• Journal of Pharmaceutical Investigation
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• 제17권3호
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• pp.135-139
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• 1987

This study was attempted to investigate the dissolution rate and the bioavailability of commercially available sulfamethoxazole and trimethoprim (SMX-TM) tablets in rabbits. The dissolution test was conducted in artificial gastric juice by basket method with eight SMX-TM tablets which were chemically equivalent. According to the dissolution rate, SMX-TM tablets were divided into four groups, such as rapid, intermediate, slow and very slow groups for the bioavailability test in rabbits. The results were as follows: 1) The dissolution rate of brand A was most rapid but brand H was most slow in artificial gastric juice. 2) Area under the blood concentration curve was larger in the order of brand A > C > E > H in rabbits. 3) There was a little difference in pharmacokinetic parameters such as biological half life, absorption rate constant and $t_{max}$. 4) The relationship between the dissolution rate and relative bioavailability was significant in brand A, C, E and H. From the results of this experiment, the bioavailability of SMX-TM tablets in rabbits may be predicted from the results of dissolution rate studies.

• 약학회지
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• 제55권4호
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• pp.332-337
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• 2011

The purpose of this study was to investigate the effect of epigallocatechin gallate (EGCG) on the pharmacokinetics of nimodipine in rats. Pharmacokinetic parameters of nimodipine were determined in rats after oral and iv administration of nimodipine with or without EGCG and also the effect of EGCG on the cytochrome P450 (CYP) 3A4 and P-glycoprotein (P-gp) activity were evaluated. EGCG inhibited CYP3A4 and P-gp activity. EGCG significantly increased the area under the plasma concentration-time curve (AUC) and peak plasma concentration ($C_{max}$) of nimodipine. The absolute bioavailability (AB%) and relative bioavailability (RB%) of nimodipine by EGCG were increased by 16% and by 48%, respectively, compared to the control. In contrast, EGCG did not affect the intravenous pharmacokinetics of nimodipine. Based on these results, the increased bioavailability of nimodipine might be due to inhibition of CYP3A4 in the small intestine and/or in the liver and inhibition of P-gp in the small intestine by EGCG.

• 약학회지
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• 제54권5호
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• pp.370-376
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• 2010

The aim of this study is to investigate the effect of apigenin on the pharmacokinetics of tamoxifen in rats. Tamoxifen was administered orally (10 mg/kg) or intravenously (2 mg/kg) without or with oral administration of apigenin (0.4, 2.0 or 8.0 mg/kg) to rats. The effect of apigenin on the P-glycoprotein (P-gp) and CYP3A4 activity was also evaluated. Apigenin inhibited CYP3A4 enzyme activity with 50% inhibition concentration ($IC_{50}$) of 1.8 ${\mu}M$. In addition, apigenin significantly enhanced the cellular accumulation of rhodamine 123 in MCF-7/ADR cells overexpressing P-gp. The plasma concentrations of tamoxifen were increased significantly by apigenin compared to control. The areas under the plasma concentration-time curve (AUC) and the peak concentrations ($IC_{max}$) of tamoxifen with apigenin were significantly higher than those of the control group. Consequently, the relative bioavailability (RB%) of tamoxifen with apigenin was 2-3-fold higher than the control, and absolute bioavailability (AB%) of tamoxifen were significantly higher (p<0.05 with co-administration, p<0.01 with pretreatment) than those of the control. The increased bioavailability of tamoxifen in rats with apigenin might be associated with the inhibition of an efflux pump P-glycoprotein and CYP3A4 by apigenin. From these results, dosage regimen of tamoxifen may be need to adjust when concomitantly administered with apigenin.

• Journal of Pharmaceutical Investigation
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• 제19권3호
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• pp.131-136
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• 1989

This study was attempted to investigate the dissolution rate and the bioavailability after oral administration of commercially available aspirin tablets in normal volunteers. The dissolution test was conducted in artificial gastric juice using basket method with three aspirin preparations (A, B and C) which were chemically equivalent. The results were as follows; The dissolution rate was higher in the order of three different brand B>A >C. Area under the blood concentration and peak blood concentration were larger in the order of brand A>B>C. Absorption rate constant and peak time were larger in the order of brand B>A>C, and there was a little difference in elimination rate constant and biological half-life. The correlation of the dissolution rate and absorption rate constant, as well as correlation of the dissolution rate and peak time showed significant linear relationship respectively. From the results of this experiment, it can be concluded that the bioavailability of aspirin tablets showed much difference according to commercial preparations, and that the bioavailability of aspirin tablets in human may be predicted from the results of dissolution rate studies.

