A Novel Ecofriendly, Cost effective mobile phase for HPLC- Simultaneous estimation and Validation of Paracetamol and Diclofenac sodium in Bulk and Pharmaceutical Formulation by RP-HPLC using Hydrotropic Solution as Mobile phase

Remi. S. L¹*, Joyamma Varkey², R. K. Maheshwari³, A. Jayakumaran Nair⁴

¹Assistant Professor, PIPMS, Govt Medical College, Thiruvananthapuram, Kerala, India.

²T D Government Medical College, Alappuzha, Kerala.

³Shri. G. S Institute of Technology and Science, Indore, Madhya Pradesh.

⁴IUCGGT, University of Kerala, Karyavattom, Thiruvananthapuram.

*Corresponding Author E-mail: remisanthosh@yahoo.com

ABSTRACT:

High performance liquid chromatography of drugs is usually performed with the help of organic mobile phase like Methanol, Acetonitrile etc., which are toxic, volatile and expensive. In the present study, an Ecofriendly cost-effective hydrotropic solution (5% Urea in HPLC grade water) was employed as mobile phase for the estimation of poorly aqueous soluble drugs Paracetamol and Diclofenac sodium by RP-HPLC. The analysis was carried out on Shimadzu LC6AD dual pump with PDA Detector SPD-M20A, and Rheodyne injector (20μL loop). The analytical column used was Shimadzu shim packC₁₈ column with 5μm particle size and dimension of 4.6×250mm. Urea solution (5%) at a flow rate of 1.0mL/minute was employed as mobile phase and the drugs were detected at 268nm at ambient temperature. Novel ecofriendly mobile phase, comprising of 5% Urea solution was found to be satisfactory and give sharp peaks for Paracetamol and Diclofenac sodium with retention time 3.272 and 1.772 min respectively. The method was validated as per ICH guidelines. Linearity for detector response was observed in 100- 500μg/mL for Paracetamol and 10- 50μg/mL for Diclofenac sodium. Percentage recovery for Paracetamol and Diclofenac sodium were 99.97 and 99.79 respectively, indicates accuracy of the proposed method. The %RSD for both tablet analysis and recovery studies were less than 2% indicates high degree of precision. The LOD and LOQ values showed that the proposed method is sensitive. Therefore, the developed method employing hydrotropic solution as mobile phase was novel, simple, precise, cost effective, ecofriendly, safe and can be successfully applied for the routine analysis of Paracetamol and Diclofenac sodium in pharmaceutical dosage forms.

KEYWORDS: Paracetamol, Diclofenac sodium, RP-HPLC, Hydrotropic mobile phase, Urea, Method validation.

INTRODUCTION:

Chemically Paracetamol¹ is N-(4-hydroxy phenyl) acetamide used as analgesic and antipyretic. Diclofenac sodium² is chemically sodium salt of 2-[(2,6-dichloro phenyl) amino] benzene acetic acid, having analgesic and anti-inflammatory properties. HPLC estimation is usually performed with the help of organic mobile phase, which are harmful, volatile and expensive. In the present study, hydrotropic solution was employed as mobile phase for the estimation of poorly aqueous soluble drugs Paracetamol and Diclofenac sodium by RP-HPLC. Single method was reported till date for the estimation of drugs in RP-HPLC by using hydrotropic solution as mobile phase³. Literature survey revealed that a few spectrophotometric^4-9, HPLC^10-15and HPTLC¹⁶ methods were reported for the estimation of Paracetamol and Diclofenac sodium individually, or in combination with other drugs in pharmaceutical dosage forms. In all reported methods expensive, volatile and toxic organic solvents are used as mobile phase. It was observed that various poorly water-soluble drugs were analyzed spectrophotometrically^17-22using various hydrotropic agents. Also, hydrotropy had applications in TLC^23,24 and HPTLC²⁵. Hydrotropy²⁶ refers to the ability of a concentrated solution of a chemical compound to increase the aqueous solubility of another compound (usually a sparingly soluble organic compound). Each hydrotropic agent is effective in increasing the water solubility of selected hydrophobic drugs. Examples for hydrotropic agents include Sodium acetate, Sodium caprylate, Sodium salicylate, Sodium citrate, Sodium benzoate, Nicotinamide, Urea etc. Hence, the present study is aiming to develop and validate accurate, simple, sensitive, eco-friendly, cost effective method for the estimation of Paracetamol and Diclofenac sodium by using hydrotropic solution (5% urea solution) as mobile phase.

