Water-Soluble β-cyclodextrin Polymers as Drug Carriers to Improve Solubility, Thermal Stability and Controlled Release of Nifedipine

Cyclodextrin Host-Guest Recognition in Glucose-Monitoring Sensors

Diabetes mellitus is a prevalent chronic health condition that has caused millions of deaths worldwide. Monitoring blood glucose levels is crucial in diabetes management, aiding in clinical decision making and reducing the incidence of hypoglycemic episodes, thereby decreasing morbidity and mortality rates. Despite advancements in glucose monitoring (GM), the development of noninvasive, rapid, accurate, sensitive, selective, and stable systems for continuous monitoring remains a challenge. Addressing these challenges is critical to improving the clinical utility of GM technologies in diabetes management. In this concept, cyclodextrins (CDs) can be instrumental in the development of GM systems due to their high supramolecular recognition capabilities based on the host-guest interaction. The introduction of CDs into GM systems not only impacts the sensitivity, selectivity, and detection limit of the monitoring process but also improves biocompatibility and stability. These findings motivated the current review to provide a comprehensive summary of CD-based blood glucose sensors and their chemistry of glucose detection, efficiency, and accuracy. We categorize CD-based sensors into four groups based on their modification strategies, including CD-modified boronic acid, CD-modified mediators, CD-modified nanoparticles, and CD-modified functionalized polymers. These findings shed light on the potential of CD-based sensors as a promising tool for continuous GM in diabetes mellitus management.

Ultrasound-assisted synthesis of MIL-88(Fe) conjugated starch-Fe3O4 nanocomposite: A safe antibacterial carrier for controlled release of tetracycline

A constructing antibiotic carrier with a sustained release profile is a promising method to stop long-term bacterial infection, which is of ideal interest in different biomedical fields. To end this, the present study aims to design a novel carrier based on the modification of biopolymeric starch for the rising possible interaction between carrier and antibiotic agent. We established an in-situ ultrasound-assisted method was applied to grow and create MIL-88(Fe) framework in the structure of magnetic polysaccharide (i.e., St/Fe₃O₄) synthesized by precipitation method resulting in St/Fe₃O₄/MIL-88(Fe) nanocomposite. It was loaded with a high amount of Tetracycline (TC) through its immersion into the TC aqueous solution. The release profile of TC-loaded St/Fe₃O₄/MIL-88(Fe) displays a lower initial burst release (about 26 % after 12 h) and followed by a controlled and sustained release (about 73 % up to 168 h) in the simulated physiological environment at pH 7.4. The in vitro cytotoxicity showed good cytocompatibility against Human skin fibroblast (HFF-1) cells. TC-loaded St/Fe₃O₄/MIL-88(Fe) showed higher antibacterial activity against both S. aureus and E. coli with the MIC value of 64 and 128 μg·mL^-1, respectively.

Ultrasound-assisted synthesis of MIL-88(Fe) coordinated to carboxymethyl cellulose fibers: A safe carrier for highly sustained release of tetracycline

For stopping long-time harmful bacterial infection, designing a drug carrier with a highly prolonged release profile is a promising approach that is of interest to different biomedical areas. The subject of this work is to synthesis a novel carrier system through coordination of MIL-88(Fe) to carboxymethyl cellulose (CMC) for enhancing interaction between drug and carrier. We established an ultrasound-assisted synthetic method for in situ synthesis of MIL-88(Fe) in the presence of CMC resulting in CMC/MIL-88(Fe) composite. The CMC/MIL-88(Fe) was loaded with a high amount of Tetracycline (TC) by immersion of carrier to the TC aqueous solution. The release profile in the simulated physiological conditions, pH 7.4, revealed a low initial burst release followed by a sustained and prolonged release over 384 h. The in vitro cytotoxicity of CMC/MIL-88(Fe) against Human skin fibroblast (HFF-1) cells was calculated by MTT assay and showed a good cytocompatibility. The antibacterial activity was found for TC-loaded CMC/MIL-88(Fe) toward both E. coli and S. aureus with MIC 64 mg·ml^-1.

