Facile Preparation of Modifying Layered Double Hydroxide Nanoparticles for Drug Delivery.

Mg-Al-NO3 hydrotalcite (p-LDH) was employed as a carrier for the controlled release of 5-Fluorouracil (5-FU). The p-LDH was pretreated by acid-pretreatment to gain a more stable material (a-LDH) in acid medium for oral administration. It demonstrated that the a-LDH had smaller crystal size, particle sizes and higher permanent charge density (σp) compared with that of the p-LDH by means of XRD, SEM, FT-IR, UV-vis DRS, TG-DSC, BET/BJH and other techniques. The FU/a-LDH and FU/p-LDH delivery systems were obtained using anion-exchange method. The in vitro 5-FU drug release studies showed that no burst release phenomenon was observed at the beginning of release tests. The in vitro 5-FU release behaviors of the delivery systems at initial pH 4.6 and 7.5 were studied which could be described by first-order and Bhaskas models. Combined with the XRD and FT-IR analyses of the solid residues of the FU/a-LDH and FU/p-LDH after the release, it was found that the dissolution mechanism was mainly responsible for the release behavior of the FU/p-LDH at initial 4.6, while the anion-exchange between intercalated 5-FU and phosphate anions mechanism was responsible for the FU/a-LDH at pH 4.6 and 7.5 as well as FU/p-LDH at pH 7.5. It is concluded that the hydrotalcites could be used as the basis of a tunable drug delivery carrier for 5-FU.

Lack of association between the COMT rs4680 polymorphism and ovarian cancer risk: evidence from a meta-analysis of 3,940 individuals.

Catechol-O-methyltransferase (COMT) is involved in estrogen metabolism and is vital to estrogen-induced carcinogenesis, including that of ovarian cancer. Although many recent epidemiologic studies have investigated associations between the COMT rs4680 polymorphism and ovarian cancer risk, the results remain inconclusive. We therefore performed a meta-analysis to derive a more precise estimate of associations. Systematic searches of the PubMed, Embase, Web of Science, Cochrane Library, Wanfang, China National Knowledge Infrastructure, and Chinese Biomedicine databases were undertaken to retrieve eligible studies. Odds ratios (ORs) with their corresponding 95% confidence intervals (CIs) were pooled to assess the strength of the association. In total, 8 case-control studies involving 1,293 cases and 2,647 controls were included in the meta-analysis. Overall, the results showed no evidence of significant association between the COMT rs4680 polymorphism and ovarian cancer risk in any of the assessed genetic models. Subgroup analyses by ethnicity also did not reveal any significant association in any genetic model (p>0.05). In conclusion, our findings suggest that the COMT rs4680 polymorphism may not contribute to the risk of ovarian cancer.