New broom fiber (Spartium junceum L.) derivatives: preparation and characterization

Multifunctional Microspheres Based on D-Mannose and Resveratrol for Ciprofloxacin Release

This article describes the preparation, characterization, and performance evaluation of functional microspheres useful for the release of ciprofloxacin. The particles were obtained using D-mannose, a natural aldohexose sugar, and resveratrol, a powerful antioxidant. In particular, the above compounds were initially converted into D-mannose carboxylate and resveratrol methacrylate and, therefore, subjected to an esterification reaction. The resulting product was used for the preparation of the microspheres which were characterized by light scattering, FT-IR spectrophotometry and scanning electron microscopy (SEM). Subsequently, their degree of bloating was evaluated at pH 1.2 to simulate the pH of the stomach, at pH 6.8 and pH 7.4 to mimic the intestinal environment. The antibiotic ciprofloxacin was then loaded into the microspheres, with an encapsulation efficiency of 100%. The cumulative amount of drug released was 55% at pH 6.8 and 99% at pH 7.4. The tests conducted to evaluate the antibacterial activity demonstrated the ability of the microspheres obtained to inhibit the growth of Escherichia coli. The antioxidant efficacy, due to the presence of resveratrol in their structure, was confirmed using rat liver microsomal membranes. The results obtained have highlighted how the microspheres based on D-mannose and resveratrol can be considered promising multifunctional vectors useful in the treatment of intestinal and urinary infections.

Multifunctional Membranes Based on β-Glucans and Chitosan Are Useful in Wound Treatment

In this work, bio-based membranes prepared using a crosslinked β-glucans–chitosan dispersed in the chitosan matrix useful in promoting wound healing were studied for the first-time. Wound healing is a process that includes sequential steps designed to restore the structure and function of damaged cells and tissue. To minimize damage and the risk of infection during the healing process and to promote restoration of the integrity of damaged tissue, the wound should be dressed. Generally, according to their function in the wound, dressings are classified on the basis of type of material and physical form. The substances used to make a dressing are generally natural polymers such as hydrocolloids, alginates, polyurethane, collagen, chitosan, pectin and hyaluronic acid. The combination of polymeric substances, with antibacterial and antioxidant properties, could be exploited in the biomedical field for the development of biocompatible materials able to act as a barrier between the wound and the external environment, protecting the site from bacterial contamination and promoting healing. To this aim, bio-based membranes were prepared by the phase inversion induced by solvent evaporation, using the crosslinked β-glucans–chitosan obtained by esterification reactions as a functional additive in the chitosan membrane. The reaction intermediates and the final products were characterized by Fourier transform infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC) while the morphological properties of membranes were analyzed using electronic scanning microscopy (SEM). The chemical bonding between chitosan and β-glucans allowed for the obtainment of a better dispersion of the combined new material into the membrane’s matrix and as a consequence, an enhanced antibacterial property evaluated through in vitro tests, with respect to the starting materials.

Chitosan Membranes Filled with Cyclosporine A as Possible Devices for Local Administration of Drugs in the Treatment of Breast Cancer

The aim of this work is the design, preparation and characterization of membranes based on cyclosporine A (CsA) and chitosan carboxylate (CC) to be used as an implantable subcutaneous medical device for a prolonged therapeutic effect in the treatment of breast cancer. The choice to use CsA is due to literature data that have demonstrated its possible antitumor activity on different types of neoplastic cells. To this end, CsA was bound to CC through an amidation reaction to obtain a prodrug to be dispersed in a chitosan-based polymeric membrane. The reaction intermediates and the final product were characterized by Fourier transform infrared spectroscopy (FT-IR) and proton nuclear magnetic resonance (¹H-NMR). Membranes were analyzed by differential scanning calorimetry (DSC) and scanning electron microscopy (SEM). The data obtained showed the effective formation of the amide bond between CsA and CC and the complete dispersion of CsA inside the polymeric membrane. Furthermore, preliminary tests, conducted on MDA-MB-231, a type of breast cancer cell line, have shown a high reduction in the proliferation of cancer cells. These results indicate the possibility of using the obtained membranes as an interesting strategy for the release of cyclosporin-A in breast cancer patients.

