Mesoporous silica-based dosage forms improve bioavailability of poorly soluble drugs in pigs: case example fenofibrate

Taurine Protects against Silica Nanoparticle-Induced Apoptosis and Inflammatory Response via Inhibition of Oxidative Stress in Porcine Ovarian Granulosa Cells

Silica nanoparticles (SNPs) induce reproductive toxicity through ROS production, which significantly limits their application. The protective effects of taurine (Tau) against SNP-induced reproductive toxicity remain unexplored. So this study aims to investigate the impact of Tau on SNP-induced porcine ovarian granulosa cell toxicity. In vitro, granulosa cells were exposed to SNPs combined with Tau. The localization of SNPs was determined by TEM. Cell viability was examined by CCK-8 assay. ROS levels were measured by CLSM and FCM. SOD and CAT levels were evaluated using ELISA and qPCR. Cell apoptosis was detected by FCM, and pro-inflammatory cytokine transcription levels were measured by qPCR. The results showed that SNPs significantly decreased cell viability, while increased cell apoptosis and ROS levels. Moreover, SOD and CAT were decreased, while IFN-α, IFN-β, IL-1β, and IL-6 were increased after SNP exposures. Tau significantly decreased intracellular ROS, while it increased SOD and CAT compared to SNPs alone. Additionally, Tau exhibited anti-inflammatory effects and inhibited cell apoptosis. On the whole, these findings suggest that Tau mitigates SNP-induced cytotoxicity by reducing oxidative stress, inflammatory response, and cell apoptosis. Tau may be an effective strategy to alleviate SNP-induced toxicity and holds promising application prospects in the animal husbandry and veterinary industry.

Evaluation of amorphous and lipid-based formulation strategies to increase the in vivo cannabidiol bioavailability in piglets

Cannabidiol (CBD) suffers from poor oral bioavailability due to poor aqueous solubility and high metabolism, and is generally administered in liquid lipid vehicles. Solid-state formulations of CBD have been developed, but their ability to increase the oral bioavailability has not yet been proven in vivo. Various approaches are investigated to increase this bioavailability. This study aimed to demonstrate the enhancement of the oral bioavailability of oral solid dosage forms of amorphous CBD and lipid-based CBD formulation compared to crystalline CBD. Six piglets received the three formulations, in a cross-over design. CBD and 7 - COOH - CBD, a secondary metabolite used as an indicator of hepatic degradation, were analyzed in plasma. A 10.9-fold and 6.8-fold increase in oral bioavailability was observed for the amorphous and lipid formulations, respectively. However, the lipid-based formulation allowed reducing the inter-variability when administered to fasted animals. An entero-hepatic cycle was confirmed for amorphous formulations. Finally, this study showed that the expected protective effect of lipids against hepatic degradation of the lipid-based formulation did not occur, since the ratio CBD/metabolite was higher than that of the amorphous one.

Supersaturation and Precipitation Applicated in Drug Delivery Systems: Development Strategies and Evaluation Approaches

Supersaturation is a promising strategy to improve gastrointestinal absorption of poorly water-soluble drugs. Supersaturation is a metastable state and therefore dissolved drugs often quickly precipitate again. Precipitation inhibitors can prolong the metastable state. Supersaturating drug delivery systems (SDDS) are commonly formulated with precipitation inhibitors, hence the supersaturation is effectively prolonged for absorption, leading to improved bioavailability. This review summarizes the theory of and systemic insight into supersaturation, with the emphasis on biopharmaceutical aspects. Supersaturation research has developed from the generation of supersaturation (pH-shift, prodrug and SDDS) and the inhibition of precipitation (the mechanism of precipitation, the character of precipitation inhibitors and screening precipitation inhibitors). Then, the evaluation approaches to SDDS are discussed, including in vitro, in vivo and in silico studies and in vitro-in vivo correlations. In vitro aspects involve biorelevant medium, biomimetic apparatus and characterization instruments; in vivo aspects involve oral absorption, intestinal perfusion and intestinal content aspiration and in silico aspects involve molecular dynamics simulation and pharmacokinetic simulation. More physiological data of in vitro studies should be taken into account to simulate the in vivo environment. The supersaturation theory should be further completed, especially with regard to physiological conditions.

