• Title/Summary/Keyword: drug release

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Drug Release Characteristics from Chain-extended and Crosslinked Polypropylene Glycol Hydrogels (폴리프로필렌 글리콜 하이드로겔의 가교도 및 고분자사슬 길이조절에 의한 약물방출특성)

  • Lee, Seung-Jin
    • Journal of Pharmaceutical Investigation
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    • v.24 no.4
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    • pp.251-256
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    • 1994
  • Polypropylene glycol (M.W. 4000) was crosslinked and chain-extended by using triisocyanate and diisocyanate to synthesize rubbery and water swellable hydrogels. Model drugs, i.e., sodium salicylate and indomethacin were incorporated in the polymer matrices by swelling loading. The drug release rates of drugs could be regulated by varying the degrees of crosslinking and chain-extension. Whereas, no correlation was observed between the drug release profiles and the swelling behaviours of the matrices. The release of drugs from the matrices was considered to be governed by the mobility and mesh size of the polymer chains in the matrices.

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Application of Carrageenan for Sustained Drug Release (약물의 서방출을 위한 ${\kappa}-Carrageenan$의 응용)

  • Lee, Seung-Jin
    • Journal of Pharmaceutical Investigation
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    • v.23 no.4
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    • pp.213-216
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    • 1993
  • ${\kappa}-Carrageenan$, an anionic polysaccharide, was employed in tablet formulations and its function as a drug release sustaining agent was investigated. Tablets composed of ${\kappa}-carrageenan$ and hydroxypropyl methylcellulose were fabricated by using direct compression method. Lactose and sodium alginate were utilized as controls for ${\kappa}-carrageenan$. Drug release experiments performed at pHs 1.2 and 7.4 revealed that ${\kappa}-carrageenan$ retains pH-dependent sustained release effects due to its anionic characteristics. Also, the ionic interaction between ${\kappa}-carrageenan$ and drugs exerted significant affects on drug release kinetics. ${\kappa}-Carrageenan$ was found out to be a useful additive for sustained release tablet formulations.

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Transdermal Drug Release of Polymer Matrix of Unsaturated Poly(3-hydroxyalkanoate) (불포화 폴리(3-히드록시알칸오에이트)를 기질로 한 경피제제의 약물방출)

  • 이수홍;신병철;이영하;김형우;김영백;김승수
    • Polymer(Korea)
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    • v.27 no.6
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    • pp.536-541
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    • 2003
  • Unsaturated poly(3-hydroxyalkanoate) (UPHA) was biosynthesized and the properties of drug delivery using the polymer matrix were investigated. The biosynthesis of UPHA was carried out by pH-stat fed batch fermentation of Pseudomonas oleovorans (ATCC 29347) grown solely with 10-undecenoic acid as a carbon source. The physical and chemical properties of the biosynethesized UPHA were characterized using NMR, FT-IR, GPC and DSC. The drug release experiments were carried out using HPLC with a diffusion cell fur the release amount of ketoprofen as model drug. The effects of crosslinking degree, patch thickness, and enhancer on the drug release were studied. The drug release rate was linearly decreased and consistent with increased crosslinking degree of the polymer matrix. The duration of drug release was enhanced by the Increased patch thickness. The drug release rate was increased with increased amount of propylene gylcol as an enhancer.

Drug Release Characteristics of Famotidine-Cationic Exchange Resin Complexes and Their Pharmacokinetics in Rats (파모티딘-양이온 교환수지 복합체의 약물방출 특성 및 흰쥐에서의 체내동태)

  • Shin, Dong-Sun;Song, Woo-Heon;Choi, Young-Wook
    • Journal of Pharmaceutical Investigation
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    • v.27 no.4
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    • pp.313-321
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    • 1997
  • Ion exchange resin complexes of famotidine have been prepared by the reaction of famotidine solution with activated ion exchange resins. Complex formation efficiency between famotidine and ion exchange resin was about $80{\sim}90%$ in average, calculated by HPLC determination. Drug release characteristics from the resin complexes were evaluated by the modified percolation method. Famotidine release was dependent on the type of ion exchange resins. In the case of weakly acidic resin complexes, the cumulative released amount of famotidine was more than 90% for 1hr in pH 1.2 buffer solution. However, in the case of strongly acidic resin complexes, it was less than 5% for 3hr in the same medium. Strongly acidic resins revealed some advantages over weakly, acidic resins for overcoming instability of famotidine in gastric juice. In addition, strongly acidic resin complexes showed controlled release of famotidine in pH 6.8 buffer solution, showing the result of about 60 to 70% of drug release for 5hr. After oral administrations of famotidine-resin complexes to rats as dose of 40 mg equivalent/kg, the pharmacokinetic parameters of famotidine were obtained by model independent analysis and compared with those of famotidine solution or suspension. $C_{max}$ of famotidine-resin complex was lower than that of famotidine solution or suspension. MRT, MAT, and MDT of the complexes were greater than those of famotidine solution or suspension. From these results, it was expected that famotidine was released slowly from the complexes and absorbed continuously into systemic circulation. It was recognized that drug release from the complexes was the rate-limiting step in drug absorption, since there were close correlations between in vitro drug release and in vivo pharmacokinetic parameters.

