PURPOSE: Affinisol HPMC HME is a new popular form of hypromellose specifically designed for the hot melt extrusion and 3D printing of pharmaceutical products. However, reports of its thermal stability include only data obtained under inert N2 atmosphere, which is not consistent with the common pharmaceutical practice. Therefore, detailed investigation of its real-life thermal stability in air is paramount for identification of potential risks and limitations during its high-temperature processing. METHODS: In this work, the Affinisol HPMC HME 15LV powder as well as extruded filaments will be investigated by means of thermogravimetry, differential scanning calorimetry and infrared spectroscopy with respect to its thermal stability. RESULTS: The decomposition in N2 was proceeded in accordance with the literature data and manufacturer's specifications: onset at ~260°C at 0.5°C·min-1, single-step mass loss of 90-95%. However, in laboratory or industrial practice, high-temperature processing is performed in the air, where oxidation-induced degradation drastically changes. The thermogravimetric mass loss in air proceeded in three stages: ~ 5% mass loss with onset at 150°C, ~ 70% mass loss at 200°C, and ~ 15% mass loss at 380°C. Diffusion of O2 into the Affinisol material was identified as the rate-determining step. CONCLUSION: For extrusion temperatures ≥170°C, Affinisol exhibits a significant degree of degradation within the 5 min extruder retention time. Hot melt extrusion of pure Affinisol can be comfortably performed below this temperature. Utilization of plasticizers may be necessary for safe 3D printing.
Melanins belong to a group of pigments of different structure and origin. They can be produced synthetically or isolated from living organisms. A number of studies have reported testing of various melanins in neurological studies providing different outcomes. Because the structure of melanins can have an effect on obtained results in cell toxicity studies, we present here our original study which aimed to compare the biological effects of bacterial melanin (biotechnologically obtained from B. thuringiensis) with that of synthetic melanin in neuroblastoma cells. Both melanins were structurally characterized in detail. After melanin treatment (0-200 μg/mL), cell viability, glutathione levels, cell morphology and respiration were assessed in SH-SY5Y cells. The structural analysis showed that bacterial melanin is more hydrophilic according to the presence of larger number of -OH moieties. After melanin treatment, we found that synthetic melanin at similar dosage caused always larger cell impairment compared to bacterial melanin. In addition, more severe toxic effect of synthetic melanin was found in mitochondria. In general, we conclude that more hydrophilic, bacterial melanin induced lower toxicity in neuroblastoma cells in comparison to synthetic melanin. Our findings can be useable for neuroscientific studies estimating the potential use for study of neuroprotection, neuromodulation or neurotoxicity.
- MeSH
- Bacteria MeSH
- glutathion MeSH
- lidé MeSH
- melaniny * MeSH
- mitochondrie MeSH
- neuroblastom * farmakoterapie MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- srovnávací studie MeSH
In this work, a hybrid copolymer consisting of poly(3-hydroxybutyrate) grafted to hyaluronic acid (HA) was synthesised and characterised. Once formed, the P(3HB)-g-HA copolymer was soluble in water allowing a green electrospinning process. The diameters of nanofibres can be tailored by simply varying the Mw of polymer. The optimization of the process allowed to produce fibres of average diameter in the range of 100-150 nm and low polydispersity. The hydrophobic modification has not only increased the fibre diameter, but also the obtained layers were homogenous. At the nanoscale, the hybrid copolymer exhibited an unusual hairy topography. Moreover, the hardness and tensile properties of the hybrid were found to be superior compared to fibres made of unmodified HA. Particularly, this reinforcement was achieved at the longitudinal direction. Additionally, this work reports the use in the composition of a water-soluble copolymer containing photo cross-linkable moieties to produce insoluble materials post-electrospinning. The derivatives as well as their nanofibrous mats retain the biocompatibility of the natural polymers used for the fabrication.
- MeSH
- biokompatibilní materiály * chemická syntéza chemie MeSH
- biomechanika MeSH
- hydrofobní a hydrofilní interakce MeSH
- hydroxybutyráty chemická syntéza chemie MeSH
- kyselina hyaluronová chemie MeSH
- nanovlákna chemie MeSH
- polyestery chemická syntéza chemie MeSH
- polymery chemická syntéza chemie MeSH
- poskytování zdravotní péče MeSH
- tkáňové podpůrné struktury chemie MeSH
- vstřebatelné implantáty * MeSH
- zdravotnické prostředky MeSH
- Publikační typ
- časopisecké články MeSH
