Preparation, Physicochemical Characterisation and DoE Optimisation of a Spray-Dried Dry Emulsion Platform for Delivery of a Poorly Soluble Drug, Simvastatin

A novel Posaconazole oral formulation using spray dried solid dispersion technology: in-vitro and in-vivo study

SD (solid dispersion) technology is one of the well-recognized solubility enhancement methods; but the use of versatile carriers in ASD (amorphous SD) to achieve the added advantage of modified release along with solubility improvement is an emerging area of exploration. Spray drying is a widely used technology with excellent scalability and product attributes. The SD carriers explored were Soluplus®, possessing excellent solubilization properties that may enhance bioavailability and is suitable for innovative processing, and Gelucire 43/01, a lipid polymer utilized in a non-effervescent-based floating gastro-retentive DDS for the modified release of API. The CPPs of spray drying were screened during preliminary trials, and the formulation variables were optimized using a 32 Full Factorial Design. All nine batches were evaluated for % yield, % drug content, flow properties, floating behavior, saturation solubility, and in-vitro drug release in 0.1 N HCl. The optimized batch characterized based on DSC (differential scanning calorimetry) and PXRD (powder X-ray diffraction) confirmed the amorphous nature of entrapped drug in SDD (spray-dried dispersion). Particle size analysis and SEM (scanning electron microscopy) demonstrated micron size irregular shaped particles. Residual solvent analysis by GCMS-HS confirmed the elimination of organic solvents from SDD. The optimized batch was found stable after 6 months stability study as per ICH guidelines. In-vivo roentgenography study in New Zealand white rabbit showed the residence of SDD in gastric environment for sufficient time. The pharmacokinetic study was performed in male Sprague-Dawley rats to determine the bioavailability of developed SDD based product in fasting and fed conditions, and to compare the data with marketed Noxafil formulation. The current research is focused on the development of a novel ternary SDD (spray-dried dispersion)-based gastro-retentive formulation for an anti-fungal drug Posaconazole.

Development of Delayed Release Oral Formulation Comprising Esomeprazole Spray Dried Dispersion Utilizing Design of Experiment As An Optimization Strategy

Solid dispersion (SD) technology is one of the most widely preferred solubility enhancement methods, especially for Biopharmaceutics classification system class II and IV drugs. Since the last decade, its application for the dual purpose of solubility hike and modified release using novel carriers has been in demand for its added advantages. Spray drying is a commercially accepted technique with high aspects of scalability and product characteristics. The current study used spray-dried dispersion to design delayed release capsule for the proton pump inhibitor esomeprazole. The SD carrier hydroxypropyl methylcellulose acetate succinate-medium grade (HPMCAS-MF) enhanced solubility, inhibited precipitation of saturated drug solutions, and allowed enteric release owing to its solubility above pH 6. The proposed approach avoided compression, coating with enteric polymers, and the development of multi-particulate pellet-based formulations, improving manufacturing feasibility. The formulation was optimized using Box-Behnken design, considering significant formulation variables like HPMCAS-MF proportion and critical process parameters like feed flow rate and inlet temperature. The optimized spray-dried dispersion were characterized based on Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), powder X-ray diffraction (PXRD), and scanning electron microscopy (SEM) and also evaluated for solubility, in vitro drug release, residual solvent content, and stability testing. Response surface methodology optimization anticipated that formulation variables affected solubility and release profile, whereas CPPs affected yield. The design space was developed via overlay plot based on constraints specified to attain the desired response and validated using three checkpoint batches with desirability 1. FTIR showed active pharmaceutical ingredient-polymer compatibility. Particle size and SEM studies showed spherical particles with an average Z-value of 1.8 µ. DSC and PXRD confirmed SD's amorphous nature. The drug release investigation and release kinetics prediction utilizing DD-solver software showed a 2-h lag time with > 90% cumulative drug release up to 4 h for the DR formulation. ESM SDD were prepared by spray drying technique using the novel solid dispersion carrier HPMCAS-MF to serve the dual purpose of solubility enhancement and delayed release. The ratio of API:carrier and process variables like feed flow rate and inlet temperature were varied using the Box-Behnken Design to determine the design space of optimized product to procure the desired characteristics of solubility improvement compared to crystalline API and delayed release of PPI to avoid the degradation in the gastric environment. The developed formulation represents several benefits over the already existing marketed products.

