• 폴리머
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• 제28권4호
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• pp.291-297
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• 2004

수용성 키토산의 농도와 가교제 (글루타알데히드)의 양을 변화시키면서 미네랄오일 내에서 키토산용액의 유화법에 의해 수용성 키토산 미세구를 제조하였다. 그러고 약물이 봉입되어진 수용성 키토산 미세구의 분해에 따른 형태의 변화, 약물의 봉입효율, 약물 방출 거동과 같은 물리화학적 특성을 규명하였다. Norfloxacion 이 봉입된 수용성 키토산 미세구는 표면의 약물에 의해 나타나는 과량의 약물 방출이 없는 높은 약물 봉입 함량을 보였다. 표면에 약물이 존재하지 않음을 선 회절 분석으로 확인하였다. 수용성 키토산 미세구의 분해 특성과 약물방출 거동을 관찰한 결과 가교제의 양이 약물의 봉입량, 방출, 그리고 분해에 중요한 역할을 하는 것을 확인하였다. 수용성 키토산 미세구는 가교제의 양이 증가함에 따라 분해속도가 느렸으며, 이와 동시에 약물이 천천히 방출되었음을 확인하였다.

• 약학회지
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• 제35권3호
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• pp.197-202
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• 1991

In order to study drug release from the suppository, three types of hollow suppositories and one conventional suppository were prepared using indomethacin(IDM) as a model drug and Witepsol H-15 as a base. The 4 types of suppository prepared are as follows: type I, conventional suppository containing 50 mg of IDM powder, type II, hollow supository containing 50 mg of IDM powder in the cavity, type III, hollow suppository containing 25 mg of IDM powder in the base and IDM microcapsules (25 mg as IDM powder) in the cavity, and type IV, hollow suppository containing IDM microcapsules (25 mg as IDM powder) in the base and 0.5 ml of 5%(w/v) IDM-PEG 300 solution in the cavity. The drug amount released(%) from type II and I within 24 hrs was 46.7% and 66.9%, respectively. Comparing with the drug amount released from four types of suppository within initial 2 hrs and 24 hrs, that of type IV was high as 32.7% and 76.6%, respectively. IDM-ethycellulose microcapsules passed through 270 mesh sieve and the IDM content was 20.95%.

• Journal of Pharmaceutical Investigation
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• 제27권4호
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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.

• Journal of Pharmaceutical Investigation
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• 제24권3호
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• pp.155-165
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• 1994

Some mucoadhesive polymers such as hydroxypropylcelluose (HPC) and carbopol-934 (CP) have been employed for the preparation of mucoadhesive polymeric systems, and their physical properties including mucoadhesion, swelling, and drug release were evaluated. A new simple experimental technique that can quantitatively measure the bioadhesive properties of various polymeric systems has been developed by the methods of detachment force test. As the polymeric systems, the discs of freeze-dried HPC/CP solid dispersions were prepared. The mucosa used in these tests were upper, middle, and lower parts of small intestine of male rats weighing $300{\sim}350\;g$. Detachment forces were increased as the mole fraction of CP increased in discs of HPC/CP solid dispersions. In the points of intestinal site dependence of mucoadhesion, the solid dispersions revealed non-specific mucoadhesion to the intestine. Swelling and drug release characteristics of mucoadhesive polymeric systems were studied extensively to find out the feasibility for the oral controlled delivery systems. Swelling ratio, expressed as the final height/initial height, has been determined in various pH buffer solutions. Hydrochlorothiazide (HCT) was employed as a model drug for release study. Apparent swelling and drug release rate constants, $K_s$ and $K_r$ respectively, were obtained from the square-root time plot of either swelling ratio or released amount of drug, particularly for the time periods before reaching the equilibrium. As a result, the swelling ratio of HPC/CP solid dispersions was increased as the weight percentage of CP increased. Similarly, the release of HCT from the solid dispersions was dependent on pH changes and CP contents, resulted in the slower release of HCT with the increases of pH and CP contents.

• Journal of Pharmaceutical Investigation
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• 제23권1호
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• pp.19-26
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• 1993

The purpose of this paper is to explore the possible applicability of alginate beads as an oral controlled release system of polymeric drugs. Cellulase was used as a model polymeric drug. The release of cellulase from alginate beads was moderately affected by the ratio of cellulase to sodium alginate and strongly affected by $CaCl_2$ concentration. However, the release was not particularly affected by the other factors such as sodium alginate concentration and curing time. The drug was not released from alginate beads at pH 1.2, but was released continuously up to 8 hr at pH 6.8. At pH 6.8, the beads were swollen highly up to 3 hr, thereafter, were eroded into the bulk solution up to 6 hr, completely. Drug release from the beads can be caused due to diffusion and erosion of the matrix. Activity of cellulase was reduced when alginate beads containing cellulase were stored in simulated gastric juice. Further investigation would be necessary to improve the acid resistance of the beads. Since the release of cellulase as a model polymeric drug could be controlled by the regulation of the preparation conditions of alginate beads, the alginate beads may be used for a potential oral controlled release system of such polymeric drugs as polypeptide drugs.

