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

Design of Coamorphous Systems for Flavonoid Components Coformed with Meglumine by Integrating Theory-Model-Experiment Techniques

Flavonoids represent an extensive group of phenolic substances in vegetables, fruits, grains, tea, flowers, etc., which show a variety of biological activities in various nutraceutical, cosmetic, and medicinal fields. Despite demonstrating multifunctional bioactive properties relevant to nutraceutical and pharmaceutical applications, their clinical utilization faces challenges due to their generally low water solubility. This study established a systematic methodology combining computational modeling and experimental validation for developing flavonoid-meglumine (MEG) coamorphous formulations. The initial screening identified 13 flavonoid compounds exhibiting favorable miscibility with MEG from 15 candidates through Hansen solubility parameter analysis. Subsequent molecular dynamics simulations revealed potential hydrogen bond formation in six selected flavonoids (BAI, HES, NAR, KAE, QUE, and ISO) with MEG. Then, six flavonoid coamorphous systems were successfully prepared via the melt-quenching method and characterized by PLM, PXRD, and differential scanning calorimetry. FTIR and radial distribution function analysis results collectively confirmed intermolecular hydrogen bond interactions within these binary systems. In vitro dissolution studies revealed significant solubility/dissolution enhancement in both pH 1.2 HCl and pH 6.8 phosphate buffers, maintaining long-term supersaturation for all six coamorphous formulations. Meanwhile, six flavonoid coamorphous systems had superior stability over individual flavonoid amorphous components, which were attributed to the stronger intermolecular interactions by higher binding energy calculation. These results indicated that the obtained flavonoid coamorphous systems performed a promising application potential in functional products. Importantly, this study presents a novel design framework integrating computational prediction, molecular modeling, and experimental validation for systematic screening of flavonoid coamorphous formulations.

A New Screening Strategy for Flavonoid Components to Obtain a Satisfactory Co-Amorphous System with Piperine

Flavonoids are a large class of compounds with a variety of biological activities. Nevertheless, their therapeutic application remains limited due to the generally low water solubility. In the present study, an integrated approach was provided to guide the design of flavonoid co-amorphous systems co-formed with piperine (PIP). Firstly, 7 flavonoid compounds showed good miscibility with PIP from 13 flavonoid candidates. Then, molecular dynamics simulation confirmed hydrogen bond formation between 5 flavonoid compounds (i.e., BAI, HES, ISO, NAR and KAE) and PIP. Herein, 5 flavonoid compounds were successfully co-amorphized with PIP by the melting and quench cooling method, which were proved via PLM, PXRD and DSC measurements. FTIR results showed the potential hydrogen bond interactions between -OH of flavonoid molecules and C = O of PIP molecule in the formed co-amorphous systems, which were consistent with RDF analyses in molecular models. For dissolution tests, 4 co-amorphous systems (i.e., BAI-PIP CM, HES-PIP CM, ISO-PIP CM and NAR-PIP CM) appeared abnormally reduced dissolution compared to their original crystalline counterparts arising from the formation of gels during dissolution, while only KAE-PIP CM displayed significantly enhanced dissolution (5.83-fold of crystalline KAE at 12 h) with long-time supersaturated concentration. Meanwhile, KAE-PIP CM kept physically stable at least 3 months under 25°C and 40°C conditions, and possessed excellent physical stability over individual amorphous components, which was attributed to the stronger intermolecular interaction by higher binding energy analysis. Therefore, this study provides a design strategy to guide the screening of flavonoid co-amorphous systems through combining theory-model-experiment techniques.

Preparation and characterization of immediate release 3D printed tablets using hot melt extruded amorphous cyclosporine a filament

3D printing technology is gaining attention as a next-generation approach to drug formulation. Among 3D printing techniques, fused deposition modeling is cost-effective but depends heavily on suitable filaments. Hot melt extrusion enables filament production by incorporating poorly water-soluble drugs like cyclosporine A into polymers to form solid dispersions. However, achieving immediate release formulations with 3D printing remains challenging due to issues such as inadequate tablet disintegration or drug entrapment within the polymer matrix. This study aimed to develop and evaluate immediate release 3D-printed cyclosporine A tablets using HME filaments. Three parameters were modified in the 3D printing process: varying fill speeds, infill densities, and channel lengths. Filaments composed of Kollidon® VA 64 and HPC-SSL (1:1) were used to print tablets. Solid-state analysis confirmed cyclosporine A 's amorphous state and partial crystallinity in Xylisorb® 300. Dissolution studies revealed that lower infill densities (30%) and fewer walls enhanced drug release by increasing internal void space and reducing hardness. Conversely, greater tablet height (channel length) delayed dissolution. These findings emphasize the critical role of geometric design in drug release, showcasing the potential of 3D printing to create personalized dosage forms tailored to patient needs by optimizing structural parameters.

