The substitution of selenium oxyanions in the hydroxyapatite structure was examined using multinuclear solid-state resonance spectroscopy (ssNMR). The study was supported by powder X-ray diffractometry (PXRD) and wavelength dispersion X-ray fluorescence (WD-XRF). Samples of pure hydroxyapatite (HA300) and selenate (HA300-1.2SeO4) or selenite (HA300-1.2SeO3) substituted hydroxyapatites were synthesized using the standard wet method and heated at 300 °C to remove loosely bonded water. PXRD data showed that all samples are single-phase, nanocrystalline hydroxyapatite. The incorporation of selenite and selenate ions affected the lattice constants. In selenium-containing samples the concentration of Se was very similar and amounted to 9.55% and 9.64%, for HA300-1.2SeO4 and HA300-1.2SeO3, respectively. PXRD and ssNMR data showed that the selenite doping significantly decreases the crystallite size and crystallinity degree. 31P and 1H NMR experiments demonstrated the developed surface hydrated layer in all samples, especially in HA300-1.2SeO3. 1H NMR studies showed the dehydroxylation of HA during the selenium oxyanions substitution and the existence of hydrogen bonding in structural hydroxyl group channels. 1H→77Se cross polarization NMR experiments indicated that selenites and selenates are located in the crystal lattice and on the crystal surface.

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In vitro dissolution is a major indicator of potential in vivo calcium absorption. It can be used to assess the bioavailability of Ca from different sources. The aim of this study was to analyze the in vitro dissolution of calcium carbonate from the eggshell samples collected before and after the incubation period. The samples of chicken eggshell were characterized by good dissolution, better than that of precipitated CaCO 3 . The dissolution of the eggshell before incubation was found to be faster than that after incubation. Good dissolution (after 30 min both types of eggshells were dissolved in over 75%) of the chicken eggshell and the presence of other valuable microelements (boron, strontium) make this biomaterial an excellent source for dietary supplements production.

Due to the growing interest in running a healthy life, including the diet a special interest has been put in searching for products that are rich in nutrients, macro and micronutrients and vitamins. Dates are the fruits that meet these requirements and show multidirectional pro-health effects. These fruits are a source of potassium and other macro-and micronutrients. They have antioxidant properties thanks to the content of flavonoids and polyphenols. The elemental composition (Al, Ca, Cu, Fe, K, Mg, Mn, P, Sr and Zn) and antioxidant properties (total equivalent antioxidant capacity, total polyphenol content, total flavonoid content) of various dates from different regions of the world was determined. The results have shown that the peel and flesh of dates differ significantly in chemical composition. The peel is significantly richer in chemical components of biological importance. Discriminant analysis of the results obtained for dates originated from various regions indicated that the main factor determining the tested chemical composition is the place of cultivation, not the variety.

In this study, a new copper(II) ion-imprinted polymer (Cu(II)-IIP) was synthesized by the precipitation method. Itaconic acid, ethylene glycol dimethacrylate and 2,2 0 -azobisisobutyronitrile were used as functional, cross-linking monomer and a free-radical initiator, respectively. This polymer has been characterized on the basis of Fourier transform infrared spectroscopy and surface area measurements. The imprinted Cu(II) ions were completely removed from the polymer by leaching with the mixture of 0.1 M EDTA and 1 M HCl. The optimum pH for the adsorption of Cu(II) on to the polymer was 6. The selective performance of the polymer was compared to non-imprinted polymer (NIP) for the binary mixture Cu 2? /Ni 2? and Cu 2? /Zn 2? . The relative selectivity of Cu(II)-IIP was 12.8 and 32.4 times greater than that of NIP as compared with the Zn 2? and Ni 2? ions, respectively. At optimal pH value, the maximum static adsorption capacity of Cu(II)-IIP and NIP was found to be 14.8 and 4.08 mg/g, respectively.

Rectal drug delivery is an effective alternative to oral and parenteral treatments. This route allows for both local and systemic drug therapy. Traditional rectal dosage formulations have historically been used for localised treatments, including laxatives, hemorrhoid therapy and antipyretics. However, this form of drug dosage often feels alien and uncomfortable to a patient, encouraging refusal. The limitations of conventional solid suppositories can be overcome by creating a thermosensitive liquid suppository. Unfortunately, there are currently only a few studies describing their use in therapy. However, recent trends indicate an increase in the development of this modern therapeutic system. This review introduces a novel rectal drug delivery system with the goal of summarising recent developments in thermosensitive liquid suppositories for analgesic, anticancer, antiemetic, antihypertensive, psychiatric, antiallergic, anaesthetic, antimalarial drugs and insulin. The report also presents the impact of various types of components and their concentration on the properties of this rectal dosage form. Further research into such formulations is certainly needed in order to meet the high demand for modern, efficient rectal gelling systems. Continued research and development in this field would undoubtedly further reveal the hidden potential of rectal drug delivery systems.

Some atomic spectrometric determinations of metals in aliphatic polyester and polycarbonate biomedical polymers Summary-Contents of Al, Zn, Sn and Cr have been investigated in several aliphatic polyesters and polycarbonates obtained in ring opening polymerization and copolymerization of heterocyclic monomers in the presence of coordination catalytic systems with these metals. The metals were reliably determined using spectroscopic atomic techniques: flame atomic absorption spectrometry (FAAS), electrothermal atomic absorption spectrometry (ETAAS) and inductively coupled plasma optical emission spectrometry (ICP-OES). Commercial materials like NatureWorks® polylactide, poly(propylene carbonate) and medical sutures (e.g. Dexon®, Vicryl®) were also tested. The results are discussed in terms of applicable catalytic systems for the syntheses of biodegradable polymers, which are sufficient to reach metal concentrations specified in European Pharmacopoeia.