Simultaneous determination of amantadine and rimantadine by HPLC in rat plasma with pre-column derivatization and fluorescence detection for pharmacokinetic studies

Abstract

We investigated simultaneous high-performance liquid chromatographic (HPLC) determination of amantadine hydrochloride (AMA) and rimantadine hydrochloride (RIM) levels in rat plasma after fluorescent derivatization with o-phthalaldehyde and 2-mercaptoethanol. Afterwards, the method was applied to determine their pharmacokinetics. The retention times of AMA and RIM derivatives were 12.6 and 22.2 min and the lower limits of detection were 0.025 and 0.016 microg/mL, respectively. The coefficients of variation for intra- and inter-day assay of AMA and RIM were less than 5.1 and 7.6%, respectively. After i.v. administration of AMA or RIM to rats, the total body clearance and distribution volume at the steady-state of RIM were higher than those of AMA. Bioavailability of AMA and RIM was 34.9 and 37.2%, respectively. When AMA and RIM were p.o. co-administered, the area under the plasma concentration--time curve of RIM was significantly lower than that after RIM alone. On the other hand, pharmacokinetic parameters of AMA did not significantly change. These results indicate that our HPLC assay is simple, rapid, sensitive and reproducible for simultaneously determining AMA and RIM concentrations in rat plasma and is applicable to their pharmacokinetic studies. Also, co-administration of AMA and RIM may result in the lack of pharmacological effects of RIM.

Simultaneous liquid chromatographic assay of amantadine and its four related compounds in phosphate-buffered saline using 4-fluoro-7-nitro-2,1,3-benzoxadiazole as a fluorescent derivatization reagent

“…Also, our previous results using LC assay after pre-column derivatization with dansyl chloride showed that AMA and 2-ADA derivatives exhibited the same retention times (Higashi et al, 2005a). Thus, there has not been a labeling agent for the simultaneous determination of AMA, 2-ADA, ADAMA, RIM and MEM by HPLC after pre-column derivatization.…”

“…Also, we have developed an HPLC assay that simultaneously measures AMA and RIM after the derivatization with o-phthalaldehyde and 2-mercaptoethanol using 2-ADA as IS (Higashi et al, 2005a). However, our preliminary tests showed that RIM and MEM derivatives with o-phthalaldehyde and these thiol agents co-eluted.…”

High‐performance liquid chromatographic determination of memantine hydrochloride in rat plasma using sensitive fluorometric derivatization

“…Most HPLC methods involved dansyl chloride [4], o-phthalaldehyde (OPA) [10,11], 4-fluoro-7-nitro-2,1,3-benzoxadiazole (NBD-F) [12] and 1-fluoro-2,4-dinitrobenzene (DNFB) [21] as derivatization reagents to react with tricyclic amines. In this study, dansyl chloride, 4-fluoro-7-nitro-2,1,3-benzoxadiazole and 1-fluoro-2,4-dinitrobenzene were tested to react with memantine hydrochloride and we found that FMOC-Cl derivates of memantine hydrochloride had advantages of higher sensitivity, less interference, and simpler reaction conditions than others.…”

“…1) for UV or fluorimetric detection. The assay of tricyclic amines is always performed using precolumn [4,[10][11][12] derivatization methods, or other detections, MS [13,14]. And memantine hydrochloride also has been determined by GC-MS [15] and UPLC [16].…”

Potentiometric Determination of Trace Amounts of Amantadine Using a Modified Carbon-Paste Electrode

“…The HPLC method requires the derivatization of amantadine to produce a chromophore detectable by UV or fluorescence spectroscopy. [3][4][5] The GC method requires the derivatization of amantadine to improve the volatility, and avoid column interactions. 6 The formation step of the derivative compound increases the time of sample preparation and the cost of the methods.…”