Effect of particle size on in vitro and in vivo behavior of astilbin nanosuspensions

Quercetin nanocrystals for bioavailability enhancement: impact of different functional stabilizers on in vitro/in vivo drug performances

The purpose of this study was to investigate the impact of different functional stabilizers on in vitro/in vivo drug performances after oral administration of drug nanocrystals. Quercetin nanocrystals (QT-NCs) respectively stabilized by five types of functional stabilizers, including hydroxypropyl methyl cellulose E15 (HPMC E15), poloxamer 407 (P407), poloxamer 188 (P188), D-α-tocopherol polyethylene glycol succinate (TPGS), and glycyrrhizin acid (GL), were fabricated by wet media milling technique. The particle size, morphology, physical state, drug solubility, drug dissolution in vitro, and orally pharmacokinetic behaviors of all QT-NCs were investigated. All QT-NCs with similar particle size about 200 nm were obtained by controlling milling speed and milling time. No significant differences in particles shape and crystalline nature were found for QT-NCs stabilized by different functional stabilizers. But the solubility and dissolution of QT-NCs were significantly influenced by the different functional stabilizers. The AUC0∼t of all QT-NCs after oral administration was in the following order: QT-NCs/P188 ≈ QT-NCs/HPMC E15 > QT-NCs/GL > QT-NCs/P407 ≈ QT-NCs/TPGS, and the Cmax showed an order of QT-NCs/P407 > QT-NCs/P188 ≈ QT-NCs/GL > QT-NCs/HPMC E15 > QT-NCs/TPGS. Both of QT-NCs/P407 and QT-NCs/TPGS exhibited faster oral absorption with Tmax at 0.5 h and 0.83 h, respectively, while the other three QT-NCs (QT-NCs/P188, QT-NCs/GL and QT-NCs/HPMC E15) showed a relatively slow absorption with same Tmax at 5.33 h. The longest MRT0∼t (11.72 h) and t1/2z (32.22 h) were observed for QT-NCs/HPMC E15. These results suggested that the different functional stabilizers could significantly influence on drug solubility, drug dissolution in vitro and orally pharmacokinetic behavior of QT-NCs, and it is possible to alter the drug dissolution in vitro, oral absorption and drug retention in vivo by changing the type of functional stabilizers in NCs preparation.

Nanosuspension-Based Drug Delivery Systems for Topical Applications

Nanosuspensions have garnered recent attention as a promising strategy for mitigating the bioavailability challenges of hydrophobic drugs, particularly those characterized by poor solubility in both aqueous and organic environments. Addressing solubility issues associated with poorly water-soluble drugs has largely resolved the need to enhance drug absorption and bioavailability. As mucosal formulations and topical administration progress in the future, nanosuspension drug delivery, straightforward formulation techniques, and versatile applications will continue to be subjects of interest. Nanosuspensions have undergone extensive scrutiny in preparation for topical applications, encompassing ocular, pulmonary, and dermal usage. Among the numerous methods aimed at improving cutaneous application, nanocrystals represent a relatively recent yet profoundly intriguing approach. Despite the increasing availability of various nanosuspension products, primarily designed for oral administration, only a limited number of studies have explored skin permeability and drug accumulation in the context of nanosuspensions. Nevertheless, the scant published research unequivocally underscores the potential of this approach for enhancing cutaneous bioavailability, particularly for active ingredients with low to medium solubility. Nanocrystals exhibit increased skin adhesiveness in addition to heightened saturation solubility and dissolution rate, thereby augmenting cutaneous distribution. The article provides a comprehensive overview of nanosuspensions for topical application. The methodology employed is robust, with a well-defined experimental design; however, the limited sample size raises concerns about the generalizability of the findings. While the results demonstrate promising outcomes in terms of enhanced drug delivery, the discussion falls short of addressing certain limitations. Additionally, the references largely focus on recent studies, but a more diverse inclusion of historical perspectives could offer a more holistic view of the subject.

Nanosuspensions as carriers of active ingredients: Chemical composition, development methods, and their biological activities

Nanosuspensions (NSps) are colloidal dispersions of particles that have the potential to solve the delivery problems of active ingredients associated with their low solubility in water or instability due to environmental factors. It is essential to consider their chemical composition and preparation methods because they directly influence drug loading, size, morphology, solubility, and stability; these characteristics of nanosuspensions influence the delivery and bioavailability of active ingredients. NSps provides high loading of drugs, protection against degrading agents, rapid dissolution, high particle stability, and high bioavailability of active ingredients across biological membranes. In addition, they provide lower toxicity compared to other nanocarriers, such as liposomes or polymeric nanoparticles, and can modify the pharmacokinetic profiles, thus improving their safety and efficacy. The present review aims to address all aspects related to the composition of NSps, the different methods for their production, and the main factors affecting their stability. Moreover, recent studies are described as carriers of active ingredients and their biological activities.

