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IJPCBS 2014, 4(3), 522-528 MrutyunjayaRaoet al. ISSN: 2249-9504
INTERNATIONAL JOURNAL OF PHARMACEUTICAL, CHEMICAL AND BIOLOGICAL SCIENCES
Research Article
Available online atwww.ijpcbs.com
ASSAY OF TRICLABENDAZOLE IN PHARMACEUTICAL
FORMULATIONS BY VISIBLE SPECTROPHOTOMETRY
1 2 2 2
R.Mrutyunjaya Rao *, C.S.P. Sastry , U.Viplavaprasad and K.Ramakrishna
1
Department of Chemistry, V.S.M.College,Ramachandrapuram - 533255.
E.G.Dt. Andhra Pradesh, India.
2
Foods and Drugs Laboratories, Department of Organic Chemistry Foods, Drugs and Water,
Andhra University, Visakhapatnam-530003, Andhra Pradesh, India.
ABSTRACT
Three simple and sensitive procedures (methods M1, M2 and M3) for the assay of triclabendazole
in pure form and formulations are described. Methods M1, M2 andM3 are based on the selective
redox - reactions of triclabendazole with an excess of oxidant(chloramine T) (CAT) in methodM
1
or NBS in method M or inAM-H SO method M ) in acidic medium. The unreacted oxidant is
2 2 4 3
then estimated calourimetrically by using an oxidisable dye (galocynine GC) in method M ((
1 max
540 nm) Celesta mine blue in method M ( 540 nm) and ammonium molybdate in method M
2 max 3
( 660 nm). The variable parameters in all these methods have been optimized. The results
max
were statistically validated.
Keywords:Triclabendazole. CAT, NBS, CB.
INTRODUCTION EXPERIMENTAL
Triclabendazole (TB) is an antifungal drug. It is Instruments
chemically known as 1H-Benzimidazole, 5- Chloro A Milton Roy spectronic 1201 and systronic 106
–6-(2, 3- dichlorophenoxy), –2-(methyl thio) and digital spectro- photometers were used for the
it is only available in Egypt as oral tablets fasinex spectral and absorbance measurements. An Elico
1-11
(250 mg). A number of methods such as HPLC Li-120 digital pH meter was used for pH
1, 2
and UV were reported for estimation of TB. The measurements.
present paper describes three simple and
sensitive spectrophotometric methods (M , M Reagents and solutions
1 2
andM ) for the determination of TB based on its All the reagents were of analytical grade and all
3
tendency to react with oxidizing agents such as the solutions were prepared in double distilled
CAT (It acts as a selective oxidising agent in both water. Freshly prepared solutions were always
acid and alkaline media14,15). , NBS(It’s more used. Aqueous solution of CAT solution (Loba:
important application is an oxidant and as a -4
0.02%, 7.10 10 M), GC solution (Chroma:
reagent for a number of interesting substitution -4
0.01%, 2.969 10 M) and HCl (E.Merck: 5.0 M)
16, 17
and addition reactions.)and ammonium for methodM N B S Solution(BDH: 0.088%, 4.94
molybdate. They act as selective oxidizing agents -3 1. –
10 M), AcOH solution (Qualigens: 5%; 8.75 10
for the drug triclabendazole. 1M) for method M and Ammonium molybdate
2
-2
solution (BDH: 2%: 5.1 10 M) and H SO (BDH)
2 4
for method M .
3
522
IJPCBS 2014, 4(3), 522-528 MrutyunjayaRaoet al. ISSN: 2249-9504
Standard drug solution After 5 min. the absorbances were measured at
1 mg/ml stock solution of drug (TB) was prepared 540 nm. against distilled water. The blank
by dissolving 100 mg of drug was initially (omitting drug) and dye (omitting drug and
dissolved in 50 ml glacial acetic acid and made up oxidant) solutions were prepared in a similar
to 100 ml with double distilled water. The manner and their absorbances corresponding to
working standard solutions of TB (20 g/ml consumed NBS, and in turn to drug concentration,
method M ; 50g /ml method M and 80 g/ml were obtained by subtracting the decrease in
1 2 absorbance of test solution (dye minus test) from
method M ) were prepared by further diluting the
3 that of the blank solution (dye minus blank). The
stock solution with acetic acid.
calibration graph was drawn by plotting the
Sample drug solution decrease in the absorbance of the dye (CB) against
To compare the results obtained by proposed the amount of the drug. The drug concentration in
methods, the author has developed methodin the the sample was readout from the calibration
laboratory according to literature methods for graph.
determination of TB in pure form as the tablets
Method M
are not available in Indian market. 3
Portions of drug 50 mg was dissolved in 10 ml of Aliquots of the standard drug solution (TB: 0.5-3.0
isopropanol and shaken well and filtered and ml, 50 g.ml-1) were transferred into a series of
removed impurities if any. The filtrate was diluted -
10ml calibrated tubes. Then 1.0 ml of (5.1 10
in isopropanol to get 1 mg /ml. Stock solution was 2M) ammonium molybdate and 4.0 ml of conc.
further diluted as in standard solution H SO were added to each tube and the contents
2 4
preparation. were heated for 20 min. in a boiling water bath.
