INTRODUCTION:

One of the most frequently employed techniques in pharmaceutical analysis is UV-Visible spectrophotometry. The amount of ultraviolet or visible radiation absorbed by a substance in a solution is measured by UV spectrophotometer¹.

Figure 1: Chemical structure of Dapsone

Dapsone used as a medication to treat leprosy and skin infection. Solubility of Dapsone is in Methanol, Ethanol, DMF, DMSO etc. Dapsone, also known as diaphenylsulfone or dadps, belongs to the class of organic compounds known as benzenesulfonyl compounds. These are aromatic compounds containing a benzenesulfonyl group, which consists of a monocyclic benzene moiety that carries a sulfonyl group^1-5.

MATERIALS AND METHODS:

Instruments:

UV/Visible double beam spectrophotometer Systronic 2201. Standard cuvettes having 10mm of path length are used for analysis. Ultrasonicator (microclean-103) was used to sonicate the formulation sample. Drug sample was weighed by using electronic analytical balance (Shimadzu AY220).

Chemicals and reagents:

Active pharmaceutical ingredient of Dapsone is gifted as a sample from Aadhaar Life Sciences Pvt. Ltd. Solapur. Marketed formulation of Dapsone was procured from local pharmacy.

EXPERIMENTAL:

Method Development:

Preparation of standard stock solution of Dapsone:

10mg of standard drug Dapsone was accurately weighed and transferred into 10ml volumetric flask and sufficient amount of methanol: ROWater (75:25) was added into it and sonicated for 15 minutes, finally volume was made up to the mark with the same solvent to make 1000µg/ml stock solution. From this 1ml was again diluted to 10ml to get a concentration of 100µg/ml of Dapsone. From 100µg/ml solution 5ml was again diluted to 10ml to get a concentration of 50µg/ml.

Selection of Wavelength:

To determine the wavelength for measurement, Dapsone (50µg/ml) solution was scanned in the range of 200-400nm against methanol: RO water (75:25) as blank. Wavelength of maximum absorption was determined for drug. Dapsone showed maximum absorption at 260nm.

Assay of Dapsone gel:

1gm of gel was accurately weighed and transferred into 10ml volumetric flask and dissolve in 5ml of Methanol: RO Water (75:25). This solution was sonicated for 15 minutes and final volume was made up to the mark with Methanol: RO Water (75:25). From this solution 1ml is transferred into 10ml volumetric flask and diluted up to 10ml with Methanol: RO Water (75:25). From this solution 0.6ml is transferred into volumetric flask and diluted up to 10ml. The absorbance of this solution was measured at 260nm.

RESULT AND DISCUSSION:

METHOD VALIDATION:

Figure 2: UV Visible Spectrophotometer Graph

The method was validated for several parameters like Linearity, Accuracy, Precision, Robustness, Limit of Detection (LOD), Limit of Quantification (LOQ) and Specificity of Dapsone^6-12.

1. Linearity and Range:

The linear relation between absorbance and concentration of drug was evaluated using three replicates over concentration range in 3-18µg/ml by making the replicates (Table 1 and Fig 3).

Table 1: Results of Linearity

Sr. No	Concentration (µg/ml)	Absorbance
1	3	0.178
2	6	0.345
3	9	0.502
4	12	0.661
5	15	0.789
6	18	0.982

Figure 3: Calibration curve for Dapsone

The wavelength for linearity was scanned at 260nm. By taking five different concentrations for linearity the regression coefficient was found to be 0.9982 i.e. in limit of standard. Hence linearity parameter was found to be validated.

2. Specificity: Assay was found to be 99.9%.

Table 2: Results of Assay

Formulation	Labelled amount	Amount obtained	% Purity
Acnewar Gel	5gm	4.99	99.9

3. Accuracy:

Accuracy of the method was confirmed by recovery studies from marketed formulation at three different levels of standard i.e. 50%, 100%, 150% was done to confirm accuracy of the developed method. The amount of Dapsone is calculated at each level and percentage recoveries were calculated (Table 3).

Table 3: Results of Accuracy

Name of drug	Recovery levels	Concentration (µg/ml)	Amount recovered	% Recovery with S.D.
Dapsone	50 %	3	3.001	100.01±0.70
	100 %	6	6.001	100.03±0.13
	150 %	9	9.004	100.05±0.25

4. Precision:

Precision of the developed method expressed in terms of relative standard deviation of the absorbance. The solution was analyzed in 6 replicates for intra-day precision and in two successive days for inter-day precision. The % RSD value was found to be less than 2. Results confirmed that the precision of the method was found to be accepted. Precision results were given in table 3 and table 4 for intra and inter-day precision respectively.

Table 4: Results for Intra-day Precision

Sr. No.	Concentration (µg/ml)	Absorbance
1	9	0.502
2	9	0.503
3	9	0.503
4	9	0.502
5	9	0.501
6	9	0.502
S.D.		0.000753
%RSD		0.149905%

Table 5: Results for Inter-day precision

Sr. No.	Concentration (µg/ml)	Absorbance (Day1)	Absorbance (Day2)
1	9	0.502	0.504
2	9	0.503	0.505
3	9	0.503	0.504
4	9	0.502	0.503
5	9	0.501	0.502
6	9	0.502	0.503
S.D.		0.000753	0.001049
%RSD		0.149905%	0.208304%

For Intra-day and inter-day precision relative standard deviation is in limit i.e. less than 2% hence parameter is validated.

5. Robustness:

Robustness is a measure of its capacity to remain unaffected by small, but deliberate variations in method parameters and provides an indication of its reliability during normal usage. Robustness was carried out on two different instruments and also carried out by using two different analysts (Table 6).

Table 6: Results for robustness

Wavelength	260nm	263nm
Concentration	10µg/ml	10µg/ml
Absorbance	0.638	0.638
	0.637	0.637
	0.639	0.638
	0.638	0.637
	0.637	0.638
	0.638	0.638
Average	0.637833	0.637667
S.D.	0.000753	0.000516

By change in concentration and wavelengths i.e. 260nm and 263nm. So parameter was validated

5. Ruggedness:

The degree of reproducibility of test results of same sample within different laboratories and different analyst under same condition with same concentration.

Table7: Results for ruggedness

Concentration	Analyst 1	Analyst 2
15(µg/ml)	0.789	0.788
	0.788	0.789
	0.789	0.789
	0.787	0.789
	0.788	0.788
	0.789	0.787

By change in analyst and laboratory, there is no effect on absorbance with same conditions (Table 7). Hence, parameter was validated.

6. Limit of detection (LOD):

Limit of detection of an individual analytical procedure is the lowest amount of analyte in the sample which can be detected but not necessarily quantitated as an exact value. LOD was found to be 0.826.

7. Limit of quantitation (LOQ):

Limit of quantitation of an individual analytical procedure is the lowest amount of an analyte in the sample which can be quantified as an exact value. LOQ was found to be 2.504.

CONCLUSION:

The proposed UV spectroscopic method is found to be accurate, precise, stable, linear, specific, and simple for quantitative estimation of Dapsone in bulk and Semisolid dosage form. Hence the present UV spectroscopic method is suitable for routine assay of Dapsone in bulk Semisolid dosage form.

ACKNOWLEDGEMMENT:

The authors are thankful to the principal and the management, DSTS Mandal’s College of Pharmacy Solapur, for providing the necessary facilities for research.

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Received on 23.09.2020 Modified on 28.10.2020

Research J. Pharm. and Tech. 2021; 14(9):5007-5009.

DOI: 10.52711/0974-360X.2021.00872