Generation of quercetin/cellulose acetate phthalate systems for delivery by supercritical antisolvent process

Fabrication, characterization and release behavior of α-tocopherol acetate-loaded pH-responsive polyhydroxybutyrate/cellulose acetate phthalate microbeads

Microbeads are used in personal care and cosmetic products (PCCPs) but are produced from nondegradable materials. Biodegradable polyhydroxybutyrate (PHB) has been recognized as a promising alternative material for use in PCCPs; however, utilizing PHB to encapsulate PCCPs is challenging because PCCPs need to be protected from the environment but their release needs to be permitted under specific physiological conditions. The aim of this work was to develop and evaluate pH-responsive cellulose acetate phthalate (CAP) to formulate lipophilic α-tocopherol acetate (α-TA)-loaded pH-responsive PHB/CAP microbeads. The influences of the PHB/CAP ratio and initial α-TA loading on the microbead size, surface morphology, encapsulation efficiency (%EE), loading capacity (%LC), and α-TA release profile were studied. The microbeads exhibited a spherical shape with a size of 328.7 ± 2.9 μm. The EE and LC were 86.7 ± 2.6 % and 13.5 ± 0.4 %, respectively. The release profile exhibited pH-responsive characteristics. These α-TA-loaded pH-responsive microbeads were stable with >50 % of the α-TA remaining after 90 days at 4, 25 and 45 °C in the dark. The results from the cytotoxicity assay with PSVK1 cells demonstrated that the microbeads were nontoxic. Hence, our developed formulation has the potential to be used to encapsulate oil-based drugs to formulate lipophilic substance-loaded pH-responsive microbeads.

Particle preparation of pharmaceutical compounds using supercritical antisolvent process: current status and future perspectives

The low aqueous solubility and subsequently slow dissolution rate, as well as the poor bioavailability of several active pharmaceutical ingredients (APIs), are major challenges in the pharmaceutical industry. In this review, the particle engineering approaches using supercritical carbon dioxide (SC CO₂) as an antisolvent are critically reviewed. The different SC CO₂-based antisolvent processes, such as the gas antisolvent process (GAS), supercritical antisolvent process (SAS), and a solution-enhanced dispersion system (SEDS), are described. The effect of process parameters such as temperature, pressure, solute concentration, nozzle diameter, SC CO₂ flow rate, solvent type, and solution flow rate on the average particle size, particle size distribution, and particle morphology is discussed from the fundamental perspective of the SAS process. The applications of the SAS process in different formulation approaches such as solid dispersion, polymorphs, cocrystallization, inclusion complexation, and encapsulation to enhance the dissolution rate, solubility, and bioavailability are critically reviewed. This review highlights some areas where the SAS process has not been adequately explored yet. This review will be helpful to researchers working in this area or planning to explore SAS process to particle engineering approaches to tackle the challenge of low solubility and subsequently slow dissolution rate and poor bioavailability.

Particle Size Tailoring of Quercetin Nanosuspensions by Wet Media Milling Technique: A Study on Processing and Formulation Parameters

Background

A large number of new substances have insufficient biopharmaceutical properties for oral administration caused by their slow dissolution rate and poor solubility.

Objective

The purpose of our experiment was to improve the physicochemical properties of a hydrophobic drug, quercetin, by the nanomilling approach.

Methods

Quercetin nanosuspensions were prepared using a wet-milling method followed by lyophilization. Stabilizer type and ratio, drug content, milling time, and bead size were identified as critical variables, and their impacts on quercetin particle size were assessed. The optimized nanocrystal was characterized by its morphology, crystallinity, molecular interactions, saturation solubility, and dissolution properties.

Results

At optimized process conditions of milling at 500 rpm for 18 cycles of grinding with 0.3 - 0.4 mm zirconium oxide beads, minimum particle size, and PDI values were 281.21 nm and 0.22, respectively. Nanocrystals showed rod-like nanostructures, and XRD scans confirmed a decrease in drug crystallinity. The optimized formulation showed increased solubility and dissolution rate, as well as good physical stability.

Conclusions

Particle size reduction by media milling technique was an efficient method for the solubility enhancement of hydrophobic drugs.

