• Title/Summary/Keyword: drug release

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Development of Controlled Release Oral Drug Delivery System by Membrane-Coating Method-I - Preparation and pharmaceutical evaluation of controlled release acetaminophen tablets-

  • Shim, Chang-Koo;Kim, Ki-Man;Kim, Young-Il;Kim, Chong-Kook
    • Archives of Pharmacal Research
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    • v.13 no.2
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    • pp.151-160
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    • 1990
  • In order to develop a controlled-release oral drug delivery system (DDS) which sustains the plasma acetaminophen (AAP) concentration for a certain period of time, microporous membrane-coated tablets were prepared and evaluated in vitro. Firstly, highly water-soluble core tablet of AAP were prepared with various formulations by wet granulation and compression technique. Then the core tablets were coated with polyvinychloride (PVC) in which micronized sucrose particles were dispersed. Effect of formula compositions of core tablets and coating suspensions on the pharmaceutical characteristics such as drug release kinetics and membrane stability of the coated tablets was investigated in vitro. AAP was released from the coated tablets as a zero-order rate in a pH-independent manner. This independency of AAP release to pH change from 1.2 to 7.2 is favorable for the controlled oral drug delivery, since it will produce a constant drug release in the stomach and intestine regardless of the pH change in the GI tract. Drug release could be extended upto 10 h according to the coating condition. The release rate could be controlled by changing the formula compositions of the core tablets and coating suspensions, coat weight per each tablet, and especially PVC/sucrose ratio and particle size of the sucrose in the coating suspension. The coated tablets prepared in this study had a fairly good pharmaceutical characteristics in vitro, however, overall evaluation of the coated tablet should await in vivo absorption study in man.

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Alginate/Carboxymethyl Scleroglucan Hydrogels for Controlled Release of Protein Drugs

  • Lee, Chang-Moon;Jeong, Hwan-Jeong;Kim, Dong-Woon;Lee, Ki-Young
    • Macromolecular Research
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    • v.16 no.5
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    • pp.429-433
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    • 2008
  • Alginate/carboxymethyl scleroglucan (CMSG) hydrogels were suggested as a novel carrier for the controlled release of protein drugs. The drug release characteristics of alginate hydrogels were improved by CMSG addition. Scleroglucan (Sclg) was carboxymethylated using monochloroacetic acid in aqueous alkaline medium. Alginate/CMSG hydrogels were prepared by dropping the mixture solution of alginate/CMSG into calcium chloride solution. The swelling behaviors and drug release characteristics of the hydrogels were investigated in the buffers of pH 1.2 or 7.4. As the CMSG content increased in the hydrogels, the swelling ratio of the alginate/CMSG hydrogel increased rapidly in the buffer of pH 7.4. At pH 1.2, however, the swelling ratio significantly decreased compared to that at pH 7.4. According to in vitro release tests, only 15% of ovalbumin, investigated as a model protein drug, was released from the alginate/CMSG hydrogels at pH 1.2 within 6 h. At pH 7.4, however, the drug release significantly increased due to the rapid swelling of the hydrogels. The release and swelling behaviors of the hydrogels could be controlled by changing the CMSG content in the hydrogels. These results supported the use of alginate/CMSG hydrogels as a suitable carrier for the controlled release of protein drugs in a pH responsive manner.

All-trans Retinoic Acid Release from Surfactant-free Nanoparticles of Poly(DL-lactide-co-glycolide)

  • Jeong, Young-Il;Kim, Don-Gon;Jang, Mi-Kyeong;Nah, Jae-Woon;Kim, Yong-Bae
    • Macromolecular Research
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    • v.16 no.8
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    • pp.717-724
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    • 2008
  • In this study, we prepared all-trans retinoic acid (ATRA)-encapsulated, surfactant-free, PLGA nanoparticles. The nanoparticles were formed by nanoprecipitation process, after which the solvent was removed by solvent evaporation or dialysis method. When a nanoparticle was prepared by the nanoprecipitation - solvent evaporation method, the nanoparticles were bigger than the nanoparticles of the nanoprecipitation - dialysis method, despite the higher although loading efficiency. Nanoparticles from the nanoprecipitation - dialysis method were smaller than 200 nm in diameter, while the loading efficiency was not significantly changed. Especially, nanoparticles prepared from DMAc, 1,4-dioxane, and DMF had a diameter of less than 100 nm. In the transmission electron microscopy (TEM) observations, all of the nanoparticles showed spherical shapes. The loading efficiency of ATRA was higher than 90% (w/w) at all formulations with exception of THF. The drug content was increased with increasing drug-feeding amount while the loading efficiency was decreased. In the drug release study, an initial burst was observed for $2{\sim}6$ days according to the variations of the formulation, after which the drug was continuously released over one month. Nanoparticles from the nanoprecipitation - dialysis method showed faster drug release than those from the nanoprecipitation - solvent evaporation method. The decreased drug release kinetics was observed at lower drug contents. In the tumor cell cytotoxicity test, ATRA-encapsulated, surfactant-free, PLGA nanoparticles exhibited similar cytotoxicity with that of ATRA itself.

