Indo American Journal of Pharmaceutical Research, 2021 ISSN NO: 2231-6876

DEVELOPMENT AND VALIDATION OF FT-IR SPECTROPHOTOMETRIC

METHOD FOR SIMULTANEOUS ESTIMATION OF DICLOFENAC SODIUM AND
RABEPRAZOLE SODIUM IN TABLET DOSAGE FORM
Anitha K*1, N. T. Rangari2, T.M. Kalyankar3 and V. Y. Patil 3
1
Department of Chemistry, Sri Krishnadevaraya University, Ananthapuram - 515003, Andhra Pradesh, India.
2
KJs Educational Institute, Trinity College of Pharmacy, Yewalewadi, Pune-411048 Maharashtra, India.
3
Department of Quality Assurance, School of Pharmacy, S. R. T. M. University, Vishnupuri, Nanded, Maharashtra 431606, India.

ARTICLE INFO ABSTRACT

Article history For the purpose of performing simultaneous determinations of diclofenac sodium and
Received 12.06.2021 rabeprazole sodium in tablet dosage form, an easy-to-use, cost-effective, accurate, precise and
Available online validated diffuse reflectance infrared fourier transform spectroscopy method has been
30.08.2021 developed. Measurement of the spectral wave number of the infrared band corresponding to
the NH2 group stretch at 3388 cm-1 for diclofenac sodium and the S=O group at 1274 cm-1 for
Keywords rabeprazole sodium is included in the newly developed approach. The approach was found to
Diclofenac Sodium (DCL), be linear over the range of 1%-6% weight by weight for diclofenac sodium and 0.2%-1.2%
Rabeprazole Sodium (RAB), weight by weight for rabeprazole sodium, and demonstrated a correlation coefficient (r2) of
FT-IR, ICH guidelines. 0.991 and 0.991, respectively. The method that was developed was validated to ensure that it
met the requirements set forth by the ICH regarding linearity, precision, accuracy, limit of
detection, and limit of quantitation. In addition to this, the behaviours of deterioration of the
solid state of diclofenac sodium and rabeprazole sodium were investigated by exposing them
to photolysis, sunlight and thermal degradation.

Corresponding author
Dr. Anitha K.
Department of Chemistry,
S. K. University, Ananthapuram - 515003,
Andhra Pradesh, India
Phone No: +91–9951406931
Email address: anitbios@gmail.com

Please cite this article in press as Anitha K et al. Development and validation of FT-IR spectrophotometric method for
simultaneous estimation of diclofenac sodium and Rabeprazole sodium in tablet dosage form. Indo American Journal of
Pharmaceutical Research.2021:11(08).
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Copy right © 2021 This is an Open Access article distributed under the terms of the Indo American journal of Pharmaceutical
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Research, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
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Vol 11 Issue 08, 2021. Anitha K. et al. ISSN NO: 2231-6876

Introduction
Chemically, diclofenac sodium is known as Sodium-2-[2-(2,6 dichloroanilino)phenyl]acetate. In addition to
treating osteoarthritis, rheumatoid arthritis, and ankylosing spondylitis. It is also used to treat a wide range of
other inflammatory conditions that are not related to rheumatoid arthritis (1-3).
Thechemicalnameforrabeprazoleis 2-([4-(3-Methoxypropoxy)-3-methyl-2 pyridyl]methylsulfinyl)-1H-
benzimidazole sodium. It is classified as an example of an inhibitor of the proton pump.
Atthesecretorysurfaceofthestomachparietalcell,itdoesthisviablockingtheH+/K+-
ATPaseenzymesystem.Thisbringsinareductioninthequantityofgastricacidthatissecretedasaconsequence.
Clinically, rabeprazole is administered to patients suffering from acid-peptic diseases such esophageal, gastric
and duodenal ulcers in order to promote healing, alleviate symptoms and avoid relapse [4].

Na+

O O

H3C

HN Na
N O H3C O O

Cl Cl S

Figure1: Structure of Diclofenac sodium Figure2: Structure of Rabeprazole sodium

A review of the relevant literature revealed that, various reports of individual estimation of rabeprazole from its
formulations including, the stability of rabeprazole in aqueous media [5], analytical methods including HPLC
[6], UV [7], determination of the enantiomeric configuration [8] and photodegradation products estimation by
UV and HPLC [9,10] have been reported. A study of the relevant literature indicated that there are few reports
on analytical methods for estimating individual drug diclofenac from formulations using methods such as
potentiometric and fluorimetric determination [11]. In spite of this, there were no methods that had been
published up until this point for the simultaneous determination of both drugs through the use of FT-IR
spectroscopy as a tool for simultaneous estimation. The development of a novel FT-IR method for the routine
analysis of diclofenac sodium and rabeprazole sodium in combined tablet dosage form is the aim of the
research work.

