, and PCA analysis were explored. An application of water dispersions directly on levetiracetam was feasible only in a multistep process. All prepared formulations exhibited a 12-hour sustained release profile characterized by a reduced burst effect in a concentration-dependent manner. No effect on swelling extent of HPMC K100M was observed in the presence of Eudragit®. Contrary, higher rigidity of formed gel layer was observed using combination of HPMC and Eudragit®. Not only the type and concentration of Eudragit®, but also the presence of the surfactant in water dispersions played a key role in the dissolution characteristics. The dissolution profile close to zero-order kinetic was achieved from the sample containing levetiracetam directly granulated by the water dispersion of Eudragit® NE (5% of solid polymer per tablet) with a relatively high amount of surfactant nonoxynol 100 (1.5%). The initial burst release of drug was reduced to 8.04% in 30 min (a 64.2% decrease) while the total amount of the released drug was retained (97.02%).

Development of tools for direct thrombus imaging represents a key step for diagnosis and treatment of stroke. Nanoliposomal carriers of contrast agents and thrombolytics can be functionalized to target blood thrombi by small protein binders with selectivity for fibrin domains uniquely formed on insoluble fibrin. We employed a highly complex combinatorial library derived from scaffold of 46 amino acid albumin-binding domain (ABD) of streptococcal protein G, and ribosome display, to identify variants recognizing fibrin cloth in human thrombus. We constructed a recombinant target as a stretch of three identical fibrin fragments of 16 amino acid peptide of the Bβ chain fused to TolA protein. Ribosome display selection followed by large-scale Enzyme-Linked ImmunoSorbent Assay (ELISA) screening provided four protein variants preferentially binding to insoluble form of human fibrin. The most specific binder variant D7 was further modified by C-terminal FLAG/His-Tag or double His-tag for the attachment onto the surface of nanoliposomes via metallochelating bond. D7-His-nanoliposomes were tested using in vitro flow model of coronary artery and their binding to fibrin fibers was demonstrated by confocal and electron microscopy. Thus, we present here the concept of fibrin-targeted binders as a platform for functionalization of nanoliposomes in the development of advanced imaging tools and future theranostics.

New synthetic aminooxy lipid was designed and synthesized as a building block for the formulation of functionalised nanoliposomes (presenting onto the outer surface of aminooxy groups) by microfluidic mixing. Orthogonal binding of cellular mannan (Candida glabrata (CCY 26-20-1) onto the outer surface of functionalised nanoliposomes was modified by orthogonal binding of reducing termini of mannans to oxime lipids via a click chemistry reaction based on aminooxy coupling (oxime ligation). The aminooxy lipid was proved as a suitable active component for preparation of functionalised nanoliposomes by the microfluidic mixing method performed with the instrument NanoAssemblr™. This "on-chip technology" can be easily scaled-up. The structure of mannan-liposomes was visualized by transmission and scanning electron microscopy, including immunogold staining of recombinant mannan receptor bound onto mannosylated-liposomes. The observed structures are in a good correlation with data obtained by DLS, NTA, and TPRS methods. In vitro experiments on human and mouse dendritic cells demonstrate selective internalisation of fluorochrome-labelled mannan-liposomes and their ability to stimulate DC comparable to lipopolysaccharide. We describe a potentially new drug delivery platform for mannan receptor-targeted antimicrobial drugs as well as for immunotherapeutics. Furthermore, the platform based on mannans bound orthogonally onto the surface of nanoliposomes represents a self-adjuvanted carrier for construction of liposome-based recombinant vaccines for both systemic and mucosal routes of administration.

The solubility of weakly basic drugs in passage through gastrointestinal tract leads to their pH-dependent release from extended release formulations and to lower drug absorption and bioavailability. The aim of this study was to modulate the micro-environmental pH of hypromellose/montanglycol wax matrices and to observe its influence on the release of weakly basic drug verapamil hydrochloride (VH) with a pH-dependent solubility with respect to gel layer formation and its dynamics. For this study, malic and succinic acids differing in their solubility and pKa were selected as pH modifiers. The dissolution studies were performed by the method of changing pH. Within the same conditions, pH, thickness, and penetration force of the gel layer were measured as well. From the PCA sub-model, it is evident that a higher acid concentration ensured lower gel pH and conditions for higher drug solubility, thus creating larger gel layer with smaller rigidity, resulting in higher VH release during the dissolution test. Incorporation of stronger and more soluble malic acid (100 mg/tablet) created the most acidic and the thickest gel layer through which a total of 74% of VH was released. Despite having lower strength and solubility, matrices containing succinic acid (100 mg/tablet) released a comparable 71% of VH in a manner close to zero-order kinetics. The thinner and less rigid gel layers of the succinic acid matrices allowed an even slightly faster VH release at pH 6.8 than from matrices containing malic acid. Thus acid solubility is more parametrically significant than acid pKa for drug release at pH 6.8.

Nanofibre-based mucoadhesive films were invented for oromucosal administration of nanocarriers used for delivery of drugs and vaccines. The mucoadhesive film consists of an electrospun nanofibrous reservoir layer, a mucoadhesive film layer and a protective backing layer. The mucoadhesive layer is responsible for tight adhesion of the whole system to the oral mucosa after application. The electrospun nanofibrous reservoir layer is intended to act as a reservoir for polymeric and lipid-based nanoparticles, liposomes, virosomes, virus-like particles, dendrimers and the like, plus macromolecular drugs, antigens and/or allergens. The extremely large surface area of nanofibrous reservoir layers allows high levels of nanoparticle loading. Nanoparticles can either be reversibly adsorbed to the surface of nanofibres or they can be deposited in the pores between the nanofibres. After mucosal application, nanofibrous reservoir layers are intended to promote prolonged release of nanoparticles into the submucosal tissue. Reversible adsorption of model nanoparticles as well as sufficient mucoadhesive properties were demonstrated. This novel system appears appropriate for the use in oral mucosa, especially for sublingual and buccal tissues. To prove this concept, trans-/intramucosal and lymph-node delivery of PLGA-PEG nanoparticles was demonstrated in a porcine model. This system can mainly be used for sublingual immunization and the development of “printed vaccine technology”.