• Archives of Pharmacal Research
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• 제13권4호
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• pp.293-297
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• 1990

Sustained release microspheres containing phenylpropanolamine HCI (PPA) were prepared with acrylic polymer (Eudragit RL/RS) sand hydroxypropylmethylcellulose phthalate (HPMCP) using a emulsion-solvent evaporation method. Magnesium strate was used a smoothing agent for preparation of microspheres. The microspheres obtained were very spherical and free-flowing particles. Scanning electron microscopy showed that microspheres have a smooth surface and a sponage-like internal structure. The dissolution rate of PPA from the microspheres was dependent on the pH of dissolution media. PPA showed faster relase in hP 1. 2 solution than in pH 7.4 solution due to the solubility of PPA. Therefore we prepared new microspheres containing 5% (w/v) HPMCP in order to control the release of PPA. The release rate of PPA from these new microspheres was similar in pH 1.2 and pH 7.4 solution.

• Journal of Pharmaceutical Investigation
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• 제31권4호
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• pp.257-263
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• 2001

The microspheres have been developed as a new drug delivery system. Although many particulate drug carriers, such as liposome, niosome and emulsion, have been introduced, injectable and biodegradable microspheres appears to be a particularly ideal delivery system because the local anesthesia is not necessary for the insertion of large implants and for the removal of the device after the drug release is finished. Biodegradable microspheres with nicotine and triamcinolone acetonide are prepared and evaluated. As biodegradible polymers, PLA (M.W. 15,000, PLA-0015), PLGA (M.W. 17,000, RG 502) and PLGA (M.W. 8,600, RG 502H) are used. This study attempted to prepare and evaluate the nicotine and triamcinolone acetonide-incorporated microspheres, which were prepared by two methods, solvent-evaporation and spray-drying methods. The microspheres, as a disperse system for injections, were evaluated by particle size, size distribution, entrapment efficiency, and in vitro drug release patterns. The differences of preparation method, partition coefficient, types of polymer, and preparation conditions of microspheres influence the particle size, entrapment efficiency, and in vitro drug release patterns.

• 한국염색가공학회지
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• 제10권2호
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• pp.29-36
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• 1998

Poly(L-lactide) microcapsules containing hydrophilic penetrate were prepared by interfacial precipitation method through solvent evaporation from w/o/w emulsion. Effect of four determinative process parameters on the particle size distributions, morphologies, and release properties of microcapsules coated with poly(L-lactide) was investigated. Moreover, susceptible functional cotton fabrics treated with the mentioned microcapsules were prepared and laundry test up to 15 times were done to determine fastness properties. As a result, the prepared poly(L-lactide) microcapsules with a more sharp-distributive, rounder, and more permeable membranes could be prepared by means of protective colloid concentration, solution volume and stirring rate.

• Applied Microscopy
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• 제10권1_2호
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• pp.7-17
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• 1980

Electron microscope radioautography introduced by Liquier-Milward (1956) is now used routinely in many laboratories. Most of the technical difficulties in specimen preparation have been overcome. This method is modified from loop method for improvement of EM radioautographic techniques. The advantages of this method are: 1. the use of single specimens on small corks and of a large wire loop, allows the experimenter to avoid the blemishes in the membrane; 2. the surfactant dioctyl sodium sulphosuccinate is added to diluted ILford L4, thus greatly prolonging the period of time over which good emulsion layers can be made; 3. corks can be handled in perspex holder which allows about 20 specimens to be developed simultaneously. The steps of the method comprise: 1. Cut ribbons of ultrathin sections of silver interference colour 2. Pick them up on formvar-coated 200 mesh grids 3. Prestaining of tissues 4. Coat the specimens with a thin layer of carbon by evaporation (30-60A) 5. Mount the specimens on corks (about 1cm apical diameter) using double-sided scotch tape 6. Emulsion coating; a. Take a 250m1 beaker, place it on the pan of a sliding weight balance and weigh it. Add 10 grams extra to the beam. Add pieces of ILford L4 emulsion to the beaker until the balance is swinging freely. Add the 20ml of distilled water that was previously measured out. b. Surfactant dioctyl sodium sulphosuccinate is added to diluted ILford L4. 7. Prepare a series of membranes of gelled emulsion with the wire loop and apply one to each cork-borne specimen. 8. Put the specimens away to expose by pushing the corks into short length of PVC tubing, each tube having a small hole in the side 9. Place the tubes in small boxes together with silica gel. 10. Exposure 11. Developer - Kodak Microdol X for 3 minutes 12. Fixer - A perspex holder can be manufactured which allows 20 specimens to be developed simultaneously. 12. Fixer - 30% sodium thiosulfate for 10 minutes 13. Examination with Siemens Elmiskop 1A electron microscope

• 폴리머
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• 제34권6호
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• pp.527-533
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• 2010

Pioglitazone을 봉입한 poly(lactide-co-glycolide)(PLGA) 나노입자를 emulsion-evaporation 방법을 이용하여 제조하여 최적의 나노입자와 봉입률을 조절하였다. 제조된 나노입자의 크기는 125~170 nm이었으며 30% pioglitazone이 봉입된 나노입자(3% PVA)의 봉입률은 85% 이상이었다. 이러한 나노입자들은 40일 동안 일정하게 용출이 되었다. 당뇨병 모델을 이용한 동물실험에서 글루코오스 농도를 저하시켰을 뿐만 아니라, 조직검사에서는 낮은 독성을 가지고 있는 것을 확인하였다. 이러한 결과는 pioglitazone 경구투여를 위한 약물전달을 위한 운반체로 사용될 수 있음을 확인하였다.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2003년도 학술.기술논문발표회
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• pp.35-38
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• 2003

