Nanocrystalline Suspensions of Irbesartan Enhance Oral Bioavailability by Improving Drug Solubility and Leading Endocytosis Uptake into the Intestine

Construction of the pulmonary bio-adhesive delivery system of nintedanib nanocrystalline for effective treatment of pulmonary fibrosis

Pulmonary fibrosis (PF) is a chronic, progressive, and fatal lung disease with a high mortality rate. Nintedanib, as a multi-tyrosine kinase inhibitor, is widely used as the first line drug for PF patients. However, only nintedanib oral formulations are used currently in clinic and show a low drug selectivity, significant first-pass effect and low bioavailability with 4.7%, thus limiting the clinical outcome of nintedanib. In this study, nintedanib was prepared in the form of nintedanib nanocrystalline (Nib-NC) and then encapsulated with hyaluronic acid (HA) to construct a nanocrystalline-in-adhesive delivery system Nib-NC@HA with high drug loading efficacy and pulmonary bio-adhesive properties, which could avoid the first-pass effects, increase the bioavailability and reduce the systemic side effects of nintedanib. After inhalation administration of Nib-NC@HA, due to the bio-adhesive properties of HA, Nib-NC@HA could prolong the retention time of drug in the lungs and inhibit the expression of inflammation associated factors such as IL-6, IL-1β and TNF-α in lung tissue, reduce the release of pro-fibrotic growth factor, and improve the lung function, thus showing enhanced anti-fibrotic effect than Nib-NC. The results suggested that Nib-NC@HA is an efficient and optimal targeted bio-adhesive delivery system for the lungs to treat pulmonary fibrosis.

Factors affecting the preparation of nanocrystals: characterization, surface modifications and toxicity aspects

INTRODUCTION

The fabrication of well-defined nanocrystals in size and form is the focus of much investigation. In this work, we have critically reviewed several recent instances from the literature that shows how the production procedure affects the physicochemical properties of the nanocrystals.

AREAS COVERED

Scopus, MedLine, PubMed, Web of Science, and Google Scholar were searched for peer-review articles published in the past few years using different key words. Authors chose relevant publications from their files for this review. This review focuses on the range of techniques available for producing nanocrystals. We draw attention to several recent instances demonstrating the impact of various process and formulation variables that affect the nanocrystals' physicochemical properties. Moreover, various developments in the characterization techniques explored for nanocrystals concerning their size, morphology, etc. have been discussed. Last but not least, recent applications, the effect of surface modifications, and the toxicological traits of nanocrystals have also been reviewed.

EXPERT OPINION

The selection of an appropriate production method for the formation of nanocrystals, together with a deep understanding of the relationship between the drug's physicochemical properties, unique features of the various formulation alternatives, and anticipated in-vivo performance, would significantly reduce the risk of failure during human clinical trials that are inadequate.

Orally disintegrating tablets containing famotidine nanoparticles provide high intestinal absorbability via the energy-dependent endocytosis pathway

The permeability of the Biopharmaceutics Classification System (BCS) class III drugs are low, and their oral bioavailability needs to be improved. In this study, we attempted to design oral formulations containing famotidine (FAM) nanoparticles to overcome the limitations of BCS class III drugs. Dispersions containing FAM nanoparticles with a particle size of approximately 50–220 nm were produced by the bead-milling treatment. Moreover, we succeeded in preparing an orally disintegrating tablet containing FAM nanoparticles using the dispersions described above, additives (D-mannitol, polyvinylpyrrolidone, and gum arabic), and freeze-dry treatment (FAM-NP tablet). The FAM-NP tablet was disaggregated 3.5 s after addition to purified water, and the FAM particles in the redispersion of the FAM-NP tablet stored for 3 months were nano-sized (141 ± 6.6 nm). The ex-vivo intestinal penetration and in vivo absorption of FAM in rats applied with the FAM-NP tablet were significantly higher than those in rats applied with the FAM tablet containing microparticles. In addition, enhanced intestinal penetration of the FAM-NP tablet was attenuated by an inhibitor of clathrin-mediated endocytosis. In conclusion, the orally disintegrating tablet containing FAM nanoparticles improved low mucosal permeability and low oral bioavailability and overcame these issues of BCS class III drugs as oral formulations.