Effect of process parameters in high shear granulation on characteristics of a novel co-processed mesoporous silica material

In this study, insights into the development and optimization of a co-processed excipient based on mesoporous silica are presented. The main advantage of such a material is that it is appropriate for direct tablet compression and has a sufficiently large specific surface area to be suitable for potential subsequent drug loading and formulation of (amorphous) solid dispersions. Our aim was to use a Design of Experiments approach to investigate which process parameters in high shear granulation affect the characteristics of such a co-processed material. The parameters included were the amount of binder (isomalt), the amount of water (granulation liquid), the water addition rate and the speed of the impeller. The responses evaluated and modelled were particle size and its distribution, specific surface area, bulk density, flowability, compressibility and compactibility. The models obtained showed good quality in terms of goodness of fit and predictive power. Active effects were identified for all responses, giving a thorough insight into factors affecting the material characteristics. Optimization experiments resulted in products with the desired characteristics (high specific surface area, large particle size, good flow and compression properties) and confirmed the validity of the generated models.

Development of Simvastatin-Loaded Particles Using Spray Drying Method for Ex Tempore Preparation of Cartridges for 2D Printing Technology

In this work, a spray drying method was developed to produce drug/polymer (simvastatin/polycaprolactone) microparticles that have the potential to be used as a pre-formulation for ex tempore preparation of 2D printing cartridges. An experimental model was designed with the process parameters set to predict the smallest particle size required for successful 2D printing. Three different types of particles (lactose, nanocellulose/lactose, calcium silicate) were produced, and the average size of the dry particles varied depending on the sampling location (cyclone, collection vessel). The encapsulation efficiency of simvastatin was highest with nanocellulose/lactose from the collection vessel. The one-month stability of simvastatin in the particles showed low content, but the addition of ascorbic acid as an antioxidant increased the chemical stability of the drug. Interestingly, the addition of antioxidants decreased the stability of simvastatin in the calcium silicate particles from the collection vessel. Dispersion of the particles in three different propylene glycol and water mixtures (10/90, 50/50, and 90/10% (v/v)), representing a printable ink medium with three different viscosity and surface tension properties, showed that nanocellulose/lactose was the most suitable antiadhesive in terms of dispersed particle size (˂1 µm). After one month of storage, the dispersed particles remained in the same size range without undesirable particle agglomeration.

Studies on spray dried topical ophthalmic emulsions containing cyclosporin A (0.05% w/w): systematic optimization, in vitro preclinical toxicity and in vivo assessments

Cyclosporin A (CsA, 0.05% w/w)-loaded positively charged emulsions were prepared based on castor oil, chitosan, poloxamer 188, glycerin and double-distilled water. To augment the shelf/storage-stability of original emulsions, the solid-dry powder for reconstitution was made by spray drying technique. The screening (Taguchi OA) and optimization (face-centered central composite) designs produced the optimized conditions for spray drying: 40 Nm3/h aspirator flow rate, 15 ml/min feed rate, 115 °C inlet temperature, 10% mannitol and 1.25% trehalose. The % drug entrapment efficiency values of original and reconstituted emulsions ranged from 73.20 ± 0.13 to 71.55 ± 1.25%. At 20 min post-dissolution, two times higher CsA release was seen from reconstituted emulsions than the original emulsions (85.78 ± 1.14 vs. 42.25 ± 1.84%) in simulated tear fluid. Using MTT assay, the reconstituted emulsions with or without CsA produced 94.512 ± 2.12 to 99.941 ± 1.89% cell viability values in HCE-2 cells. No appreciable change in capillary integrity was visualized in HET CAM following reconstituted emulsions treatment. At equivalent 15 µg drug, the in vitro protein denaturation assay showed augmented inhibition value (~ 85%) for tested CsA emulsions compared to diclofenac reference (68.30 ± 2.05) indicating enhanced anti-inflammatory activity. The CsA concentrations in multiple ocular matrices of rabbit eyes determined by the UPLC-MS/MS method attained the therapeutic drug level of 50-300 ng/ml even at 90 min post-topical instillation of both emulsions. Overall, the CsA emulsion eyedrops can be supplied as a spray dried storable intermediate product for reconstitution.

