• Korean Journal of Clinical Pharmacy
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• v.13 no.1
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• pp.13-17
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• 2003

This study was carried out to compare the bioavailability of $Ceclex^{(R)}$ SR TAB (test drug, cefaclor 375 mg/Tablet) with that of Ceclor $MR^{(R)}$ SR IAB (reference drug) and to estimate the pharmacokinetic parameters of cefaclor in healthy Korean volunteers. The bioavailability was examined on 24 healthy volunteers who received a single dose (375 mg) of each drug in the fasting state in a randomized balanced 2-way crossover design. After dosing, blood samples were collected for a period of 7 hours. Plasma concentrations of cefaclor were determined using HPLC with UV detection. The pharmacokinetic parameters $(AUC_{0-7h},\;C_{max},\;T_{max},\;AUC_{inf},\;K_e,\;t_{1/2},\;V_d/F,\;and\;CL/F)$ were calculated with non-compartmental pharmacokinetic analysis. The ANOVA test was utilized for the statistical analysis of the $T_{max}$, log-transformed $AUC_{0-7h$}$, log-transformed $C_{max},\;t_{1/2},\;V_d/F$, and $CL/F$. The ratios of geometric means of $AUC_{0-7h}\;and\;C_{max}$ between test drug End reference drug were $95.67\%\;(8.55\;vs\;8.18{\mu}g{\cdot}hr/ml)\;and\;103.86\%\;(2.85\;vs\;2.96{\mu}g/ml)$, respectively. The $T_{max}$ of test drug and reference drug was $2.56\pm0.15\;and\;2.23\pm0.13\;hrs,\;respectively.\;The\;90\%$ confidence intervals of mean difference of logarithmic transformed $AUC_{0-7h}\;and\;C_{max}$ were log0.90-log1.04 and log0.91-log1.13, respectively. It shows that the bioavailability of test drug is equivalent with that of reference drug.

• Journal of Pharmaceutical Investigation
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• v.34 no.6
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• pp.513-519
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• 2004

A sensitive method for quantification of pinaverium bromide in human plasma was established using liquid chromatography-electrospray ionization tandem mass spectrometry(LC-ESI-MS/MS). Glimepiride was used as internal standard. Pinaverium bromide and internal standard in plasma sample were extracted using tert-butylmethylether(TBME). A centrifuged upper layer was then evaporated and reconstituted with mobile phase of acetonitrile-5 mM ammonium formate (80/20, pH 3.0). The reconstituted samples were injected into a $C_{18}$ reversed-phase column. Using MS/MS with multiple reaction monitoring (MRM) mode, pinaverium and glimepirde were detected without severe interference from human plasma matrix. Pinaverium produced a protonated precursor ion $([M+H]^+)$ at m/z 510.3 and a corresponding product ion at m/z 228.9. Internal standard produced a protonated precursor ion $([M+H]^+)$ at m/z 491.5 and a corresponding product ion at m/z 352.0. Detection of pinaverium bromide in human plasma was accurate and precise, with limit of quantitation at 0.5 ng/ml. The method has been successfully applied to bioavailability study of pinaverium bromide tablet in Korean healthy male volunteers. Pharmacokinetic parameters such as $AUC_t,\;C_{max},\;T_{max},\;K_{el}\;and\;t_{1/2}$ were calculated.

• YAKHAK HOEJI
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• v.39 no.6
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• pp.636-644
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• 1995