• Archives of Pharmacal Research
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• 제29권4호
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• pp.333-338
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• 2006

The aim of this study was to investigate the effect of morin on the bioavailability of nimodipine after administering nimodipine (15 mg/kg) orally to rabbits either co-administered or pretreated with morin (2, 10 and 20 mg/kg). The plasma concentrations of nimodipine in the rabbits pretreated with morin were increased significantly (p<0.05 at 10 mg/kg, p<0.01 at 20 mg/kg) compared with the control, but the plasma concentrations of nimodipine co-administered with morin were not significant. The areas under the plasma concentration-time curve (AUC) and the peak concentrations $(C_{max})$ of the nimodipine in the rabbits pretreated with morin were significantly higher (p<0.05 at 10 mg/kg, p<0.01 at 20 mg/kg), but only the $C_{max}$ of nimodipine coadministered with morin 10 mg/kg was increased significantly (p<0.05). The absolute bioavailability $(A.B\%)$ of nimodipine in the rabbits pretreated with morin was significantly (p<0.05 at 10 mg/kg, p<0.01 at 20 mg/kg) higher $(54.1-65.0\%)$ than the control $(36.7\%)$. The increased bioavailability of nimodipine in the rabbits pretreated with morin might have been resulted from the morin, which inhibits the efflux pump P-glycoprotein and the first-pass metabolizing enzyme by cytochrome P-450 3A4 (CYP 3A4).

• 대한약학회:학술대회논문집
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• 대한약학회 2002년도 Proceedings of the Convention of the Pharmaceutical Society of Korea Vol.2
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• pp.411.1-411.1
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• 2002

The purpose of this study was to investigate the effect of quercetin on the bioavailability of paclitaxel orally coadministered in rats Paclitaxel is reported to be metabolized by cytochrome p-450(CYP3.A,)in both the liver and epithelial cells of small intestine and also absorption of paclitaxel is inhibited by p-glycoprotein efflux Pump in the intestinal mucosa. This resulted in poor orall bioavailability of paclitaxel. Area under the plasma concentration-time curve (AUC) of paclitaxel in combination with quercetin were significantly (p＜ 0.01) higher than those of control. (omitted)

• Archives of Pharmacal Research
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• 제15권3호
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• pp.208-210
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• 1992

Comparative bioavailability of two tablet dosage forms of ofloxacin (either as Hoechst (India) or Ranbaxy preparation ) was investigated. In a randomized cross-over study, eitht healthy human volunteers received single 200 mg dose of film coated ofloxacin in fasting state. The concentration of ofloxacin in the collected saliva and serum samples were measured by high performance liquid chromatography. No significant difference in bioavailability of both preparations was judged from various serum and seliva pharmacokinetic parameters such as peak concentration, time to peak concentration and are under the curves. Intersubject variation was also found to be insignificant.

• Preventive Nutrition and Food Science
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• 제7권3호
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• pp.327-331
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• 2002

Tea is a pleasant, popular and safe beverage in the world. During the past decade, epidemiological studies have shown that tea catechins intake is associated with lower risk of cardiovascular disease. Tea provides a dietary source of health-promoting components to help humans reduce a wide variety of cancer risks and chronic diseases. The antioxidative activity of tea-derived catchins has been extensively studied. The antioxidant effect is a synergistic action between catechins e.g. EGCG, EGC, ECG, EC, pheophytins a and b, and other components in tea leaves, which aye more bioavailable for human body. Green tea has a Higher content of catechins than other kinds of tea. Green tea extract with hot water has high potential and more efficiency to reduce cancer risk than any other tea products or pure EGCG. Protein, iyon, and other food components may interfere with the bioavailability of ten catechins. Interaction of catechins with drug affects the cancer-preventive activity of some cancer-fighting medication. Further studies are required to determine the bioavailability of tea catechins and cancer-preventive functionality.

• 한국응용약물학회:학술대회논문집
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• 한국응용약물학회 1997년도 춘계학술대회
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• pp.3-5
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• 1997

Properties of a good drug include safety, efficacy, half-life and bioavailability. With the current approach to drug discovery based on receptor-based and cell-based screening methods, compounds are frequently moved into development with poor bioavailability. With low bioavailability, drug administration is typically limited to parenteral routes, thus limiting the potential wide-spread utility of these therapeutic agents. The first and most important factor limiting a drug's bioavailability is the intestinal membrane permeability which in turn determines the maximum fi:action of the dose administered that can be absorbed. We have recently utilized new intubation methods for performing permeability measurements in humans and establishing a fundamental human data base for correlating intestinal jejunal membrane permeabilities with permeabilities determined in other systems, e.g., animals, tissue culture, as well as physical chemical properties.

• Journal of Pharmaceutical Investigation
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• 제29권1호
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• pp.1-5
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• 1999

The bioavailabilities of baicalin in water, oil, w/o and o/w emulsion were evaluated in rats. The dissolution rate of baicalin in o/w emulsion was smaller than those of w/o form in dilute hydrochloric acid solution (pH 1.2) and in PBS (pH 6.8). The absorption rate of baicalin from w/o emulsion was smaller than that of o/w emulsion in the different parts of rat intestine of the rats. Following oral administration in rats, the $C_{max}$ of baicalin from water phase, oil phase, o/w wand w/o emulsion were 2.11, 0.61, 1.57, and $1.35\;{\mu}g/ml$, respectively. The relative bioavailability of w/o emusion was 129 % when it was compared with water phase. This result suggests that the improvement of bioavailability for baicalin in w/o emulsion might be practically available.