Optimization of Methionine in Inhalable High-dose Spray-dried Amorphous Composite Particles using Response Surface Method, Infrared and Low frequency Raman Spectroscopy

The influence of amino acids, other than leucine, in improving aerosolization of inhalable powders has not been widely explored. This detailed study focused on the use of methionine, another promising endogenous amino acid, in high dose spray-dried co-amorphous powders by investigating the influence of methionine proportion (0 - 20% ^w/_w), and feed concentration (0.2 - 0.8% ^w/_v) on aerosolization of kanamycin, a model drug, using a design of experiment approach. Low frequency Raman spectroscopy was used to assess the stability of the powders stored at 25 °C/53% relative humidity over 28 days. An increase in concentration of methionine was associated with an increase in fine particle fraction (FPF), with the highest FPF of 84% being achieved at 20% ^w/_w and 0.2% ^w/_v feed concentration. With an increase in feed concentration, both yield and particle size increased for all formulations; the FPF did not change except for kanamycin only formulation in which it decreased. During storage at high humidity, similar aerosolization stabilities were offered by different proportions of methionine although methionine crystallized out in all formulations. Furthermore, the crystallization was accompanied by surface enrichment of methionine on the particles. This study suggests that there is a direct relationship between methionine content and aerosolization for kanamycin-methionine amorphous matrices but feed concentration has little effect. In addition, methionine proportion has no effect on physical stability of such matrices at high humidity.

Optimization of Spray-Drying Parameters for Formulation Development at Preclinical Scale

Spray-drying dispersion (SDD) is a well-established manufacturing technique used to prepare amorphous solid dispersions (ASDs), allowing for poorly soluble drugs to have improved bioavailability. However, the process of spray-drying with multiple factors and numerous variables can lead to a lengthy development timeline with intense resource requirements, which becomes the main obstacle limiting spray-drying development at the preclinical stage. The purpose of this work was to identify optimized preset parameters for spray-drying to support the early development of ASDs suitable for most circumstances rather than individual optimization. First, a mini-DoE (Design of Experiment) study was designed to evaluate the critical interplay of two key variables for spray-drying using a BUCHI B-290 mini spray dryer: solid load and atomizing spray gas flow. The critical quality attributes (CQAs) of the ASDs, including yield, particle size, morphology, and in vitro release profile, were taken into account to identify the impact of the key variables. The mini-DoE results indicated that a 5% solid load (w/v %) and 35 mm height atomizing spray gas flow were the most optimized parameters. These predefined values were further verified using different formulation compositions, including various polymers (Eudragit L100-55, HPMCAS-MF, PVAP, and PVP-VA64) and drugs (G-F, GEN-A, Indomethacin, and Griseofulvin), a range of drug loading (10 to 40%), and scale (200 mg to 200 g). Using these predefined parameters, all ASD formulations resulted in good yields as well as consistent particle size distribution. This was despite the differences in the formulations, making this a valuable and rapid approach ideal for early development. This strategy of leveraging the preset spray-drying parameters was able to successfully translate into a reproducible and efficient spray-drying platform while also saving material and reducing developmental timelines in early-stage formulation development.

Relative bioavailability enhancement of simvastatin via dry emulsion systems: comparison of spray drying and fluid bed layering technology

Comprehensive comparisons of similar lipid based drug delivery systems produced by different technologies are scarce. Spray drying and fluid bed layering technologies were compared with respect to the process and product characteristics of otherwise similar simvastatin loaded dry emulsion systems. Fluid bed layering provided higher process yield (83.3% vs 71.5%), encapsulation efficiency (80.0% vs 68.4 %), relative one month product stability (93.8% vs 85.5%), larger and more circular particles (336 µm vs 56 µm) and lower median oil droplet size after product reconstitution in water (2.85 µm vs 4.27 µm), compared to spray drying. However, spray dried products exhibited higher drug content (22.2 mg/g vs 9.34 mg/g). An in-vivo pharmacokinetic study in rats was performed and a pharmacokinetic model was developed in order to compare the optimised simvastatin loaded dry emulsion systems, a simvastatin glyceride mimetic loaded in the dry emulsion and a simvastatin loaded SMEDDS with a reference physical mixture. Of the formulation tested, fluid bed layered pellets excelled and provided a 115% relative increase in bioavailability. Among the two technologies, fluid bed layering provided dry emulsion products with higher relative bioavailability and better product characteristics for further processing into final dosage forms.

