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Glasses of xCaO∙(80-x)P2O5·20Na2O system (0 ≤ x ≤ 30% mol %) with constant Na2O content were studied in order to evidence both structural and dissolution properties determined by CaO addition. Transparent vitreous samples were obtained in the investigated composition range. Thermal analysis evidenced the increase of both crystallisation and melting temperatures with CaO content. The relative mass loss of samples in simulated body fluid progressively increased with the extent of P2O5 substitution by CaO. The dissolution properties could be explained in relation with the structural changes concerning the PO4 units connectivity as pointed out by DTA and FTIR analysis.

The present study reports the results obtained by X-ray photoelectron spectroscopy (XPS) for new solid forms of antineoplastic agent 5-fluorouracil with anthelmintic piperazine obtained by liquid assisted ball milling and slurry crystallization methods as co-crystal and salt, respectively. The interest for these new solid forms of 5-fluorouracil with another drug consists in obtaining new compounds with potential pharmaceutical and biomedical applications. The XPS results bring additional deciding information on the atomic environments in the newly obtained solid forms of 5-fluorouracil with piperazine beside the earlier reported X-ray diffraction and infrared spectroscopy data. The deconvolution of N 1s core level spectra allows to distinguish unequivocally the protonated (salt) from hydrogen-bonded (co-crystal) nitrogen species based on the N 1s binding energy associated with the protonation of nitrogen atoms. The N 1s component around 402 eV observed only for the solid form obtained following the slurry route proves in this case the formation of a salt on basis of positively charged nitrogen resulted by protonation of secondary amine groups. Moreover, for the solid form obtained following the ball milling route, one notices a large negative shift of N 1s binding energy that supports the development of a co-crystal.

Monodispersed silica-based microspheres have been prepared by hydrolysis and condensation of tetraethoxysilane (TEOS) in a water–ethanol mixed solution using dodecylamine (DDA) as hydrolysis catalyst and template. Core-shell samples were produced by electrostatic attraction and heterogeneous nucleation of alumina or mixed alumina and iron oxide (1:1) shells on mesoporous silica core microspheres. The iron oxide embedded in the shell structure may be considered both for contrast improvement in magnetic resonance imaging and for the local treatment of cancer by hyperthermia. SEM/TEM analysis proves the spherical shape of the silica particles, the shell development on their surface as well as the distribution of aluminum and iron in the whole shell. The outermost layer of the microspheres was primary investigated by XPS, while the structural characterization of the samples was achieved using XRD, FTIR, EPR and NMR techniques.

The aim of the present study was to asses the formation of solid forms between the 5-fluorouracil chemotherapy drug and the anthelmintic piperazine. Two new solid forms of antineoplastic agent 5-fluorouracil with anthelmintic piperazine were obtained by liquid assisted ball milling and slurry crystallization methods. The N H hydrogen bonding donors and C = O hydrogen bonding acceptors of 5-fluorouracil allow to form co-crystals with other drugs delivering improved properties for medical applications, as proved for other compounds of pharmaceutical interest. Both new solid forms were investigated using X-ray powder diffraction (XRD), differential thermal analysis (DTA) and Fourier transform infrared (FTIR) spectroscopy. The XRD results show that by both methods were successfully synthesized new solid forms of 5-fluorouracil with piperazine. According to FTIR results the form prepared by lichid assisted grinding process was obtained as co-crystal and the other one, prepared by slurry method, resulted as a salt.

Simultaneous radiotherapy and hyperthermia yield synergistic improvement of therapeutic efficacy in cancer therapy. The study is focussed on sol-gel derived particles of 60SiO2•20Al2O3•10Fe2O3•10Dy2O3 (mol%) system functionalized with type I collagen. The addition to aluminosilicate matrix of Fe2O3•was thought for hyperthermia and of Dy2O3 for internal radiation therapy after neutron activation of dysprosium to 165Dy radioisotope. The collagen functionalization of these particles aimed to make them well accepted in the body and to contribute to destruction of reactive oxygen species, what has to be taken into account when nanoparticles are used for cancer therapy. The XRD, FTIR and XPS investigations were carried out on Fe-Dy-aluminosilicate particles of average size around tens of nanometers, before and after their incubation in collagen solution in order to prove the protein functionalization particles and to assess the changes in secondary structure of protein following this process. The results show the anchoring of the protein on particles surface in a few nanometers thin layer as well as some relative changes of protein secondary structure. After interface processes with particles surface, the secondary structure of amide I in collagen consists overwhelmingly of α-helices and only about 12 % of β-turns structure.

The sol–gel derived 50SiO 2 ⋅30CaO⋅10Fe 2 O 3 ⋅10Dy 2 O 3 system was subjected to heat treatments at 500, 800 and 1200 °C in order to obtain crystalline phases of interest for biomedical applications. The structural changes were investigated by Fourier transform infrared spectroscopy (FTIR) and electron paramagnetic resonance (EPR). Both FTIR and EPR results support the development of wollastonite, hematite and magnetite crystalline phases desirable for samples bioactivity and heating possibility for hyperthermia treatment. Dysprosium addition was considered for subsequent radioactivation of the samples that could extend their application to thermoradiotherapy.

The study is focused on Na 2 O and/or K 2 O influence on a new sol–gel derived SeO 2 –B 2 O 3 –SiO 2 –P 2 O 5 –CaO bioactive system. The structural changes induced by Na 2 O and/or K 2 O addition were correlated with the samples behavior in simulated biological media. X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy were used to characterize the structure and the type of the chemical bonds. The morphology of the samples was characterized through scanning electron microscopy (SEM). XRD results pointed out a prevalent vitreous structure with an incipient hydroxyapatite (HA) crystalline phase. FTIR results revealed a complex network consisting of silicate, phosphate and borate units, as well as the development of both A- and B-type of carbonate-substituted HA. The bioactivity of the samples was tested in vitro following the evolution of the apatite layers self-assembled on the samples surface in simulated body fluid. Their biocompatibility was investigated after samples surface functionalization with protein. The results indicate that sodium and potassium addition improves the biocompatibility by enhancement of protein adherence on samples surface and without to prevent the samples bioactivity.

Bioactive glass with the composition 0.55SiO 2 ·0.41CaO·0.04P 2 O 5 was prepared following the sol–gel route as controlled delivery systems for tetracycline (TC). The maturation and drying of the gel under different conditions led to different behavior regarding the loading and release of TC from these matrices. The pore size modifications upon TC loading evidenced by BET method show different ability of the glass matrices with respect to TC incorporation, also supported by experimental EPR and fluorescence spectroscopy. EPR spectra of both TC solution and immobilized TC on the porous structure of glass specimens demonstrated changes in tetracycline structure during loading and upon adsorption. The TC release profile monitored by differential pulse voltammetry shows a maximum concentration after 2 h and a continuously slow release during the next 24 h. The obtained results demonstrate that the pores size modification related to different maturation and drying procedures seems to be a determinative factor in tetracycline release process.