Materials and methods

Apparatus and instruments:
The FT-IR spectrophotometer known as the IR-Affinity-1, which was made in Japan by Shimadzu Corp., was
the instrument that was utilised for the objectives of data collecting and analysis. This instrument had a diffuse
reflectance sampling interface built into it, and it was connected to a computer that had Shimadzu IR solution
software running on it. In addition to this, it makes use of a high-energy, long-life ceramic light source and is
fitted with a DLATGS detector. The FT-IR spectra were acquired throughout the entire range of 400-4000 cm-1
using 45 scans and a resolution of 8 cm-1 during the entire process. Analytical weighing balance: A named,
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model AA-2200. [Max. 200 g, Min. 0.01 g; e = 0.0001 g].

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Chemical and reagent:

Wockhardt Pvt. Ltd. in Aurangabad was kind enough to provide us with working standard drug sample as
gift sample. R-Clonac, a commercially available formulation consisting of diclofenac sodium 100 mg and
rabeprazole sodium 20 mg, was acquired from local market. As the working diluent, pure KBr of
analytical grade was utilised and throughout the process, only calibrated glassware was utilised.

Preparation of working standard:

Pure drugs weighing 10 milligrammes of diclofenac sodium and 2 milligrammes of rabeprazole sodium
accurately were combined with 990 milligrammes and 998 milligrammes of KBr (of spectrometric grade)
and thoroughly triturated in order to produce a homogenous combination.

Selection of analytical wave number:

Both drugs' working standard of concentrations 1% and 0.2% w/w were scanned in the infrared range of
4000-400 cm-1, with a resolution of 4 scans and 45 scans respectively. The wave number was chosen
accordingly, in order to eliminate the possibility of interference caused by one drug with another, so that
one functional group of one drug should not be present in another drug. The NH2 functional group was
chosen for the DCL, and the wave number that was determined was 3388 cm -1. The S=O functional group
was chosen for RAB, and the wave number that was discovered was 1274 cm-1.

Figure3: FT-IR Spectrum of DCL

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Figure4: FT-IR spectrum of RAB

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Figure 5: FT-IR spectrum of overlain spectra of standard DCL and RAB

Selection of analytical concentration range and linearity study:

In order to achieve concentrations ranging from 1-6% w/w and 0.2-1.2% w/w for DCL and RAB,
respectively, pure drug samples of both RAB and DCL were diluted with KBr. Using KBr as a blank, we
were able to determine that the peak intensity of these dilutions fell somewhere between 3388 cm-1 for
DCL and 1274 cm-1 for RAB. It was found that a linear relationship existed when peak intensity was
plotted versus concentration was plotted.

Figure 6: Calibration curve of DCL

Figure7: Calibration curve of RAB

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Analysis of marketed tablet formulation:

Twenty tablets of the formulation that is available commercially were measured to a high degree of
accuracy, and the average weight of those tablets was computed. After that, these tablets were ground into
a fine powder, and then out of that powder, a quantity was taken that weighed equivalent to 10 mg of
DCL and 2 mg of RAB. After combining it with 988 mg of KBr, the resulting dilution for DCL was found
to be 1% w/w, whereas the dilution found for RAB was 0.2% w/w.

Figure 8: FT-IR spectra of Tablet excipients and formulation

Figure 9: FT-IR overlain of tablet excipients and standard drug of DCL and RAB
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Figure 10: FT-IR overlain of tablet excipients

Method Validation
Linearity:
In order to conduct the linearity investigation, standard dilutions of 1, 2, 3, 4, 5 and 6% w/w were prepared for
DCL, and 0.2, 0.4, 0.6, 0.8, 1 and 1.2% w/w were prepared for RAB. After doing so, for each concentration the
calibration graph was plotted, as the concentration versus the intensity of the DCL and RAB, respectively. The
linearity of the suggested technique was determined to be in between 1-6% w/w for DCL and between 0.2-
1.2%w/wforRAB.
Precision:
Inter-day and intra-day variation studies were conducted in order to evaluate the method's level of precision.
When conducting intraday investigations, working dilutions of the sample were evaluated in triplicate within a
single day and the percentage relative standard deviation (% RSD) was computed.
For the purpose of carrying out the calculation, Formula 1 was utilised.
-------- (1)
Accuracy:
In accordance with the guidelines provided by the ICH, the recovery studies were conducted at three distinct
levels: 80%, 100%, and 120%. This was done so that the accuracy of the proposed methods could be
determined.
The tablet is said to have 100 mg of DCL and 20 mg of RAB, as per label claim. When conducting recovery
studies, various levels of the standard concentration, based on 80%, 100%, and 120%, are created, and the %
mean recoveries are determined. The material was carefully combined before being examined. The percentage
of recovery was determined by applying the formulas 2 and 3.
--------- (2)