Figure 1: Structure of Paracetamol

Figure 2: Structure of Diclofenac sodium

MATERIALS AND METHODS:

Reagents and chemicals:

· Paracetamol RS

· Diclofenac sodium RS

· HPLC grade water from Merck specialties Pvt limited, Mumbai.

· Urea Analytical grade from Loba Chemie, Mumbai.

· Diclowin Plus tablet (containing Paracetamol 325mg and Diclofenac sodium 50mg), manufactured by Wings Pharmaceuticals Pvt. Ltd., Delhi.

Instrumentation:

The HPLC system used for this method was Shimadzu LC6AD dual pump with PDA Detector SPD-M20A and Rheodyne injector (20μL loop). Analytical column used was Shimadzu shim pack c18 Column with 5μm particle size and dimension of 4.6 x250mm. Apart from this, Shimadzu analytical balance was used for weighing standards and samples. Membrane filter of pore size 0.45μm from Merck Millipore was used for mobile phase filtration and PVDF syringe filters 0.2μm pore size from Agilent technologies were used for sample filtration.

Preparation of standard drug solutions:

Stock solution of Paracetamol:

Weighed accurately about 50mg of Paracetamol and transferred to a 50mL standard flask. 40ml of 5% Urea solution was added and flask was shaken for 10-15 minutes. The final volume was made up to 50ml with distilled water to get a concentration of 1mg/mL (solution A).

Stock solution of Diclofenac Sodium:

Weighed accurately about 50mg of Diclofenac sodium and transferred to a 50mL standard flask. 40ml of 5% Urea solution was added and flask was shaken for 10-15 minutes. Rest of the volume was made up to 50ml with distilled water to get a concentration of 1mg/mL (solution B).

Preparation of standard drug mixture:

Weighed accurately 50mg Diclofenac sodium and 325mg Paracetamol separately and transferred to a 50mL standard flask. 40ml of 5% Urea solution was added and shake the mixture for 10-15 minutes. Rest of the volume was made up to 50ml with distilled water to obtain a mixture with concentration of 1000μg/mL of Diclofenac sodium and 6500μg/mL of Paracetamol.

Determination of solubility:

Preliminary Solubility Studies:

Solubility of Paracetamol and Diclofenac sodium were determined at 28±1°C. An excess amount of drug was added to screw capped 30ml glass vials containing different aqueous systems viz. distilled water, 5% urea solution and other hydrotropic agents. The vials were shaken mechanically for12 hours at 28±1°C in a mechanical shaker. These solutions were allowed to equilibrate for next 24hrs and then centrifuged for 5min at 2000rpm. The supernatant liquid was taken for appropriate dilution after filtration through Whatman filter paper #41 and analyzed spectrophotometrically against corresponding solvent blank. After analysis, it was found that there was tremendous increase in solubility of Paracetamol and Diclofenac sodium in 5% urea solution as compared to solubility studies in other solvents.

