INTRODUCTION:

Isoxsuprine hydrochloride is chemically 4-[1-hydroxy-2-(1-phenoxypropan-2-ylamino)propyl] phenol is an alkyl benzene (molecular weight 301.4g/mol). Isoxsuprine is benzyl alcohol derivative with vasodilator activity. The mechanism of action of isoxsuprine hydrochloride is controversial, because isoxsuprine has beta-adrenergic activities that could not be offset by beta-adrenergic blockers. Although stimulation of the beta-adrenergic receptor increases blood flow to produce vasodilatation, this agent may also have direct effects on the contractility of smooth muscle. Additionally, isoxsuprine causes relaxation of uterine smooth muscle and may also produce positive inotropic and chronotropic effects on the myocardium. Literature survey reveals the spectrophotometric^1-9 and Titrimetric ¹⁰methods for the estimation of isoxsuprine hydrochloride.

Simple, rapid and reliable aqueous titration method is developed for the determination of isoxsuprine hydrochloride. This method can be used for the routine analysis. In the proposed methods optimization and validation of this method are reported.

Structure of isoxsuprine hydrochloride:

MATERIAL AND METHODS:

Experimental:

Instrumentation:

A Shimazu analytical balance with 0.01mg was used.

Reagents and chemical:

Sodium hydroxide, succinic acid and ethanol of A. R. grade were used.

General procedure:

Standardization of 0.1Nsodium hydroxide solution:

4.0g. of sodium hydroxide was transferred in 500ml of beaker and dissolved in 250ml of distilled water. It was transferred into 1000ml of standard volumetric flask and diluted to 1000ml with distilled water to give concentration as 0.1N. This solution was standardized by using 0.1Nsuccinic acid. (0.1Nsuccinic acid was prepared by dissolving 1.475g. of succinic acid in 250 ml of distilled water). This Standard 0.1Nsuccinic acid was titrated with 0.1Nsodium hydroxide using 0.01% w/v phenolphthalein indicator until colour of phenolphthalein changes from colorless to pink.

The titration was performed in duplicate.

N₁ x V₁

Normality of sodium hydroxide = –––––––––––

V₂

Where N₁is Normality of standard succinic acid V₁ is volume of succinic acid and V₂is burette reading (Volume of sodium hydroxide required for titration)

Quantitative determination of isoxsuprine hydrochloride:

About 0.05g. of isoxsuprine hydrochloride as isoxsuprine hydrochloride test sample was weighed accurately into a clean and dried titration jar. It was dissolved in 20ml. A.R. grade ethanol. It was titrated with 0.1 N sodium hydroxide solution using 0.01%w/v phenolphthalein indicator.

Blank determination was also carried out for necessary correction.

One ml of 0.1N sodium hydroxide is equivalent to 0.01507g. of isoxsuprine hydrochloride

% Isoxsuprine hydrochloride on the dried basis was calculated as below.

B.R. x N x 0.01507 x 100 x 100

% assay = –––––––––––––––––––––––––––––––––

W x 0.1

Where B.R. is burette reading in ml at the end point.

N is actual normality of 0.1N sodium hydroxide.

W is weight of the sample taken in g.

RESULT AND DISCUSSION:

Determination of isoxsuprine hydrochloride:

The objective of this work was to determine accurately the content of isoxsuprine hydrochloride. The assay of isoxsuprine hydrochloride (on the dried basis) of various batches of isoxsuprine hydrochloride test sample was analyzed using the above method. It was in the range of 99.15% to 100.25%.

Analytical method validation:

The method precision was checked after analyzing six different preparations of homogeneous test sample of isoxsuprine hydrochloride as isoxsuprine hydrochloride fumarate. The % RSD of results obtained was found to be 0.4058. It confirms good precision of the method. The results are presented in table 1.

