• YAKHAK HOEJI
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• v.44 no.5
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• pp.424-431
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• 2000

A biopharmaceutics drug classification system for correlation between in vitro dissolution and in vivo bioavailability is proposed based on recognizing that drug dissolution and gastrointestinal permeability are the fundamental parameters controlling the rate and extent of drug absorption. The objective of this study was to assess whether in vitro dissolution profiles of immediate-release beta-blocker tablets can be correlated with intestinal membrane permeability and/or in vivo bioavailability In vitro dissolution of the beta-blocker tablets was examined using KP VII Apparatus II methods at various pH. Intestinal membrane permeability was determined in vitro using the diffusion chamber method. Bioavailablity parameters were cited from literatures. The dissolution profiles did not accurately represent the in vivo bioavailablity However there were good correlations between intestinal membrane permeability and log P (noctanol/buffer). The correlations obtained in this study indicated that in vitro diffusion chamber method could be used to predict intestinal absorption in vivo.

• Korean Journal of Clinical Pharmacy
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• v.18 no.2
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• pp.120-123
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• 2008

The purpose of this study was to investigate the effect of naringin, one of flavonoids, on the pharmacokinetics and bioavailability of nimodipine in rabbits. Pharmacokinetic parameters of nimodipine were determined in rabbits after oral administration of nimodipine (16 mg/kg) with or without naringin (1, 5 or 15 mg/kg). Nimodipine was analyzed by high performance liquid chromatography using Hypersil ODS column. Naringin significantly (p<0.05) increased the area under the plasma concentration-time curve (AUC) and the peak concentration ($C_{max}$) of nimodipine at 5 and 15 mg/kg. The absolute bioavailability (AB%) of nimodipine by prescence of naringin (5 or 15 mg/kg) increased from 32.2-36.9% (p<0.05) compared to the control (22.0%). However, presence of naringin had no significant effect on the elimination rate constant ($K_{el}$) of nimodipine. There were no apparent changes of the time of peak concentration ($T_{max}$) of nimodipine by coadministration. These results suggest that the increased bioavailability and the significant changes of these pharmacokinetic parameters of nimodipine by naringin may be attributed to the potential of narigin to inhibit cytochrome P450 (CYP) 3A4 and P-glycoprotein efflux pump in the liver and intestinal mucosa.

• YAKHAK HOEJI
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• v.42 no.5
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• pp.513-518
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• 1998

Fluoxetine is a nontricyclic antidepressant which blocks serotonin reuptake selectively. Its N-demethyl metabolite, norfluoxetine is also selective inhibitor of serotonin uptake . This study was carried out to compare the bioavailability of Myung-in fluoxetine (20mg/cap.) with that of Prozac$^{\circde{R}}$. The bioavailability was conducted on 24 healthy volunteers who received a single dose (80mg) of each drug in the fasting state, in a randomized balanced 2-way crossover design. After closing, serial blood samples were collected for a period of 48 hours, Plasma was analyzed for fluoxetine and norfluoxetine by a sensitive and validated HPLC assay. The major pharmacokinetic parameters ($AUC_{0-48\;hr}$, Cmax, Tmax , $AUC_{inf.}$, MRT. $T_{1/2}$, Vd and Cl) were, calculated from the plasma fluoxetine concentration-time data of each volunteer. The microcomputer program, 'WinNonlin' was used for compartmental analysis. A two-compartment model with first-order input, first-order output and no lag time was chosen as the most appropriate pharmacokinetic model. The data were best described by using a weighting factor of $1/y^2$. Though the plasma fluoxetine concentrations of Myung-in fluoxetine were higher than those of Prozac$^{\circde{R}}$ at all observed time from 7.9% to 16.9% (P<0.05 at 6.7 and 10 hr), the bioavailability of Myung-in fluoxetine appeared to be bioequivalent with that of Prozac$^{\circde{R}}$. There were no statistical significant differences between the two drugs in all pharmacokinetic parameters including $AUC_{0-48\;hr}$ of norfluoxetine.

