• 한국식품영양학회지
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• 제31권2호
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• pp.308-312
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• 2018

Even though chlorine dioxide ($ClO_2$) is utilized in a pre-treatment due to its effective sterilizing activity for microorganisms and its safety for food, it has a limitation in maintaining freshness of the food product. In this study, a low-concentration $ClO_2$ gas was produced in a packaging form of air-permeable gel pack so that it could be released continuously over several days. The amount of $ClO_2$ gas emission and microbial inactivation effect against foodborne pathogens were measured during the release of $ClO_2$ gas. As a result of measuring the change of color in order to confirm whether the chlorine dioxide gas was eluted in the form of a sustained release, the yellowness was significantly higher at higher gel pack concentration and higher value during storage periods. The slow-released $ClO_2$ gel-pack showed clear inactivation effect against Escherichia coli and Staphylococcus aureus with 99.9% inactivation efficiency. As a result of measuring the sterilization effect of Listeria monocytogenes by the concentration of chlorine dioxide gas, the sterilization effect was increased as the concentration was increased. Therefore, the slow-released $ClO_2$ gel-pack is feasible to apply for industry usages.

• 자원리싸이클링
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• 제16권4호
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• pp.10-16
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• 2007

전로슬래그를 완효성 칼리비료로 활용하기 위한 기초연구로, 전로슬래그 분말에 시약급 $SiO_2$와 $K_2CO_3$를 첨가하여 염기도를 각각 0.7, 1.0및 1.4로 조절하고, $K_2O$의 함량은 22mass%로 고정한 후 볼밀에서 24시간 이상 혼합하여 $900^{\circ}C{\sim}1000^{\circ}C$ 사이의 온도에서 10분${\sim}$60분 동안 소결하였다. 소결 후 X-선 회절과 ICP분석을 이용하여 제조된 칼리비료의 특성을 조사하고 또한 염기도, 소결온도 및 소결시간이 완효성 칼리비료의 제조 조건에 미치는 영향을 검토하였다. 소결체의 수용성 $K_2O$의 용출특성은 소결시간이 길어질수록, 소결온도가 높아질수록, 염기도가 감소할수록 용출율이 감소하였다. 한편 구용성 $K_2O$의 용출특성은 염기도가 증가할수록 증가하는 경향이 뚜렷하였으며, 소결온도가 높을수록 용출율은 완만하게 감소하였다.

• Archives of Pharmacal Research
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• 제15권2호
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• pp.162-168
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• 1992

Release characteristics of five different types of hydrophilic albumin microspheres (HAM) containing different ratios of methotrexate-albumin (MTX-HSA) conjugates to free MTX: 1 : 0 (HAMC), 3 :1 (HAMC 3F), 1 :1 (HAMCF), 1:3 (HAMCF3) and 0 : 1 (HAMF) were investigated in the absence or presence of protease using dissolution tester. In all the HAMs studied except HAMC, the MTX was released bi-exponentially in the absence of protease; an initial fast release period up to approximately 6h, and thereafter the release rate was very much slower. The fast release of MTX from the HAMs (such as HAMC3F, HAMCF, HAMCF3 and HAMF) at the initial phase in probably due to the release of "physically associated" MTX from the core of the HAMs. The initial rate constants were 7.2, 8.7, 8.5 and 5.9 times greater than the second rate constants for HAMF, HAMCF3, HAMCF and HAMC3F, respectively. MTX release from HAMC was very slow and mono-phasic. It was at most 2.2% of the total entrapped amount by 24 h. The protease accelerated the release of MTX from the HAMs. The percentages of MTX released from HAMs up to 24 h were 100, 89.0, 75.0, 66.0 and 61.0% for HAMF, HAMCF3, HAMCF, HAMC3F and HAMC, respectively in the presence of protease and the corresponding values in the absence of protease were 30.2 19.0, 10.0, 6.5 and 2.2%, respectively. In vitro release of MTX in the presence of protease varied according to the ratios of MTX-HSA conjugates to MTX; the data set from HAMF, HAMCF3 and HAMCF fits better to monophasic first-order profile more adequately than to zero-order profile, that of HAMC3 monophasic first-order, and that of HAMC to bi-phasic zero-order. Above results suggested that zero-order release rate can be achieved by adjusting the ratio of MTX-HSA conjugates to MTX in the preparation of HAMs such as HAMC3F.as HAMC3F.