Table no. 1: Method of precision

Sr. No	Weight of Terbutaline sulphate in g.	Burette reading in ml	Normality of sodium hydroxide	% assay
1	0.0500	3.29	0.1009	100.05
2	0.0502	3.3	0.1009	99.95
3	0.0501	3.28	0.1009	99.54
4	0.0499	3.29	0.1009	100.25
5	0.0504	3.3	0.1009	99.56
6	0.0503	3.28	0.1009	99.15
			Mean	99.75
			Std. Deviation	0.4048
			RSD	0.4058

Linearity:

For the establishment of method linearity, five different weights of isoxsuprine hydrochloride test samples corresponding to 10%, 20%, 30%, 40% and 50% of the about weight (0.500g.) were taken and analyzed for % (percentage) of isoxsuprine hydrochloride content. The results are in table 2.

Table No. 2: Linearity

Sr. No.	Weight of Isoxsuprine hydrochloride in g.	Burette reading in ml	Normality of sodium hydroxide	% assay
1	0.0500	3.3	0.1009	100.35
2	0.1002	6.6	0.1009	100.15
3	0.1501	9.9	0.1009	100.29
4	0.2002	13.1	0.1009	99.49
5	0.2504	16.5	0.1009	100.19
			Mean	100.09
			Std. Deviation	0.3457
			RSD	0.3453

The potentiometric titration was conducted once at each level. Linearity curve Figure no.1 was drawn by plotting test sample weight in gram on x axis and titre values on y axis.

Fig. No.1: Linearity curve

The values of correlation coefficient, slope and intercept are given in table 3.

Table no.3: Regression values

Parameter	Values
Slope	65.94
Intercept	-0.006
Coefficient of co-relation	0.9999

Table no 4 : accuracy and precision

Level No.	Weight of Isoxsuprine hydrochloride added in g	Weight of Isoxsuprine hydrochloride found in g.	% Assay	Mean % assay
1	0.05	0.04998	99.959	99.55
	0.0501	0.04982	99.457
	0.0502	0.04983	99.259
2	0.1	0.09980	99.807	98.60
	0.101	0.09995	98.969
	0.103	0.09996	97.047
3	0.1502	0.15009	99.927	99.92
	0.15	0.15024	100.161
	0.1504	0.14993	99.693
4	0.2004	0.19855	99.079	99.02
	0.2003	0.19840	99.053
	0.2005	0.19841	98.954
5	0.2502	0.24989	99.879	99.84
	0.2501	0.24974	99.858
	0.2504	0.24989	99.799

Accuracy and recovery:

Accuracy was determined at five different levels i.e., 10%, 20%, 30%, 40% and 50% of the nominal concentration. (0.500 g.) The titration was conducted in triplicate at each level and the titre value was recorded. The tire value obtained in linearity study was considered as true value during the calculation of percentage (%) recovery. The percentage recovery is calculated using following equation.

Titre value x 100

Percentage recovery = –––––––––––––––––––

True titre value

The percentage range recovery of Isoxsuprine hydrochloride was in 98.6 to 99.92 %. It confirms the accuracy of the proposed method. (Table 4).

Ruggedness:

The ruggedness of the method is defined as degree of reproducibility of results obtained by analysis of isoxsuprine hydrochloride sample under variety of normal test conditions such as different laboratories, different analysts and different lots of reagents. Quantitative determination of isoxsuprine hydrochloride was conducted titrimetrically on one laboratory. It was again tested in another laboratory using different instrument by different analyst. The assays obtained in two different laboratories were well in agreement. It proved ruggedness of the proposed method.

CONCLUSION:

The proposed method of simple titrimetric method was found to be precise, accurate and rugged. The values of percentage recovery and standard deviation showed good sensitivity. The method was completely validated. It showed satisfactory data for all the parameters of validation. This is most simple method as compared to all of the methods reported in literature for assay of isoxsuprine hydrochloride. It requires simple apparatus and less costly chemicals. From validation at a it is observed that method is as sensitive as other methods were reported in literature hence it can be used in any analytical laboratory for assay of isoxsuprine hydrochloride as isoxsuprine hydrochloride fumarate form its pharmaceutical dosage such as tablets. Hence it can be easily applied for routine quality control application.

REFERENCES

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Received on 16.02.2020 Modified on 07.03.2020

Asian J. Research Chem. 2020; 13(3):187-189.

DOI: 10.5958/0974-4150.2020.00036.X