Selection of Hydrotropic Agent:

Paracetamol and Diclofenac sodium were scanned separately in various solutions of hydrotropic agents in the spectrum mode over the UV range (200-400nm) and was found to be most appropriate in 5% urea solution because Paracetamol and Diclofenac sodium were soluble and stable in urea solution. Also, Urea solution has no interference with the λ-max of Paracetamol and Diclofenac sodium (268nm)

Method development and optimization:

The mobile phase influences resolution, selectivity and efficiency of separation. In reverse phase chromatography, usually the mobile phase consists of an aqueous phase and non-UV active water miscible organic solvent. But here an attempt was made to find out an eco-friendly, cost effective, nonvolatile mobile phase for the simultaneous estimation of poorly water soluble drugs Paracetamol and Diclofenac sodium. Selection of mobile phase was carried out by trial and error method. Initially trial was done using 3% and 4% Urea solution as mobile phase but didn’t get good resolution. Then the trial was carried out by using 5% Urea solution. This resulted in a good resolution and sharp peaks for Paracetamol and Diclofenac sodium. pH of Urea solution also changed, but no significant change occurred on the shape and resolution of peaks. Finally, the mobile phase was optimized as 5% Urea solution. All the stock solutions are prepared by using mobile phase and further dilutions are made by HPLC grade water.

HPLC operating conditions:

Column	:	Shimadzu shim pack c18 (4.6 x250 mm with 5μm particle size)
Detector	:	PDA Detector (SPD-M20A)
Injection volume	:	20μL
Flow rate	:	1.0ml per minute
Temperature	:	Ambient
Run time	:	10 Minutes
Mobile phase	:	5% Urea solution
Wave length	:	268nm

Preparation of sample solution:

Weighed accurately twenty Diclowin Plus tablets and average weight was calculated and then finely powdered. Then powder equivalent to about 50mg of Diclofenac sodium (containing 325mg of Paracetamol) was weighed and transferred to a stoppered flask. The powder was extracted initially using 20mL of 5% urea solution (5% urea in HPLC grade water) by vigorous shaking for 15 minutes. Then solution was transferred to a 50mL standard flask through Whatman filter paper # 41. The residue was further extracted twice with 10mL of urea solution and transferred to the standard flask through the same filter paper and then washed out the filter paper using HPLC grade water. The volume was finally made up to 50mL with HPLC grade water to attain a concentration of 1000μg/mL of Diclofenac sodium and 6500μg/mL of Paracetamol. From the above solution, accurately pipetted out 5mL and transferred into a 100mL standard flask and made up the volume using HPLC grade water. The resulting solution contains 50μg/mL of Diclofenac sodium and 325μg/mL Paracetamol.

RESULTS AND DISCUSSIONS:

Method development

The detection wavelength was set at 268nm. A volume of 20μL standard drug mixture was injected and the components eluted from the system were monitored for a run time of 10 minutes. Two sharp peaks for Paracetamol and Diclofenac sodium were appeared with retention time 3.272 and 1.772 minutes respectively. Typical chromatogram for the standard and sample were presented in Fig-3 and Fig-4.

Fig3: Pacetamol and Diclofenac sodium Standard

Fig4: Paracetamol and Diclofenac sodium Sample

Table 1: Result of Assay of Tablet

Drug	Amount of drug claimed(mg)	Amount of drug found(mg)*	% Label Claim
Paracetamol	325	324.80	99.94
Diclofenac sodium	50	49.89	99.79

*Average of 6 determinations

METHOD VALIDATION:

The optimized method for simultaneous determination of Paracetamol and Diclofenac sodium has been validated as per ICH guidelines²⁷for evaluating system suitability, specificity, precision, accuracy, linearity, limit of detection (LOD), limit of quantitation (LOQ), ruggedness and robustness.