Exploring the impact of material selection on the efficacy of hot-melt extrusion

Hot-melt extrusion (HME) has emerged as a versatile and efficient technique in pharmaceutical formulation development, particularly for enhancing the solubility and bioavailability of poorly water-soluble drugs. This review delves into the fundamental principles of HME, exploring its application in drug delivery systems. A comprehensive analysis of polymers utilized in HME, such as hydroxypropyl methylcellulose, ethyl cellulose, hydroxypropyl cellulose, and polyvinylpyrrolidone, is presented, highlighting their roles in achieving controlled drug release and improved stability. The incorporation of plasticizers, such as triacetin, poly(propylene glycol), glycerol, and sorbitol, is critical in reducing the glass transition temperature (Tg) of polymer blends, thereby enhancing the processability of HME formulations. A comparison of Tg values for various polymer-plasticizer combinations is discussed using different predictive models. For researchers and industry professionals looking to optimize drug formulation strategies, this article offers valuable insights into the mechanisms through which HME enhances drug solubility and bioavailability two critical factors in oral drug delivery. Furthermore, by reviewing recent patents and marketed formulations, the article serves as a comprehensive resource for understanding both the technical advancements and commercial applications of HME. Readers will gain a deep understanding of the role of polymers and additives in HME, alongside future perspectives on how emerging materials and techniques could further revolutionize pharmaceutical development. This review is essential for those aiming to stay at the forefront of pharmaceutical extrusion technologies and their potential to improve therapeutic outcomes. The review concludes that meticulous material selection is vital for advancing pharmaceutical manufacturing processes and ensuring optimal outcomes in HME applications, thereby enhancing the overall efficacy of drug delivery systems.

Ionic Liquid-Mediated Transdermal Delivery of Organogel Containing Cyclosporine A for the Effective Treatment of Psoriasis

The dermal delivery of peptide therapeutics that are of high molecular weight is a challenge. Cyclosporine A (CsA) is a cyclic undecapeptide with poor aqueous solubility and high molecular weight (1202 Da) indicated for psoriasis. The objective of the study was to evaluate the effect of ionic liquids mixed with the Pluronic F127 matrix in skin permeation of CsA and its efficacy in psoriasis treatment. Choline and geranic acid (CAGE) ionic liquids in a 1:2 molar ratio were mixed with Pluronic F127 (22.7%) and PEG 400 (45%) to prepare an organogel formulation. The CsA-loaded CAGE (CsA-CAGE) and CAGE-Pluronic F127 gels (CsA-CAGE-P gel) were characterized for physical and rheological characteristics. The skin transport studies showed that free CsA did not permeate across the excised porcine skin after 48 h. The amount of CsA permeated across the oleic acid (0.25% v/v) and palmitic acid (0.25% w/v) cotreated skin was found to be 244 ± 4 and 1236 ± 17 μg/cm2, respectively. The application of CsA-CAGE and CsA-CAGE-P gel enhanced CsA flux by 110- and 135-fold, respectively, compared with the control. The thermal analysis and biophysical studies changed the barrier property of the skin significantly (p < 0.05) after incubation with CAGE and CAGE-P gel. The pharmacokinetic studies in the rat model showed that topical application of CsA-CAGE-P gel provided 2.6- and 1.9-fold greater C max and AUC0-t, respectively, compared to the control group. In vitro-in vivo level A correlations were established with R 2 values of 0.991 and 0.992 for both linear and polynomial equations for the CsA-CAGE-P gel formulation using the Wagner-Nelson method. The topical application of CsA-CAGE-P gel (10 mg/kg) on an imiquimod-induced plaque psoriatic model reduced the area of the psoriasis and severity index (PASI) score significantly for erythema and scaling, reversing the changes to skin thickness, blood flow rate, and transepidermal water loss. Together, CAGE-Pluronic F127 organogel was developed as an effective topical formulation for the local and systemic delivery of CsA for the treatment of psoriasis.

