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 a 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, titrimetric¹⁰and miscellaneous^11,12 methods for the estimation of isoxsuprine hydrochloride. Simple, rapid and reliable non 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

EXPERIMENTAL:

Instrumentation:

An potentiometric titrator was used (Lab-India-Auto titrator) for assay method development and validation.

A Simadzu analytical balance with 0.01mg was used.

Reagents and chemical:

Reference standard of isoxsuprine hydrochloride was obtained from reputed firm with certificate of analysis.

Potassium hydrogen phthalate, perchloric acid, mercury acetate and glacial acetic acid of A. R. grade were used.

General procedure

Standardization of 0.1 N perchloric acid

About 0.350mg of potassium hydrogen phthalate (previously powdered lightly, dried at 120^oC for 2 hours) was weighed accurately into clean and dry titration jar. It was dissolved in 50ml of glacial acetic acid. It was titrated with 0.1N perchloric acid by using auto titrator. Blank determination was performed out for necessary correction. The titration was performed in duplicate.

One ml of 0.1 N HClO₄ is equivalent to 0.2042g. of potassium hydrogen phthalate (C₈H₅KO₄)

Normality of perchloric acid = ----------------

B.R. x 0.2042

Where W is weight of potassium hydrogen phthalate in g.

B.R. is burette reading in ml.

Quantitative determination of Isoxsuprine hydrochloride:

About 0.100g. of isoxsuprine hydrochloride test sample was weighted accurately into a clean and dried titration jar. It was dissolved in 60ml. of anhydrous glacial acetic acid. It was heated to dissolve isoxsuprine hydrochloride and 15ml of 5% (w/v) mercuric acetate was added.

It was titrated with 0.1N perchloric acid potentiometrically.

Blank determination was also carried out for necessary correction.

One ml of 1N perchloric acid is equivalent to 0.03014g. of terbutaline sulphate

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

B.R. x N x 0.03014 x 100 x 100

% assay = _____________________________

W x 0.1

Where

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

N is actual normality of 0.1 N perchloric acid.

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 terbutaline sulphate. The assay of isoxsuprine hydrochloride (on the dried basis) of various batches of test sample was analyzed using the above method. It was in the range of 98.65 to 99.96%.

Analytical method validation:

The method precision was checked after analyzing six different preparations of homogeneous test sample of terbutaline sulphate. The % RSD of results obtained was found to be 0.4656. 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	Burette reading in ml	Normality of perchloric acid	% assay
1	0.100	3.29	0.1009	99.65
2	0.102	3.3	0.1009	98.96
3	0.104	3.28	0.1009	99.35
4	0.101	3.29	0.1009	98.66
5	0.100	3.3	0.1009	99.95
6	0.105	3.28	0.10	99.35
			Mean	99.32
			Std. Deviation	0.4624
			RSD	0.4656

Linearity:

For the establishment of method linearity, five different weights of isoxsuprine hydrochloride test samples corresponding to 20%, 40%, 60% 80% and 100% 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 gm	Burette reading	Normality of Perchloric acid	% assay
1	0.1	3.3	0.1005	99.95
2	0.2	6.6	0.1005	99.95
3	0.3	9.9	0.1005	99.95
4	0.4	13.1	0.1005	99.20
5	0.5	16.5	0.1005	99.95
			Mean	99.80
			Std. Deviation	0.3386
			RSD	0.3393

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	32.9
Intercept	0.01
Coefficient of co-relation	0.9999

Accuracy and recovery:

Accuracy was determined at five different levels i.e., 20 % ,40 % ,60 % ,80 % and 100 % 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 99.06 to 99.94 %. It confirms the accuracy of the proposed method. (Table 4).

Table no 4: accuracy and precision

Level no.	Weight of Isoxsuprine hydrochloride added	Weight of Isoxsuprine hydrochloride found	% assay	Mean % assay
1	0.1	0.099959	99.95931	99.42
	0.101	0.099656	98.66971
	0.1	0.099656	99.6564
2	0.2	0.199616	99.80786	99.74
	0.201	0.199919	99.462
	0.2	0.199919	99.95931
3	0.3	0.300181	100.0603	99.94
	0.3	0.300484	100.1612
	0.301	0.299878	99.62722
4	0.4	0.397111	99.27777	99.06
	0.401	0.396808	98.95466
	0.401	0.396808	98.95466
5	0.501	0.499797	99.75979	99.80
	0.5	0.499494	99.89873
	0.501	0.499797	99.75979

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 potentiometrically 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 non-aqueous potentiometric titration was found to be precise, accurate and rugged. The values of percentage recovery and standard deviation showed sensitivity. The method was completely validated. It showed satisfactory data for all the parameters of validation. Hence it can be applied for routine quality control application.

REFERENCES:

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12. Rele Rajan V. Tiwatane Prathamesh P. A Non-aqueous Potentiometric Titration Method for Validation of Imatinib mesylate from Pharmaceutical Dosages. Asian J. Research Chem. 12(6); 2019:307-310.

Received on 23.07.2020 Modified on 02.08.2020

Asian J. Research Chem. 2020; 13(6):465-468.

DOI: 10.5958/0974-4150.2020.00082.6