------------------------ (3)

LOD AND LOQ:

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The ICH guideline outlines multiple methodologies that can be utilised to ascertain the detection and
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quantitation thresholds. A visual inspection, a signal-to-noise ratio calculation, the application of the response's

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standard deviation and the calibration curve's slope are some of the methods. In the present investigation, the
LOD and LOQ were determined utilising the third approach i.e. by application of standard deviations and were
computed with the aid of the equations given below:
3.3
LOD 
S

10
LOQ 
S
Where σ is the standard deviation of the peak areas of the drugs, which is used as a measure of noise, and S is
the corresponding calibration curve's slope. Standardpeakintensityandpercentage of degradationandpercentage
of assaywascalculated.

Result and Discussion

The absorbance intensity of 3388 cm-1 and 1274 cm-1 was found in the FTIR spectra for pure samples of DCL
and RAB, respectively. Because the dilution in dry potassium bromide did not have a significant impact on the
intensity of absorbance bands that resulted from DCL and RAB. Hence, we decided to make use of dry
potassium bromide as a diluent for this particular study.
Themostprominentabsorbanceband,whichcorrespondstotheNH2group,wascentredintheintensityof3388cm-1for
diluted samples of DCL in dry potassium bromide, and the S=Ogroup,which was centred in the intensity of
1274 cm-1 for diluted samples of RAB in dry potassium bromide,was with in 2.0 absorbance unit. As can be
seen in figure 7, the intensities of 3388 cm-1 and 1274 cm-1 were employed in the creation of a calibration curve
for DCL and RAB, respectively. In the case of DCL, the calibration curve can be described by the equation y =
0.006x+0.332. In the case of RAB, the calibration curve can be summarised by the equation y=0.044x+0.163.
Initially, different ranges of samples were tried. We were able to establish a calibration curve that had good
linearity and had arrange that went from 1-6% w/w for DCL and 0.2-1.2% w/w for RAB in KBr. For both the
drugs, DCL and RAB, the correlation coefficient for the calibration curve was 0.991. The linear regression
equation that corresponds to DCL was y = 0.006xs+0.332 and the linear regression equation that corresponded
to RAB was y = 0.044xs+0.163.

Table 1: Linearity study data of DCL

Sr.no. Concentration Intensity
(% w/w) (3388cm-
1
)
1 1 0.385

2 2 0.471
3 3 0.522
4 4 0.607
5 5 0.648
6 6 0.711
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Table 2: Linearity study data of RAB

Sr.no. Concentration Intensity
(%w/w) (1274cm-1)
1 0.2 0.259
2 0.4 0.322
3 0.6 0.439
4 0.8 0.537
5 1 0.589
6 1.2 0.701

Table3: Analysis of tablet formulation

Sr. no. Label claim mg/tab Amount found (mg/tab) %assa

y
DCL RAB DCL RAB DCL RAB
1 10 2 9.8 1.96 98.03 98.49
2 10 2 10.06 2.05 100.65 102.5
3 10 2 10.21 2.06 102.17 103.17
4 10 2 9.97 1.97 99.78 98.99
5 10 2 10.28 2.07 102.83 103.51
6 10 2 10.04 2.01 100.43 100.66

Table 4: Statistical validation: analysis of tablet formulation

Name of the drug Me SD %RS

an D
DCL 100 1.71 1.69
.64
RAB 101 2.16 2.13
.22
*Indicates average of six determinations

Table 5: Linear regression data for calibration curve of DCL and RAB

Nameof the Linearity r2 Slope Intercept

drug range(%w/w)

DCL 10-60 0.991 0.006 0.332

RAB 2-12 0.991 0.044 0.163
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The coefficient of variation (%RSD) was used to express the precision, while the mean and standard deviation
were utilised to express the accuracy. The %RSD value for three DCL samples was observed to be 0.901%
during intra-day precision studies, it was observed to be 1.066% during inter-day precision studies. For RAB,
the %RSD value for three DCL samples was observed to be 0.597% for intra-day precision and 0.41% for inter-
day precision studies. Both the intraday and the interday precision results were within the variable limitations
that were considered acceptable.