Comparison of bioavailabflity (BA) of three brands of ranitidine (RT) tablets has been studied m rats. The purpose of this study was to characterize the pharniacolunetics of RT tablets in the rat and to coinpare phannacolunetic parameters of three brands of RT tablets. In addition, it was investigated whether plasma RT concentrations m humans can be predicted from pharmacokinetic parameters obtained in rats. RT was administered intravenously in dose of RT.HCI 10mg/kg and orally in dose of RT.HCI 50mg/kg as solution or crushed sample of thablets. Plasma RT concentrations were determned by HPLC. Plasma RT concentrations as a function of time were fitted to two compartment model. Plasma RT concentrations declined with a terminal half life ($t_{{1}/2{\betha}}$) of 40.9 min. The plasma RT concentration-time curve showed two peak plasma concentrations following an oral administration of solution or crushed sample in rats like humans. No significant difference among pharmacokinetic parameters was observed except $T_{max2}$ (p<0.05). The BA for crushed sample A, B and C were found to be 54.6 40.7 and 40.0%, respectively. Equivalence of $C_{max1}$ and $T_{max2}$ were guaranteed in this study. However, it was concluded that three brands of RT tablets are bioequivalent, taking the following characteristics of RT into consideration;(1) rapid onset of the effect is not required, (2) $C_{max1}$ and $T_{max2}$ do not seem to influence the effectiveness of the drug during a long-term treatment by the usual administration of twice a day. Results from this study were combined with plarmacokinetic data for RT in dogs and humans to develop a basis for interspecies scale-up of the disposition characteristics of the drug. there were similarities in the general disposition of the drug. Allometric relationships were sought between pharmacokinetic parameters nd species body weight. Significant interspecies correlations were found for total body clearance($Cl_{t}$) and steady state volume of distribution ($Bd_{ss}$). Thus, plasma RT concentrations in humans can be predicted from pharmacokinetic parameters obtained in rats.

• YAKHAK HOEJI
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• v.50 no.2
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• pp.118-123
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• 2006

The aim of this study was to investigate the effect of fluvastatin on the pharmacokinetics of diltiazem and its active metabolite, desacetyldiltiazem, in rats. Pharmacokinetic parameters of diltiazem and desacetyldiltiazem were deter-mined after an oral administration of diltiazem (15 mg/kg) to rats pretreated with fluvastatin (0.5 and 1.5 mg/kg). Compared with the control (given diltiazem alone), the pretreatment of fluvastatin significantly (p<0.05) increased the area under the plasma concentration (AUC), peak plasma concentration $(C_{max})\;and\;K_a$ of diltiazem. Relative bioavailability $(RB\%)$ of diltiazem increased from 1.36- to 1.55-fold. However there were no significant changes in $t_{max},\;K_{el}\;and\;t_{1/2}$ of diltiazem. The pretreatment of fluvastatin also altered the pharmacokintic parameters of desacetyldiltiazem. The pretreatment of fluvastatin (1.5 mg/kg) significantly (p<0.05) increased the AUC of desacetyldiltiazem, whereas the metabolite parent ratio (MR) of desacetyldiatlazem was decreased significantly (p<0.05), suggesting that fluvastatin might inhibit the metabolism of diltiazem. The pretreatment of fluvastatin enhanced the bioavailability of diltiazem in a dose dependent manner at doses ranging from 0.5 to 1.5 mg/kg. further studies for the drug Interaction will be needed in the clinical trials when dilitazem is administrated concomitantly with fluvastatin in humans.

• Archives of Pharmacal Research
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• v.29 no.1
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• pp.102-107
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• 2006

The aim of present study is to investigate the effect of naringin on the pharmacokinetics of verapamil and its major metabolite, norverapamil in rabbits. The pharmacokinetic parameters of verapamil and norverapamil were determined after administering verapamil (9 mg/kg) orally to rabbits in the pretreated with naringin (1.5, 7.5, and 15 mg/kg). Naringin pretreatment significantly altered the pharmacokinetic parameters of verapamil. Compared with the control group (given verapamil alone), the $K_a,\;C_{max}$ and AUC of verapamil were significantly (p<0.05 or p<0.01) increased in the pretreatment of naringin, However there were no significant change in $T_{max}\;and\;t_{1/2}$ of verapamil. Consequently, pretreatment of naringin significantly (p<0.05, p<0.01) increased the AB% of verapamil significantly in a dose dependent manner (p<0.05 or p<0.01 ), and elevated the RB% of verapamil by 1.26- to 1.69-fold. the MR of verapamil were significantly (p<0.05) increased in the pretreatment of naringin, implying that pretreatment of naringin may effectively inhibit the CYP3A4-mediated metabolism of verapamil. In conclusion, pretreatment of naringin enhanced the oral bioavailability of verapamil. Based on these results, the verapamil dosage should be adjusted when given with naringin or a naringin-containing dietary supplement.