Herbal Medicine Nanocrystals: A Potential Novel Therapeutic Strategy

Herbal medicines have gained recognition among physicians and patients due to their lower adverse effects compared to modern medicines. They are extensively used to treat various diseases, including cancer, cardiovascular issues, chronic inflammation, microbial contamination, diabetes, obesity, and hepatic disorders, among others. Unfortunately, the clinical application of herbal medicines is limited by their low solubility and inadequate bioavailability. Utilizing herbal medicines in the form of nanocrystals (herbal medicine nanocrystals) has shown potential in enhancing solubility and bioavailability by reducing the particle size, increasing the specific surface area, and modifying the absorption mechanisms. Multiple studies have demonstrated that these nanocrystals significantly improve drug efficacy by reducing toxicity and increasing bioavailability. This review comprehensively examines therapeutic approaches based on herbal medicine nanocrystals. It covers the preparation principles, key factors influencing nucleation and polymorphism control, applications, and limitations. The review underscores the importance of optimizing delivery systems for successful herbal medicine nanocrystal therapeutics. Furthermore, it discusses the main challenges and opportunities in developing herbal medicine nanocrystals for the purpose of treating conditions such as cancer, inflammatory diseases, cardiovascular disorders, mental and nervous diseases, and antimicrobial infections. In conclusion, we have deliberated regarding the hurdles and forthcoming outlook in the realm of nanotoxicity, in vivo kinetics, herbal ingredients as stabilizers of nanocrystals, and the potential for surmounting drug resistance through the utilization of nanocrystalline formulations in herbal medicine. We anticipate that this review will offer innovative insights into the development of herbal medicine nanocrystals as a promising and novel therapeutic strategy.

Size-Dependent Polymeric Nanoparticle Distribution in a Static versus Dynamic Microfluidic Blood Vessel Model: Implications for Nanoparticle-Based Drug Delivery

Nanoparticles (NPs) have been widely investigated in the nanomedicine field. One of the main challenges is to accurately predict the NP distribution and fate after administration. Microfluidic platforms acquired huge importance as tools to model the in vivo environment. In this study, we leveraged a microfluidic platform to produce FITC-labeled poly(lactide-co-glycolide)-block-poly(ethylene glycol) (PLGA-PEG) NPs with defined sizes of 30, 50, and 70 nm. The study aimed to compare the ability of NPs with differences of 20 nm in size to cross an endothelial barrier using static (Transwell inserts) and dynamic (microfluidic perfusion device) in vitro models. Our results evidence a size-dependent NP crossing in both models (30 > 50 > 70 nm) and highlight the bias deriving from the static model, which does not involve shear stresses. The permeation of each NP size was significantly higher in the static system than in the dynamic model at the earliest stages. However, it gradually decreased to levels comparable with those of the dynamic model. Overall, this work highlights clear differences in NP distribution over time in static versus dynamic conditions and distinct size-dependent patterns. These findings reinforce the need for accurate in vitro screening models that allow for more accurate predictions of in vivo performance.

Highly water-soluble dapsone nanocrystals: Towards innovative preparations for an undermined drug

Dapsone (DAP)is a dual-function drug substance; however, its limited water solubility may impair its bioavailability. Drug nanocrystals are an alternative to overcome this limitation. Herein, a DAP nanosuspension was prepared using adesign space approach aiming to investigate the influence of raw material properties and process parameters on the critical quality attributes of the drugnanocrystals. Optimized nanocrystals with 206.3 ± 6.7 nm using povacoat™ as stabilizer were made. The nanoparticles were characterized by dynamic light scattering, laser diffraction, scanning electron microscopy, differential scanning calorimetry, X-ray powder diffraction, and saturation solubility. Compared to the raw material, the nanocrystals were 250-times smaller. Meanwhile, its crystalline state remained basically unchanged even after milling and drying. The nanosuspension successfully maintained its physical stability inlong-termandaccelerated stability studiesover, 4 and 3 months. Furthermore, toxicity studiesshowed low a toxicity at a20 mg/kg. As expected for nanocrystals, the size reduction improvedsaturation solubility3.78 times in water. An attempt to scale up from lab to pilot scale resulted nanocrystals of potential commercial quality. In conclusion, the present study describes the development of dapsone nanocrystals for treating infectious and inflammatory diseases. The nanocrystal formuation can be scaled up for commercial use.