Two Novel Hydrate Salts of Norfloxacin with Phenolic Acids and Their Physicochemical Properties

Norfloxacin (NORF) is a broad-spectrum quinolone that is widely utilized for the treatment of various bacterial infections and is considered one of the most commonly used fluoroquinolone antibiotics. However, NORF's clinical utility is limited by its poor water solubility and relatively low oral bioavailability. This study presents an optimization and synergistic enhancement approach through salt/co-crystal, aiming to maximize the biopharmaceutical properties of NORF with the use of phenolic acid. Following this strategy, two new hydrate salts of NORF with phenolic acid, namely, NORF-3,5-DBA hydrate (salt 1) and NORF-VA hydrate (salt 2), were prepared and systematically confirmed. Two hydrate salts were produced by means of the slow evaporation crystallization method, and the structures were determined through single-crystal X-ray diffraction (SCXRD). Additionally, powder X-ray diffraction (PXRD), Fourier-transform infrared (FT-IR) spectroscopy, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and high-performance liquid chromatography (HPLC) were applied to analyze the features of the two salts. The experimental results indicated that the formation of the two salts could enhance the solubility and improve the release behavior of NORF. Interestingly, the physicochemical properties of NORF were significantly improved as a result, leading to an enhancement in its antibacterial activity. This was demonstrated by the enhanced inhibition of bacterial strains and the lower minimum inhibitory concentration values.

Modeling the Structure of Ketoprofen-Poly(vinylpyrrolidone) Amorphous Solid Dispersions with Empirical Potential Structure Refinements of X-ray Scattering Data

The metastability of amorphous formulations poses barriers to their safe and widespread commercialization. The propensity of amorphous solid dispersions (ASDs) to crystallize is directly linked to their molecular structure. Amorphous structures are inherently complex and thus difficult to fully characterize by experiments, which makes structural simulations an attractive route for investigating which structural characteristics correlate with ASD stability. In this study, we use empirical potential structure refinement (EPSR) to create molecular models of ketoprofen-poly(vinylpyrrolidone) (KTP/PVP) ASDs with 0-75 wt % drug loading. The EPSR technique uses X-ray total scattering measurements as constraints, yielding models that are consistent with the X-ray data. We perform several simulations to assess the sensitivity of the EPSR approach to input parameters such as intramolecular bond rotations, PVP molecule length, and PVP tacticity. Even at low drug loading (25 wt %), ∼40% of KTP molecules participate in KTP-KTP hydrogen bonding. The extent of KTP-PVP hydrogen bonding does not decrease significantly at higher drug loadings. However, the models' relative uncertainties are too large to conclude whether ASDs' lower stabilities at high drug loadings are due to changes in drug-excipient hydrogen bonding or a decrease in steric hindrance of KTP molecules. This study illustrates how EPSR, combined with total scattering measurements, can be a powerful tool for investigating structural characteristics in amorphous formulations and developing ASDs with improved stability.

Comparison of the liquisolid technique and co-milling for loading of a poorly soluble drug in inorganic porous excipients

Drug loading into mesoporous carriers may help to improve the dissolution of poorly aqueous-soluble drugs. However, both preparation method and carrier properties influence loading efficiency and drug release. Accordingly, this study aimed to compare two preparation methods: formulation into liquisolid systems (LSS) and co-milling for their efficiency in loading the poorly soluble model drug cyclosporine A (CyA) into mesoporous magnesium aluminometasilicate Neusilin® US2 (NEU) or functionalized calcium carbonate (FCC). Scanning electron microscopy was used to visualize the morphology of the samples and evaluate the changes that occurred during the drug loading process. The solid-state characteristics and physical stability of the formulations, prepared at different drug concentrations, were determined using X-ray powder diffraction. In vitro release of the drug was evaluated in biorelevant media simulating intestinal fluid. The obtained results revealed improved drug release profiles of the formulations when compared to the milled (amorphous) CyA alone. The dissolution of CyA from LSS was faster in comparison to the co-milled formulations. Higher drug release was achieved from NEU than FCC formulations presumably due to the higher pore volume and larger surface area of NEU.

