Formulation and optimization of cilnidipine loaded nanosuspension for the enhancement of solubility, dissolution and bioavailability

Acoustic resonance technology and quality by design approach facilitate the development of the robust tetrandrine nano-delivery system

The aim of this study was to develop a sufficiently robust tetrandrine (Tet) nano-delivery system using acoustic resonance (AR) technology and freeze-drying technology. This system can effectively improve the solubility and dissolution properties of Tet, along with high stability and scale-up adaptability. Firstly, 54 stabilizers were screened simultaneously in a high-throughput manner with the help of AR technology to fully explore the optimal prescription space of tetrandrine nanosuspension (Tet-NS). The Plackett-Burman design was used to screen for critical variables severely affecting the quality of Tet-NS. The Box-Behnken design was used to investigate and optimize critical variables to obtain optimal nanosuspensions. The optimal prescription was successfully scaled up by 100 times, which was the initial exploration of its commercial scale production. Solidification studies have shown that formulations with 2.44% fructose as the cryoprotectant have excellent redispersibility. Compared with pure Tet, Tet in Tet-NS showed a significant increase in solubility and dissolution rate in water. Fourier transform infrared (FT-IR) demonstrated that no significant interactions occurred between the drug and excipients in Tet-NS. Powder x-ray diffraction analysis (PXRD) indicated that some of the Tet transformed into amorphous state during the preparation process. In short-term stability study, Tet-NS successfully maintained its physical stability. In summary, under the guidance of the QbD concept, this study rapidly developed Tet-NS using acoustic resonance technology, which can effectively improve the solubility and dissolution properties of Tet. During the development of Tet-NS, AR technology has demonstrated high particle size reduction capability, the ability to process multiple sets of formulations in parallel, and excellent scale-up capability. Meanwhile, the method and concept of this study are not limited to Tet, but also applicable to other poorly water-soluble drugs.

Co-crystallization of Hesperidin with different co-formers to enhance solubility, antioxidant and anti-inflammatory activities

Hesperidin (HSP) is a natural flavonoid glycoside with very low aqueous solubility and a slow dissolution rate, limiting its effectiveness. This study aims to address these issues by creating co-crystals of hesperidin with water-soluble small molecules (co-formers) such as L-arginine, glutathione, glycine, and nicotinamide. Using the solvent drop grinding method, we prepared three different molar ratios of hesperidin to co-formers (1:1, 1:3, and 1:5) and conducted in-vitro solubility and dissolution studies. The results demonstrated that the prepared co-crystals exhibited significantly enhanced solubility and dissolution rates compared to untreated hesperidin. Of particular note, the HSP co-crystals formula (HSP: L-arg 1:5) displayed approximately 4.5 times higher dissolution than pure hesperidin. Further analysis using FTIR, powder x-ray diffraction patterns, and DSC thermograms validated the formation of co-crystals between HSP and L-arginine. Additionally, co-crystallization with L-arginine improved the in vitro anti-inflammatory and antioxidant activities of hesperidin compared to the untreated drug. This study highlights the potential of using water-soluble small molecules (co-formers) through co-crystallization to enhance the solubility, dissolution, and biological activities of poorly water-soluble drugs. Furthermore, in vivo studies are crucial to validate these promising results.

Drug Nanocrystals in Oral Absorption: Factors That Influence Pharmacokinetics

Despite the safety and convenience of oral administration, poorly water-soluble drugs compromise absorption and bioavailability. These drugs can exhibit low dissolution rates, variability between fed and fasted states, difficulty permeating the mucus layer, and P-glycoprotein efflux. Drug nanocrystals offer a promising strategy to address these challenges. This review focuses on the opportunities to develop orally administered nanocrystals based on pharmacokinetic outcomes. The impacts of the drug particle size, morphology, dissolution rate, crystalline state on oral bioavailability are discussed. The potential of the improved dissolution rate to eliminate food effects during absorption is also addressed. This review also explores whether permeation or dissolution drives nanocrystal absorption. Additionally, it addresses the functional roles of stabilizers. Drug nanocrystals may result in prolonged concentrations in the bloodstream in some cases. Therefore, nanocrystals represent a promising strategy to overcome the challenges of poorly water-soluble drugs, thus encouraging further investigation into unclear mechanisms during oral administration.

