Polyisobutylene-paclitaxel conjugates with pendant carboxylic acids and polystyrene chains: Towards multifunctional stent coatings with slow drug release

Drug-eluting stents are used in the treatment of atherosclerosis, where the incorporation of anti-proliferative or anti-inflammatory drugs decreases the rate of restenosis, the recurrence of artery narrowing. However, these stents can suffer from limitations such as drug depletion and delamination of the drug-eluting coating from the stent surface. Described here is an approach aimed at addressing these issues. Starting from a maleic anhydride adduct of polyisobutylene (PIB) prepared from butyl rubber, ring opening using paclitaxel (PTX) or a combination of PTX and polystyrene (PS) afforded covalent conjugates of PTX and PIB or PIB-PS graft copolymers bearing pendant carboxylic acids. When coated on stainless steel, the drug release was slower than that from a control coating that ressembles a clinical formulation comprising a physical mixture of a PS-PIB-PS triblock copolymer (SIBS) and PTX. The PTX conjugates also exhibited enhanced adhesion to stainless steel and increased tensile strength in comparison with the starting rubber. Cytotoxicity assays indicated that the materials did not leach toxic levels of PTX into cell culture media. Nevertheless, they were capable of inhibiting the adhesion and proliferation of C2C12 cells on their surfaces. These properties are advantageous for the potential application of the materials as stent coatings

Potential Role of Plants <em>Hordeum vulgare</em> L. and <em>Panax ginseng</em> L. in Resolving the Fertility Disorders and Stress-Induced Oxidative Stress Arises from Hypothyroidism in Adult Female Rats

Hordeum vulgare (Barley) and Panax ginseng have antioxidant activity referring to their diverse phytonutrient. Hypothyroidism in adult female rats was induced by pituitary-gonadal-adrenal disturbance, depleting the serum FSH levels with the elevation of corticosterone, prolactin, progesterone and testosterone hormones as well as (ERK1/2). Hypothyroidism evoked an oxidative stress status by increasing 8-hydroxy guanosine, which initiated apoptosis by uplifting apoptotic marker Caspase-3 both in serum and brain tissues. This is confirmed by the increase in the percentage of DNA-damage in the brain tissues. Significant decrease in all monoamines’ levels in different brain areas, downregulation of dopamine and 5-hydroxytryptamine receptors transcription, with a significant increase in excitatory amino acids was noted. Barley and ginseng renormalized cortisol and oxidative stress markers by increasing cellular resistance to stress and potentiated the role of the immune system through phytosterol and ginsenosides, so they considered potent free radical scavengers. Barley and Panax ginseng ameliorate the hormonal and neural dysfunction resulting from hypothyroidism, so they are recommended for relieving stress and improving mood and depression