• Biomolecules & Therapeutics
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• v.18 no.2
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• pp.226-232
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• 2010

The aim of this study was to investigate the effect of atrovasatatin on the pharmacokinetics of nicardipine after oral and intravenous administration of nicardipine to rats. Nicardipine was administered orally (12 mg/kg) or intravenously (i.v., 4 mg/kg) without or with oral administration of atrovasatatin (0.3 or 1.0 mg/kg) to rats. The effect of atorvastatin on the P-glycoprotein (P-gp) as well as CYP3A4 activity was also evaluated. Atorvastatin inhibited CYP3A4 enzyme activity in a concentration-dependent manner with 50% inhibition concentration ($IC_{50}$) of 48 ${\mu}M$. Compared to the controls (nicardipine alone), the area under the plasma concentration-time curve (AUC) of nicardipine was significantly (1.0 mg/kg, p<0.05) greater by 16.8-45.4%, and the peak plasma concentration ($C_{max}$) was significantly (1.0 mg/kg, p<0.05) higher by 28.0% after oral administration of nicardipine with atorvastatin, respectively. Consequently, the relative bioavailability (R.B.) of nicardipine was increased by 1.17- to 1.45-fold and the absolute bioavailability (A.B.) of nicardipine with atrovasatatin was significantly greater by 16.7-20.9% compared to that of the controls (14.3%). Compared to the i.v. control, atrovasatatin did not significantly change pharmacokinetic parameters of i.v. administration nicardipine. The enhanced oral bioavailability of nicardipine by atorvastatin suggests that CYP3A subfamily-mediated metabolism were inhibited in the intestine and/or in the liver rather than P-gp-mediated efflux of nicardipine. Based on these results, modification of nicardipine of dosage regimen is required in the patients. Human studies are required to prove the above hypothesis.

• YAKHAK HOEJI
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• v.36 no.6
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• pp.598-603
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• 1992

The purpose of this study was to assess the effect of three formulations; product A (polyethylene glycol was used as a main dispersing agent), product B (wax mixture was used as a main dispersing agent) and product C(silicon dioxide was used as a main dispersing agent) on bioavailability of acetaminophen soft gelatin capsules(softgels) and to develop an effective acetaminophen softgel which exhibits an excellent bioavailability. Acetaminophen softgels of various formulations were prepared as 4 minim round type by rotary die method. Four softgels of the three formulation (A, B, C), each of which contained 50 mg acetaminophen, were administered orally to 12 normal healthy rabbits using a three-way cross over design. Plasma acetaminophen concentrations were measured by HPLC. The results obtained in this study were as follows: 1. The Tmax rank order of acetaminophen softgel was C$(63.75{\pm}10.62\;min)$>A$(36.25{\pm}5.37\;min)$>B$(35{\pm}6.74\;min)$. 2. The decreasing Cmax order of softgel product was A$(93.51{\pm}0.55\;{\mu}g/ml)$>B$(3.16{\pm}0.37\;{\mu}g/ml)$>C$(2.6{\pm}0.55\;{\mu}g/ml)$. 3. The $[AUC]^{\infty}_0$ rank order for three acetaminophen softgel formulations was A $(14.89{\pm}1.56\;{\mu}g/ml{\cdot}min)$ >B$(14.39{\pm}1.43\;{\mu}g/ml{\cdot}min)$>C$(11.45{\pm}1.49\;{\mu}g/ml{\cdot}min)$. 4. Pharmacokinetic parameters such as Tmax, Cmax and $[AUC]^{\infty}_0$ of product A and B did not differ significantly(p>0.05). On the other hand, those of product C were significantly different(p>0.05).

• Biomolecules & Therapeutics
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• v.18 no.3
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• pp.343-349
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• 2010