Studies on Osmotically Driven Drug Infusion Pump Under the Change in Body-Simulating Environment (인체 내부 환경 변화 모사에 따른 삼투압 기반 약물주입펌프의 기능 평가 연구)

  • Yoon, Chul Whan;Ahn, Jae Hong;Park, Doh;Lee, Jae Yeon;Park, Chun Gwon;Park, Min;Choy, Young Bin
    • Journal of Biomedical Engineering Research
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    • v.36 no.6
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    • pp.291-295
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    • 2015
  • Various types of implantable drug delivery devices have attracted significant attention for several decades to improve drug bioavailability and reduce side effects, thus enhancing therapeutic efficacy and patients' compliance. However, when implanted into the body, the devices may be influenced by the changes in physiological condition, such as temperature, pH or ionic concentration. Thus, the drug release rates could be also altered concurrently. Therefore, in this work, we employed an implantable ALZET$^{(R)}$ Osmotic Pump, which has been widely used to locally deliver various therapeutic agents and examined the effect of pH, temperature and ionic concentration on its drug release rate. For this, we performed in vitro cell tests to simulate the condition of local tissues influenced by the altered drug release rates, where we used diclofenac sodium as a model drug.

Drug Delivery Effect Using Biopolymer Chitosan Nanoparticles (생명고분자 키토산의 나노입자를 이용한 약물전달 효과)

  • Lee, Do Hun;Lee, Sang-wha;Yoo, In Sang;Park, Kwon-pil;Kang, Ik Joong
    • Applied Chemistry for Engineering
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    • v.16 no.6
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    • pp.790-793
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    • 2005
  • Recently, the interest in the extension of human life and personal health has been increased. Accordingly, many researchers in a pharmacy and a medical world have been making efforts to improve the sustained drug release property and the stability of drug release property in a body. Many biological researches have demonstrated that chitosan derivatives are effective, safe absorption enhancers that can improve the delivery efficiency of drug and vaccine, and they are suitable for controlled drug release because they have good stability, bio-compatibility, and biodegradability. In this study the experiment was performed in vivo by utilizing chitosan nanoparticles as a biopolymer to control drug delivery rate at an optimal temperature, pH, and concentration. It was observed that nanoparticles containing insulin could effectively control the blood glucose at a low level.

Effect of Surfactants on the Controlled Release of Bupivacaine HCl from Biodegradable Microfluidic Devices (생분해성 마이크로 유체 약물전달장치의 Bupivacaine HCl 전달특성에 대한 계면활성제의 영향)

  • Yang, Sung-Yeun;Lee, Kang-Ju;Ryu, Won-Hyoung
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.36 no.5
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    • pp.545-551
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    • 2012
  • We investigated the diffusive transport of bupivacaine HCl through the microchannels of microfluidic drug delivery devices. In the biodegradable microfluidic drug delivery devices developed in this research, the drug release rate can be controlled by simply modulating the geometrical parameters of the microchannels, such as the length, number, and cross-sectional area of the microchannels, when the microchannels are used as paths for drug release. However, the hydrophobic nature of a biodegradable polymer, 85/15 poly(lactic-co-glycolic acid), hinders the infiltration of a release medium (phosphate-buffered saline) through the microchannels into the reservoir of a device that contains bupivacaine HCl, at the early stage of drug release. This can have an adverse effect on the early stage release of local analgesic compounds from the device. In this study, microfluidic channels were surface-treated with surfactants such as PEG600 and Tween80, and the effects of the surfactants on the release performance are presented and analyzed.

Swelling and Proxyphylline Release Kinetics of Enzyme-Digestible Swelling Hydrogel Tablet (효소 소화성 하이드로겔 정제의 팽윤 및 프록시필린 방출 특성)

  • Shim, Chang-Koo;Lee, Young-Mee;Yeo, So-Hyeon
    • YAKHAK HOEJI
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    • v.36 no.3
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    • pp.212-219
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    • 1992
  • Although oral route is the most convenient route for drug administration, the short and variable transit of drug through GI tract restricts the sustained drug absorption after oral administration. Thus, for sustained absorption of drugs, it is desirable to prolong the GI transit time by retaining the dosage forms in the stomach. In this study, the enzyme-digestible swelling hydrogel was synthesized by heating the mixed solution of N-vinyl-2-pyrrolidone[monomer], acrylated albumin[crosslinking agent] and proxyphylline[drug] at $65^{\circ}C$ for 10 hours in the cylindrical test tube. The resultant hydrogel tablet (diameter; 0.77 cm, thickness; 0.47 cm) was designed to swell in the gastric fluid after oral administration to such a size that passing through the pylorus could be inhibited during the drug release. After releasing drug, the hydrogel was expected to be degraded by pepsin, an enzyme in the stomach, and eventually solubilized. Actually, the hydrogel synthesized in the study swelled to a size larger than the diameter of the pylorus ($1.3{\pm}0.7$ cm) and slowly digested in the presence of pepsin. Drug release from the hydrogel was prolonged up to about 12 hours. The swelling kinetics was dependent on albumin acrylation time, drug content and gel thickness. Particularly the gel thickness was the most important factor that influences on drug release. By adjusting these factors, the albumin-crosslinked hydrogel was expected to be retained in the stomach for up to 60 hours and used as a potential platform of drugs for long-term GI absorption.