Organically surface engineered mesoporous silica nanoparticles control the release of quercetin by pH stimuli

Controlling the premature release of hydrophobic drugs like quercetin over physiological conditions remains a challenge motivating the development of smart and responsive drug carriers in recent years. This present work reported a surface modification of mesoporous silica nanoparticles (MSN) by a functional compound having both amines (as a positively charged group) and carboxylic (negatively charged group), namely 4-((2-aminoethyl)amino)-4-oxobut-2-enoic acid (AmEA) prepared via simple mechanochemistry approach. The impact of MSN surface modification on physical, textural, and morphological features was evaluated by TGA, N₂ adsorption-desorption, PSA-zeta, SEM, and TEM. The BET surface area of AmEA-modified MSN (MSN-AmEA) was found to be 858.41 m² g^-1 with a pore size of 2.69 nm which could accommodate a high concentration of quercetin 118% higher than MSN. In addition, the colloidal stability of MSN-AmEA was greatly improved as indicated by high zeta potential especially at pH 4 compared to MSN. In contrast to MSN, MSN-AmEA has better in controlling quercetin release triggered by pH, thanks to the presence of the functional groups that have a pose-sensitive interaction hence it may fully control the quercetin release, as elaborated by the DFT study. Therefore, the controlled release of quercetin over MSN-AmEA verified its capability of acting as a smart drug delivery system.

A numerical approach to determine the optimal condition of the gas anti-solvent supercritical process for nanoparticles production

Supercritical gas antisolvent (GAS) process is an efficient method for nanoparticles production, in which accurate selection of operational condition is essential. Thermodynamic models can be applied for evaluation the phase equilibrium behavior and determination the required precipitation pressure of GAS process. In this research, thermodynamic behavior of (CO₂—dimethyl sulfoxide (DMSO)) binary system and both of (CO₂–DMSO-anthraquinone Violet 3RN (AV3RN)) and (CO₂–DMSO-solvent Yellow 33 (SY33)) ternary systems in the GAS process were studied at different temperatures (308, 318, 328 and 338) K and pressures (1.0–14.0) MPa, using Peng–Robinson equation of state (PR-EoS). The minimum precipitation pressure of AV3RN and SY33 at 308, 318, 328 and 338 K were 7.80, 8.57, 9.78 and 11 MPa and 8, 8.63, 9.5 and 10.77 MPa, respectively. Also, the mole fraction of substances in liquid phase of ternary systems were determined by PR-EoS, at 328 K versus pressure. The accuracy of the obtained results were investigated using the experimental data reported in the literatures.

Preparation, Characterization, and Evaluation of Breviscapine Nanosuspension and Its Freeze-Dried Powder

As a biopharmaceutics classification system (BCS) class IV drug, breviscapine (Bre) has low solubility in water, poor chemical stability, a short biological half-life and rapid removal from plasma. This paper prepared a Bre nanosuspension (Bre-NS) by an ultrasound-assisted anti-solvent precipitation method. Characterization of Bre-NS was studied using a Box–Behnken design concerning drug concentration in DMSO, an anti-solvent-to-solvent ratio, and sonication time. Under the optimized conditions of 170 mg/mL for the drug concentration, a 1:60 solvent-to-anti-solvent ratio, and a 9 min sonication time, the particle size of Bre-NS was 303.7 ± 7.3 nm, the polydispersity index was 0.178 ± 0.015, and the zeta potential was −31.10 ± 0.26 mV. Combined with the results from differential scanning calorimetry (DSC), powder X-ray diffraction (PXRD), and Fourier transform-infrared spectroscopy (FT-IR), the findings indicated that the crystal form and chemical structure of Bre-NS did not change during the entire process. The optimized formulation displayed good stability, increased solubility, and better in vitro release. Therefore, the results of this study can be a reference for the delivery system design of insoluble active components and effective parts in traditional Chinese medicine.

