This paper provides an analytical characterization of chitosan scaffolds obtained by freeze-gelation toward the uptake and the controlled release of chondroitin sulphate (CS), as cartilage repair agent, under different pH conditions. Scanning electron microscopy (SEM), attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR), and liquid chromatography-UV spectrophotometry (LC-UV) techniques were exploited to obtain qualitative and quantitative descriptions of polymer and drug behaviour in the biomaterial. As for morphology, SEM analysis allowed the evaluation of scaffold porosity in terms of pore size and distribution both at the surface (Feret diameter 58 ± 19 μm) and on the cross section (Feret diameter 106 ± 51 μm). LC and ATR-FTIR evidenced a pH-dependent CS loading and release behaviour, strongly highlighting the role of electrostatic forces on chitosan/chondroitin sulphate interactions.

Direct administration of drugs to the lung is commonly used for the treatment of local respiratory diseases, but it can also be employed to obtain a systemic effect. Besides the advantages offered in terms of higher therapeutic efficacy, this administration route raised specific drug delivery issues. In fact, to obtain a suitable bioavailability and therapeutic effect, the drug has to be efficiently deposited in the lower airways. Formulation is required to render the drug respirable. Area covered: The present paper deals with dry powders formulations, in particular it reviews the literature of the last two decades with respect to the role of the solid-state characteristics of the excipients used as carriers in adhesive mixture toward respirability of the active ingredient. Expert opinion: Many of the literature data on this topic are still not completely understood and sometimes they appear contradictory despite the intent to be complementary. More accurate and sensitive analytical methods for solid state characterization both for the drug and the carrier as well as a more systematic approach for the evaluation of the energetics of the carrier vs the drug surface is foreseen as a useful way to address some of the issues still opened in this field.

Calcium is recognized as an essential nutritional factor for bone health. An adequate intake is important to achieve or maintain optimal bone mass in particular during growth and old age. The aim of the present study was to evaluate the efficiency of hake fish bone (HBF) as a calcium source for bone mineralization: in vitro on osteosarcoma SaOS-2 cells, cultured in Ca-free osteogenic medium (OM) and in vivo on young growing rats fed a low-calcium diet. Lithotame (L), a Ca supplement derived from Lithothamnium calcareum, was used as control. In vitro experiments showed that HBF supplementation provided bone mineralization similar to standard OM, whereas L supplementation showed lower activity. In vivo low-Ca HBF-added and L-added diet similarly affected bone deposition. Physico-chemical parameters concerning bone mineralization, such as femur breaking force, tibia density and calcium/phosphorus mineral content, had beneficial effects from both Ca supplementations, in the absence of any evident adverse effect. We conclude HBF derived from by-product from the fish industry is a good calcium supplier with comparable efficacy to L.