• Journal of Pharmaceutical Investigation
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• 제22권2호
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• pp.133-137
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• 1992

A novel oral controlled release tablet which may offer more uniform drug level in the body than simple zero-order was developed. The tablet is composed of three layers; outer film layer, middle part compression-coated hydroxypropylmethylcellulose (HPMC) matrix layer, and inner core layer. Each layer contains nicardipine HCl as a model drug. In vitro dissolution test showed that the tablet released the drug in clear three steps; a rapid initial release, followed by a constant rate of release, and then a second phase of fast release of drug. The dissolution characteristics could be modified easily by changing the grade of HPMC, thickness of matrix layer, content of methylcellulose in matrix layer, content of active ingredient in each layer. The pH of dissolution medium did not affect the release profile. This three-step release system is expected to raise the blood concentration rapidly to effective level and to maintain effective blood level longer than simple slow-release systems.

• Archives of Pharmacal Research
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• 제28권9호
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• pp.1092-1096
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• 2005

Huperzine A-loaded microspheres composed of poly(D,L-lactide-co-glycolide) were prepared by an O/w emulsion solvent evaporation method. The characterization of the microspheres such as drug loading, size, shape and release profile was described. The in vitro release in the initial 7 days was nearly linear with $10\%$ released per day. Thereafter drug release rate became slow gradually and about $90\%$ drug released at day 21. The in vitro release rate determined by dialysis bag method had a good correlation with the in vivo release rate. Huperzine A aqueous solution was intramuscularly injected (i.m.) at 0.4mg/kg and microspheres were intra­muscularly injected at 8.4 mg eq huperzine A/kg in rats. The maxium plasma concentration $(C_{max})$ after i.m. microspheres was only $32\%$ of that after i.m. solution. Drug in plasma could be detectd until day 14 and about $5\%$ of administered dose was residued at the injection site at day 14. The relative bioavailability of huperzine A microspheres over a period of 14 days was $94.7\%$. Inhibition of acyecholinesterase activity (AchE) in rat's cortex, hippocampus and striatum could sustain for about 14 days. In conclusion, huperzine A-loaded microspheres possessed a prolonged and complete drug release with significant inhibition of AchE for 2 weeks in rats.

• 약학회지
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• 제41권1호
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• pp.48-59
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• 1997

Sustained release matrix tablets, pellets, and coated pellets for the delivery of sulindac were prepared using cellulose derivatives at various ratios, and evaluated for the dis solution pattern. The release of sulindac, from matrix tablets prepared with low viscosity HPMC was relatively fast, and especially the tablets made of Metolose SM released all of sulindac within 1 hr. The release of drug from tablets made of other HPMC derivatives were retarded in the order of the following: Pharmacoat 645>Pharmacoat 606>Pharrnacoat 606+HPC-L>HPC-L. The most sustained release pattern was observed with the preparation of high viscous polymer. Metolose 90 SH. While release of sulindac, from matrix type pellet containing 10mg/cap of Metolose 90 SH or 60 SH was completed within 1 hr, a prolonged release formulation (30% in 1 hr) was obtained by the inclusion of EC. Pellets coated with HPMC showed a fast release pattern (${\geq}$ 80% within 2 hrs), whereas pellets coated with HPMC and EC (molar ratio 1 : 1) showed a sustained release pattern (${\geq}$ 80% in 12 hrs), vath the release from EC pellets being the most sustained. Fast (naked) and slow release pellets coated with EC, Metolose 60SH 50cps and propylene glycol. and enteric pellets coated with HPMCP 55 and Myvacet$^{\circledR}$ were prepared, and combined at various ratios for the assessment of dissolution pattern. The result indicates the possibility that the development of 24 hr sustained release delivery systems containing sulindac for oral administration could be achieved by means of combining sustained and fast release pellets at a proper portion.

• International Journal of Industrial Entomology and Biomaterials
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• 제28권2호
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• pp.66-70
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• 2014

In order to the feasibility of silk materials as protein delivery system, silk beads incorporated with bovine serum albumin (BSA) were prepared by dropping silk fibroin extract into dope solution composed of ethanol and dichloromethane. Structural and morphological characteristics of silk beads were examined using scanning electron microscopy (SEM), infrared spectrometry, and X-ray diffractometry. Swelling ratio of silk beads was also measured. Release behavior of prototypical protein, BSA, was studied by observing the electropheretic phenomenon and release profile. SEM showed that silk beads are spherical with porous interior structure. Infrared spectrometry and X-ray diffraction confirm that the silk beads have a ${\beta}$-sheet conformation. The swelling capability of silk beads increased with the incorporation of the protein. The protein was released from the beads with slow release following an initial burst release. Therefore, silk beads show promise as materials for encasing protein drugs to be delivered to targets in the human body.