Improved Release of a Drug with Poor Water Solubility by Using Electrospun Water-Soluble Polymers as Carriers

In an attempt to improve the solubility of valsartan, a BCS II drug, fibers containing the drug were prepared from three water-soluble polymers, hydroxypropyl-methyl-cellulose (HPMC), polyvinyl-pyrrolidone (PVP), and polyvinyl-alcohol (PVA). Fiber spinning technology was optimized for each polymer separately. The polymers contained 20 wt% of the active component. The drug was homogenously distributed within the fibers in the amorphous form. The presence of the drug interfered with the spinning process only slightly, the diameters of the fibers were in the same range as without the drug for the HPMC and the PVA fibers, while it doubled in PVP. The incorporation of the drug into the fibers increased its solubility in all cases compared to that of the neat drug. The solubility of the drug itself depends very much on pH and this sensitivity remained the same in the HPMC and PVP fibers; the release of the drug is dominated by the dissolution behavior of valsartan itself. On the other hand, solubility and the rate of release were practically independent of pH in the PVA fibers. The different behavior is explained by the rate of the dissolution of the respective polymer, which is larger for HPMC and PVP, and smaller for PVA than the dissolution rate of the drug. The larger extent of release compared to neat valsartan can be explained by the lack of crystallinity of the drug, its better dispersion, and the larger surface area of the fibers. Considering all facts, the preparation of electrospun devices from valsartan and water-soluble polymers is beneficial, and the use of PVA is more advantageous than that of the other two polymers.

Characterization of excipients to improve pharmaceutical properties of sirolimus in the supercritical anti-solvent fluidized process

Enhanced drug release and bioavailability of poorly soluble active pharmaceutical ingredient (API) can be achieved via a fluidized bed coating integrated with supercritical anti-solvent (SAS-FB) - a process of precipitating drug particles onto carrier granules. However, in the absence of excipients, SAS-FB often results in crystalline of the API on the surface of carriers, limiting the improvement of pharmaceutical properties. Co-processing with excipients is considered an effective approach to improve drug release in the SAS-FB process. Our study used sirolimus, an immune suppressive agent, as the model API to characterize excipients for their effect on pharmaceutical properties in the SAS-FB process. We show that co-precipitation of excipients and sirolumus impacts on carrier specific surface area and drug yield. Among the tested excipients, formulation containing polyvinylpyrrolidone K30 achieved the highest drug yield. Importantly, compared with Rapamune® tablet, our optimized formulation displayed a superior in vivo oral bioavailability by 3.05-fold in Sprague-Dawley rats and 3.99-fold in beagle dogs. A series of characterization of the processed API was performed to understand the mechanism by which excipients contributed to drug dissolution properties. Our study provides a useful guidance for the use of excipients in the SAS-FB technology to improve pharmaceutical properties of sirolimus and other poorly soluble drugs.

Anti-rheumatic effect of quercetin and recent developments in nano formulation

Quercetin is a potential anti-rheumatoid drug. Nano formulation strategies could improve its solubility and efficacy.

Microwave-initiated rapid synthesis of phthalated cashew gum for drug delivery systems

Chemical modification of polysaccharides is an important approach for their transformation into customized matrices that suit different applications. Microwave irradiation (MW) has been used to catalyze chemical reactions. This study developed a method of MW-initiated synthesis for the production of phthalated cashew gum (Phat-CG). The structural characteristics and physicochemical properties of the modified biopolymers were investigated by FTIR, GPC, ¹H NMR, relaxometry, elemental analysis, thermal analysis, XRD, degree of substitution, and solubility. Phat-CG was used as a matrix for drug delivery systems using benznidazole (BNZ) as a model drug. BNZ is used in the pharmacotherapy of Chagas disease. The nanoparticles were characterized by size, PDI, zeta potential, AFM, and in vitro release. The nanoparticles had a size of 288.8 nm, PDI of 0.27, and zeta potential of -31.8 mV. The results showed that Phat-CG has interesting and promising properties as a new alternative for improving the treatment of Chagas disease.

Supercritical Antisolvent Process for Pharmaceutical Applications: A Review

The supercritical antisolvent (SAS) technique has been widely employed in the biomedical field, including drug delivery, to obtain drug particles or polymer-based systems of nanometric or micrometric size. The primary purpose of producing SAS particles is to improve the treatment of different pathologies and to better the patient’s compliance. In this context, many active compounds have been micronized to enhance their dissolution rate and bioavailability. Aiming for more effective treatments with reduced side effects caused by drug overdose, the SAS polymer/active principle coprecipitation has mainly been proposed to offer an adequate drug release for specific therapy. The demand for new formulations with reduced side effects on the patient’s health is still growing; in this context, the SAS technique is a promising tool to solve existing issues in the biomedical field. This updated review on the use of the SAS process for clinical applications provides useful information about the achievements, the most effective polymeric carriers, and parameters, as well as future perspectives.