Nose-to-brain delivery: A comparative study between carboxymethyl chitosan based conjugates of dopamine

Herein, the synthesis of a novel polymeric conjugate N,O-CMCS-Dopamine (DA) based on an amide linkage is reported. The performances of this conjugate were compared with those of an analogous N,O-CMCS-DA ester conjugate previously studied (Cassano et al., 2020) to gain insight into their potential utility for Parkinson's disease treatment. The new amide conjugate was synthesized by standard carbodiimide coupling procedure and characterized by FT-IR, ¹H NMR spectroscopies and thermal analysis (Differential Scanning Calorimetry). In vitro mucoadhesive studies in simulated nasal fluid (SNF) evidenced high adhesive effect of both ester and amide conjugates. Results demonstrated that the amide conjugate exerted an important role to prevent DA spontaneous autoxidation both under stressed conditions and physiological mimicking ones. MTT test indicated cytocompatibility of the amide conjugate with Olfactory Ensheating Cells (OECs), which were shown by cytofluorimetry to internalize efficiently the conjugate. Overall, among the two conjugates herein studied, the N,O-CMCS-DA amide conjugate seems a promising candidate for improving the delivery of DA by nose-to-brain administration.

Synthesis and characterization of novel chitosan-dopamine or chitosan-tyrosine conjugates for potential nose-to-brain delivery

This work aims to the synthesis of novel carboxylated chitosan-dopamine (DA) and -tyrosine (Tyr) conjugates as systems for improving the brain delivery of the neurotransmitter DA following nasal administration. For this purpose, ester or amide conjugates were synthesized by N,N-dicyclohexylcarbodiimide (DCC) mediated coupling reactions between the appropriate N-tert-butyloxycarbonyl (Boc) protected starting polymers N,O-carboxymethyl chitosan and 6-carboxy chitosan and DA or O-tert-Butyl-L-tyrosine-tert-butyl ester hydrochloride. The resulting conjugates were characterized by FT-IR and ¹H- and ¹³C NMR spectroscopies and their in vitro mucoadhesive properties in simulated nasal fluid (SNF), toxicity and uptake from Olfactory Ensheathing Cells (OECs) were assessed. Results demonstrated that N,O-carboxymethyl chitosan-DA conjugate was the most mucoadhesive polymer in the series examined and, together with the 6-carboxy chitosan-DA-conjugate were able to release the neurotransmitter in SNF. The MTT assay showed that the starting polymers as well as all the prepared conjugates in OECs resulted not toxic at any concentration tested. Likewise, the three synthesized conjugates were not cytotoxic as well. Cytofluorimetric analysis revealed that the N,O-carboxymethyl chitosan DA conjugate was internalized by OECs in a superior manner at 24 h as compared with the starting polymer. Overall, the N,O-CMCS-DA conjugate seems promising for improving the delivery of DA by nose-to-brain administration.

Hemostatic gauze based on chitosan and hydroquinone: preparation, characterization and blood coagulation evaluation

This work concerns on the preparation and performance evaluation of a new chitosan hydroquinone based gauze for hemostatic use. Chitosan and hydroquinone were firstly connected by etherification and then linked to the pre-carboxylate gauze. The functionalized material and the chitosan-hydroquinone ether were characterized by Fourier Transform Infrared (FT-IR) Spectroscopy and Differential Scanning Calorimetry (DSC). FT-IR results showed that an esterification occurred on carboxylic group of the gauze. The gauze functionalization degree was also evaluated by volumetric analysis. The ether hydroquinone content was obtained by the Folin test. Moreover, the linkage between hydroquinone and chitosan was confirmed by nuclear magnetic resonance (NMR). The hemostatic activity of functionalized gauze was evaluated by dynamic blood clotting assays. The obtained results showed that the prepared material can shorten the blood clotting time and induce the adhesion and activation of platelets. Finally, swelling characteristic of the new gauze was evaluated to confirm its high capacity to absorb the blood.