• 한국재료학회지
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• 제31권6호
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• pp.367-374
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• 2021

This paper presents the characteristics of gentamicin-loaded into cetyl trimethyl ammonium intercalated montmorillonite (GtM/CTMA/Mt) as a hybrid composite for a slow-released antibacterial delivery systems. The work describes the successful immobilization of gentamicin into the interlayers of surfactant-modified montmorillonite. Physicochemical characterization of the material is carried out by means of X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and Fourier transform infrared spectroscopy. The kinetics of the gentamicin release is investigated by in vitro study and analyzed based on UV-Vis spectrometry. In addition, antibacterial study is performed towards Klebsiella pneumoniae Staphylococcus aureus, Escherichia coli, and Streptococcus pyogenes. The results show that the gentamicin loading into CTMA/Mt increases the effectiveness of the antibacterial activity, as shown by the higher inhibition zone for all tested bacteria, compared to gentamicin as a positive control. The kinetics study suggests that the gentamicin release obeys the modified Korsmeyer-Peppas model. The physicochemical study and activity test demonstrate the feasibility of the GtM/CTMA/Mt for practical applications.

• Journal of Pharmaceutical Investigation
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• 제19권4호
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• pp.191-194
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• 1989

Bioequivalence test of $Asthcontin^{\circledR}$ tablet, a commercial slow-release theophylline (TP) dosage form, was performed using $Slo-bid^{\circledR}$ capsule as the reference. Since it has been confirmed that the saliva concentration of TP is closely correlated with the plasma concentration in man, the area under the saliva concentration-time curve was used as a bioavailability parameter. The statistical analysis showed that the two dosage forms are equivalent in bioavailability estimating from the saliva concentration. The results supported that the use of soliva as a test sample provides simple and easy techniques for bioequivalence tests of TP-containing dosage forms.

• Journal of Pharmaceutical Investigation
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• 제22권1호
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• pp.1-10
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• 1992

The use of erythrocyte as drug carrier has been reviewed, Carrier erythrocytes have proven to offer many advantages for delivery of therapeutic agents, especially in the treatment of inherited enzyme deficiency and cancer. Carrier erythrocytes are biodegradable and nonimmunogenic. Encapsulated drugs may be protected from premature degradation, inactivation and excretion. Carrier erythrocytes may be used as a slow-release system. Targeting of encapsulated drugs directly to a site of action is another possibility. Methods for encapsulating drugs into erythrocytes, the fate of carrier erythrocytes in vivo, the strategies of targeting carrier erythrocytes to special organs and in vivo applications of erythrocytes have been discussed. The encapsulation of drugs in erythrocytes has shown attractive possibilites in future use.

• 한국식품저장유통학회지
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• 제5권2호
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• pp.127-132
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• 1998

In order to fad out an efficient way of topdressing nitrogen fertilizer in mulch-cropping system of onion(Allium cepa L.), solid, slow-release, and liquid forms of nitrogen fertilizers were allied to cv. 'Changnyungdaego' various number of times at different time, with 5 topdress applications of solid fertilizer serving as a control. Whole basal application of conventional solid fertilizer and 2 slow-release fertilizers were labor-saving and showed improved storage quality of bulbs, but resulted in poor plant growth and considerably low yield due to fertilizer shortage from early April. This suggests that topdress application is necessary. Liquid form of nitrogen fertilizer was more effective for plant growth and yield and saving labor than the solid form. Early applications was effective for increasing yield and storage quality of onion bulbs harvested. Thus two applications of liquid form of nitrogen fertilizer in February and March at rome month interval are recommended in mulch crowing system of onion.

• 한국지하수토양환경학회지:지하수토양환경
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• 제27권3호
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• pp.41-49
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• 2022

This study utilized citric acid as a floating agent in biological denitrification process and assessed its role under different carbon supplying conditions. Several microcosm tests including citric acid active (CAA), precipitating tablet release active (PTRA) and floating tablet release active (FTRA) were conducted to evaluate nitrate denitrification efficacy. In CAA reactors, nitrate removal was accompanied by the formation of denitrification by-products such as nitrite and nitrous oxide, with the extent of nitrate removal being proportional to citric acid concentration. These results suggest that citric acid induced heterotrophic biological denitrification. PTRA reactor that incorporated CAA and the same electron donor showed a similar denitrification efficiency to CAA reactor. FTRA reactor, which contained the same amount of fumarate as PTRA, enhanced denitrification by 7% as compared to the PTRA reactor. The overall results of this work indicate that surplus citric acid can be efficiently utilized in heterotrophic denitrification.

• Journal of Pharmaceutical Investigation
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• 제27권3호
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• pp.225-231
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• 1997

For the effective administration of naloxone, we attempted to investigate the naloxone sustained-release implants. Using the biodegradable polymer, poly[(diethyl glutamate)-co-(ethyl glycinate)phosphazenes](PGGP), the implantable devices containing naloxone hydrochloride(NLX HCl) and naloxone base(NLX) were prepared. The release rates of NLX and NLX HCl were compared. Influences of NLX contents on release rates were examined. For pharmacokinetic studies, NLX and NLX HCl loaded devices were implanted subcutaneously in rabbits and then the plasma concentrations of NLX were determined by HPLC(ECD). NLX-containing devices were implanted with various doses and pharmacokinetic parameters according to dose were calculated. The relative bioavailabilities were evaluated and compared. Incorporation of NLX in the polymer leaded to a slow release. There were no differences of release rates based on drug contents. In pharmacokinetic parameters determined in 216 hours, NLX loaded devices resulted in enhanced bioavailability with the higher AUC (p<0.01) than NLX HCl loaded devices and MRT was significantly (p<0.05) increased. This result demonstrates that NLX is more suitable for sustained release devices than NLX HCl. Therefore it is anticipated that the effective concentrations of naloxone could be maintained for longer periods and bioavailabilities could be improved by naloxone sustained-release implants, with varying drug base/hydrochloride.