This study was designed to investigate the effects of ticlopidine on the pharmacokinetics of carvedilol after oral or intravenous administration of carvedilol in rats. Carvedilol was administered orally (3 mg/kg) or intravenously (1 mg/kg) without or with oral administration of ticlopidine (4, 12 mg/kg) to rats. The effects of ticlopidine on P-glycoprotein (P-gp) and cytochrome P450 (CYP) 2C9 activity were also evaluated. Ticlopidine inhibited CYP2C9 activity in a concentration-dependent manner with 50% inhibition concentration ($IC_{50}$) of $25.2\;{\mu}M$. In addition, ticlopidine could not significantly enhance the cellular accumulation of rhodamine 123 in MCF-7/ADR cells overexpressing P-gp. Compared with the control group (given carvedilol alone), the area under the plasma concentration-time curve (AUC) was significantly (12 mg/kg, p<0.05) increased by 14-41%, and the peak concentration ($C_{max}$) was significantly (12 mg/kg, p<0.05) increased by 10.7-73.3% in the presence of ticlopidine after oral administration of carvedilol. Consequently, the relative bioavailability (R.B.) of carvedilol was increased by 1.14- to 1.41-fold and the absolute bioavailability (A.B.) of carvedilol in the presence of ticlopidine was increased by 36.2-38.5%. Compared to the i.v. control, ticlopidine could not significantly change the pharmacokinetic parameters of i.v. administered carvedilol. The enhanced oral bioavailability of carvedilol may result from inhibition of CYP2C9-mediated metabolism rather than P-gpmediated efflux of carvedilol in the intestinal and/or in liver and renal eliminatin of carvedilol by ticlopidine.

• Journal of Pharmaceutical Investigation
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• v.22 no.2
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• pp.125-131
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• 1992

The effects of domperidone, scopolamine butylbromide and cimetidine on the absorption and bioavailability of ciprofloxacin were studied in female rats. Ciprofloxacin was given in a single oral dose of 30 mg/kg to control group. Ciprofloxacin was concurrently administered with domperidone $(T_1\;group)$, scopolamine butylbromide $(T_2\;group)$, and cimetidine $(T_3\;group)$ to rats, respectively. Significantly changed pharmacokinetic parameters observed in $T_2$group when compared with control group were first-order absorption rate constant, $Ka(4.43{\pm}0.85$\;versus\;2.86{\pm}0.41\;hr^{-1},\;p<0.05)$, time needed to reach peak concentration, $T_{max}\;(32.27{\pm}2.46\;versus\;51.75{\pm}5.51\;min,\;p<0.05)$, area under the plasma concentration-time curve, AUC $(332{\pm}19\;versus\;477{\pm}27\;{\mu}g{\cdot}min/ml,\;p<0.05)$ and absolute bioavailability, Fabs $(60.6{\pm}3.6\;versus\;87.0{\pm}5.0%,\;p<0.05)$. On the other hand, domperidone and cimetidine did not significantly affect the absorption of ciprofloxacin. It is suggested that when scopolamine butylbromide is selected for clinical use, there is need for awareness of the reduction in absorption rate and the enhancement in absorption extent of ciprofloxacin.

• Journal of Pharmaceutical Investigation
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• v.25 no.1
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• pp.19-29
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• 1995

The study was carried out to develop useful formulation for omeprazole(OMP) through OMP-ethylendiamine complex(OMPED), and the pharmaceutical properties of formula were tested to find out the difference in vivo behaviors of formulations between the free and complexed OMP. Oral and suppository dosage forms were also formulated and the dissolution profiles and pharmacokinetic parameters were measured to observe the difference in bioavailability between the free and complex form, and the correlation between dissolution rate and bioavailability was evaluated. The results are summarized as follows; In the case of formulation for oral administration, the release of OMP from enteric OMPED pellets was found satisfactory to the requirement standard and no decomposition of OMP in the pellets was found in acidic solution. Therefore the enteric OMPED pellets are anticipated to be a stable formulation. The release of OMP from OMPED tablet with chitosan as excipient and coated with cellulose acetate phthalate was found to be significantly retarded. The results of bioavailability test for OMP and OMPED tablets with lactose-excipient showed that the AUC value of OMP tablet was $116.89\;{\mu}g\;{\cdot}\;min/ml$, that of OMPED tablet was $161.10\;{\mu}g\;{\cdot}\;min/ml$, respectively. The reason why was thought that OMP decomposes more readily in body than OMPED, and the AUC of the tablet with chitosan-excipient and coated with cellulose acetate phthalate was most enhanced. In the case of bioavailability for suppositories with OMP, $OMP-{\beta}\;-cyclodextrin$ complex and OMPED, the AUC of OMPED suppository was most increased. From the above results, it is thought that the more stable and bioavailable oral or rectal dosage forms could be developed by using the OMPED as a potential OMP complex.