1. System suitability:

System suitability was performed by injecting six replicate injections of Paracetamol and Diclofenac sodium standard mixture. The obtained results showed that all the parameters tested were within the acceptable range. Paracetamol and Diclofenac sodium were repeatedly retained and well separated at 3.272 min and 1.772 min respectively expressing excellent resolution between both peaks with low %RSD. The tailing factor for both Paracetamol and Diclofenac sodium peaks never exceeded 1.25 in all peaks indicating good peak symmetry (acceptance limit is < 2) and the number of theoretical plates were always >2000 in all chromatographic runs to ensure good column efficacy throughout the developed separation process. Results were presented in Table-2

Table 2: System suitability data for Paracetamol and Diclofenac sodium

Sl No	Parameter	Diclofenac sodium	Paracetamol
1	Retention time	1.772	3.272
2	Resolution	-	4.1
3	Theoretical plates	3015.6	5235.1
4	Peak Tailing	1.212	1.160

2. Precision:

Precision was done at two levels- Repeatability and intermediate precision.

Repeatability (Intra-day precision):

Repeatability was assessed by injecting six independent combined samples of paracetamol (325μg/mL) and Diclofenac sodium (50μg/mL) on the same day under same operating conditions. The results are furnished below.

Table 3: Repeatability study- Peak area of Paracetamol and Diclofenac sodium

Sl No	Peak area of Paracetamol	Peak area of Diclofenac sodium
1	7620895	1263679
2	7611610	1264676
3	7620786	1265099
4	7620781	1265671
5	7613955	1265998
6	7620884	1262465

Table 4: Repeatability study- % Label claim

Sl No	Amount present (Label claim) mg/tablet		Amount obtained (mg/tablet)		Percentage Recovery
Sl No	Paracetamol	Diclofenac sodium	Paracetamol	Diclofenac sodium	Paracetamol	Diclofenac sodium
1	325	50	324.90	49.90	99.96	99.81
2	325	50	324.60	49.94	99.87	99.89
3	325	50	324.91	49.96	99.97	99.92
4	325	50	324.80	49.80	99.93	99.60
5	325	50	324.70	49.90	99.91	99.80
6	325	50	324.91	49.97	99.97	99.72

Table 5: Repeatability study – Statistical validation

Component	Mean of % recovery	Standard Deviation	%RSD	Coefficient of Variation
Paracetamol	99.94	0.036742	0.036764	0.0003676
Diclofenac sodium	99.79	0.043588	0.043679	0.0004367

Intermediate or Inter-day precision:

Intermediate precision was assessed by comparing the results of 3 independent determinations on three different days. The results are furnished below.

Table 6: Inter-day Precision: Peak area and % label claim

Parameter	Peak area of Paracetamol	Peak area of Diclofenac sodium	%Label claim of Paracetamol	%Label claim of Diclofenac sodium
Day 1	7619899	1263994	99.98	99.84
	7619848	1263957	99.98	99.83
	7609869	1263964	99.85	99.83
Day 2	7609879	1263956	99.85	99.84
	7609871	1263982	99.84	99.83
	7609884	1263981	99.85	99.83
Day 3	7562367	1263115	99.23	99.77
	7562256	1262256	99.20	99.83
	7562966	1263450	99.24	99.79

Table 7: Inter-Day Precision: Statistical Validation

Parameter	Mean of % Label claim		Standard Deviation		% RSD		Co-efficient of Variation
Parameter	Paracetamol	Diclofenac Sodium	Paracetamol	Diclofenac Sodium	Paracetamol	Diclofenac Sodium	Paracetamol	Diclofenac Sodium
Day 1	99.94	99.83	0.061283	0.004714	0.061319	0.004722	0.0006131	0.0000472
Day 2	99.85	99.82	0.004714	0.012472	0.004721	0.012495	0.000472	0.0001249
Day 3	99.22	99.79	0.016996	0.024944	0.017130	0.024996	0.0001713	0.0002499

The results for both intra-day and inter-day determinations ensure the high precision and repeatability of the designed method. All the data were expressed in % RSD and never exceeded the acceptance limit <2. Statistical validation of the results of intra and inter-day precision are given in Table- 5 and Table-7 respectively.

3. Specificity:

Specificity was performed by injecting samples of mobile phase, placebo, sample solution and spiked sample. The results showed no interference at the retention time of Paracetamol and Diclofenac Sodium. The representative chromatogram of placebo was shown in Fig -5.