The purpose of this study is to investigate the manufacture of light weight concrete panel using the artificial light-weight aggregate as a part of the substitution of foamed styrene and polyurethane because of narrow allocable temperature Bone in use. The experimental parameter of this study is 40, 60 and 8$0^{\circ}C$ of curing temperature at 100% relative humidity and the type of admixture such as cement, 6mm glass fiber and St/BA emulsion. Testing item is compressive and flexural strength and strength of specimen cured at standard condition is compared to that of specimen cured at 40, 60 and 8$0^{\circ}C$ of curing temperature at 100% relative humidity. As a result or this, it was revealed that the maximum or strength is developed in 6$0^{\circ}C$ or cure temperature at 100% relative humidity in case of the most of the specimen. Specimens modified by St/BA emulsion show the highest development of strength dependent on the curing tmeperature. So, it seems to be effective that evaporation curing method shoud be considered to curing the specimen as the panel core.

• Journal of Pharmaceutical Investigation
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• 제35권2호
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• pp.95-99
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• 2005

Mucoadhesive microspheres were prepared by interpolymer complexation of chitosan with poly(acrylic acid) (PAA) and solvent evaporation method to increase gastric residence time. The chitosan-PAA complex formation was confirmed by differential scanning calorimetry and swelling study. The DSC thermogram of chitosan-PAA microspheres showed two exothermic peaks for the decomposition of chitosan and PAA. The swelling ratio of the chitosan-PAA microspheres was dependent on the pH of the medium. The swelling ratio was higher at pH 2.0 than at neutral pH. The results indicated that the microspheres were formed by electrostatic interaction between the carboxyl groups of PAA and the amine groups of chitosan. The effect of various process parameters on the formation and morphology of microspheres was investigated. The best microspheres were obtained when 1.5% of the high molecular weight chitosan and 0.3% of PAA were used as an internal phase. The optimum internal phase volume was 7%. The com oil was used as the external phase of emulsion, and span 80 was used as the surfactant. The prepared microspheres had spherical shape.

• Macromolecular Research
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• 제10권5호
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• pp.246-252
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• 2002

In order to the development of the delivery device of long-acting local anesthetics for postoperative analgesia and control of chronic pain of cancer patient, fentnyl-loaded poly (L-lactide-co-glycolido) (PLGA, molecular weight, 5,000 g/mole; 50 : 50 mole ratio by lactide to glycolide) microspheres (FMS) were studied. FMS were prepared by an emulsion solvent-evaporation method. The influence of several preparation parameters such as initial drug loading, PLGA concentration, emulsifier concentration, oil phase volume, and fabrication temperature has been investigated on the fentanyl release profiles. Generally, the drug showed the biphasic release patterns, with an initial diffusion followed by a lag period before the onset of the degradation phase, but there was no lag time in our system. Fentanyl was slowly released from FMS over 10 days in vitro with a quasi-zero order property. The release rate increased with increasing drug loading as well as decreasing polymer concentration with relatively small initial burst effect. From the results, FMS may be a good formulation to deliver the anesthetic for the treatment of chronic pain.

• Korean Chemical Engineering Research
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• 제56권4호
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• pp.461-468
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• 2018

Poly-L-lactic acid (PLLA)를 출발물질로 하여 용매증발법에 의해 마이크로스피어를 제조하고, 제조 변수가 형성된 마이크로스피어의 형상 및 평균 입경에 미치는 영향을 살펴보았다. PVA 수용액의 농도가 1~5 wt%로 증가함에 따라 평균입경이 $370{\sim}160{\mu}m$으로 감소하다가 7 wt%에서다시 $240{\mu}m$으로 증가하였다. 그리고 PVA의첨가부피가 10~50 mL로 증가함에 따라 평균 입경은 $370{\sim}220{\mu}m$으로 감소하였다. 또한 교반속도가 500~1,500 rpm으로 증가함에 따라 평균 입경은 $370{\sim}110{\mu}m$으로 감소하였다. 유기용매로써 dichloromethane과 chloroform을 각각 사용한 경우 평균 입경은 큰 차이를 보이지 않았으며, dichloromethane을 사용한 경우 표면에서 공극이 확인되었으나 chloroform을 사용한 경우 매끈한 형상의 구형입자가 얻어졌다.

• Journal of Pharmaceutical Investigation
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• 제26권1호
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• pp.13-22
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• 1996

Poly(D,L-lactic acid) (PLA) microspheres containing alprazolam(APZ) were prepared by a solvent-emulsion evaporation method and their release patterns were investigated in vitro. Various batches of microspheres with different size and drug content were obtained by changing the ratio of APZ to PLA, PLA concentration in the dispersed phase and stirring rate. Rod-like APZ crystals on microsphere surface, which were released rapidly and could act as a loading dose, were observed with increasing drug content. The release rate was increased with increase in drug contents and decrease in the molecular weight of PLA. The release rate of APZ for long-acting injectable delivery system in vitro, which would aid in predicting in vitro release profile, could be controlled by properly optimizing various factors affecting characteristics of microspheres.