الفهرس 
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Abstract
Chapter I
This chapter includes a general introduction on the drugs investigated in the thesis. Four amino group-containing drugs prescribed for the treatment of various central nervous system disorders were selected, namely; gabapentin, lamotrigine, memantine hydrochloride and pramipexole dihydrochloride monohydrate. The chemical structures, physicochemical characteristics, pharmacological actions and therapeutic uses of the aforementioned drugs were illustrated in this chapter. In addition, an up-to-date literature review of the analysis of the studied drugs in biological fluids and in pharmaceutical dosage forms was given.
Chapter II
It deals with the derivatization of memantine hydrochloride using two reagents: 4-chloro-7-nitro-2,1,3-benzoxadiazole and o-phthalaldehyde in the presence of N-acetyl-L-cysteine. The reaction of the drug with the former reagent was carried out at 90 °C in borate buffer pH 8.6. The reaction conditions were optimized and the yellow-orange colored product was measured spectrophotometrically at 476 nm. Moreover, upon dilution with acetone, it exhibits maximum fluorescence intensity at 500 nm when excited at 455 nm. On the other hand, the reaction of the drug with o-phthalaldehyde/ N-acetyl-L-cysteine reagents in borate buffer pH 9.6 at room temperature was studied and reaction conditions were optimized. The colored product was measured spectrophotometrically at 340 nm. The applicability of the developed methods was evaluated through the determination of memantine hydrochloride in commercially available tablets. The results obtained were compared with those obtained from a reference method.
Chapter III
In this chapter, the reaction of memantine hydrochloride with o-phthalaldehyde in the presence of N-acetyl-L-cysteine was extended to the development of a high performance liquid chromatographic method for the determination of the investigated drug in human urine. The drug and amantadine hydrochloride, the internal standard, were extracted from urine using a simple, neat and fast solid phase extraction procedure. The extract was derivatized using the above reagents in borate buffer pH 9.6 and the produced derivatives were chromatographed on an octadecyl column after being injected into the chromatographic system. Separation was achieved isocratically using a mobile phase of water-methanol (65:35 v/v) with the UV/VIS detector set at 340 nm. The developed assay was linear over the final concentration range of 0.02-4 μg/mL. Memantine hydrochloride is excreted mainly unchanged in human urine; therefore, the method was applied for its determination in real life human sample following the administration of a 10 mg tablet to a healthy volunteer. The described assay was able to track the unchanged drug in urine over 72 h.