Elucidating the Particle Size Effect of Andrographolide Suspensions on Their IVIVC Performance in Oral Absorption

The study aimed to explore the size effect on the in vitro-in vivo correlation (IVIVC) in the oral absorption of andrographolide nanosuspensions (Ag-NS). Ag-NS with controllable particle sizes were prepared by ultrasonic dispersion method, and the formulation and process parameters were optimized through single factor experiments using mean particle size, polydispersity index, and stability as evaluation indicators. The morphology of Ag-NS was observed by scanning electron microscopy (SEM), and the crystalline state of the nanosuspensions was characterized by X-ray powder diffraction (XRPD) and differential scanning calorimetry (DSC). The dissolution tests were carried out with the paddle method in two different mediums simulating the pH conditions in intestinal fluid pH 6.8 and gastric fluid (pH 1.2), respectively. The pharmacokinetic behaviors were investigated in rats after oral administration, and a deconvolution approach was introduced to determine the correlation between in vitro dissolution and in vivo absorption (IVIVC). The formulation with the use of lecithin and PEG-800 as stabilizers showed its potential in the size-controllable preparation of Ag-NS. Via altering the ultrasonication amplitude and time, three Ag-NS suspensions with particle sizes of particle size, i.e., Ag-NS 250 (244.3 ± 0.4 nm), Ag-NS 450 (464.3 ± 32.2 nm), Ag-NS 1000 (1015 ± 36.1 nm) were prepared. Their morphological and crystal characteristics did not change during the size reduction process, but both of their in vitro dissolution and in vivo absorption were improved. Relatively better IVIVC performance was observed with the in vitro dissolution data at pH 6.8 (r > 0.9). With the reduction of particle size, the in vivo absorption fraction was more closed to the level of the in vitro dissolution. In conclusion, the decrease in particle size would improve the dissolution and absorption of Ag-NS, and also affect their IVIVC performance. The study would facilitate the design and quality control of Ag-NS in terms of particle size and dissolution specifications.

Development of herpetrione nanosuspensions stabilized by glycyrrhizin for enhancing bioavailability and synergistic hepatoprotective effect

The objective of this study was to develop novel herpetrione (HPE) nanosuspensions stabilized by glycyrrhizin (HPE NSs/GL) for enhancing bioavailability and hepatoprotective effect of HPE. HPE NSs/GL were prepared by wet media milling method and then systemically evaluated by particle size analysis, scanning electronic microscopy (SEM), X-ray powder diffraction (XRPD), dissolution test, pharmacokinetics, and hepatoprotective effect. HPE-NSs stabilized by poloxamer 407 (HPE NSs/P407) were also prepared and used as a reference for comparison. HPE NSs/GL and HPE-NSs/P407 with similar particle sizes around 450 nm and PDI less than 0.2 were successfully prepared and both of them appeared to be spherical under SEM. The XRPD results demonstrated that HPE in both HPE NSs/GL and HPE NSs/P407 was presented in the amorphous state and the addition of GL or P407 and the milling process didn't alter the physical state of HPE. The dissolution and pharmacokinetic studies demonstrated that HPE NSs/GL exhibited significant enhancement in drug dissolution (72.44% within 24 h) and AUC_0-t (24.91 ± 3.3 mg/L·h) as compared to HPE coarse suspensions (HPE CS, 34.19% & 13.07 ± 1.02 mg/L·h), but was similar with those of HPE NSs/P407 (80.06% & 26.75 ± 4.06 mg/L•h). Moreover, HPE NSs/GL exhibited significantly better hepatoprotective effect as compared to HPE CS and HPE NSs/P407 as indicated by the lowering of the elevated serum ALT and AST levels and the improvement of the hepatic morphology and architecture, which might be attributed to the improved bioavailability of HPE, and synergistic hepatoprotective effect of GL via alleviating inflammation evidenced by the significant decreased hepatic levels of inflammatory cytokines IL-1β, IL-6 and TNF-α. It could be concluded that GL might be an effective stabilizer for preparing HPE NSs, and HPE NSs/GL is a potential formulation strategy for improving oral bioavailability and hepatoprotective effect of HPE.

Immunoenhancement effects of chitosan-modified ginseng stem-leaf saponins-encapsulated cubosomes as an ajuvant