Sorafenib tosylate-loaded nanosuspension: preparation, optimization, and in vitro cytotoxicity study against human HepG2 carcinoma cells

This study aimed to optimize nanosuspension of sorafenib tosylate (an anticancer hydrophobic drug molecule) using a central composite design. Nanosuspension was prepared using a nanoprecipitation-ultrasonication approach. FTIR and DSC analyses demonstrated that the drug and excipients were physicochemically compatible. X-ray powder diffraction analysis confirmed amorphous form of the payload in the formulation. The optimized formulation (batch NSS6) had a zeta potential of -18.1 mV, a polydispersity of 0.302, and a particle size of 97.11 nm. SEM analysis confirmed formation of rod-shaped particles. After 24 h, about 64.45% and 86.37% of the sorafenib tosylate was released in pH 6.8 and pH 1.2, respectively. The MTT assay was performed on HepG2 cell lines. IC50 value of the optimized batch was 39.4 µg/mL. The study concluded that sorafenib tosylate nanosuspension could be a promising approach in the treatment of hepatocellular cancer.

Enhanced Anti-Inflammatory Activity of Tilianin Based on the Novel Amorphous Nanocrystals

Tilianin (Til), a flavonoid glycoside, is well-known for its therapeutic promise in treating inflammatory disorders. Its poor water solubility and permeability limit its clinical applicability. In order to overcome these restrictions, an antisolvent precipitation and ultrasonication technique was used to prepare amorphous tilianin nanocrystals (Til NCs). We have adjusted the organic solvents, oil-to-water ratio, stabilizer composition, and ultrasonic power and time by combining single-factor and central composite design (CCD) methodologies. The features of Til NCs were characterized using powder X-ray diffraction (PXRD), scanning calorimetry (DSC), and transmission electron microscopy (TEM). Specifically, the optimized Til NCs were needle-like with a particle size ranging from 90 to 130 nm. PVA (0.3%, w/v) and TPGS (0.08%, w/v) stabilized them well. For at least two months, these Til NCs stayed amorphous and showed an impressive stability at 4 °C and 25 °C. Remarkably, Til NCs dissolved almost 20 times faster in simulated intestinal fluid (SIF) than they did in crude Til. In RAW264.7 cells, Til NCs also showed a better cellular absorption as well as safety and protective qualities. Til NCs were shown to drastically lower reactive oxygen species (ROS), TNF-α, IL-1β, and IL-6 in anti-inflammatory experiments, while increasing IL-10 levels and encouraging M1 macrophages to adopt the anti-inflammatory M2 phenotype. Our results highlight the potential of amorphous Til NCs as a viable approach to improve Til's anti-inflammatory effectiveness, solubility, and dissolving rate.

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.

Rutin Nanocrystals with Enhanced Anti-Inflammatory Activity: Preparation and Ex Vivo/In Vivo Evaluation in an Inflammatory Rat Model

Rutin is a polyphenolic flavonoid with an interestingly wide therapeutic spectrum. However, its clinical benefits are limited by its poor aqueous solubility and low bioavailability. In an attempt to overcome these limitations, rutin nanocrystals were prepared using various stabilizers including nonionic surfactants and nonionic polymers. The nanocrystals were evaluated for particle size, zeta potential, drug entrapment efficiency, morphology, colloidal stability, rutin photostability, dissolution rate, and saturation solubility. The selected nanocrystal formulation was dispersed in a hydrogel base and the drug release kinetics and permeability through mouse skin were characterized. Rutin's anti-inflammatory efficacy was studied in a carrageenan-induced rat paw edema model. The nanocrystals had a size in the range of around 270-500 nm and a polydispersity index of around 0.3-0.5. Nanocrystals stabilized by hydroxypropyl beta-cyclodextrin (HP-β-CD) had the smallest particle size, highest drug entrapment efficiency, best colloidal stability, and highest drug photostability. Nanocrystals had around a 102- to 202-fold and 2.3- to 6.7-fold increase in the drug aqueous solubility and dissolution rate, respectively, depending on the type of stabilizer. HP-β-CD nanocrystals hydrogel had a significantly higher percent of drug released and permeated through the mouse skin compared with the free drug hydrogel. The cumulative drug amount permeated through the skin was 2.5-fold higher than that of the free drug hydrogel. In vivo studies showed that HP-β-CD-stabilized rutin nanocrystals hydrogel had significantly higher edema inhibition compared with the free drug hydrogel and commercial diclofenac sodium gel. These results highlight the potential of HP-β-CD-stabilized nanocrystals as a promising approach to enhance drug solubility, dissolution rate, and anti-inflammatory properties.