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Effect of Curing and Compression Process on the Drug Release of Coated Ion-Exchange Resin Complexes

  • Jeong, Seong-Hoon;Wang, Hun-Sik;Koo, Ja-Seong;Choi, Eun-Joo;Park, Ki-Nam
    • Journal of Pharmaceutical Investigation
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    • v.41 no.2
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    • pp.67-73
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    • 2011
  • Ion exchange resins can be one of the good carriers for sustained drug release. However, the sustained release may not be enough only with themselves and hence film coating with rate controlling polymers can be applied to have a further effect on the drug release. Due to the environmental and economic issues of organic solvent for the polymer coating, aqueous polymeric systems were selected to develop dosage forms. Among the many aqueous polymeric dispersions for the film coating, EC (ethylcellulose) based polymers such as Aquacoat$^{(R)}$ ECD and Surelease$^{(R)}$ were evaluated.A fluid-bed coating was applied as a processing method. The drug release rate was quite dependent on the coating level so the release rate could be modified easily by changing different levels of the coating. The drug release rate in the Aquacoat$^{(R)}$ coated resin particles was strongly dependent on curing, which is a thermal treatment to make homogeneous films and circumvent drug release changes during storage. After dissolution test using the compressed tablets in which the coated resin particles are contained, inhomogeneous coating and even pores could be observed showing that the mechanical properties of EC were not resistant to granulation and compaction process. However, when tablets were prepared in different batches, the release profiles were almost identical showing the feasibility of the coated resin particle as incorporated into the tablet formulation.

Ultrasound-Triggered Drug Release of Hydroxyapatite Coated Liposomes (하이드록시아파타이트 코팅 리포솜의 초음파에 의한 약물방출)

  • Cho, Sung Keun;Wee, Tae In;Ha, Jeung;Cho, Sun Hang;Han, Kun;Han, Hee Dong;Shin, Byung Cheol
    • Journal of the Korean Chemical Society
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    • v.57 no.4
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    • pp.493-498
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    • 2013
  • Liposomes, which can deliver payload at target site, have been studied as drug carrier. However, conventional liposomes have limitation for drug release at target site. Therefore, we developed hydroxyapatite (HA) coated ultrasound sensitive liposomes to increase drug release at target site and to enhance stability in blood stream. Control liposome was prepared using hydrogenated soy phosphatidylcholine (HSPC) and cholesterol, and then we assessed HA coating on the surface of control liposomes using calcium acetate, phosphoric acid, and 25% ammonium solution. Doxorubicin was used as a model drug. Size of HA coated liposomes was 120 nm and encapsulation efficiency of doxorubicin in liposomes was up to 95%. Size of HA coated liposomes are not changed in 30% serum solution, however, the control liposomes was 1.4 fold increased. After ultrasound triggered drug release from liposomes, intracellular efficiency of drug released from HA coated liposomes was 3 fold increased compared to control liposomes. In this study, we developed ultrasound sensitive liposomes to enhance drug release, which will be applied in controlled drug release at disease site.

Drug Release Behavior of Poly($\varepsilon$-caprolactone )-b-Poly( acrylic acid) Shell Crosslinked Micelles below the Critical Micelle Concentration

  • Hong Sung Woo;Kim Keon Hyeong;Huh June;Ahn Cheol-Hee;Jo Won Ho
    • Macromolecular Research
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    • v.13 no.5
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    • pp.397-402
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    • 2005
  • To explore the potential of shell crosslinked micelle (SCM) as a drug carrier, the drug release behavior of poly($\varepsilon$-caprolactone)-b-poly(acrylic acid) (PCL-b-PAA) SCMs was investigated. PCL-b-PAA was synthesized by ring opening polymerization of $\varepsilon$-caprolactone and atom transfer radical polymerization of tert-butyl acrylate, followed by selective hydrolysis of tert-butyl ester groups to acrylic acid groups. The resulting amphiphilic polymer was used to prepare SCMs by crosslinking of PAA corona via amidation chemistry. The drug release behavior of the SCMs was studied, using pyrene as a model drug, and was compared with that of non-crosslinked micelles, especially below the critical micelle concentration (CMC). When the shell layers were crosslinked, the drug release behavior of the SCMs was successfully modulated at a controlled rate compared with that of the non-crosslinked micelles, which showed a burst release of drug within a short time.