• 한국식품영양학회지
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• 제30권4호
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• pp.823-829
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• 2017

To increase the shelf-life of strawberry, samples were treated with two gel packs containing slow-released chlorine dioxide ($ClO_2$) gas at 3~5 ppm for 6 days at room temperature and the changes in the major chemical components (ascorbic acid, polyphenols, flavonoids and anthocyanin) contents and antioxidative activities (DPPH, ABTS radical scavenging and metal chelating activity) were investigated. The content of ascorbic acid of control was 40.38 mg% and contained 35.67~44.75 mg% during 6 days. There was no tendency to increase or decrease during storage period. The contents of ascorbic acid of control and 3~5 ppm $ClO_2$ gas treated samples were not significantly different during storage period. The content of polyphenol compounds of initial stage was 111.23 mg% and contained 117.78~132.40 mg% during 6 days. The contents of polyphenol compounds of 3~5 ppm $ClO_2$ gas treated samples were 103.51~130.25 mg%. There were no significant different between them during storage. The flavonoids and anthocyanin contents were not different from the control during storage period regardless of 3~5 ppm $ClO_2$ gas treatment. Furthermore, antioxidative activities were not different among the control and $ClO_2$ gas treatments during storage.

• 한국식품영양학회지
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• 제32권4호
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• pp.294-303
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• 2019

To extend the shelf-life of chicken breast meat, samples were treated with gel-packs containing slow-released $ClO_2$ gas at 7-15 ppm for 8 days at $4^{\circ}C$. And the changes in lipid oxidation and taste compounds of the samples were investigated. TBARS value of the chicken breast was slightly increased during storage. TBARS value of gas treatments was similar to the control during storage. There were 14 fatty acids in the chicken breast. And there was no change in the fatty acid composition during storage, and there was no significant difference between the control and gas treatments. The content of free amino acids was gradually increased during storage. The content of free amino acids were not significantly different between the control and gas treatments during storage. The content of GMP in the control and gas treatments were decreased during storage. However, gas treatments showed slightly higher content than that of control. AMP was not significantly different between the control and gas treatments. IMP gradually decreased during storage and the content of inosine and hypoxanthine was increased. IMP, inosine and hypoxanthine contents of gas treatment were similar to control, but the control tended to change more rapidly than those of gas treatments.

• Macromolecular Research
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• 제14권5호
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• pp.573-578
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• 2006

Three different, polymer-platinum conjugates (hydrogels, microparticles, and nanoparticles) were synthesized by complexation of cis-dichlorodiammineplatinum(II) (cisplatin) with partially succinylated glycol chitbsan (PSGC). Succinic anhydride was used as a linker to introduce cisplatin to glycol chitosan (GC). Succinylation of GC was investigated systematically as a function of the molar ratio of succinic anhydride to glucosamine, the methanol content in the reaction media, and the reaction temperature. By controlling the reaction conditions, water-soluble, partially water-soluble, and hydrogel-forming PSGCs were synthesized, and then conjugated with cisplatin. The complexation of cisplatin with water-soluble PSGC via a ligand exchange reaction of platinum from chloride to the carboxylates induced the formation of nano-sized aggregates in aqueous media. The hydrodynamic diameters of PSGC/cisplatin complex nano-aggregates, as determined by light scattering, were 180-300 nm and the critical aggregation concentrations (CACs), as determined by a fluorescence technique using pyrene as a probe, were $20-30{\mu}g/mL$. The conjugation of cisplatin with partially water-soluble PSGC, i.e., borderline between water-soluble and water-insoluble PSGC, produced micro-sized particles $<500{\mu}m$. Cisplatin-complexed PSGC hydrogels were prepared from water-insoluble PSGCs. All of the cisplatin-incorporated, polymer matrices released platinum in a sustained manner without any significant initial burst, suggesting that they may all be useful as slow release systems for cisplatin. The release rate of platinum increased with the morphology changes from hydrogel through microparticle to nanoparticle systems.