Drug loading to mesoporous silica carriers by solvent evaporation: A comparative study of amorphization capacity and release kinetics

The sorption of poorly aqueous soluble active pharmaceutical ingredients (API) to mesoporous silica carriers is an increasingly common formulation strategy for dissolution rate enhancement for this challenging group of substances. However, the success of this approach for a particular API depends on an array of factors including the properties of the porous carrier, the loading method, or the attempted mass fraction of the API. At present, there is no established methodology for the rational selection of these parameters. In the present work, we report a systematic comparison of four well-characterised silica carriers and seven APIs loaded by the same solvent evaporation method. In each case, we find the maximum amorphization capacity by x-ray powder diffraction analysis and measure the in vitro drug release kinetics. For a selected case, we also demonstrate the potential for bioavailability enhancement by a permeation essay.

Insights into the ameliorating ability of mesoporous silica in modulating drug release in ternary amorphous solid dispersion prepared by hot melt extrusion

In this work, the application of various mesoporous silica grades in the preparation of stabilized ternary amorphous solid dispersions of Felodipine using hot melt extrusion was explored. We have demonstrated the effectiveness of mesoporous silica in these dispersions without the need for any organic solvents i.e., no pre-loading or immersion steps required. The physical and chemical properties, release profiles of the prepared formulations and the surface concentrations of the various molecular species were investigated in detail. Formulations containing 25 wt% and 50 wt% of Felodipine demonstrated enhanced stability and solubility of the drug substance compared to its crystalline counterpart. Based on the Higuchi model, ternary formulations exhibited a 2-step or 3-step release pattern which can be ascribed to the release of drug molecules from the organic polymer matrix and the external silica surface, followed by a release from the silica pore structure. According to the Korsmeyer-Peppas model, the release rate and release mechanism are governed by a complex quasi-Fickian release mechanism, in which multiple release mechanisms are occurring concurrently and consequently. Stability studies indicated that after 6 months storage of all formulation at 30% RH and 20 °C, Felodipine in all formulations remained stable in its amorphous state except for the formulation comprised of 40 wt% Syloid AL-1FP with a 50 wt% drug load.

Effect of Shape on Mesoporous Silica Nanoparticles for Oral Delivery of Indomethacin

The use of mesoporous silica nanoparticles (MSNs) in the field of oral drug delivery has recently attracted greater attention. However, there is still limited knowledge about how the shape of MSNs affects drug delivery capacity. In our study, we fabricated mesoporous silica nanorods (MSNRs) to study the shape effects of MSNs on oral delivery. MSNRs were characterized by transmission electron microscopy (TEM), nitrogen adsorption/desorption, Fourier transform infrared spectroscopy (FTIR), and small-angle X-ray diffraction (small-angle XRD). Indomethacin (IMC), a non-steroidal anti-inflammatory agent, was loaded into MSNRs as model drug, and the drug-loaded MSNRs resulted in an excellent dissolution-enhancing effect. The cytotoxicity and in vivo pharmacokinetic studies indicated that MSNRs can be applied as a safe and efficient candidate for the delivery of insoluble drugs. The use of MSNs with a rod-like shape, as a drug delivery carrier, will extend the pharmaceutical applications of silica materials.

Enhancing oral bioavailability of poorly soluble drugs with mesoporous silica based systems: opportunities and challenges

Porous silica-based drug delivery systems have shown considerable promise for improving the oral delivery of poorly water-soluble drugs. More specifically, micro- and meso-porous silica carriers have high surface areas with associated ability to physically adsorb high-drug loads in a molecular or amorphous form; this allows molecular state drug release in aqueous gastrointestinal environments, potential for supersaturation, and hence facilitates enhanced absorption and increased bioavailability. This review focuses primarily on the ability of porous silica materials to modulate in vitro drug release and enhance in vivo biopharmaceutical performance. The key considerations identified and addressed are the physicochemical properties of the porous silica materials (e.g. the particle and pore size, shape, and surface chemistry), drug specific properties (e.g. pKa, solubility, and nature of interactions with the silica carrier), potential for both immediate and controlled release, drug release mechanisms, potential for surface functionalization and inclusion of precipitation inhibitors, and importance of utilizing relevant and effective in vitro dissolution methods with discriminating dissolution media that provides guidance for in vivo outcomes (i.e. IVIVC).

