• Polymer(Korea)
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• v.34 no.4
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• pp.333-340
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• 2010

Zaltoprofen, a propionic acid derivative non-steroidal anti-inflammatory drug (NSAID), is known to have powerful inhibitory effects on acute, subacute and chronic inflammation. We developed poly(lactide-co-glycolide)(PLGA) microspheres loaded with zaltoprofen for sustained controlled delivery using an oil-water solvent evaporation methods by varying PLGA molecular weight and cosurfactant contents. Physicochemical properties and morphology of zaltoprofen-loaded PLGA microspheres were investigated by scanning electron microscope, X-ray diffraction and differential scanning calorimeter. The size of microspheres increased with the molecular weight of PLGA and the content of cosurfactants. The increase of PLGA molecular weight and cosurfactant content decreased the porosity of microspheres, subsequently resulting in the slow drug release. The results demonstrated that the adjustment of PLGA molecular weight and the cosurfactant content allowed us to control the drug release profiles of drug-loaded microspheres.

• Korean Journal of Psychosomatic Medicine
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• v.18 no.2
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• pp.62-71
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• 2010

Objectives : The aim of the study was to investigate the prevalence by gender and to evaluate associations of depression, anxiety and sleep disturbances in a large sample of adolescents from the general population. Methods : 1422 subjects, aged 14 years students were recruited in the seven middle-school of the local community. The self-report questionnaire(Children's Depression Inventory : CDI, Beck Anxiety Inventory : BAI and Pittsburgh Sleep Quality Index : PSQI) was used for screening depression, anxiety and sleep disturbances in adolescent. CDI, BAI, and PSQI score was categorized into the following quartiles : $\leq$21, 22-25, 26-28, and $\geq$29 ; $\leq$21, 22-26, 27-31, and $\geq$32 ; $\geq$5, <5. The cut-off score is that CDI is 22, BAI is 22 and PSQI is 5. The result was analyzed using the independent t-test, the chi-square test and logistic regression analyses. Results : The mean CDI score($12.52{\pm}8.32$ vs. $10.39{\pm}7.52$ ; p=0.003), BAI($7.77{\pm}7.93$ vs. $9.84{\pm}9.04$ ; p<0.001) and PSQI($4.57{\pm}2.67$ vs. $3.64{\pm}2.30$ ; p=0.013) of girls were significantly higher than for boys. But, boys in the fourth quartile of CDI(CDI$\geq$29) and BAI(BAI$\geq$32) were at significantly elevated risk for sleep disturbances more than for girls after adjustment for sex, history of psychiatric treatment(CDI odd ratio, 14.66 ; 95% CI, 4.17-51.53, BAI odd ratio, 32.99 ; 95% CI, 4.26-255.39). Conclusion : The results suggest that high CDI, BAI score appears to increase the risk for developing sleep disturbances in boys more than girls.

• Applied Chemistry for Engineering
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• v.34 no.3
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• pp.258-263
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• 2023

In this study, conductive polymers and the enzyme tyrosinase (Tyr) were deposited on the surface of a screen printed carbon electrode (SPCE), which can be fabricated as a disposable sensor chip, and applied to the detection of bisphenol F (BPF), an endocrine disruptor with proven links to male diseases and thyroid disorders, using electrochemical methods. On the surface of the SPCE working electrode, which was negatively charged by oxygen plasma treatment, a positively charged conductive polymer, poly(diallyldimethyl ammonium chloride) (PDDA), a negatively charged polymer compound, poly(sodium 4-styrenesulfonate) (PSS), and another layer of PDDA were layered by electrostatic attraction in the order of PDDA, PSS, and finally PDDA. Then, a layer of Tyr, which was negatively charged due to pH adjustment to 7.0, was added to create a PDDA-PSS-PDDA-Tyr sensor for BPF. When the electrode sensor is exposed to a BPF solution, which is the substrate and target analyte, 4,4'-methylenebis(cyclohexa-3,5-diene-1,2-dione) is generated by an oxidation reaction with the Tyr enzyme on the electrode surface. The reduction process of the product at 0.1 V (vs. Ag/AgCl) generating 4,4'-methylenebis(benzene-1,2-diol) was measured using cyclic and differential pulse voltammetries, resulting in a change in the peak current with respect to the concentration of BPF. In addition, we compared the detection performance of BPF using an ionic liquid electrolyte as an alternative to phosphate-buffered saline, which has been used in many previous sensing studies. Furthermore, the selectivity of bisphenol S, which acts as an interfering substance with a similar structure to BPF, was investigated. Finally, we demonstrated the practical applicability of the sensor by applying it to analyze the concentration of BPF in real samples prepared in the laboratory.