Synthesis and characterization of MFI-type borosilicate zeolites and evaluation of their efficiency as drug delivery systems

Zeolites as Ingredients of Medicinal Products

Development of new medicinal products for particular therapeutic treatment or for better manipulations with better quality and less side effects are possible as a result of advanced inorganic and organic materials application, among which zeolites, due to their properties and versatility, have been gaining attention. This paper is an overview of the development in the use of zeolite materials and their composites and modifications as medicinal products for several purposes such as active agents, carriers, for topical treatments, oral formulations, anticancer, the composition of theragnostic systems, vaccines, parenteral dosage forms, tissue engineering, etc. The objective of this review is to explore the main properties of zeolites and associate them with their drug interaction, mainly addressing the advances and studies related to the use of zeolites for different types of treatments due to their zeolite characteristics such as molecule storage capacity, physical and chemical stability, cation exchange capacity, and possibility of functionalization. The use of computational tools to predict the drug-zeolite interaction is also explored. As conclusion was possible to realize the possibilities and versatility of zeolite applications as being able to act in several aspects of medicinal products.

Lower olefins from methane: recent advances

Modern methods for methane conversion to lower olefins having from 2 to 4 carbon atoms per molecule are generalized. Multistage processing of methane into ethylene and propylene via syngas or methyl chloride and methods for direct conversion of CH4 to ethylene are described. Direct conversion of syngas to olefins as well as indirect routes of the process via methanol or dimethyl ether are considered. Particular attention is paid to innovative methods of olefin synthesis. Recent achievements in the design of catalysts and development of new techniques for efficient implementation of oxidative coupling of methane and methanol conversion to olefins are analyzed and systematized. Advances in commercializing these processes are pointed out. Novel catalysts for Fischer – Tropsch synthesis of lower olefins from syngas and for innovative technique using oxide – zeolite hybrid catalytic systems are described. The promise of a new route to lower olefins by methane conversion via dimethyl ether is shown. Prospects for the synthesis of lower olefins via methyl chloride and using non-oxidative coupling of methane are discussed. The most efficient processes used for processing of methane to lower olefins are compared on the basis of degree of conversion of carbonaceous feed, possibility to integrate with available full-scale production, number of reaction stages and thermal load distribution.

The bibliography includes 346 references.

Biomedical Applications of Zeolitic Nanoparticles, with an Emphasis on Medical Interventions

The advent of porous materials, in particular zeolitic nanoparticles, has opened up unprecedented putative research avenues in nanomedicine. Zeolites with intracrystal mesopores are low framework density aluminosilicates possessing a regular porous structure along with intricate channels. Their unique physiochemical as well as physiological parameters necessitate a comprehensive overview on their classifications, fabrication platforms, cellular/macromolecular interactions, and eventually their prospective biomedical applications through illustrating the challenges and opportunities in different integrative medical and pharmaceutical fields. More particularly, an update on recent advances in zeolite-accommodated drug delivery and the prevalent challenges regarding these molecular sieves is to be presented. In conclusion, strategies to accelerate the translation of these porous materials from bench to bedside along with common overlooked physiological and pharmacological factors of zeolite nanoparticles are discussed and debated. Furthermore, for zeolite nanoparticles, it is a matter of crucial importance, in terms of biosafety and nanotoxicology, to appreciate the zeolite-bio interface once the zeolite nanoparticles are exposed to the bio-macromolecules in biological media. We specifically shed light on interactions of zeolite nanoparticles with fibrinogen and amyloid beta which had been comprehensively investigated in our recent reports. Given the significance of zeolite nanoparticles' interactions with serum or interstitial proteins conferring them new biological identity, the preliminary approaches for deeper understanding of administration, distribution, metabolism and excretion of zeolite nanoparticles are elucidated.

Silicalite-1 Layers as a Biocompatible Nano- and Micro-Structured Coating: An In Vitro Study on MG-63 Cells

Silicalite-1 is a purely siliceous form of zeolite, which does not contain potentially harmful aluminum in its structure as opposed to ZSM-5 aluminosilicate types of zeolite. This paper reports on a study of a silicalite-1 film, deposited on a silicon Si(100) substrate, as a potential anti-corrosive and biocompatible coating for orthopaedic implants. Silicalite-1 film was prepared in situ on the surface of Si(100) wafers using a reaction mixture of tetrapropyl-ammonium hydroxide (TPAOH), tetraethyl-orthosilicate (TEOS), and diH₂O. The physico-chemical properties of the obtained surface were characterized by means of X-ray photoelectron spectroscopy, water contact angle measurement, atomic force microscopy, and scanning electron microscopy. The biocompatibility was assessed by interaction with the MG-63 cell line (human osteosarcoma) in terms of cell adhesion, morphology, proliferation, and viability. The synthesized silicalite-1 film consisted of two layers (b- and a, b-oriented crystals) creating a combination of micro- and nano-scale surface morphology suitable for cell growth. Despite its hydrophobicity, the silicalite-1 film increased the number of initially adhered human osteoblast-like MG-63 cells and the proliferation rate of these cells. The silicalite-1 film also improved the cell viability in comparison with the reference Si(100) substrate. It is therefore a promising candidate for coating of orthopaedic implants.

Strategies to control zeolite particle morphology

Methods to synthesize zeolites with different crystal habits and assemble zeolite crystals into specific structures are reviewed for the rational design of zeolite particle morphologies.