Dissolution of amorphous nifedipine from micelle-forming carboxymethylcellulose derivatives

We show that a novel amphiphilic graft copolymer combining the biodegradability and biocompatibility of oxidized carboxymethylcellulose (CMC) with that of hydrophilic poly(ethylene glycol) (PEG), and hydrophobic dodecylamine (DDA), improves the solubility and dissolution performance of nifedipine (NIF), considered as a model hydrophobic drug. The hydrophobic components of the graft copolymer have the multiple effect of favouring micelle formation and loading. At the same time, the interaction between the hydrophobic core and NIF has the secondary effect to suppress drug crystallization, favouring its dissolution, and to increase photostability. Oxidized CMC-g-PEG-DDA micelles reached values of drug concentration, loading capacity and encapsulation efficiency as high as 340 μg mL^-1, 6.4 % and 34.1 %, respectively. Loaded micelles showed a good stability with a limited release profile at pH 1.2, whereas at pH 7.4 the swollen cores enable much higher and progressive release, that reaches 3.4 and 6.6 % after 3 and 5 h, respectively, corresponding to very competitive concentration of 34 and 66 μg mL^-1.

An overview on the mathematical modeling of hydrogels' behavior for drug delivery systems

Hydrogels-based systems (HBSs) for drug delivery are nowadays extensively used and the interest in modeling their behavior is dramatically increasing. In this review a critical overview on the modeling approaches is given, quantitatively and qualitatively analyzing the publications on the subject, the trend of the publications per year and the type of modeling approaches. It was found that, despite the drug release fitting models (i.e. Higuchi's equation) are the most abundant, their use for HBSs is decreasing in the last years and luckily, considering the limiting assumption on which they were built, they will be confined to simple mathematical fitting equations. Within the mechanistic models the "multi-component" with the swelling approximation (mass transport only) and with the mechanics (fully coupled) are experiencing the highest growth rate, with much more interest toward the last one that, in the next years could be able to provide a first principles model. Statistical models, especially based on the response surface methodology, are rapidly spreading in the scientific community mainly thanks to their ability to be predictive, regardless of the phenomenology, in the analyzed design space with very low efforts. Neural Networks models for HBSs, in countertrend with their use in the pharmaceutical industry, have never take off preferring less data demanding statistical models.

Hypoxia-responsive micelles self-assembled from amphiphilic block copolymers for the controlled release of anticancer drugs

Amphiphilic block copolymers poly(ethylene glycol)-block-poly(methacrylic acid-co-2-nitroimidazole methacrylate) (PEG-b-P(MAA-co-NIMA)) were synthesized by the combination of atom transfer radical polymerization (ATRP), hydrolysis and EDC reactions. These copolymers could self-assemble into spherical micelles in water. 2-Nitroimidazole (NI) groups presented hypoxia-responsive properties under hypoxia conditions. The hydrophobic NI groups could be converted into hydrophilic aminoimidazole (AI) groups, which would lead to the expansion of micelles. Moreover, the content of NI groups in the copolymers would affect the hydrophilic-hydrophobic balance and therefore influence the self-assembly behaviour of the copolymer and the morphologies of the micelles. The copolymer micelles were used as a drug delivery system for controlled release of anticancer drug doxorubicin (DOX). The in vitro cytotoxicity investigation revealed that the DOX-loaded micelles showed higher toxicity to hypoxic cells than to normoxic cells. As a result, the block copolymers are expected to be used as an intelligent carrier for hydrophobic drugs to treat hypoxia-associated diseases.

Selective binding of methotrexate to monomeric, dimeric and polymeric cyclodextrins

Selective binding of methotrexate to monomeric, dimeric and polymeric cyclodextrins characterized by formation of more stable complexes with dimeric β-cyclodextrin.