Oral supramolecular nanovectors for dual natural medicine codelivery to prevent gastric mucosal lesion

The oral administration of a single formulation loaded with more than one natural medicine to treat chronic diseases has advantages such as convenience, effectiveness, and economy. Here, using biomaterials approved by the drug administration, we fabricated supramolecular nanovectors containing dual natural medicines to prevent gastric mucosal lesions. Nanovectors exhibited superior intestinal absorption and bioavailability, which might be due to their high dispersion, good muco-adhesiveness, blood-lymph circulation transport, lipid sensing, and protective effects. Molecular docking results clarified the possible mechanisms in aspects of efflux pump (p-glycoprotein and multidrug resistance protein 1) inhibition effects, metabolic enzyme (cytochrome P450 3A4/1A2) blocking effects, serum albumin deposit effects, and dual drug interaction effects. Nanovectors decreased ethanol-induced gastric mucosal lesions by lowering the gastric ulcer index, preventing oxidative damage, decreasing interleukin-6, tumor necrosis factor-α and malondialdehyde, increasing glutathione, superoxide dismutase, and prostaglandin E2 levels. The interactions of inhibitor of nuclear factor-κB or κB kinase-related proteins and dual drugs or nanovector components were simulated computationally to provide an understanding of the gastro-protective action mechanism. In all, industrializable supramolecular nanovectors could effectively co-deliver dual natural medicines via the oral route by improving the pharmacokinetic behavior and exerting protective efficacy of the gastric mucosa by decreasing the oxidative stress and inflammatory level.

Drug Nanocrystals: Focus on Brain Delivery from Therapeutic to Diagnostic Applications

The development of new drugs is often hindered by low solubility in water, a problem common to nearly 90% of natural and/or synthetic molecules in the discovery pipeline. Nanocrystalline drug technology involves the reduction in the bulk particle size down to the nanosize range, thus modifying its physico-chemical properties with beneficial effects on drug bioavailability. Nanocrystals (NCs) are carrier-free drug particles surrounded by a stabilizer and suspended in an aqueous medium. Due to high drug loading, NCs maintain a potent therapeutic concentration to produce desirable pharmacological action, particularly useful in the treatment of central nervous system (CNS) diseases. In addition to the therapeutic purpose, NC technology can be applied for diagnostic scope. This review aims to provide an overview of NC application by different administration routes, especially focusing on brain targeting, and with a particular attention to therapeutic and diagnostic fields. NC therapeutic applications are analyzed for the most common CNS pathologies (i.e., Parkinson’s disease, psychosis, Alzheimer’s disease, etc.). Recently, a growing interest has emerged from the use of colloidal fluorescent NCs for brain diagnostics. Therefore, the use of NCs in the imaging of brain vessels and tumor cells is also discussed. Finally, the clinical effectiveness of NCs is leading to an increasing number of FDA-approved products, among which the NCs approved for neurological disorders have increased.

Oral Formulation Based on Irbesartan Nanocrystals Improve Drug Solubility, Absorbability, and Efficacy

We previously reported that the bioavailability (BA) of irbesartan (IRB), a BSC class II drug, was improved by preparing nanocrystalline suspensions. However, nanocrystalline suspensions have chemical and physical instabilities and must be converted into tablets through drying approaches in order to overcome such instabilities. In this study, we attempted to design a molded tablet based on nanocrystalline IRB suspensions (IRB-NP tablet) and investigated the effects of this IRB-NP tablet on blood pressure (BP) in a stroke-prone spontaneously hypertensive (SHR-SP) rat. The IRB-NP tablet (with a hardness of 42.6 N) was developed by combining various additives (methylcellulose, 2-hydroxypropyl-β-cyclodextrin HPβCD, D-mannitol, polyvinylpyrrolidone, and gum arabic) followed by bead-milling and freeze-drying treatments. The mean particle size in the redispersions of the IRB-NP tablet was approximately 118 nm. The solubility and intestinal absorption of IRB in the IRB-NP tablet were significantly enhanced in comparison with the microcrystalline IRB tablet (IRB-MP tablet), and both solubility and clathrin-dependent endocytosis helped improve the low BA of the IRB. In addition, the BP-reducing effect of the IRB-NP tablet was significantly higher than that of the IRB-MP tablet. These results provide useful information for the preservation of nanocrystalline suspensions of BCS class II drugs, such as IRB.

Instillation of Ophthalmic Formulation Containing Nilvadipine Nanocrystals Attenuates Lens Opacification in Shumiya Cataract Rats

We developed ophthalmic formulations based on nilvadipine (NIL) nanocrystals (NIL-NP dispersions; mean particle size: 98 nm) by using bead mill treatment and investigated whether the instillation of NIL-NP dispersions delivers NIL to the lens and prevents lens opacification in hereditary cataractous Shumiya cataract rats (SCRs). Serious corneal stimulation was not detected in either human corneal epithelial cells or rats treated with NIL-NP dispersions. The NIL was directly delivered to the lens by the instillation of NIL-NP dispersions, and NIL content in the lenses of rats instilled with NIL-NP dispersions was significantly higher than that in the ophthalmic formulations based on NIL microcrystals (NIL-MP dispersions; mean particle size: 21 µm). Moreover, the supply of NIL prevented increases in Ca²⁺ content and calpain activity in the lenses of SCRs and delayed the onset of cataracts. In addition, the anti-cataract effect in the lens of rats instilled with NIL-NP dispersions was also significantly higher than that in NIL-MP dispersions. NIL-NPs could be used to prevent lens opacification.