Preparation of a novel starch-derived three-dimensional ordered macroporous carbon for improving the dissolution rate and oral bioavailability of water-insoluble drugs

Highly Drug-Loaded Nanoaggregate Microparticles for Pulmonary Delivery of Cyclosporin A

Introduction

Nanoparticles have the advantages of improving the solubility of poorly water-soluble drugs, facilitating the drug across biological barriers, and reducing macrophage phagocytosis in pulmonary drug delivery. However, nanoparticles have a small aerodynamic particle size, which makes it difficult to achieve optimal deposition when delivered directly to the lungs. Therefore, delivering nanoparticles to the lungs effectively has become a popular research topic.

Methods

Nanoaggregate microparticles were used as a pulmonary drug delivery strategy for the improvement of the bioavailability of cyclosporine A (CsA). The nanoaggregate microparticles were prepared with polyvinyl pyrrolidone (PVP) as the excipient by combining the anti-solvent method and spray drying process. The physicochemical properties, aerodynamic properties, in vivo pharmacokinetics and inhalation toxicity of nanoaggregate microparticles were systematically evaluated.

Results

The optimal nanoparticles exhibited mainly spherical shapes with the particle size and zeta potential of 180.52 nm and -19.8 mV. The nanoaggregate microparticles exhibited irregular shapes with the particle sizes of less than 1.6 µm and drug loading (DL) values higher than 70%. Formulation NM-2 as the optimal nanoaggregate microparticles was suitable for pulmonary drug delivery and probably deposited in the bronchiole and alveolar region, with FPF and MMAD values of 89.62% and 1.74 μm. In addition, inhaled NM-2 had C max and AUC0-∞ values approximately 1.7-fold and 1.8-fold higher than oral cyclosporine soft capsules (Neoral®). The inhalation toxicity study suggested that pulmonary delivery of NM-2 did not result in lung function damage, inflammatory responses, or tissue lesions.

Conclusion

The novel nanoaggregate microparticles for pulmonary drug delivery could effectively enhance the relative bioavailability of CsA and had great potential for clinical application.

Inhaled curcumin mesoporous polydopamine nanoparticles against radiation pneumonitis

Radiation therapy is an effective method to kill cancer cells and shrink tumors using high-energy X-ray or γ-ray. Radiation pneumonitis (RP) is one of the most serious complications of radiation therapy for thoracic cancers, commonly leading to serious respiratory distress and poor prognosis. Here, we prepared curcumin-loaded mesoporous polydopamine nanoparticles (CMPN) for prevention and treatment of RP by pulmonary delivery. Mesoporous polydopamine nanoparticles (MPDA) were successfully synthesized with an emulsion-induced interface polymerization method and curcumin was loaded in MPDA via π‒π stacking and hydrogen bonding interaction. MPDA owned the uniform spherical morphology with numerous mesopores that disappeared after loading curcumin. More than 80% curcumin released from CMPN in 6 h and mesopores recovered. CMPN remarkably protected BEAS-2B cells from γ-ray radiation injury by inhibiting apoptosis. RP rat models were established after a single dose of 15 Gy ⁶⁰Co γ-ray radiation was performed on the chest area. Effective therapy of RP was achieved by intratracheal administration of CMPN due to free radical scavenging and anti-oxidation ability, and reduced proinflammatory cytokines, high superoxide dismutase, decreased malondialdehyde, and alleviated lung tissue damages were observed. Inhaled CMPN paves a new avenue for the treatment of RP.

Development and Characterization of a Glimepiride-Loaded Gelatin-Coated Mesoporous Hollow Silica Nanoparticle Formulation and Evaluation of Its Hypoglycemic Effect on Type-2 Diabetes Model Rats

In this study, we prepared gelatin-coated mesoporous hollow silica nanospheres (GSN) as a drug carrier to improve the water solubility and regulate the release rate of glimepiride (GLM). GLM was loaded into GSN by an absorption method, and drug-loaded samples (GLM-GSN) were characterized by differential scanning calorimeter (DSC) and X-ray diffraction (XRD). Cellular uptake and in vivo intestinal uptake experiments were performed in rats. In addition, the studies of in-vitro drug dissolution, pharmacokinetics, and pharmacodynamic experiments also were performed. GLM-GSN showed excellent drug loading (39.7% ± 0.7%) and sustained GLM release. The state of GLM in GSN was amorphous according to DSC and XRD results. Cellular uptake and in vivo intestinal uptake experiments indicated that GSN could be effectively absorbed, and an MTT experiment demonstrated that GSN had good biocompatibility. Furthermore, the GLM-GSN had a higher bioavailability in pharmacokinetics experiments and a prominent hypoglycemic effect on type-2 diabetes model rats in pharmacodynamic experiments. This study clearly shows that GSN is a promising platform for delivering GLM for the treatment of type-2 diabetes.