Table 6: Repeatability data

Sr.no. Concentration(mg) Absorbance % Recovery

DCL RAB DCL RAB DCL RAB

1 10 2 0.458 0.595 99.78 99.49
2 10 2 0.460 0.598 100.21 100
3 10 2 0.459 0.599 100 100.16
4 10 2 0.450 0.589 98.03 98.49
5 10 2 0.472 0.619 102.83 103
6 10 2 0.461 0.602 100.43 100.6

Table7: Statistical validation of repeatability data

Name of the drug Mean SD %RSD

DCL 100.21 1.54 1.53
RAB 100.29 1.51 1.50
*Indicates average of six determinations

Table 8: Precision data of marketed formulation

Sr.no. Interval of time Concentration(mg) %recovery

DCL RAB DCL RAB
1 0 hr 10 2 100.21 100.50
2 3 hr 10 2 101.96 100.16
3 6 hr 10 2 100.65 101.33
4 Day-1 10 2 100.65 100.5
5 Day-2 10 2 98.69 100.16
6 Day-3 10 2 100.4 101
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Table 9: Statistical validation of intra-day precision data

Name of the drug Mean SD %RSD
DCL 100.94 0.91 0.901
RAB 100.66 0.601 0.597
*Indicates average of three determinations

Table10: statistical validation of inter-day precision data

Name of the drug Mean SD %RSD
DCL 99.91 1.066 1.066
RAB 100.55 0.422 0.41
*Indicates average of three determinations

Standard addition method was used to recover pure drug at three different levels (80%, 100%, and 120% w/w of
label claim), and the assay method's accuracy was determined based on the results of this evaluation, which can
be found in tables 11 and 12.
At various concentrations that were added, better recoveries of DCL were obtained in the range of 100.28-
100.72% w/w with the % RSD ranging from 0.65-0.87 and for RAB it were in range of 99.84-100.05% w/w,
with the % RSD ranging from 0.79-1.62.

Table11: Recovery study data

Level of Amount Added Amount

Recovery present concentration recovered(mg) %Recovery
(mg)

DCL RAB DCL RAB DCL RAB DCL RAB

10 2 8 1.6 18 3.56 100 98.99
80% 10 2 8 1.6 18.15 3.6 100.87 100
10 2 8 1.6 18.23 3.62 101.3 100.55
10 2 10 2 19.91 3.96 99.56 99.16
100% 10 2 10 2 20.26 4 101.30 100
10 2 10 2 20.04 4.02 100.2 102.34
10 2 12 2.4 22.09 4.40 100.43 100.16
120% 10 2 12 2.4 22.19 4.43 100.87 100.83
10 2 12 2.4 21.90 4.36 99.56 99.16
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Table12: Statistical validation of recovery study data

Level of %Mean recovery SD %RSD

recovery DCL RAB DCL RAB DCL RAB
80 100.72 99.84 0.66 0.79 0.65 0.79
100 100.35 100.5 0.88 1.64 0.87 1.62
120 100.28 100.05 0.66 0.84 0.65 0.83
*Indicates average of three determinations

Quantification of Diclofenac Sodium and Rabeprazole Sodium in combined tablet dosage form was
successfully accomplished by applying the proposed validated method. Figure 4 displays the FTIR spectra
obtained from the relevant sample of tablet dosage form which was diluted with potassium bromide. For DCL,
the LOD was 2.583% w/w and LOQ was 0.2454% w/w, while for RAB, the the LOD was 7.828% w/w and
LOQ was 0.7436% w/w.
Table13: LOD and LOQ

Name of the LOD LOQ

drug (%w/w) (%w/w)
DCL 2.583 7.828
RAB 0.2454 0.7436

Conclusion
The FT-IR spectrophotometric method was developed, validated and found to be suitable for simultaneous
estimation of diclofenac sodium and rabeprazole sodium in tablet dosage form. This was accomplished in
accordance with the guidelines provided by ICH. Analysis of the combined mixture using the proposed method
yielded results that were found to be highly reproducible and reliable. The methods that have been developed
are simple while also being sensitive, accurate and precise. Both diclofenac sodium and rabeprazole sodium
were subjected to forced degradation studies, and the results of these studies can demonstrate the extent to
which degradation occurs under the experimental conditions that were selected. This method is both quick and
environmentally friendly, making it suitable for use in the pharmaceutical industry for quality control and
routine analysis of finished products. It does not involve the use of hazardous chemicals or solvents and
involves relatively simple sample preparation which leads to an economical and environmentally friendly
method.

Acknowledgement
The authors would like to express their gratitude to Wockhardt Pvt. Ltd., which is located in Aurangabad, India,
for supplying gift sample of the pure drug that contains Diclofenac Sodium and Rabeprazole Sodium. The
authors also grateful to the both the Alard College of Pharmacy in Pune and the S. R. T. M. University in
Nanded for making respective research facilities available.
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