Lipophilicity and hydrophobicity considerations in bio-enabling oral formulations approaches – a PEARRL review

Objectives

This review highlights aspects of drug hydrophobicity and lipophilicity as determinants of different oral formulation approaches with specific focus on enabling formulation technologies. An overview is provided on appropriate formulation selection by focussing on the physicochemical properties of the drug.

Key findings

Crystal lattice energy and the octanol–water partitioning behaviour of a poorly soluble drug are conventionally viewed as characteristics of hydrophobicity and lipophilicity, which matter particularly for any dissolution process during manufacturing and regarding drug release in the gastrointestinal tract. Different oral formulation strategies are discussed in the present review, including lipid-based delivery, amorphous solid dispersions, mesoporous silica, nanosuspensions and cyclodextrin formulations.

Summary

Current literature suggests that selection of formulation approaches in pharmaceutics is still highly dependent on the availability of technological expertise in a company or research group. Encouraging is that, recent advancements point to more structured and scientifically based development approaches. More research is still needed to better link physicochemical drug properties to pharmaceutical formulation design.

Application of the solubility parameter concept to assist with oral delivery of poorly water-soluble drugs – a PEARRL review

Objectives

Solubility parameters have been used for decades in various scientific fields including pharmaceutics. It is, however, still a field of active research both on a conceptual and experimental level. This work addresses the need to review solubility parameter applications in pharmaceutics of poorly water-soluble drugs.

Key findings

An overview of the different experimental and calculation methods to determine solubility parameters is provided, which covers from classical to modern approaches. In the pharmaceutical field, solubility parameters are primarily used to guide organic solvent selection, cocrystals and salt screening, lipid-based delivery, solid dispersions and nano- or microparticulate drug delivery systems. Solubility parameters have been applied for a quantitative assessment of mixtures, or they are simply used to rank excipients for a given drug.

Summary

In particular, partial solubility parameters hold great promise for aiding the development of poorly soluble drug delivery systems. This is particularly true in early-stage development, where compound availability and resources are limited. The experimental determination of solubility parameters has its merits despite being rather labour-intensive because further data can be used to continuously improve in silico predictions. Such improvements will ensure that solubility parameters will also in future guide scientists in finding suitable drug formulations.

Approaches to increase mechanistic understanding and aid in the selection of precipitation inhibitors for supersaturating formulations – a PEARRL review

Objectives

Supersaturating formulations hold great promise for delivery of poorly soluble active pharmaceutical ingredients (APIs). To profit from supersaturating formulations, precipitation is hindered with precipitation inhibitors (PIs), maintaining drug concentrations for as long as possible. This review provides a brief overview of supersaturation and precipitation, focusing on precipitation inhibition. Trial-and-error PI selection will be examined alongside established PI screening techniques. Primarily, however, this review will focus on recent advances that utilise advanced analytical techniques to increase mechanistic understanding of PI action and systematic PI selection.

Key findings

Advances in mechanistic understanding have been made possible by the use of analytical tools such as spectroscopy, microscopy and mathematical and molecular modelling, which have been reviewed herein. Using these techniques, PI selection can be guided by molecular rationale. However, more work is required to see widespread application of such an approach for PI selection.

Summary

Precipitation inhibitors are becoming increasingly important in enabling formulations. Trial-and-error approaches have seen success thus far. However, it is essential to learn more about the mode of action of PIs if the most optimal formulations are to be realised. Robust analytical tools, and the knowledge of where and how they can be applied, will be essential in this endeavour.