Fabrication of nanostructured mesoporous starch encapsulating soy-derived phytoestrogen (genistein) by well-tuned solvent exchange method

The present research was concerned with preparation of mesoporous starch (MPS) as a carrier for genistein, a model of poorly water-soluble phytoestrogen isoflavone; and exploration of the impact of different fabrication parameters on structural and loading properties. MPS is considered as a highly porous biomaterial which typically possesses nanometer-sized porous microstructure and low density, providing a large effective specific surface area (SSA) and hydrophilic surface to improve solubility, stability and bioavailability of poorly water-soluble active agents. To fabricate MPS, various concentrations (8-14% w/v) of starch from different sources (corn, potato and tapioca) was used for gel formation and the successive solvent exchange process was performed with use of various ethanol concentrations (40-70% v/v), which were then dried by different techniques (rotary vacuum evaporation, microwave and freeze drying). MPS quality attributes such as SSA, total porous volume, BJH pore diameter and swelling ratio were determined and effects of the fabrication parameters were investigated using L9-Taguchi orthogonal array design. The results indicate that second order polynomial regression models were well fitted for all response variables. Interestingly, the starch components greatly influenced physical properties of MPS. Also, the drying type and ethanol concentration altered significantly the model equations. The overall best fabrication condition (14% corn starch, 100% ethanol concentration in aging step and rotary vacuum drying) resulted in favorable MPS preparation with mean size of 105.4 nm and unimodal distribution. In the next step, genistein was encapsulated in MPS microstructure at different ratios, resulting in high loading capacity and efficiency (44.71% and 79.9%, respectively) at 1:1 weight ratio. Equilibrium adsorption isotherm of genistein was evaluated also by four different kinetics models including Langmuir, Freundlich, Dubinin-Radushkevich, and Temkin isotherms. The experimental data were found to be fitted well to the Langmuir model (R2 = 0.989). According to the electron microscopy and XRD analysis, the degree of genistein crystallinity lowered remarkably after the impregnation in to MPS, indicating improved solubility. In-vitro release profile of genistein from MPS in the simulated gastrointestinal buffer solutions (pH 1.2 and 6.8) demonstrated that incorporating genistein into the MPS enhanced the dissolution rate compared with genistein powder. Release kinetic data were fitted to the Higuchi model (R2 = 0.98), indicating diffusion-controlled release mechanism. Altogether, well-tuned MPS fabrication method can be utilized for an efficient encapsulation and dissolution enhancement of poorly soluble phytochemicals, such as genistein.

Synthesis of a Porous C3N-Derived Framework with High Yield by Gallic Acid Cross-Linking Using Salt Melts

Porous carbon/nitrogen frameworks are an emerging class of noble organic materials with a wide range of potential applications. However, the design and controlled synthesis of those materials are still a challenge. Herein, we present the rational design of such a system with high microporosity, specific surface areas of up to 946 m² g^-1, and excellent condensation yields. The obtained noble frameworks were used for the delivery of larger organic molecules and changed the melting behavior of some daily drug molecules along their highly polarizable surfaces.

Polymer blends used to develop felodipine-loaded hollow microspheres for improved oral bioavailability

Felodipine (FD) has been widely used in anti-hypertensive treatment. However, it has extremely low aqueous solubility and poor bioavailability. To address these problems, FD hollow microspheres as multiple-unit dosage forms were synthesized by a solvent diffusion evaporation method. Particle size of the hollow microspheres, types of ethylcellulose (EC), amounts of EC, polyvinyl pyrrolidone (PVP) and FD were investigated based on an orthogonal experiment of three factors and three levels. In addition, the release kinetics in vitro and pharmacokinetics in beagle dogs of the optimized FD hollow microspheres was investigated and compared with Plendil (commercial FD sustained-release tablets) as a single-unit dosage form. Results showed that the optimal formulation was composed of EC_{10 cp}:PVP:FD (0.9:0.16:0.36, w/w). The FD hollow microspheres were globular with a hollow structure and have high drug loading (17.69±0.44%) and floating rate (93.82±4.05%) in simulated human gastric fluid after 24h. Pharmacokinetic data showed that FD hollow microspheres exhibited sustained-release behavior and significantly improved relative bioavailability of FD compared with the control. Pharmacodynamic study showed that the FD hollow microspheres could effectively lower blood pressure. Therefore, these findings demonstrated that the hollow microspheres were an effective sustained-release delivery system for FD.

Phytosterol nanoparticles with reduced crystallinity generated using nanoporous starch aerogels

Phytosterol nanoparticles with reduced crystallinity were generated by impregnation of the phytosterols into nanoporous starch aerogels using supercritical carbon dioxide.