Formulation of re-dispersible dry o/w emulsions using cellulose nanocrystals decorated with metal/metal oxide nanoparticles

This study describes for the first time the preparation of re-dispersible surfactant-free dry eicosane oil emulsion using cellulose nanocrystals (CNCs) using the freeze-drying technique. Surface properties of CNCs constitute a critical point for the stability of o/w emulsions and thus can affect both the droplet size and dispersion properties of the emulsion. Therefore, surface modification of CNCs was performed to understand its effect on the size of the obtained re-dispersible dry o/w eicosane emulsion. Decoration of the CNC surface with metal and metal oxide nanoparticles was conducted through the available alcoholic groups of glycosidic units of CNC, which played a dual role in reducing and stabilizing nanoparticles. Of these nanoparticles, silver (AgNPs), gold (AuNPs), copper oxide (CuO-NPs), and iron oxide (Fe₃O₄-NPs) nanoparticles were prepared via a facile route using alkali activated CNCs. Thorough characterizations pertaining to the as-prepared nanoparticles and their re-dispersible dry eicosane o/w emulsions were investigated using UV-vis spectroscopy, TEM, XRD, particle size, zeta potential, and STEM. Results confirmed the ability of CNCs to stabilize and/or reduce the formed nanoparticles with different sizes and shapes. These nanoparticles showed different shapes and surface charges accompanied by individual morphologies, reflecting on the stability of the re-dispersed dry eicosane emulsions with droplet sizes varying from 1.25 to 0.5 μm.

Schematic diagram for the detailed preparation of dry eicosane o/w emulsions.

Solid self emulsifying drug delivery system: Superior mode for oral delivery of hydrophobic cargos

A significant proportion of recently approved drug molecules possess poor aqueous solubility which further restrains their desired bioavailability. Poor aqueous solubility of these drugs poses significant hurdles in development of novel drug delivery systems and achieving target response. Self-emulsifying drug delivery systems (SEDDS) emerged as an insightful approach for delivering highly hydrophobic entities to enhance their bioavailability. Conventional SEDDS were developed in a liquid form which owned numerous shortcomings like low stability and drug loading efficiency, fewer choices of dosage forms and irreversible precipitation of drug or excipients. To address these curbs solid-SEDDS (S-SEDDS) was introduced as an efficient strategy that combined advantages of solid dosage forms such as increased stability, portability and patient compliance along with substantial improvement in the bioavailability. S-SEDDS are isotropic mixtures of oil, surfactant, solvent and co-solvents generated by solidification of liquid or semisolid self-emulsifying ingredients onto powders. The present review highlights components of S-SEDDS, their peculiarities to be considered while designing solid dosage forms and various methods of fabrication. Lastly, key challenges faced during development, applications and future directions for the research in this area are thoroughly summarized.

The Potential of Macroporous Silica-Nanocrystalline Cellulose Combination for Formulating Dry Emulsion Systems with Improved Flow Properties: A DoE Study

The objective of this study was to explore the possible use of a new combination of two excipients, i.e., nanocrystalline cellulose (NCC) and macroporous silica (MS), as matrix materials for the compounding of dry emulsion systems and the effects these two excipients have on the characteristics of dry emulsion powders produced by the spray drying process. A previously developed liquid O/W nanoemulsion, comprised of simvastatin, 1-oleoyl-rac-glycerol, Miglyol 812 and Tween 20, was employed. In order to comprehend the effects that these two matrix formers have on the spray drying process and on dry emulsion powder characteristics, alone and in combination, a DoE (Design of Experiment) approach was used. The physicochemical properties of dry emulsion samples were characterised by atomic force microscopy, scanning electron microscopy, mercury intrusion porosimetry, energy-dispersive X-ray spectroscopy and laser diffraction analysis. Additionally, total release and dissolution experiments were performed to assess drug release from multiple formulations. It was found that the macroporous silica matrix drastically improved flow properties of dry emulsion powders; however, it partially trapped the oil—drug mixture inside the pores and hindered complete release. NCC showed its potential to reduce oil entrapment in MS, but because of its rod-shaped particles deposited on the MS surface, powder flowability was deteriorated.

Modeling Drying Behavior of an Aqueous Chitosan Single Droplet Using the Reaction Engineering Approach

Spray drying of Chitosan solutions to prepare microparticles either using pilot or industrial scale spray dryer is a complex process; tracking morphological changes and obtaining drying kinetics of a single droplet would be very difficult. The acoustic levitator being a non-intrusive method is a useful experimental apparatus that enables particle/droplet suspension in the gaseous medium and capable of mimicking the drying process in a spray dryer. The drying of chitosan aqueous solutions into solid particles was investigated. The prediction of the size and drying kinetics until the formation of the solid structure was performed in an acoustic levitator. Studying the drying of single droplets is crucial for revealing the influence of the drying process parameters on the formation of dried particles. Droplets with initial chitosan concentration (10, 20, and 30 mg/ml) were investigated at different air-drying temperatures. A Reaction Engineering Approach (REA) model was developed and compared with the experimental drying curves, a very well agreement was found between the drying experiments and the REA model with a relative error of about 3% between the initial droplet mass and predicted droplet mass by the REA model.