• YAKHAK HOEJI
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• v.44 no.6
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• pp.572-577
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• 2000

The effects of ibuprofen on bioavailability of ciprofloxacin were studied in rabbits. Animals were divided into three groups ; group A received 60 mg/kg of ciprofloxacin; group B and C received 60 mg/kg of ciprofloxacin with 60 and 240 mg/kg of ibuprofen, respectively. Ciprofloxacin and ibuprofen were given by single oral administration. Serum concentrations of ciprofloxacin were measured by high performance liquid chromatography with UV detector and pharmacokinetic parameters were calculated. Area under the serum concentrations versus time curve (${\pm}\;S.E.$) of ciprofloxacin were decreased in group B and C compared with group A ($12.26\;{\pm}\;0.94$ and $12.57\;{\pm}\;0.94$ vs. $15.71\;{\pm}\;1.06\;{\mu}g{\cdot}hr/ml$, p<0.05), whereas total clearances were increased ($1.81\;{\pm}\;0.13$ and $1.76\;{\pm}\;0.12$ vs. $1.40\;{\pm}\;0.09\;l/hr/kg$, p<0.05). No significant differances in these parameters were observed between group B and C. Relative bio-availability of group B and C to group A were 78 and 80%, respectively. These results suggest that the coadministration of ibuprofen with ciprofloxacin may reduce the bioavailability of ciprofloxacin.

• Archives of Pharmacal Research
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• v.15 no.3
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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.

• Korean Journal of Clinical Pharmacy
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• v.8 no.1
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• pp.19-22
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• 1998

Cefixime is an orally absorbed 3rd generation cephalosporin with a broad spectrum of activity against Gram-positive and Gram-negative bacteria and is highly resistant to $\beta-lactamase$ degradation. This study was carried out to evaluate the bioavailability of a new test drug of cefixime (100 mg/capsule) relative to the reference drug. The bioavailability was conducted on 20 healthy volunteers who received a single dose (400 mg) of the test and the reference drugs in the fasting state, in a randomized balanced 2-way crossover design. After dosing, serial blood samples were collected for a period of 12 hours. Plasma was analyzed for cefixime by a sensitive and validated HPLC assay. The major pharmacokinetic parameters $(AUC_{0-12hr},\;C_{max},\;T_{max})$ were calculated from the plasma concentration-time data of each volunteer. The $AUC_{0-12hr},\;C_{max}\;and\;T_{max}$ of the test drug were $36.91\pm11.85\;{\mu}g{\cdot}hr/ml,\;5.47\pm1.61\;{\mu}g/ml,\;and\;4.00\pm0.65\;hr,$ respectively, and those of the reference drug were $34.08\pm8.81\;{\mu}g{\cdot}hr/ml,\;5.25\pm1.40\;{\mu}g/ml,\;and\;4.20\pm0.62\;hr$, respectively. Mean differences of those parameters were 8.32, 4.29, and $4.76\%$, respectively, and the least significant differences at $\alpha$=0.05 for $AUC_{0-12hr},\;C_{max},\;T_{max}$ were 16.02, 13.78, and $11.76\%$, respectively. In conclusion, the test drug was bioequivalent with the reference drug.

• Biomolecules & Therapeutics
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• v.19 no.3
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• pp.364-370
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• 2011

The purpose of this study was to investigate the effects of curcumin on the pharmacokinetics of loratadine in rats. The effect of curcumin on P-glycoprotein (P-gp) and cytochrome P450 (CYP) 3A4 activity was evaluated. Pharmacokinetic parameters of loratadine were also determined after oral and intravenous administration in the presence or absence of curcumin. Curcumin inhibited CYP3A4 activity with an IC50 value of 2.71 ${\mu}M$ and the relative cellular uptake of rhodamine-123 was comparable. Compared to the oral control group, curcumin significantly increased the area under the plasma concentration-time curve and the peak plasma concentration by 39.4-66.7% and 34.2-61.5%. Curcumin also significantly increased the absolute bioavailability of loratadine by 40.0-66.1% compared to the oral control group. Consequently, the relative bioavailability of loratadine was increased by 1.39- to 1.67-fold. In contrast, curcumin had no effect on any pharmacokinetic parameters of loratadine given intravenously, implying that the enhanced oral bioavailability may be mainly due to increased intestinal absorption caused via P-gp and CYP3A4 inhibition by curcumin rather than to reduced renal and hepatic elimination of loratadine. Curcumin enhanced the oral bioavailability of loratadine in this study. The enhanced bioavailability of loratadine might be mainly attributed to enhanced absorption in the gastrointestinal tract via the inhibition of P-gp and reduced fi rst-pass metabolism of loratadine via the inhibition of the CYP3A subfamily in the small intestine and/or in the liver by curcumin.