Fig 5: Placebo Chromatogram

4. Linearity:

Linearity of the analytical procedure is its ability (within given range) to obtain test results, which are directly proportional to the concentration (amount) of the analyte in the sample.

The linearity concentration of Paracetamol was determined by analyzing five different concentrations of standard solution. The solutions were prepared by accurately pipetting out 1, 2, 3, 4 and 5mL from stock solution A (containing 1000μg/mL) of Paracetamol into five different 10mL standard flasks. The solution was made up to the mark using HPLC grade water and was filtered through 0.22μm pore size syringe filter. Then the chromatogram was recorded for each solution at 268nm using 5% Urea solution as mobile phase. Then the calibration curve of peak area vs. concentration was plotted and the correlation co-efficient and the regression line equation were determined. The overlay linearity chromatogram and linearity plot of Paracetamol is given in Fig-6 and Fig-7.

Figure 6: Overlay linearity chromatogram of Paracetamol

Figure 7: Linearity plot of Paracetamol

The linearity concentration of Diclofenac sodium was determined by analyzing five different concentrations of standard solution. Accurately pipetted out 0.1, 0.2, 0.3, 0.4 and 0.5mL from stock solution B (containing 1000μg/mL) of Diclofenac sodium into five different 10mL standard flasks. The solution was made up to the mark using HPLC grade water and was filtered through 0.22μm pore size syringe filter. Then the chromatogram was recorded for each solution at 268nm using 5% Urea as mobile phase. Then the calibration curve of peak area vs. concentration was plotted and the correlation co-efficient and the regression line equation were determined. The overlay linearity chromatogram and linearity plot of Diclofenac sodium is given in Fig- 8 and Fig- 9.

Figure 8: Overlay linearity chromatogram of Diclofenac sodium

Figure 9: Linearity plot of Diclofenac sodium

Table 8: Linearity data of Paracetamol and Diclofenac sodium

Parameter	Paracetamol	Diclofenac sodium
Linearity range	100- 500 μg/mL	10- 50 μg/mL
R² value	0.9997	0.9976
Regression equation	Y=23444x- 14297	Y=23718x+ 24171

The results (Table 8) showed a significant correlation between detector response and concentration level of each drug within the concentration range.

5. Accuracy:

Accuracy of the proposed method was determined by recovery study. The recovery studies were performed by standard addition method at three concentrations (80%, 100% and 120%) and the percentage recovery was calculated. The results are shown below and the statistically validated data for Paracetamol and Diclofenac sodium are shown in the Table -11 and Table-13 respectively.

Table 9: Recovery study- Peak area of Paracetamol and Diclofenac sodium

Level of % recovery	Peak area of Paracetamol	Peak area of Diclofenac sodium
80%	8130669	1366399
	8131222	1366092
	8133401	1365189
100%	9045074	1493413
	9092012	1499212
	9102639	1491546
120%	9974502	1648432
	9984102	1646378
	9969542	1649462

Table 10: Recovery study -Paracetamol

Level of % recovery	Amount present (μg/mL)	Amount added (μg/mL)	Drug recovered (μg/mL)	Drug recovery (%)
80%	0.325	0.026	0.3467	98.78
	0.325	0.026	0.3468	98.79
	0.325	0.026	0.3469	98.81
100%	0.325	0.065	0.3857	98.91
	0.325	0.065	0.3877	99.42
	0.325	0.065	0.3882	99.54
120%	0.325	0.104	0.4254	99.16
	0.325	0.104	0.4260	99.25
	0.325	0.104	0.4252	99.10

Table 11: Recovery study- Paracetamol: Statistical validation

% Recovery	Mean	Standard deviation	%RSD	Coefficient of variation
80%	98.79	0.01247	0.01260	0.000126
100%	99.29	0.27313	0.27508	0.002750
120%	99.17	0.06164	0.06220	0.000622