After cooling, the volume was made up to10 ml
Recommended procedures with ethanol. The resulting absorbance of the
Method M green colour was measured at 660nm against
1
Aliquots of standard drug (TB : 0.5-3.0 ml, 20 similarly prepared reagent blank. The amount of
-1 -4 drug was calculated from its calibration graph.
g.ml ), 1.25 ml 5.0 M HCl and 2 ml of (7.110 M)
CAT solutions were transferred into a series of 25
ml calibrated tubes and the volume in each tube For Pharmaceutical Formulations
was made up to 15.0 ml with distilled water. As the tablets (250 mg) of TB were available only
-4 in Egypt the author has prepared them in the
After 20 min. 10 ml of GC (2.96 10 M) was
12,
added and mixed thoroughly and the absorbances laboratory according to literature methods
were measured after 10 min. at 540 nm against 13.Tablet powder equivalent to 100 mg of TB was
distilled water. Blank was prepared extracted with 320 ml portions of glacial acetic
appropriately. The decrease in absorbance acid and subsequently diluted to 100 ml with
corresponding to consumed CAT, which in turn to acetic acid for Methods M , M andM .
1 2 3
the drug quantity was obtained by subtracting the
absorbance of the blank solution from that of the RESULTS AND DISCUSSIONS
test solution. The calibration graph was drawn by In the present investigations, the author proposes
plotting the decrease in the absorbance of the dye a sensitive indirect spectrophotometric procedure
(GC), against amount of drug. The amount of drug for the determination of TB. The principle
in any sample was computed from its calibration involved in this procedure is quantitative
graph. decolourisation of gallocyanine (GC), by unreacted
CAT. The probable sequences of reaction in two
MethodM steps based on analogy are presented in scheme-1.
2
To the aliquots of the standard drug (TB : 0.5- In the present investigations, the author has
3.0ml, 50 g.ml-1) solution taken in a series of proposed a simple, selective and sensitive
25ml calibrated tubes, 1.25 ml of 5.0 M HCl and spectrophotometric method for the assay of TB
-4 using NBS/CB. This method involves two steps.
2.5 ml. of NBS (5.618 10 M) were added and
the volume was made up to 15 ml with distilled First step (I) is the oxidation of the drug (TB) with
-4 NBS. The second step IIb is the quantitative
water. After 10 min. 10 ml of CB (5.49710 M) decolourisation of CB with the unreacted NBS.
was added to each tube and mixed thoroughly.
523
IJPCBS 2014, 4(3), 522-528 MrutyunjayaRaoet al. ISSN: 2249-9504
TB + CAT Products of oxidation + unreacted CAT
(Excess)
CAT + GC Unreacted dye + mixture of compounds with
(Unreacted) (coloured) rupture of conjugated system
(Corresponds to reacted, colourless not stoichiometric as several alternate pathways possible)
Scheme 1
Step I
TB + NBS Oxidation product of TB + unreacted NBS
(Excess)
Step IIa
+
N H C H N C H
2 3 3
2
-
SO
Unreacted NBS + 4
OH 2 O
PMBQMI
SO NH NCH SO NH
2 2 3 2 2 NCH3
PMBQMI +
H N H O H N H O
SA
Step IIb
Unreacted NBS+ CB Oxidation products of dye + Unreacted CB
(Colourless through disruption (coloured)
ofchromophores and auxochromes)
Scheme 2
524
IJPCBS 2014, 4(3), 522-528 MrutyunjayaRaoet al. ISSN: 2249-9504
The chemistry of molybdenum is complicated. It drug-CAT, CAT-dye does not affect the accuracy of
forms compounds corresponding to oxidation the determination.
numbers +2 to +6. The most stable and commonly
encountered compounds of molybdenum are Method M2 (NBS/CB) for TB
derived from MoO . The molybdenum compounds In order to ascertain the optimum wave length of
3
corresponding to the oxidation states ranging maximum absorption (max) of the final colour
from +2 to +5 are mostly complex species. obtained, a specified amount of the drug (TB) was
Ammonium molybdate in conc. H SO has been taken, maintaining the other parameters as given
2 4
18
used for the determination of amitriptyline HCl . in the recommended procedure as given in
In the present investigation the same reagent has method (M ). The absorption spectra of the test
2
been used for the determination of solution versus distilled water, blank (omitting
triclabendazole. The coloured species formation drug) versus distilled water and dye (CB) versus
appears to be due to reduction of distilled water were scanned on a
isopolyanionicmolybdate species to molybdenum spectrophotometer in the wave length region of
blue. 400-700nm The absorption spectra of the test,
blank and dye solution have shown the maximum
Method M1 (CAT/GC) for TB absorbance at the same wave length. The results
In order to ascertain the optimum wave length of are graphically presented in Fig.2.
maximum absorption ( ) of the final colour
max
existing in the procedure specified amount of drug Method M (AM/H SO ) for TB
3 2 4
TB was taken and preceded as under procedure In order to ascertain the optimum wavelength of
(M ). The absorption spectra of the test solution maximum absorption ( ) of the final colour
1 max
versus distilled water, blank (omitting drug) existing in the procedure (M ) specified amount of
3
versus distilled water and dye (GC) (omitting drug drug (TB) was taken and proceeded as under
and CAT) versus distilled water were scanned on a procedure (M ). The absorption spectra of the
3
spectrophotometer in the wave length region of test solution blank (omitting drug) was scanned
400-700nm. The absorption spectra of the test, on a spectrophotometer in the wave length the
blank and dye solution have shown the maximum region of 400-800nm. These results are
absorbance at the same wave length shown and graphically presented in Fig. 3.The coloured
these results are graphically presented in Fig.1. species in each method shows characteristic
Similarly in the nature of spectra indicated that absorption maximum at 660nm for both TB.
the product formed, because of interaction of
525
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