Deposition of CAP/Antioxidants Systems on Silica Particles Using the Supercritical Antisolvent Process

Supercritical carbon dioxide has been used to deposit co-precipitates of natural antioxidants with a polymer onto silica microparticles. The supercritical antisolvent process (SAS) was carried out with the antioxidants by introducing the silica microparticles into the precipitator vessel. Two different configurations were employed to pump the solution. In one configuration, the antioxidant and the polymer were dissolved and injected together through a nozzle. In the second configuration, the antioxidant and the polymer were dissolved in different solutions and sprayed through different nozzles. The use of operating conditions significantly above the critical point (180 bar and 323 K) led to the formation of composites made up of co-precipitates and silica. Delivery profiles showed that the presence of the polymer and the silica delayed release of the antioxidant into gastric media, thus protecting it and allowing its full delivery to the intestinal fluids to improve the effectiveness of the antioxidant.

Moxifloxacin Hydrochloride Electrochemical Detection at Gold Nanoparticles Modified Screen-Printed Electrode

It appeared that either the carbon paste or the screen-printed carbon electrodes that were modified with gold nanoparticles (AuNPs) gave rise to the largest current responses after a rapid screening of various nanomaterials as modifiers of carbon composite electrodes in view of designing an electrochemical sensor for Moxifloxacin Hydrochloride (Moxi). The screen-printed electrode (SPE) support was preferred over the carbon paste one for its ability to be used as disposable single-use sensor enabling the circumvention of the problems of surface fouling encountered in the determination of Moxi. The response of AuNPs modified SPE to Moxi was investigated by cyclic voltammetry (CV) (including the effect of the potential scan rate and the pH of the medium), chronoamperometry, and differential pulse voltammetry (DPV) after morphological and physico-chemical characterization. DPV was finally applied to Moxi detection in phosphate buffer at pH 7, giving rise to an accessible concentration window ranging between 8 µM and 0.48 mM, and the detection and quantification limits were established to be 11.6 µM and 38.6 µM, correspondingly. In order to estimate the applicability of Moxi identification scheme in actual trials, it was practiced in a human baby urine sample with excellent recoveries between 99.8 % and 101.6 % and RSDs of 1.1-3.4%, without noticeable interference.

Facile caffeine electrochemical detection via electrodeposited Ag nanoparticles with modifier polymers on carbon paste sensor at aqueous and micellar media

The analysis and detection of caffeine (Caf) is very useful due to its widespread usage in several daily consumed beverages, food products, and pharmacological preparations with various physiological effects. The preparation of a newly electrodeposited Ag nanoparticles – cellulose acetate phthalate (CAP) – chitosan (Chit) modified carbon paste (ACCMCP) sensor for sensitive determination of Caf in 0.01 mol L−1 H3PO4 solution (pH 1.0–5.0) both in aqueous and micellar media (0.5 mmol L−1 SDS) was achieved. The interaction of Caf was monitored using electrochemical techniques such as cyclic voltammetry, differential pulse voltammetry, electrochemical impedance spectroscopy, and chronoamperometry, and surface characterization was carried out using X-ray diffraction, scanning electron microscope, and energy dispersive X-ray techniques. The linear detection range of Caf was between 4 and 500 μmol L−1 (r2 = 0.955) and the limit of detection obtained from the calibration plot was 0.252 μmol L−1. The sensor was applicable for detecting Caf in numerous real samples with recoveries from 98.03% to 101.60% without interference of any accompanying species, which ensures high method selectivity.

