• Journal of Pharmaceutical Investigation
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• v.33 no.4
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• pp.311-317
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• 2003

Felodipine is a calcium antagonist that lowers blood pressure by reducing peripheral resistance by meas of a direct, selective action on smooth muscle in arterial resistance vessels. Futhermore, it have been approved for the effective in angina pectoris and cardiac failure. The purpose of the present study was to evaluate the bioequivalence of two felodipine extended release (ER) tablets, Splendil (YuHan Corporation) and Stapin (Hana Pharmaceutial Co., Ltd.), according to the guidelines of Korea Food and Drug Administration (KFDA). The felodipine release from the two felodipine formulations in vitro was tested using KP VIII Apparatus II method at pH 6.5 buffer solution. Twenty six healthy male subjects, $22.73{\pm}1.78$ years in age and $66.66{\pm}7.28\;kg$ in body weight, were divided into two groups and a radomized $2{\times}2$ cross-over study was employed. After two tablets containing 5 mg as felodipine were orally administered, blood sample was taken at predetermined time intervals and the concentrations of felodipine in serum were determined using column-switching HPLC method with UV detector. The dissolution profiles of two formulations were similar at pH 6.5 buffer solution. Besides, the pharmacokinetic parameters such as $AUC_t,\;C_{max}\;and\;T_{max}$ were calculated and ANOVA test was utilized for the statistical analysis of the parameters using logarithmically transformed $AUC_t\;and\;C_{max}$ and untransformed $T_{max}$. The results showed that the differences between two formulations based on the Splendil were 2.53%, 1.32% and 18.32% for $AUC_t,\;C_{max}\;and\;T_{max}$, respectively. There were no sequence effects between two formulations in these parameters. The 90% confidence intervals using logarithmically transformed data were within the acceptance rage of log(0.86) to log(1.25) $(e.g.,\;log(0.86){\sim}log(1.20)\;and\;log(0.89){\sim}log(1.23)\;for\;AUC_t,\;C_{max},\;respectively)$. Thus, the criteria of the KFDA guidelines for the bioequivalence was satisfied, indicating Stapin ER tablet and Splendil ER tablet are bioequivalent.

• Journal of Pharmaceutical Investigation
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• v.37 no.3
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• pp.193-196
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• 2007

This study aimed to evaluate and develop $Eudragit^{(R)}$-coated pellets based on the dissolution using the paddle method. As coating materials, two types of $Eudragit^{(R)}$ were applied to obtain either sustained release form or fast released form. The dissolution test was carried out in phosphate buffer solution (pH 6.5) at $37^{\circ}C$, 100 rpm. In order to develop a sustained release preparation containing felodipine, a comparative dissolution study was done using commercial product as a control. The dissolution at 30 min of felodipine from $Eudragit^{(R)}$ RS or RL-coated pellets were 0.96% and 99.65, respectively. The weight ratio of $Eudragit^{(R)}$ RL pellets to RS pellets altered the dissolution rate, but did not optimize the dissolution rate. However, the sustained dissolution of felodipine from pellets was optimized by varying the coating ratios of $Eudragit^{(R)}$ RS. It is suggested that the coating ratio of pellets is the main factor which controls dissolution rate. Taken together, $Eudragit^{(R)}$ RS 30D-coated pellets showed the most comparable dissolution rate pattern to commercial product, $Splendil^{(R)}$. This sustained release pellets for oral delivery system of felodipine was simply manufactured, and drug release behavior was highly reproducible.