• YAKHAK HOEJI
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• v.53 no.5
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• pp.259-264
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• 2009

The present study was to investigate the effect of naringin, a flavonoid, on the pharmacokinetics of losartan in rats. Pharmacokinetic parameters of losartan in rats were determined after an oral administration of losartan (9 mg/kg) in the presence or absence of naringin (0.5, 2.5 and 10 mg/kg). The pharmacokinetic parameters of losartan were significantly altered by the presence of naringin compared with the control group (given losartan alone). Presence of naringin significantly (p<0.05, 2.5 mg/kg; p<0.01, 10 mg/kg) increased the area under the plasma concentration?time curve (AUC) of losartan by 43.7~63.0% and peak plasma concentration ($C_{max}$) of losartan by 31.7~45.5%. Consequently, the absolute bioavailability (AB) of losartan in the presence of naringin was 43.8~62.9%, which was enhanced significantly (p<0.05, p<0.01) compared to that in the oral control group (22.4%). The relative bioavailability (R.B.) of losartan increased by 1.44- to 1.63-fold in the presence of naringin. However, there was no significant change in the peak plasma concentration ($T_{max}$) and terminal half-life ($t_{1/2}$) of losartan in the presence of naringin. In conclusion, the presence of naringin significantly enhanced the oral bioavailability of losartan, implying that presence of naringin might be mainly effective to inhibit the cytochrome P450 (CYP)3A-mediated metabolism, resulting in reducing gastrointestinal and hepatic first-pass metabilism and Pglycoprotein (P-gp)-mediated efflux of losartan in small intestine. Concurrent use of naringin or naringin-containing dietary supplement with losartan should require close monitoring for potential drug interactions.

• Biomolecules & Therapeutics
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• v.21 no.2
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• pp.173-179
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• 2013

Objective of present study was to prepare and characterize self-nanoemulsifying drug delivery system (SNEDDS) of lutein and to evaluate its effect on bioavailability of warfarin. The SNEDDS was prepared using an oil, a surfactant, and co-surfactants with optimal composition based on pseudo-ternary phase diagram. Effect of the SNEDDS on the bioavailability of warfarin was performed using Sprague Dawley rats. Lutein was successfully formulated as SNEDDS for immediate self-emulsification and dissolution by using combination of Peceol as oil, Labrasol as surfactant, and Transcutol-HP or Lutrol-E400 as co-surfactant. Almost complete dissolution was achieved after 15 min while lutein was not detectable from the lutein powder or intra-capsule content of a commercial formulation. SNEDDS formulation of lutein affected bioavailability of warfarin, showing about 10% increase in $C_{max}$ and AUC of the drug in rats while lutein as non-SNEDDS did not alter these parameters. Although exact mechanism is not yet elucidated, it appears that surfactant and co-surfactant used for SNEDDS formulation caused disturbance in the anatomy of small intestinal microvilli, leading to permeability change of the mucosal membrane. Based on this finding, it is suggested that drugs with narrow therapeutic range such as warfarin be administered with caution to avoid undesirable drug interaction due to large amount of surfactants contained in SNEDDS.

• Korean Journal of Clinical Pharmacy
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• v.16 no.1
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• pp.57-62
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• 2006

The purpose of this study was to investigate the effect of naringenin, one of flavonoids, on the pharmacokinetics and bioavailability of diltiazem (15 mg/kg) after oral administration of diltiazem with or without naringenin (2.0, 10 and 20 mg/kg) in rabbits. Coadministration of naringenin increased the absorption rate constant $(K_a)$, the area under the plasma concentration-time curve (AUC) and peak concentration $(C_{max})$ of diltiazem compared to the control group, but only significantly (p<0.05) by 10mg/kg of naringenin coadministration. The absolute bioavailability (AB%) of diltiazem by coadministration ranges from 7.8% to 10.3%, increased more than control (7.2%), and relative bioavailability (RB%) of diltiazem is increased from 1.08- to 1.43-fold. Coadministration caused on significant changes in the terminal half-lives $(t_{1/2})$ and the time to reach the peak concentration $(T_{max})$ of diltiazem. On the other hand, coadministration of naringenin increased the AUC desacetyldiltiazem, significantly at the dose of 10mg/kg. But the metabolite ratio (MR) was decreased, significantly at 10mg/kg of naringenin. Based on these results, we can make a conclusion that the increased bioavailability and the significant changes of these pharmacokinetic parameters might be due to naringenin, which possess the potency to inhibit the metabolizing enzyme (CYP3A4) in the liver and intestinal mucosa, and also inhibit the P-glycoprotein efflux pump in the intestinal mucosa.