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Preparation and in vitro Evaluation of a Buoyant Hydrogel Matrix with Hydroxypropylcellulose and Carbopol (히드록시프로필셀룰로오스와 카르보폴을 이용한 부유성 히드로겔 매트릭스의 제조 및 in Vitro 평가)

  • Kim, Sang-Hun;Lee, Min-Suk;Choi, Young-Wook
    • Journal of Pharmaceutical Investigation
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    • v.26 no.2
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    • pp.137-144
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    • 1996
  • The study was carried out for the preparation and evaluation of a buoyant hydrogel matrix (BHM), which is buoyant in a neutral or in pH 2.0 buffer solution, by the aspects of buoyancy, swelling, and drug release. Physical mixtures of HPC and CP in various molar ratio were employed as a mucoadhesive polymer which swells and controls the rate of drug release. Anhydrous citric acid and sodium bicarbonate in the molar ratio of 1:3 were employed as effervescing agents which provide a buoyancy for the mucoadhesive polymeric matrix. The buoyancy in vitro was expressed as both floating time$(T_{fl})$ and surfing time$(T_{sf})$, which are the time required for floating from the bottom to the surface of the medium and the time to keep the floated state at the surface of medium during release studies, respectively. A close relationship was observed between the buoyancy and the amount of effervescing agent added. $T_{fl}$ of the buoyant hydrogel matrices were decreased to about 10 seconds linearly with increasing the amount of effervescing agent in the range of 5 to 15%. $T_{sf}$ of the buoyant hydrogel matrices were varied from 1 to 3 hr depending on the amount of effervescing agent. The swelling was observed by changes in diameter of the buoyant hydrogel matrices in distilled water or acidic buffer solution, resulted in dependences on pH and the amount of effervescing agents. The release of hydrochlorothiazide from the buoyant hydrogel matrices were followed by apparent zero-order kinetics, while the buoyant hydrogel matrices were floated at the surface and maintaining their swollen shapes.

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Sustained Release Injectable of Recombinant Bovine Somatotropin in Biodegradable Poly(D,L-lactide-co-glyceride) Microspheres (생분해성 폴리락티드/글리콜리드 미립구를 이용한 재조합 소 성장호르몬(rBST)의 지속성주사제 설계)

  • Jeon, Hong-Ryeol;Lee, Bong-Sang;Kown, Do-W;Yoon, Mi-Kyoung;Jeon, Hyun-Joo;Shin, Taek-Hwan;Choi, Young-Wook
    • Journal of Pharmaceutical Investigation
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    • v.32 no.3
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    • pp.199-207
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    • 2002
  • In order to develop a sustained release formulation of bovine somatotropin (BST), which has been used to increase the body weight of oxen or the milk production of dairy cows, poly(D,L-lactide-co-glyceride)(PLGA) microspheres were made by W/O/W multiple emulsification method and solvent extraction method. Physical properties including particle size, drug entrapment, drug release, protein denaturation, and in vivo body weight increase in rats were characterized. The size of the microspheres was increased as the molecular weight of PLGA increased. When Span 65 and stearic acid during preparation were added, the size was decreased but the amount of surface protein was increased, resulting in a high loading efficiency, with fast release of BST from the microspheres. Aggregation or fragmentation of BST by SDS-PAGE during microsphere preparation and drug release study was not observed. Body weight of Sprague-Dawley's male rats was significantly increased after subcutaneous administrations of BST-loaded PLGA microspheres. There was a good correlation between in vivo weight gain and in vitro release rate of microspheres. PLGA microspheres with a high surface protein ratio could be a good candidate for the sustained delivery of BST.

Effect of Particle Size of HPMC on Dissolution Rate of Venlafaxine HCl and Carbamazepine Sustained Release Tablet (HPMC의 입도에 따른 염산벤라팍신 및 카바마제핀 서방성 정제의 용출 특성)

  • Cha, Jae-Uk;Cha, Ja-Hyun;Hong, Jun-Kee;Lee, Sung-Wan;Ko, Won-Hwa;Beak, Hyun-Ho
    • Polymer(Korea)
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    • v.36 no.3
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    • pp.332-337
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    • 2012
  • The primary objective of this work is to find the properties of sustained release dissolution pattern depending on solubility of drugs, so venlafaxine HCl and carbamazepine tablets were made by using polymer wich various particle size. Hydroxy propyl methyl cellulose (HPMC) has been utilized in this study as an excipient that is one of the most widely used polymers for an oral sustained release formulation, and drug release pattern was strongly influenced by swelling rate depending on particle size of HPMC. Scanning electron microscope (SEM) was employed to investigate the surface of tablets with various HPMC particle size, and differential scanning calorimeter (DSC) was employed to investigate the crystallization of drugs in tablets. The release model equation was applied to analyze the main mechanism of drug release pattern. The results demonstrate that drug release pattern is controlled by the drug solubility and HPMC particle size.