Table 12: Recovery study- Diclofenac Sodium

Level of % recovery	Amount present (μg/mL)	Amount added (μg/mL)	Drug recovered (μg/mL)	Drug recovery (%)
80%	0.050	0.004	0.05396	99.92
	0.050	0.004	0.05395	99.90
	0.050	0.004	0.05391	99.83
100%	0.050	0.010	0.05896	98.30
	0.050	0.010	0.05921	98.68
	0.050	0.010	0.05891	98.18
120%	0.050	0.016	0.06510	98.63
	0.050	0.016	0.06502	98.51
	0.050	0.016	0.06514	98.70

Table 13: Recovery study- Diclofenac sodium: Statistical validation

% Recovery	Mean	Standard deviation	%RSD	Coefficient of variation
80%	99.88	0.038586	0.03860	0.000386
100%	98.38	0.213125	0.21660	0.002166
120%	98.61	0.078457	0.07962	0.000796

6. Limit of Detection (LOD)andLimit of Quantitation (LOQ):

LOD of an analytical procedure is the lowest amount of analyte in a sample which can be detected but not necessarily quantified. LOD can be calculated using the following equation,

LOD = 3.3(σ/S)

Where, σ= standard deviation of y-intercept, S= slope of calibration curve

LOQ of an analytical procedure is the lowest amount of analyte in the test solution that can be quantitatively detected with reliable accuracy and precision. It can be calculated from the equation,

LOQ = 10 (σ/S)

Where, σ= standard deviation of y-intercept, S= slope of calibration curve.

The results of LOD and LOQ are furnished in Table -14

Table 14: LOD and LOQ – Results

parameter	Paracetamol	Diclofenac sodium
LOD (μg/mL)	0.007429	0.007511
LOQ (μg/mL)	0.022513	0.022759

7. Robustness:

Robustness is performed by making slight variations in the flow rate and concentration of the mobile phase. The changes and results were tabulated in Table-15.

Table 15: Robustness study: Statistical validation

Parameters	Adjusted to	% Label claim		Standard Deviation		% RSD
Parameters	Adjusted to	Paracetamol	Diclofenac sodium	Paracetamol	Diclofenac sodium	Paracetamol	Diclofenac sodium
Flow rate	0.9 mL /minute	98.87	98.27	0.166599	0.107806	0.168503	0.109703
	1 mL /minute	99.97	99.98	0.012472	0.004714	0.012475	0.004714
	1.1 mL /minute	99.07	98.59	0.386120	0.232999	0.389744	0.236331
Mobile phase composition	4%Urea solution	98.59	98.15	0.063420	0.069442	0.064327	0.070750
	5%Urea solution	99.94	99.81	0.063770	0.030912	0.063808	0.030970
	6%Urea solution	99.31	99.86	0.110855	0.070395	0.111625	0.070493

Table 16: Results and statistical validation of Ruggedness study

Parameter	Peak area		Average % Label claim		Standard Deviation		% RSD
	Paracetamol	Diclofenac sodium	Paracetamol	Diclofenac sodium	Paracetamol	Diclofenac sodium	Paracetamol	Diclofenac sodium
Analyst I	7620781	1265099	99.98	99.98	0.012472	0.004714	0.012474	0.004714
	7620895	1265671
	7620896	1265998
Analyst II	7609879	1263956	99.69	99.84	0.327244	0.008164	0.328261	0.008177
	7620885	1263957
	7562967	1264111