• 한국토양비료학회지
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• 제24권1호
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• pp.50-54
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• 1991

조입성형제(造粒成型劑)로 사용(使用)된 요소수지(尿素樹脂)의 U/F반응(反應) mole비(比) 및 첨가량(添加量)이 각각(各各) 다른 시제품(試製品) 5종(種)을 단비분시(單肥分施)를 대조(對照)로 배추에 대(對)한 비효시험(肥效試驗)을 실시(實施)한 결과(結果)를 요약(要約)하면 다음과 같다. 1. 배추수량(收量)은 U/F반응(反應) mole비(比) 1.0인 요소수지(尿素樹脂)가 6.7% 첨가(添加)된 시제품(試製品) V에서 가장 높았고 U/F반응(反應) mole비(比)가 가장 낮고 첨가량(添加量)이 가장 많은 시제품(試製品) VII에서는 3요소(要素) 분시구(分施區)에 비(比)하여 감수(減收)하였다. 2. 배추용(用) 완효성(緩效性) 복비(複肥)의 질소(窒素) 완효도(緩效度)는 24시간후(時間後) 수중전질소(水中全窒素) 용출률(溶出率) 76.1%, 100일후(日後) 토양중(土壤中) 전질소(全窒素) 용출률(溶出率) 71.7%가 적합(適合)하였다.

• 한국토양비료학회지
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• 제33권1호
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• pp.52-60
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• 2000

축분퇴비의 시용시 보충하는 비종에 따른 하우스 내부의 가스 발생양상과 미생물의 다양성을 구명하여 가스피해 정감 및 토양건전성 유지를 위한 기초자료를 얻고자 식양질 하우스토양에 축분퇴비의 시용량을 고추의 기준시비량과 퇴비에 함유된 인산함량을 기준하여 정식 2주전에 시용하고 부족한 질소성분을 요소와 완효성U/F복비로 보충처리하여 4월부터 8일 까지 재배하였다. 암모니아 및 아민류 가스는 정식초기에는 다소 낮은 농도로 배출되다가 정식 후 27일경에 peak를 보인 후 급격히 감소하여 33일경 이후에는 검출되지 않았으며, 평균농도는 요소구에 비하여 완효성U/F복비구가 암모니아 42%, 아민류 85%감소되었다. 이산화탄소는 요소구 1,200~3,200, 완효성U/F복비구 $900{\sim}2,650mg\;{\ell}^-$의 범위로 배출되었고, 평균농도는 요소구 2,260, 완효성U/F복비구 $1,590mg\;{\ell}^-$이었다. 세균, 방선균, B/F비, A/F비, 암모니아 및 아질산산화세균, 질산환원균 등의 밀도는 재배기간이 경과됨에 따라 완효성U/F복비구에서 더 높았으나 사상균 수는 요소구에서 많았고 탈질균은 비슷한 경향을 보였다. 조사한 6종 미생물 밀도의 백분율을 이용한 다양성지수는 0.10~0.35 범위로 재배기간이 경과함에 따라 감소하는 경향이었으며, 처리간에는 완효성U/F복비구가 요소구에 비하여 더 높았다.

• 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.

• 한국토양비료학회지
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• 제23권3호
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• pp.193-198
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• 1990

완효성(緩效性) 전작물(田作用) 복비(複肥)를 개발(開發)하고자 삼요소원(三要素源)으로 유안(硫安), DAP, 염화가리(鹽化加里)와 증수제(增量劑)로 석고(石膏)를 사용(使用)하고 U/F 반응(反應) mole비(比)가 0.5, 1.0, 1.5인 요소수지(尿素樹脂) 3종(種)을 점결제(粘結劑) 및 완효성(緩效性) 요소원(尿素源)으로 이용(利用)하여 복비(複肥) 제조시험(製造詩驗)을 실시(實施)한 결과(結果)는 다음과 같다. 1. 시제품(試製品) 제조시(製造時) 점결제(粘結劑) 및 첨가제(添加劑)로 사용(使用)한 요소수지(尿素樹指)는 U/F반응(反應) mole비(比)가 높을수록 A. I. 값, 전질소(全窒素) 및 미반응요소(未反應尿素) 함량(合量)이 높은 경향(傾向)이었다. 2. 시제품(試製品)은 첨가(添加)된 요소수지(尿素樹指)의 U/F반응(反應) mole 비(比)가 낮을수록 첨가량(添加量)이 많을수록 전질소(全窒素)의 수중용출속도(水中溶出速度)가 늦어지는 경향(傾向)이었으며 특(特)히 U/F반응(反應) mole비(比)는 전질소(全窒素)의 늦출속도(出速度)를, 첨가량(添加量)은 Ammonia 태(態) 질소(窒素)의 용출속도(溶出速度)를 지연(遲延)시키는 효과(效果)가 있었다. 3. 시제품(試製品)의 24 시간후(時間後) 전질소(全窒素) 용출률(溶出率)은 69~83%로 높은 것은 재배기간(栽培期間)이 짧은 작물(作物)에 낮은 것은 재배기간(栽培期間)이 긴 작물(作物)에 전량기비용(全量基肥用)으로 가능(可能)할 것으로 사료(思料)된다.