Chitosan/calcium phosphate flower-like microparticles as carriers for drug delivery platform

A special flower-like chitosan (CS)/calcium phosphate (CaP) microparticle was fabricated as a novel pH-sensitive carrier for sustained release drug system via a rapid one-pot approach. The CS-tripolyphosphate (TPP) nanocomplexes were firstly prepared through ionotropic gelation. Then, the CS nanocomplexes network acted as the template and inducer for adsorbing the mineralized CaP nanosheets and directing its assembly into the flower-like microparticles. The preparation condition optimized by Box-Behnken design-response surface methodology was achieved with 3.16 mg/ml of CS, 127.22 mg/ml of TPP, and 89.50 mM of CaCl₂. The morphologies of the system were observed by scanning electron microscopy (SEM) and transmission electron microscope (TEM), and it showed that the flower-like microparticles with a diameter of 5-7 μm are composed of sheet-like petals with about 40 nm in thickness. And the TEM results showed that the petals consist by nanosheets with the thickness of 2-5 nm. The X-ray diffraction (XRD) results showed that the P/Ca ratio of CS/CaP microparticles is 1.29/1. The in vitro release studies demonstrated well sustained-release properties and pH-sensitive releasing characteristic of CS/CaP microparticles. The drug release mechanism was fitted by Korsmeyer-Peppas model at a pH of 5.8 and 7.4, respectively. The in vitro cell viability research demonstrated the microparticles have no obvious cytotoxicity at the dosages below 500 μg/ml. This work supplied a versatile platform as a novel drug delivery system with excellent pH-sensitive and sustained release performances.

Trends on the Rapid Expansion of Supercritical Solutions Process Applied to Food and Non-food Industries

BACKGROUND

The supercritical fluids applied to particle engineering over the last years have received growing interest from the food and non-food industries, in terms of processing, packaging, and preservation of several products. The rapid expansion of supercritical solutions (RESS) process has been recently reported as an efficient technique for the production of free-solvent particles with controlled morphology and size distribution.

OBJECTIVE

In this review, we report technological aspects of the application of the RESS process applied to the food and non-food industry, considering recent data and patent survey registered in literature.

METHODS

The effect of process parameters cosolvent addition, temperature, pressure, nozzle size among others, during RESS on the size, structure and morphology of the resulted particles, and the main differences about recent patented RESS processes are reviewed.

RESULTS

Most of the experimental works intend to optimize their processes through investigation of process parameters.

CONCLUSION

RESS is a feasible alternative for the production of particles with a high yield of bioactive constituents of interest to the food industry. On the other hand, patents developed using this type of process for food products are very scarce, less attention being given to the potential of this technique to develop particles from plant extracts with bioactive substances.

Foaming of Polycaprolactone and Its Impregnation with Quercetin Using Supercritical CO2

Foamed polycaprolactone impregnated with quercetin was carried out with a batch foaming technique using supercritical CO₂. The experimental design was developed to study the influence of pressure (15–30 MPa), temperature (308–333 K), and depressurization rate (0.1–20) on the foam structure, melting temperature, and release tests of composites. The characterization of the experiments was carried out using scanning electron microscopy, X-ray diffractometer, and differential scanning calorimetry techniques. It was observed that the porosity created in the polymer had a heterogeneous structure, as well as the impregnation of the quercetin during the process. On the other hand, controlled release tests showed a significant delay in the release of quercetin compared to commercial quercetin.

Mono- and Bi-Phasic Cellulose Acetate Micro-Vectors for Anti-Inflammatory Drug Delivery

In recent years, different processing technologies have been engineered to fabricate capsules or particles with peculiar properties (e.g., swelling, pH-sensitive response) at the micro and sub-micrometric size scale, to be used as carriers for controlled drug and molecular release. Herein, the development of cellulose acetate (CA) micro-carriers with mono- (MC) or bi-phasic (BC) composition is proposed, fabricated via electrohydrodynamic atomization (EHDA)—an electro-dropping technology able to micro-size polymer solution by the application of high voltage electrostatic forces. Image analysis allows identification of the process parameters to optimize morphology, in terms of size distribution and shape. Meanwhile, an accurate rheological study has enabled investigating the interface between CA solutions with different viscosities to optimize BC systems. Release tests have confirmed that BC carriers can retain the drug more efficiently in acidic conditions, also providing a more gradual and sustained release until six days, with respect to MC carriers. Hence, all these results have proven that biphasic architecture significantly improves the capability of CA microcarriers to release ketoprofen lysinate, thus suggesting a new route to design core/shell systems for the retarded oral administration of anti-inflammatory drugs.