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

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

Accelerated Oral Healing by Angelica gigas Nakai from Hot Melt Extrusion Technology: An In Vitro Study

Background and Objectives: In spite of the oral environment being healing-prone, its dynamic changes may affect wound healing. The purpose of this study was to assess the oral wound healing effect of Angelica gigas Nakai (AG) prepared by hot-melt extrusion. Materials and Methods: Human gingival fibroblast (HGF) cells were treated with AG or AG via hot-melt extrusion (AGH) for 24 h to determine the optimal concentration. For evaluating the anti-inflammatory effect of AG and AGH, a nitric oxide assay was performed under lipopolysaccharide (LPS) stimulation. The wound-healing effects of AG and AGH were evaluated using cell proliferation/migration assays and wound-healing marker expression through qRT-PCR. Results: Both AG and AGH showed no cytotoxicity on HGH cells. Regarding nitric oxide production, AGH significantly decreased LPS-induced nitric oxide production (p < 0.05). AGH showed a significantly positive result in the cell proliferation/cell migration assay compared with that in AG and the control. Regarding wound healing marker expression, AGH showed significantly greater VEGF and COL1α1 expression levels than those in the others (p < 0.05), whereas α-SMA expression was significantly different among the groups. Conclusions: Within the limits of this study, AGH accelerated oral wound healing in vitro.

Cyclosporine A-loaded chitosan extra-fine particles for deep pulmonary drug delivery: In vitro and in vivo evaluation

In this study, the extra-fine dry powder inhalers (DPIs) with chitosan (CS) as carrier were successfully prepared by ionic gel method combined with spray drying technique for deep pulmonary drug delivery of Cyclosporine A (CsA), using sodium hyaluronate (SHA) and sodium polyglutamate (SPGA) as polyanions. The CsA-loaded DPIs of CS-SHA-CsA and CS-SPGA-CsA were spherical particles with wrinkles on the surface, which were more conducive to improving the aerosol properties. The aerodynamic evaluation of CS-SHA-CsA and CS-SPGA-CsA showed that the fine particle fraction (FPF) reached up to 79.22 ± 2.12% and 81.55 ± 0.43%, while the emitted fraction (EF) reached 77.15 ± 1.46% and 78.29 ± 2.10%. In addition, the mass median aerodynamic diameter (MMAD) was calculated as 1.58 ± 0.04 μm and 1.94 ± 0.02 μm for CS-SHA-CsA and CS-SPGA-CsA, indicating that they were all extra-fine particles (d < 2 μm). These in vitro aerodynamic results showed that CS-SHA-CsA and CS-SPGA-CsA could reach the smaller airways, further improving therapeutic efficiency. The cell viability on A549 cell line results showed that CS-SHA-CsA and CS-SPGA-CsA were safe to deliver CsA to lungs. The in vivo pharmacokinetics consequence proved that inhalation administration of CS-SHA-CsA and CS-SPGA-CsA could significantly improve the bioavailability of CsA in vivo compared with oral administration of Neoral®, effectively reducing the risk of a series of adverse effects caused by systemic overexposure. In addition, the safety and compatibility of DPIs using SHA, SPGA, and CS as carriers for pulmonary drug delivery was verified by in vivo repeated dose inhalation toxicity. From these findings, the extra-fine DPIs with CS as carrier could be a viable delivery option for the deep pulmonary drug delivery of CsA relative to orally administered drug.

Development of Large Hollow Particles for Pulmonary Delivery of Cyclosporine A

The purpose of this study was to prepare large hollow particles (LHPs) by spray drying for pulmonary delivery of cyclosporine A (CsA), using L-Leucine (LEU) and hydroxypropyl methylcellulose (HPMC) as excipients and ammonium bicarbonate (AB) as a porogen. The prepared LHPs were spherical particles composed of both CsA and LEU on the surface and HPMC on the inner layer. The formulation of CsA-LEU-0.8HPMC-AB as typical LHPs showed excellent in vitro aerodynamic performance with a minimum mass median aerodynamic diameter (MMAD) of 1.15 μm. The solubility of CsA-LEU-0.8HPMC-AB was about 5.5-fold higher than that of raw CsA, and the dissolution of CsA-LEU-0.8HPMC-AB suggested that the drug was released within 1 h. The cell viability of the A549 cell line showed that CsA-LEU-0.8HPMC-AB was safe for delivering CsA to the lungs. In addition, inhalation administration of CsA-LEU-0.8HPMC-AB with the Cmax and AUC0-∞ increasing by about 2-fold and 2.8-fold compared with the oral administration of Neoral® could achieve therapeutic drug concentrations with lower systemic exposure and significantly improve the in vivo bioavailability of CsA. From these findings, the LHPs, with the advantage of avoiding alveolar macrophage clearance, could be a viable choice for delivering CsA by inhalation administration relative to oral administration.