• Archives of Pharmacal Research
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• 제29권12호
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• pp.1179-1186
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• 2006

Cross-linked starch microspheres were prepared using different kinds of cross-linking agents. The influence of several parameters on morphology, size, swelling ratio and drug release rate from these microspheres were evaluated. These parameters included cross-linker type, concentration and the duration of cross-linking reaction. Microspheres cross-linked with glutaraldehyde had smooth surface compared with those prepared with epichlorhydrine or formaldehyde. The particle size increased with increasing the cross-linking time and increasing the drug loading. Swelling ratio of the particles was a function of cross-linker type but not the concentration or time of cross-linking. Drug release from starch microspheres was measured in phosphate buffer and also in phosphate buffer containing a-amylase. Results showed that microspheres cross-linked with epichlorhydrine released all their drug content in the first 30 minutes. However, cross-linking of the starch microspheres with glutaraldehyde or formaldehyde decreased drug release rate. SEM and drug release studies showed that cross-linked starch microspheres were susceptible to the enzymatic degradation under the influence of alpha-amylase. Changing the enzyme concentration from 5000 to 10,000 IU/L, increased drug release rate but higher concentration of enzyme (20,000 IU/L) caused no more acceleration.

• 센서학회지
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• 제13권1호
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• pp.47-55
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• 2004

This paper presents drug release properties of active drug delivery system (DDS) using volume change of polypyrrole (PPy). The incorporation of various chemical substances into the PPy and controlling its release with the externally applied voltage to the PPy are possible. In order to confirm possibility for drug delivery system qualitatively, indicator(phenol red) was examined as a dopant of PPy. The applied voltage to the PPy electrode was set to -2 V and this negative voltage makes the anionic indicator released in saline solution. After qualitative analysis, in order to confirm quantitative drug release characteristic of PPy, salicylate which is one of the aspirin substance was used as a dopant of PPy. As a result, the salicylate release characteristics with time was thoroughly investigated while varying the electrode area, polymerization time, the applied voltage for drug release. Based on these quantitative results, a preliminary experiment was carried out to check the feasibility of the PPy applicable to the neuronal system.

• 공업화학
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• 제10권2호
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• pp.201-205
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• 1999

Hydroxypropylmethylcelluloses (HPMC)는 친수성 cellulose 계통의 중합체로서 독성이 적고 가격이 저렴하여 경구용 서방출성 제제에 널리 이용되고 있다. 본 연구에서는 매트릭스로서 HPMC를 이용하여 새로운 서방출성제제인 HPMC/염산슈도에페드린계를 설계하고, 직타법에 의하여 정제를 제조하였으며, 이 팽윤될 수 있는 친수성 약물전달계를 이용하여 약물의 방출에 영향을 주는 여러 인자들이 약물의 방출속도에 미치는 영향에 대하여 조사하였다. 결과로서, HPMC/염산슈도에페드린계에서 매트릭스인 HPMC의 분자량이 클수록, HPMC의 함량이 많을수록 약물의 방출속도가 더 느려짐을 알 수 있었으며, 정제의 경도나 용출시 pH 변화에는 무관한 것으로 나타났다. 특히, 음이온 계면활성제인 sodium laurylsulfate는 HPMC로부터 염산슈도에페드린의 방출속도를 지연시키는데 큰 영향을 미치는 것으로 나타났으며, 이러한 현상은 음이온 계면활성제인 sodium laurylsulfate가 반대의 이온성을 갖는 약물인 염산슈도에페드린과 착물을 형성함으로써 약물의 용해성이 떨어져서 약물방출이 지연되는 것으로 생각된다.

• Journal of Pharmaceutical Investigation
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• 제28권1호
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• pp.51-57
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• 1998

Tetracycline lyogel ointment consisting of hydroxy ethyl cellulose(HEC) in glycerin and Eudragit RS 100 in triacetin were prepared and then release characteristic were investigated. The physical properties of lyogel ointment such as viscosity, particle size and microscopic structures were also evaluated. The microscopic structures showed that lyogel particles containing drug were dispersed in the triactin solution. The release rate of drug from lyogel ointment as a function of HEC was not changed. However the release rate was significantly decresed when the amount of Eudragit RS 100 and triacetin in lyogel ointment was increased. The viscosity and weight fraction in external phase of lyogel ointment influenced the release rate. The current studies suggest that the release rate of drug can be controlled by changing of lyogel ointment compositions.

• KSBB Journal
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• 제18권2호
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• pp.161-164
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• 2003

경구 투여가 비교적 어려운 단백질 약물을 생체적합성이 우수하고 생분해성을 가진 펙틴을 이용하여 목적하는 colon에 전달하고자 하였다. 이온결합을 통해 펙틴, 펙틴-알긴산비드를 제조할 수 있었고, 단백질 약물인 BSA를 포함하여 방출을 행한 결과, 비드의 건조온도가 높을수록 방출률이 높은 경향을 보인 반면, 동결건조된 비드가 가장 높은 방출을 나타냈다. 또한, 가교제의 농도를 높게 처리한 비드일수록 방출률이 낮았다. 경구 투여 후 colon에 도달할 것으로 예상되는 5시간 후에 펙틴 분해효소를 처리한 결과, 효소 처리하지 않은 비드에 비해 급격한 방출이 일어났다. 이러한 결과로 colon내에 존재하는 미생물이 분비하는 효소에 의해 펙턴 비드에 포함된 약물이 방출될 것으로 판단된다. 따라서, 경구로 투여된 펙틴 비드 안의 약물이 소화기관에서 안정하게 통과하고 colon에서 방출되어 효과를 나타낼 것으로 판단된다.