الفهرس 
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Abstract
The thesis comprizes General Introduction, Review of Literature, and Experimental Sections including Results and
Discussion.
The main topic of the thesis concerns the analysis of some basic drugs utilizing ,oha:I::ge-transfer (C-T) complexa-.
tion. Basic drugs containing saturated or unsubstituted
aromatic structures are often characterized by UV-absorpt-
ion bands which are unsuitable for analytical purposes.
This is due to the low probability Rnd short wavelength natt•
utre of the n- d transition of the amine moiety. CT comp-
lexes of amines vdth electron acceptors such as iodine are
characterized by large association constants and high molar
absorptivities. This fact was utilized in a sensjtive specttrophotometric assay of these basic drugs.
Solutions of amines in non-polar solvents (e.g. u” hexane) when mixed with iodine exhibited intense CT-bands in 260-
305 nm range. Molar ratio of iodine-amine in the complex was found to be 1:1 for the two drugs tested (benzylamine and methenamine) irrespective of their mono or polybasic
nature.
In more polar solvents (e.g. dichloroethane), the original
1touterli CT-complex underwent one electron transfer to yield
radicalfuns including the triiodide anion with its strong
Variations of amine structure (alkyl substitution.
hydrogen bonding, steric and stereochemical
E?ffects) was
.found to have a great infl’.J.c.nce on the yield of triiodide aninn. The basic drugs examined includ e both pharmaceuttical (methenamine, pethidine, methylphenidate, phentermine, tranylcypromine, codeine and ephedrine) and nonical amines (benzylamine, N-methylpiperidine. Npiperazine and m-xylene oL - a< d iamine) •
The effects of different experimental variables such as iodine”’ concentration, time and temperature on the rate and’extent of C-T complexation have been also worked out. Other sigma acceptors were also investigated including
bromine and iodine monochloride.
With constant iodine concentration (lXIO-4U),the intennsity of the 295-nm-band was found Jl:i.:18~J:l:7 related to amine concentration in the 1-25 ~g/ml range. The original A value (1%, 1 cm ) of uncomplexed basic drugs showed apparent increases in the triiodide band of up to 100 times the original values. This was reflected in proportionate incr-
. v,
eases in sensitivity (limit l~g/ml), accuracy and precision
upon quantifioation. The proposed method was applied to
, analyze single oomponent preparations as well as combination dosage forms of methenamine and pethidine as representatives with the same sensitivity, accuracy and preoision.
For methenamine analysis. two oolorimetric methods and
a non-aqueous titration technique were included in addi~n t,
the proposed C-T method.
•
For mixtures of weak and strong UV~absorbing amines a differential procedure was adopted based on measuring the
uncomplexed stronger absorbing component inabinary mixture
(papaverine or tripelennamine) at 335 or 315 nm respect-
ivelY.This ~ followed by measurement of total amines in the
mixture via the intensity of the 295 nm- triiodide band~
....••..•
Simple computation gave the concentration of weaker absorbing component in the binary mixture.
In the concluding
part of this tteois a preliminary
investigation has been done
~u~arding the utility of the
pi-acceptors TCNQ & TCNE in quantit~~tive analysis using
either dichloroethane or acetonitrile as solvents The meas-
ured chromogens were TCNQ• radical-anion and the hydrolytic
product of TCl~, the pentacyanopropenide.anions respectively.