Table 17: Summary of Results

Parameters	Paracetamol	Diclofenac Sodium
^{Absorption maxima (nm)}	268	268
Retention Time	3.272	1.772
^{Concentration range (}^μ^g/ml)	^100-500	10-50
^{Regression equation (y= mx+ c)}	^{Y=23444X-14297}	Y=23718X+24171
^{Correlation coefficient}	^0.9997	0.9976
^Specificity	^{No interference of any peaks}	^{No interference of any peaks}
^{Accuracy (%RSD)} ^80% ^100% ^120%	0.01260 0.27508 0.06220	0.03860 0.21660 0.07962
^{LOD (}^μ^g/ml)	0.007429	0.007511
^{LOQ (}^μ^g/ml)	0.022513	0.022759
^{Intraday Precision (%RSD)}	0.0367640	0.043679
^{Intermediate Precision} ^{Day 1} ^{Day 2} ^{Day 3}	0.061319 0.004721 0.017130	0.004722 0.012495 0.024996
^{Percentage recovery}	99.94%	99.79%
^{Robustness (%RSD)} ^{Flow rate} ^{Mobile phase composition}	^˂2 ^˂2	^˂2 ^˂2
^{Ruggedness (%RSD)} ^{Analyst 1} ^{Analyst 2}	0.012474 0.328261	0.004714 0.008177

8. Ruggedness:

Interday variations were performed by using six replicate injections of sample solutions which were prepared and analyzed by different analyst on three different days over a period of one week. Ruggedness also expressed in terms of percentage relative standard deviation and statistical analysis showed no significant difference between results obtained employing different analysts. The results are furnished in Table- 16

SUMMARY OF RESULTS:

The proposed method describes a novel ecofriendly RP-HPLC method for the simultaneous estimation of Paracetamol and Diclofenac sodium employing a special mobile phase comprising of 5% Urea solution, was found to be satisfactory and give sharp peaks for Paracetamol and Diclofenac sodium with retention time 3.272 and 1.772 min respectively. The method was validated as per ICH guidelines. Linearity for detector response was observed in 100- 500 μg/mL for Paracetamol and 10- 50 μg/mL for Diclofenac sodium. The calibration plot was given in Fig- 7 and Fig- 9. Percentage recovery for Paracetamol and Diclofenac sodium were 99.94 and 99.79 respectively, indicates accuracy of the proposed method. The percentage RSD for both the tablet analysis and recovery studies were less than 2%, indicates high degree of precision. The LOD and LOQ values showed that the proposed method is sensitive. The excipients present in the formulation did not interfere with peaks of Paracetamol and Diclofenac sodium. The proposed method was applied for the determination of Paracetamol and Diclofenac sodium in tablet formulation and the result was comparable with the corresponding labelled amount. A typical chromatogram showing the separation of Paracetamol and Diclofenac sodium was shown in Fig- 3 and summary of results are presented in Table-17.

CONCLUSION:

The proposed RP-HPLC method using hydrotropic solution as mobile phase precluded the use of organic solvents and thus avoid the problems of error due to volatility, pollution, cost etc. Also, most of the organic solvents involved in the HPLC analysis was hazardous to human body. By proper choice of solutions of hydrotropic agents as mobile phase, the use of organic solvents in analysis may be discouraged to a large extent. The proposed method for the determination of Paracetamol and Diclofenac sodium was equally effective to analyze the drugs in the bulk and pharmaceutical dosage forms and may prove to be of great importance in pharmaceutical analysis. This method can be successfully employed in the routine analysis of drugs in bulk as well as in the marketed dosage form without the use of organic solvents. The simplicity, rapidity, reproducibility, ecofriendly nature and economy of the proposed method completely fulfill the objective of this research work. Similarly, large number of dosage forms of drugs can be analyzed by RP- HPLC using hydrotropic solution as mobile phase.

ACKNOWLEDGEMENT:

The authors are thankful to State Board of Medical Research A2/ (SBMR. 2019-2020)/17842/2019/MCT for providing fund and IUCGGT, University of Kerala, Karyavattom for providing necessary facilities to carry out this research work.

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Received on 18.04.2020 Modified on 22.05.2020

Asian J. Pharm. Res. 2020; 10(3):163-170.

DOI: 10.5958/2231-5691.2020.00029.5