Hard Gelatin Capsules Containing Hot Melt Extruded Solid Crystal Suspension of Carbamazepine for improving dissolution: Preparation and In vitro Evaluation

Aqueous solubility is one of the key parameters for achieving the desired drug concentration in systemic circulation for better therapeutic outcomes. Carbamazepine (CBZ) is practically insoluble in water, is a BCS class II drug, and exhibits dissolution-dependent oral bioavailability. This study explored a novel application of hot-melt extrusion in the manufacture and development of a thermodynamically stable solid crystal suspension (SCS) to improve the solubility and dissolution rate of CBZ. The SCSs were prepared using sugar alcohols, such as mannitol or xylitol, as crystalline carriers. The drug-sugar blend was processed by hot melt extrusion up to 40 % (w/w) drug loading. The extruded SCS was evaluated for drug content, saturation solubility, differential scanning calorimetry (DSC), Fourier-transform infrared (FTIR) spectroscopy, powder X-ray diffraction (PXRD), scanning electron microscopy (SEM), in vitro release, and stability studies. The physicochemical characterization revealed the highly crystalline existence of pure drug, pure carriers, and extruded SCS. FTIR analysis did not reveal any physical or chemical incompatibilities between the drug and sugar alcohols and showed a homogeneous CBZ distribution within respective crystalline carriers. The SEM micrographs of the solidified SCS revealed the presence of approximately 100 μm crystalline agglomerates. In vitro dissolution and solubility studies showed that the CBZ dissolution rate and solubility were improved significantly from both crystalline carriers for all tested drug loads. The SCSs showed no significant changes in drug content, in vitro release profiles, and thermal characteristics over 3 months of storage at accelerated stability conditions (40±2°C/75±5% RH). As a result, it can be inferred that the SCS strategy can be employed as a contemporary alternative technique to improve the dissolution rate of BCS class II drugs via HME technology.

An Enhanced Dissolving Cyclosporin-A Inhalable Powder Efficiently Reduces SARS-CoV-2 Infection In Vitro

This work illustrates the development of a dry inhalation powder of cyclosporine-A for the prevention of rejection after lung transplantation and for the treatment of COVID-19. The influence of excipients on the spray-dried powder's critical quality attributes was explored. The best-performing powder in terms of dissolution time and respirability was obtained starting from a concentration of ethanol of 45% (v/v) in the feedstock solution and 20% (w/w) of mannitol. This powder showed a faster dissolution profile (Weibull dissolution time of 59.5 min) than the poorly soluble raw material (169.0 min). The powder exhibited a fine particle fraction of 66.5% and an MMAD of 2.97 µm. The inhalable powder, when tested on A549 and THP-1, did not show cytotoxic effects up to a concentration of 10 µg/mL. Furthermore, the CsA inhalation powder showed efficiency in reducing IL-6 when tested on A549/THP-1 co-culture. A reduction in the replication of SARS-CoV-2 on Vero E6 cells was observed when the CsA powder was tested adopting the post-infection or simultaneous treatment. This formulation could represent a therapeutic strategy for the prevention of lung rejection, but is also a viable approach for the inhibition of SARS-CoV-2 replication and the COVID-19 pulmonary inflammatory process.

Fabrication of a Shell-Core Fixed-Dose Combination Tablet Using Fused Deposition Modeling 3D Printing

Fixed-dose combinations (FDCs) achieve optimal goals for treatment with minimal side effects, decreased administration of large number of tablets, thus, greater convenience, and improved patient compliance. However, conventional FDCs do not have a guaranteed place in the future of patient-centered drug development because of the difficulty in achieving dose titration of each drug for individualized specific health needs and desired therapeutic outcomes. In the current study, FDCs of two antihypertensive drugs were fabricated with two distinct compartments using fused deposition modeling three-dimensional printing (FDM-3DP). Atorvastatin calcium and Amlodipine besylate loaded filaments were prepared by hot-melt extrusion. Shell-core FDC tablets were designed to have different infills for individualized dosing. Differential scanning calorimetry and powder X-ray diffraction revealed that both drugs were transformed into amorphous forms within the polymeric carriers. The fabricated tablets met the United States Pharmacopeia acceptance criteria for friability, content uniformity, and dissolution testing. The fabricated tablets were stable at room temperature with respect to drug content and thermal behavior over six months. This dynamic dosage form provides flexibility in dose titration and maintains the advantages of FDCs, thus achieving optimal therapeutic outcomes in different healthcare facilities.