Preparation and Evaluation of Sustained Release Aspirin Microcapsules Using Eudragit $RS^{\circledR}$ Polymer (Eudragit $RS^{\circledR}$를 이용한 지속 방출형 아스피린 마이크로캅셀의 제조 및 평가)

  • Chun, In-Koo;Shin, Dong-Won
    • YAKHAK HOEJI
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    • v.32 no.1
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    • pp.26-39
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    • 1988
  • Eudragit $RS^{\circledR}$ polymer was used as a wall material for the microencapsulation of aspirin by a phase separation method from chloroform-cyclohexane system with 5% polyisobutylene (PIB) in cyclohexane, and microcapsules obtained were evaluated by particle size analysis, scanning electron microscopy (SEM), drug release and drug stability test. With PIB as a coacervation inducing agent, smooth and tight microcapsules with less aggregation were obtained. Below 1 : 0.3 core-wall ratio, it was possible to coat individual particle. Variation of production conditions showed that increasing the proportion of wall material, particle size and wall thickness of microcapsules and the concentration of paraffin wax in cyclohexane as a sealant sustained drug release rates effectively. SEM confirmed that larger microcapsules after drug release did not rupture into smaller particles but contained a few small pores on the surface. Aspirin release from Eudragit $RS^{\circledR}$ coated microcapsules was independent of the pH of medium, and the mechanism of drug release from non-sealed and sealed microcapsules appeared to fit Higuchi matrix model kinetics. Aspirin in the mixture of aspirin microcapsules and sodium bicarbonate was by far more stable than that in the mixture of pure aspirin and sodium bicarbonate.

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Antimicrobial Drug Release Scaffolds of Natural and Synthetic Biodegradable Polymers

  • Prabu, Periasamy;Kim, Kwan-Woo;Dharmaraj, Nallusamy;Park, Jong-Hoon;Khil, Myung-Seob;Kim, Hak-Yong
    • Macromolecular Research
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    • v.16 no.4
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    • pp.303-307
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    • 2008
  • A series of biodegradable polymeric scaffolds was prepared by using a combination of natural (collagen) and synthetic (poly(caprolactone)) (PCL) polymers in various compositions. These scaffolds were soft, spongy, porous and transparent in nature and were characterized by thermogravimetric analysis (TGA) and Fourier transform infrared (FT-IR) spectroscopy. The entrapment efficiency and drug release activity of the scaffolds were analyzed using penicillin and tetracycline as antimicrobial drugs. The drug release activity of the scaffolds with various combinations of collagen and PCL were studied by measuring the optical density in a spectrophotometer at the following time intervals: 1,4, 24, 48 and 60 h. These scaffolds showed better and continuous drug release for up to 60 h. Even after such a long duration, a portion of the drug remained entrapped in the scaffolds, indicating that they can be utilized for wound healing applications.

Improved Dissolution of Poorly Water Soluble TD49, a Novel Algicidal Agent, via the Preparation of Solid Dispersion

  • Lee, Hyoung-Kyu;Cho, Hoon;Han, Hyo-Kyung
    • Journal of Pharmaceutical Investigation
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    • v.40 no.3
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    • pp.181-185
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    • 2010
  • The objective of this study was to improve the extent of drug release as well as the dissolution rate of TD49, a novel algicidal agent, via the preparation of solid dispersion (SD). Among the various carriers tested, $Solutol^{(R)}$ HS15 was most effective to enhance the solubility of TD49. Subsequently, SDs of TD49 were prepared by using $Solutol^{(R)}$ HS15 and their solubility, dissolution characteristics and drug crystallinity were examined at various drug-carrier ratios. Solubili ty of TD49 was increased significantly in accordance with increasing the ratio of $Solutol^{(R)}$ HS15 in SDs. Compared to untreated powders and physical mixtures (PMs), SDs facilitated the faster and greater extent of drug release in water. Particularly, SD having the drug-carrier ratio of 1:20 exhibited approximately 90% of drug release within 1 hr. Differential scanning calorimetry (DSC) thermograms and X-ray diffraction (XRD) patterns suggested that SDs might enhance the dissolution of TD49 by changing the drug crystallinity to an amorphous form in addition to the increased solubilization of drug in the presence of $Solutol^{(R)}$ HS15. In conclusion, SD using $Solutol^{(R)}$ HS15 appeared to be effective to improve the extent of drug release and the dissolution rate of poorly water soluble TD49.