INTRODUCTION:

Danicopan:

Chemically Danicopan is a (2S,4R)-1-{2-[3-acetyl-5-(2-methylpyrimidin-5-yl)-1H-indazol-1-yl] acetyl}-N-(6-bromopyridin-2-yl)-4-fluoropyrrolidine-2-carboxamide. ¹It is also being spelled as "Voydeya". It is available in the Indian market as tablet dosage form in the brand name Voydeya. ²It is used therapeutically in treatment of paroxysmal nocturnal hemoglobinuria.³ It is highly soluble in Acetone, DMSO, Ethanol, sparingly soluble in aqueous buffers. ⁴Mode of action of Danicopan by disabling the initiating event of complement activation, danicopan prevents generation of C5 convertases, obviating the need for downstream C5 inhibition.

Additionally, specific targeting of AP can preserve classical and lectin pathwaymediated antimicrobial activity. ⁵Literature survey revealed that, Reverse phase High Performance Liquid Chromatography method have been reported for Danicopan. But no UV spectrophotometeric method has been reported. Hence an attempt will be made to develop a UV spectrophotometeric method for the comparative estimation of Danicopan. The method so developed will be validated as per ICH guidelines. ⁶The present investigation was proposed to developed and validate Danicopan in bulk and pharmaceutical dosage form by spectroscopic method which is rather simple, sensitive, specific, precise, accurate method. The resent work was to develop and validate as per ICH guidelines so the method was developed validated according to ICH guidelines for accuracy, precision and reproductivity, repeatability and robustness.⁷

MATERIALS AND METHODS:

Materials and Reagents:

Danicopan (Gift sample obtained from Alexion Pharma GmbH manufactures danicopan, which is sold under the brand name Voydeya) 22, Bhulabhai Desai Road, Mumbai-400 026), Dimethyl sulfoxide were bought from SD fine chemicals, Mumbai, India.

Apparatus and Eqiupments Required:

1. UV-Vis double beam spectrophotometer (Model; Shimadzu: 1700S, Japan), Electric Sonicator, Volumetric flasks (10ml,50ml,100ml), Calibrated analytical pipettes, Electronic digital balance (Techno, Mumbai).

Preparation of concentration range (Beer’s limit):

Determination of concentration range which obeys the Lambert and Beer’s law is necessary for accuracy and reproducibility in Spectrophotometric analysis for quantitative determination of any drug. For this; Danicopan stock solution (100µg/ml) was prepared using pure drug in Dimethyl sulfoxide. Further dilutions were made using 0.2ml, 0.4ml, 0.6ml, 0.8ml, 1.0ml, 1.2ml, 1.4ml, 1.6ml of above solution was transferred to a series of 10ml volumetric flasks his gave a series of concentrations ranging from 2 to 16 µg/ml of Danicopan. The final volume was made up to 10ml mark using Dimethyl sulfoxide, sonicated for 5 minutes. The resultant solutions were measured using a double beam uv-vis-spectrophotometer at wave length of 552.0nm against a reagent blank. A calibration curve was plotted with concentration against absorbance. From the graph it was clear that Beer’s law was obeyed in concentration range of 2-12µg/ml and deviation was observed above these concentrations.

Preparation of Standard Calibration Curve:

100 mg of pure Danicopan drug was dissolved in little quantity of Dimethyl sulfoxide in a 100 ml volumetric flask, the volume was made up to the mark using Dimethyl sulfoxide. The solution was sonicated for 10 minutes. This gave a Danicopan solution with concentration of 1 mg /ml (1000µg/ml). 10ml of this solution was further diluted 100ml in volumetric flask using Dimethyl sulfoxide to obtain a concentration of 100µg/ml. Further dilutions were made using 0.2, 0.4, 0.6, 0.8, 1.0, 1.2, 1.4, 1.6 ml solution was transferred to a series of 10ml volumetric flasks (to Obtain a series of concentrations ranging from 2-12 µg/ml of Danicopan). The final volume was made up to 10ml mark using Dimethyl sulfoxide, sonicated for 5 minutes, the solutions were measured a of 552.0 nm against a reagent blank. A calibration curve was plotted with concentration against absorbance.