Nanoparticle delivery of functional molecules and vaccine is a promising method for enhancing the immune response. The objective of this study was to design chitosan (CS)-modified ginseng stem-leaf saponins (GSLS)-encapsulated cubosomes (Cub-GSLS^CS) as a vaccine delivery system and explore its immunologic activity and adjuvanticity. In this study, CS-modified GSLS-encapsulated cubosomes (Cub-GSLS^CS) were prepared. The storage stability of GSLS and that of ovalbumin (OVA) were measured. Additionally, the immunopotentiation of Cub-GSLS^CS were assessed on potentiating macrophage in vitro, and the adjuvant activity was evaluated through immune response triggered by OVA model antigen. The encapsulation efficiency of optimized Cub-GSLS^CS was about 65 % with Im3m nanostructure. The Cub-GSLS^CS showed excellent stability and sustained release for up to 28 days. In vitro, Cub-GSLS^CS nanoparticles improved cellular uptake, stimulated cytokines secretion of IL-6, IL-12, TNF-α, and generated more inducible nitric oxide synthase (iNOS) to produce higher levels of nitric oxide (NO) compared with other groups. Furthermore, the immunoadjuvant effects of OVA encapsulated Cub-GSLSCS nanoparticles (Cub-GSLS^CS-OVA) were observed through immunized mice. Results showed that the ratio of CD4+/CD8 + T lymphocytes was increased in Cub-GSLS^CS-OVA group. In addition, Cub-GSLS^CS-OVA nanoparticles induced dramatically high OVA-specific IgG, IgG1, and IgG2a levels and stimulated the secretion of cytokines. Cub-GSLS^CS may be a potential vaccine delivery system and induce a long-term sustained immunogenicity.

The contribution of absorption of integral nanocrystals to enhancement of oral bioavailability of quercetin

In this study, self-discriminating hybrid nanocrystals was utilized to explore the biological fate of quercetin hybrid nanocrystals (QT-HNCs) with diameter around 280 nm (QT-HNCs-280) and 550 nm (QT-HNCs-550) following oral and intravenous administration and the contribution of integral nanocrystals to oral bioavailability enhancement of QT was estimated by comparing the absolute exposure of integral QT-HNCs and total QT in the liver. Results showed that QT-HNCs could reside in vivo as intact nanocrystals for as long as 48 h following oral and intravenous administration. A higher accumulation of integral QT-HNCs in liver and lung was observed for both oral and intravenous administration of QT-HNCs. The particle size affects the absorption and biodistribution of integral QT-HNCs and total QT. As compared to QT-HNCs-550, QT-HNCs-280 with smaller particle size is more easily absorbed, but dissolves faster in vivo, leading to higher distribution of QT (146.90 vs. 117.91 h·μg/mL) but lower accumulation of integral nanocrystals (6.8 2e10 vs. 15.27e10 h·[p/s]/[µW/cm²]) in liver following oral administration. Due to its slower dissolution and enhanced recognition by RES, QT-HNCs-550 with larger diameter shows higher liver distribution for both of QT (1015.80 h·μg/mL) and integral nanocrystals (259.63e10 h·[p/s]/[µW/cm²]) than those of QT-HNCs-280 (673.82 & 77.66e10 h·[p/s]/[µW/cm²]) following intravenous administration. The absolute exposure of integral QT-HNCs in liver following oral administration of QT-HNCs are 8.78% for QT-HNCs-280 and 5.88% for QT-HNCs-550, while the absolute exposure of total QT for QT-HNCs-280 and QT-HNCs-550 are 21.80% and 11.61%, respectively. Owing to imprecise quantification method, a surprisingly high contribution of integral QT-HNCs to oral bioavailability enhancement of QT (40.27% for QT-HNCs-280 and 50.65% for QT-HNCs-550) was obtained. These results revealed significant difference in absorption and biodistrbution between integral nanocrystals and overall drugs following oral and intravenous administration of QT-HNCs, and provided a meaningful reference for the contribution of integral nanocrystals to overall bioavailability enhancement.

Amorphous Solid Dispersions and the Contribution of Nanoparticles to In Vitro Dissolution and In Vivo Testing: Niclosamide as a Case Study

We developed an amorphous solid dispersion (ASD) of the poorly water-soluble molecule niclosamide that achieved a more than two-fold increase in bioavailability. Notably, this niclosamide ASD formulation increased the apparent drug solubility about 60-fold relative to the crystalline material due to the generation of nanoparticles. Niclosamide is a weakly acidic drug, Biopharmaceutics Classification System (BCS) class II, and a poor glass former with low bioavailability in vivo. Hot-melt extrusion is a high-throughput manufacturing method commonly used in the development of ASDs for increasing the apparent solubility and bioavailability of poorly water-soluble compounds. We utilized the polymer poly(1-vinylpyrrolidone-co-vinyl acetate) (PVP–VA) to manufacture niclosamide ASDs by extrusion. Samples were analyzed based on their microscopic and macroscopic behavior and their intermolecular interactions, using differential scanning calorimetry (DSC), X-ray diffraction (XRD), nuclear magnetic resonance (NMR), Fourier-transform infrared (FTIR), and dynamic light scattering (DLS). The niclosamide ASD generated nanoparticles with a mean particle size of about 100 nm in FaSSIF media. In a side-by-side diffusion test, these nanoparticles produced a four-fold increase in niclosamide diffusion. We successfully manufactured amorphous extrudates of the poor glass former niclosamide that showed remarkable in vitro dissolution and diffusion performance. These in vitro tests were translated to a rat model that also showed an increase in oral bioavailability.