The Bioequivalence of Two Carbamazepine Controlled Release Formulations

카르바마제핀 서방형 제제간의 생물학적 동등성 비교

Carbamazepine is an anticonvulsant drug that has been shown to be as effective as phenytoin or phenobarbital in treatment of grand mal and complex partial seizures and is also approved as the drug of choice for treatment of the pain associated with trigerminal neuralgia. And the therapeutic or toxic effects of carbamazepine are better related to plasma concentration than to dosage, which can be attributed to interindividual variability in the pharmacokinetics. A slow rate of carbamazepine dissolution in the gastrointestinal tract is believed to be the cause of its relatively slow and erratic rate of absorption. For these reasons pharmacokinetic evaluation of newly formulated carbamazepine is neccessary. In this study, the bioequivalence in carbamazepine between the $TegretoI^{TM}$ CR tablet (Geigy Co.) and $Carmazepine^{TM}$ CR tablet (Myung In Co.) was evaluated. 12 normal volunteers (age $21\~27$ years old) was divided into two groups, and a randomized cross-over study was employed. The pharmacokinetic parameters ($C_{max},\;T_{max}$ and AUC) obtained of oral administration of each formulatim of carbamazepine 400 mg were evaluated and ANOVA was utilized for the statistical analysis of parameters. $C_{max}\;is\;8.26{\pm}3.1{\mu}g/ml\;(C.V.\;37.3\%)\;in\;TegretoI^{TM}\;and\;9.39\{pm}2.9{\mu}g/ml\;(C.V.\;30.5\%)$ in $Carmazepine^{TM},\;T_{max}\;is\;28.0{\pm}5.9\;hrs(C.V.\;21.1\%)$ in $Tegretol^{TM}\;and\;24.0{\pm}7.2\;hrs(C.V.\;30.2\%)$ in $Carmazepine^{TM}$ and AUC is $786.4{\pm}360.5{\mu}g{\cdot}hr/ml\;(C.V.\;45.8\%)$ in $TegretoI^{TM}\;and\;792.8{\pm}228.6{\mu}g{\cdot}hr/ml\;(C.V.\;28.8\%)$ in $Carmazepine^{TM}$, respectively. As the result of the data, two formulations are bioequvalent, and the lower C.V. of $Carmazepine^{TM}$ in every individual can be merit.