Estimation of Danicopan in Tablet Dosage Forms:

Twenty tablets were weighed accurately and powdered. The tablet powder equivalent to 100 mg of Danicopan was transferred into a 100mL volumetric flask and dissolved in little quantity of Dimethyl Sulfoxide. Then the solution was sonicated for 30 minutes and filtered using what man filter paper No#41. The filtrate so obtained was diluted with Dimethyl Sulfoxide to produce 100ml. Further dilutions were made with Dimethyl Sulfoxide to get required concentrations within Beer’s - Lambert limits. The resultant solutions were measured at wave length of 552.0 nm against a reagent blank. The concentration of drug was calculated with the help of standard calibration curve.

Analytical Method Validation:

Validation of an analytical procedure is the process by which it is established, by laboratory studies, that the performance characteristics of the procedure meet the requirements for its intended use. All analytical methods that are intended to be used for analyzing any clinical samples will need to be validated. Validation of analytical methods is an essential but time-consuming activity for most analytical development laboratories. It is therefore important to wave length. Understand the requirements of method validation in more detail and the options that are available to allow for optimal utilization of analytical resources in a development laboratory.

RESULTS AND DISCUSSION:

Results of Determination of Beer's Limit:

Table: 1 Showing Beer’s range for Danicopan

Sl. No.	Concentration in µg/ml	**Absorbance at λmax 552.0nm
1.	0.0	0.000
2.	2	0.085
3.	4	0.180
4.	6	0.270
5.	8	0.375
6.	10	0.470
7.	12	0.550
8.	14	0.640
9.	16	0.820
10.	18	1.860

(** Average of three determinations)

Figure:1 Showing Beer’s limit for Danicopan pure drug:

(Figure:1 showing Beer's limit for Danicopan at 552.0 nm)

Standard Calibration Curve of Danicopan:

Table: 2 Showing absorbance of Danicopan at various concentrations

Sl.No.	Concentration in µg/ml	Absorbance at λmax 552.0nm
1.	0.0	0.000
2.	2	0.085
3.	4	0.180
4.	6	0.270
5.	8	0.375
6.	10	0.470
7.	12	0.550

Figure 2 Showing standard calibration curve for Danicopan:

Results of Determination of Absorption Maxima:

Figure 3 Showing absorption maxima of Danicopan in 552.0nm:

Table: 9. Showing calibration data for Danicopan in 552.0nm

Parameters	Calibration data at 552.0nm
λmax	552.0nm
Beer’s law limit (µg/ ml)	2 -12µg/ml
Molar Absorptivity	1.121Lmol^-1cm^-1
Regression Equation(Y=a+bc)	Y= 0.057X+0.022
Slope (b)	0.01478 to 0.01533
Intercept(a)	- 0.005520 to 0.002777
Correlation Coefficient (R²)	0.996
Limit of detection (LOD)	1.230µg/ml
Limit of quantitation (LOQ)	5.230µg/ml

Determination of Beer’s limit: The Beer’s limit felled in the range of 2-12µg/ml under given experimental conditions.

Determination of absorption maxima: 100 ug/ml stock solution of Danicopan was prepared and absorbance were measured from 400nm to 700nm. The optimum wave length was found to be 552.0 nm.

Assay: Marketed tablets contained Danicopan were used for the assay. After extraction, proper dilution, measurement, the concentration was determined using standard calibration curve. The amount of drug found in the range of 99.80 – 100.70%w/w.

Method Validation: The proposed method was validated in accordance to ICH guidelines.

a) Accuracy: Percentage of recoveries of Danicopan in tablets was found in the range of 99.94 – 100.30% w/w.

b) Precision: The percent coefficient of variations (% C.V) was between 0.34-0.60 for intra-day and 0.23-0.62 for inter-day absorbance.

c) Repeatability: Repeatability was determined by analyzing the sample at the given concentration wavelength for at least six times and it was found that the variability in the results was not more than 0.5%.

d) Reproducibility: The standard solution of Danicopan by analyst-I and analyst-II separately. The values obtained were evaluated using F-test and t-test to verify their reproducibility. Calculated value for t-test was found to be less than the tabulated (standard) value it can calculated that no significant difference was observed in the result of analysis.

e) Ruggedness: Ruggedness of the developed method was determined by changing the analytical tools such as laboratory, instruments, analyst and chemicals. The result (in terms of %RSD) of six determinations indicated that there were no significant variations in the data.

f) Robustness: Robustness of the method was established by slightly changing the temperature and PH of the reaction mixture. The data so obtained showed no significant variation in the absorption pattern.

g) Limit of detection and limit of quantitation: were determined from the standard deviation of y – intercepts of six calibration curves and average slope of six calibration curves. LOD and LOQ of Danicopan was found to be 1.230µg/ml and 5.230µg/ml respectively.

