Spectrophotometric Determination of Bisacodyl in Pure and Pharmaceutical Preparation via Oxidative Coupling Organic Reaction

A simple, accurate and sensitive spectrophotometric way is used to determine Bisacodyl in pure and pharmaceutical preparations. The proposed method depends on using 2,4-Dinitrophenylhydrazine as chromogenic reagent . The method was based on the oxidative coupling reaction of Bisacodyl with 2,4-Dinitrophenylhydrazine with Sodium periodate in the presence of sodium hydroxide as alkaline media to form red water soluble dye product , that has a maximum absorption at λmax 522nm . Beer , s law is obeyed in the concentration of (2.00–20.00) μg.ml 1 .The molar absorptivity is (6505) L.mol -1 .cm -1 ,a sandall sensitivity of(0.0555) μg.cm -2 ), correlation coefficient of (0.9970) , Limitof detection (LOD) (0.0312 μg.ml -1 ), limit of Quantitation (LOQ) (0. 3125 μg.ml -1 ) and the relative standard deviation of RSD% (1.6). The method gave a successful determination for Bisacodyl in pharmaceutical preparations and the value of recovery % was better than (100.16%) .


Introduction:
Bisacodyl is 4,4` (pyrid -2ylmethylene) bis (phenyl acetate)[ C 22 H 19 NO 4 =361.4] Figure(1) is a laxative used for the treatment of constipation, for evacuation of the colon before radiological of the abdomen, or endoscopy, and before or after surgical operations. It has a little or no action on the small intestine. It stimulates the rectal mucosa, which raises peristaltic movements and causing defecation in 15-30 minutes [1][2][3][4][5] .Doses of 5 to 10 milligrams may be given by mouth and act within 6 to 12 hours.Suppositories of 10 milligrams given by rectum act within one hour.Children under 10 years may be given5 milligrams by mouth or by rectum [6][7][8]. The literature survey reveals that only few methods have been reported for determination of Bisacodyl in pure form and in pharmaceutiacal Open Access . Bisacodyl has been determined by various pharmacopeial and nonpharmacopeial methods. The official methods involve non aqueous titration for Bisacodyl suppositories, spectrophotometry [14][15][16].For enteric coated tablets, and high-performance liquid chromatography (HPLC) [17] for both suppositories and enteric coated tablets. The non pharmacopeial methods for Bisacodyl determination involve spectrophotometry for combinations with piribedil [18].Gas chromatography (GC) in pharmaceutical tablets; GC in urine, serum, and stool [19]. The proposed method is based on the reaction of the Bisacodyl drug with 2,4dinitrophnylhydrazine in the presence of sodium periodate in alkaline medium to form a red water soluble dye product which gave an absorption maximum at 522 nm.

Procedure for assay of Bisacodyl in pharmaceutical preparations Tablets:
Bisacodyl tablets, provided from (SDI) Samara-Iraq (10) tablets were powdered and a amount of the final powder was accurately weighted to give an equivalent to about 10 mg of Bisacodyl was dissolved in distilled water . The prepared solution transferred to 100 ml volumetric flask and made up to the mark with distilled water forming a solution of 100μg.ml -1 concentration. The solution was filtered by Whitman paper to avoid suspended particles. These solutions were diluted quantitatively to form a concentrations in the range of calibration curve.

Recommended procedures:
Into a series of 25 ml volumetric flask, transfer an increasing volume of Bisacodyl solution (100 μg.ml -1 ) to cover the range of calibration curve (2.00 -20.00) μg.ml -1 , added 0.5 ml (0.01 M) of 2,4-Dinitrophenylhydrazine and shake well . Added1.0 ml(0.01M) Sodiume periodate. added 1.0 ml (1.0 M) of NaOH, diluted to the mark with distilled water , and allow the flasks to stand for 30 min at room temperature (25 ºc) . Measure the absorption at( 522 nm) against the blank prepared in the same method but no Bisacodyl.

Results and Discussion:
Bisacodyl drug react with 2,4-Dinitro phenyl hydrazine and Sodium periodate in the presence of sodium hydroxide as alkaline media to form an intense red color product that can be measured spectrophotometrically at 522 nmFigure(1).
A:Bisacodyl Vs distilled water B: Bisacodyl Vs Blank C: Blank Vs distiled water

Study of the optimization Experimental Condition:
The effect of various parameters such as a mount of reactants, order of addition, time and temperature were studied.

Effect of 2,4-Dinitro phenyl hydrazine Volume:
The effect of various volume of 2,4dinitrophenylhydrazine were investigated. A Volume of (1.4ml) of (0.01M) of reagent show the highest absorbance at 522 nm and was chosed for further use. the results are shown in Figure(2) . nm The Effect of Sodium periodate NaIO 4 Volume: The effect of NaIO 4 volume was studied. Avolume of (2 ml) of (0.01M) gave the higher absorption intensity at λ max 522 nm. Figure(3) and thus was selected as optimum volume for further use.

Effect of alkaline media type:
Bisacodyl drug react with Dinitro pheny lhydrazin in the presence of alkaline medias therfore the type of alkaline media is an obtained showed that sodium hydroxide gave the best absorbance Table(1) and was used in the general procedure. The Effect of Sodium hydroxide NaOH volume: The effect of NaOH volume was similarly studied.Avolum of (0.6ml) of (1M ) NaOH gave the higher absorption intensity at 522 nm Figure (  The effect of order of reagents addition on the absorption of red product dye was investigated. Table(2) shows the order of addition could be followed,(Drug:2,4-Dintrophenylhydrazin:NaIO 4 : NaOH). Due to show the highest absorption and thus was selected for further use. The Effect of Temperature: The influence of Temperature on determined color intensity of the product was evaluated in practice the highest absorption was obtained when the product color was developed at (25ºc) Figure(6). Using optimum conditions, a linear calibration curve for the determination of Bisacodyl was determined over the concentration range of (2.0 -20.0) μg.ml -1 . The linear regression equation for the determination of Bisacodyl is (Y= 0.018 X + 0.176) and correlation coefficient of 0.9970 The linear calibration graph is shown in Figure(8).
The statistical treatments of the analytical data are shown in Table(3).

Nature of the dye product:
The stoichiometry of the reaction between Bisacody l,2,4-Dinitrohydrazine, NaIO 4 and NaOH was investigated using the mole ratio and Slope ratio method [21][22][23][24] unsing the optimized conditions. The results in Figure (9), (10), show a 1:1 drug to reagent product were formed. Therefore the formation of the product may probably occurs as follows: Proposed method has been applied for the determination of Bisacodyl drug in pharmaceutical preparations with good accuracy and precision for the drugs studied. The results obtained were given in Table(4) which confirm Finally, the proposed procedure was compared successfully with the standard procedure Table(3).

Conclusion:
A simple, accurate and excellent spectrophotometric method was investigated for the determination of Bisacodyl in pure and in pharmaceutical preparations. The proposed method can be carried out with no need for further steps such as solvent extraction step , pH or Temperature control .