CONCLUSION:

A new spectrophotometric method was developed to estimate Danicopan in pure and tablet dosage forms. Dimethyl sulfoxide solutions of Danicopan was estimated by using UV spectrophotometer (Shimadzu 1700S, Japan) with matched 1 cm quartz cell. It showed maximum absorption at the range of 2-12µg/ml at 552.0 nm with coefficient of correlation (R2) of 0.996. The method so developed was validated according to ICH guide lines for accuracy, precision (inter and intra-day precisions), repeatability, reproducibility, ruggedness, robustness etc. The proposed method was found to be simple, accurate, sensitive, precise, reproducible and rapid. This method can be successfully employed for routine quantitative analysis of Danicopan in bulk and tablet dosage form.

ACKNOWLEDGMENT:

The authors are thankful to Head of the Department of Chemistry.

REFERENCES:

1. http://en.m.wikipedia.org/wiki/Danicopan

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Received on 25.11.2025 Revised on 11.03.2026

Accepted on 14.05.2026 Published on 27.05.2026

Available online from May 30, 2026

Asian J. Research Chem.2026; 19(3):228-232.

DOI: 10.52711/0974-4150.2026.00035

This work is licensed under a Creative Commons Attribution-Non Commercial-Share Alike 4.0 International License. Creative Commons License.

Volume of stock Solution Used	Amount of drug (label claim) (µg/ml)	Absorbance at 552.0nm	Amount of drug found (µg/ml)	Percentage purity found ±S. D (%w/w)**
0.2ml	2	0.2000	3.016	100.85±0.25
0.6ml	6	0.608	7.043	100.80±1.67
1.0ml	10	0.600	9.999	99.85±0.88
1.4ml	14	0.738	14.985	99.92±0.59

	Initial amount (µg/ml)	Amount of pure drug added (µg/ml)	Amount recovered (µg/ml)	% Recovery ±S. D**
Brands	Initial amount (µg/ml)	Amount of pure drug added (µg/ml)	Amount recovered (µg/ml)	% Recovery ±S. D**
	10	8(80%)	9.047	100.89±0.152
Vodeya	10	10(100%)	10.901	98.69±0.238
	10	12(120%)	13.030	100.90±0.429

Sl.	Conc. in (µg/ml)	Inter-day absorbance Mean±S.D**	% C. V	Intra-day absorbance Mean±S.D**	% C.V
1.	8	0.519±0.008	0.56	0.517±0.027	0.78
2.	10	0.616±0.068	0.53	0.616±0.028	0.45
3.	12	0.709±0.043	0.78	0.719±0.039	0.39

Parameters	Laboratory	Name of the instrument	Manufacturer of the chemicals used
Lab. 1 with analyst I	M.M.U. College Of Pharmacy, Ramanagara	Shizmadzu- (model:1700S, Japan) double beam UV-Vis spectrophotometer	S.D Fine Chemicals, Mumbai.
Lab. 2 with analyst II	Dr. H.L.T. College of Pharmacy, Kengal, Channapatna	Systronic UV-Vis Double beam spectrophotometer	Loba Chemicals, Mumbai

Type	Sl. No.	Conc. In (µg/ml)	Change in temperature		Change in pH
			+5⁰C	-5⁰C	2drops of 0.1N NaOH	2drops of 0.1N HCl
			Absorbance at 552.0 nm Mean±S.D**
Pure	1	8	0.481±0.035	0.413±0.032	0.420±0.027	0.432±0.027
Drug	2	10	0.525±0.039	0.513±0.026	0.540±0.026	0.521±0.023
	3	12	0.619±0.030	0.617±0.038	0.635±0.035	0.624±0.034