Tikrit Journal of Pure Science

T his study includes determination Montelukast sodium by using flow injection chemiluminescence technique, the optimum concentrations were (150) ppm of magnesum ion, (5×10 -4 ) M luminol, (0.001) M hydrogen peroxide, linearity of concetraction (0.1-0.001) M that give the highest luminescence intensity, and correlation cofficient was (0.9054), The relative standard deviation RSD% (2.3) and detection limit (0.0001) M and relative error (0.018) ,the percent recovery (97%).


The structural formula of Montelukast Sodium
While the common name according to the factoring companies is Singulair -Montelukast Sodium [2] and the molecular formula is C 35 H 36 ClNO 3 SNa 1-1-2 drug proprties [1] It is a white hygroscopic powder, freely soluble in water, it is odorless and melting point at 130° C and dissociated at same degree, where, the drug restricting chemical compound that called Leukotrienes which plays an intersting role in allergic response and inflammations, this restricting of that activity to prevent the bronchial constriction and improves the main symptoms of asthma.1-1-3 drug uses 1-Laryngitis 2-Chronic asthma 3-Rhinitis 1-1-4 The techniquies that used for determination Montelukast Sodium Guo[3] determined the Montelukast by indirect chemiluminescence and by quinine as receptor, where the tetra cerium oxidizing by sulpheric acid and the detection limit was 0.36 µmol per ml .While, Song [4] was used photometric spectrum technique, promothymol used in determination at 420 nm and detection limit was 4mg/ml.Liang [5] could to determination drug by fluorescence technique at linear limit 0.4-4 mg/l at detection limit reached to 0.04 mg/l.while, Zeng [6] was able to determine the drug by measuring the stability of photometric spectrum and TLC, using coated thin layer (silica gel 60 F 354) and acetonitrile / ethanol-water as a mobile phase and the detection limit was 2.1 gm/ml.The researcher Zhou [7] was able to determine the drug by measuring chemiluminescence technique using cobalt ion as catalyst by chemiluminescence suppression .

2-1 Working conditions 2-1-1 Study of ion catalyst selection
The selection ofion catalyst in this technique was done by experimented numbers of ion catalyst (platinum, Zirconium, Manganese, and Thorium) to determine the ability of these ions in stimulation the luminol oxidation with hydrogen peroxide and it's ability to formation complexes with the drug which in turn leads to suppression or stimulation of chemiluminescence intensity for this substance.

2-1-2 Selection the optimum concentration of magnesium ion Mg +2
The magnesium ion was selected as catalyst, where a series of magnesium concentrations were injected into a range between 110-150 ppm ,for finding the best concentration of Mg +2 , and found the best one was 150 ppm.Where is the weight 0.0742 gram with Magnesium sulfate and dissolved in distilled water in volumetric flask 100 ml capacity thus prepare 150 ppm of Magnesium sulfate .

2-1-3 Study of Luminol concentration
The effect of Luminal concentration on the intensity of chemiluminescence was studied by taken different concentration of Luminol ranging between (5x10 -4 -10 -6 ) M , after injection 150ppm Mg +2 ion .

2-1-4 Study of hydrogen peroxide effect
The effect of different concentrations of hydrogen peroxide on the emission intensity was studied at rang (10 -3 -10 -6 ) M, after fixing the concentration of Mg +2 and Luminol solution with injected 150 ppm Mg +2 ion.

2-1-5 Study of the acidity effect for Mg +2 ion on the luminscence intensity
Series of acid concentration ranging between (10 -3 -10 -5 ) M was prepared, and the ion catalyst was dissolved in it, all that was done to show the acidic effect for ion catalyst on the emission intensity .

2-1-6 The volume effect of injection sample for ion catalyst
The effect of injector ion volume was studied, after fixing all chemical variables, by changing the length of curve tube in loop, where taken different volumes (150-400 µl) after injection 150ppm.

2-1-7 Study the effect of flow velocity rate
After fixing all chemical variables and the volume of injector ion, the effect of flow velocity rate of solutions on the emission intensity of chemiluminescence was studied by changing the flow rate from 2 to 4 ml/min.

2-1-8 Measurment the dilution degree
The effect of dilution degree on the flow injection system was studied in case of presence and absence the ion exchanger columns by the following equation :D=H 0 / H max H 0 = represents the luminscent emission of Mg +2 ion in milli volt where it passes instead of the current .H max = represents the luminscent intensity of Mg +2 ion 2-1-9 Standard curve design to determining the montelukast drug Series of montelukast solutions were prepared at different concentrations between (10 -1 -10 -4 M ) by diluted wih aqueous solution from Mg +2 at concentration 150ppm, then injected five times for each concentration simultaneously and recorded the average of five readings .

2-1-10 Measurment of accuracy and regulation in determination the montelkast drug
Theaccuracy and precision in determination montelukast drug were measured by measuring the relative standard deviation, relative error, and recovery, the optimum conditions for determination were obtained .

2-1-11 Applications
The optimum conditions that obtained were applied to determining drugs, where five tablets of drugs form were crushed and one tablet was weighted (2) gram (pioneer company pharmaceutical) As Sulaymaniyah, Iraq.then dissolved in Mg +2 ion at concentration 150 ppm using ultrasonic bath, which supplied with a water bath, in volumetric flask (100ml) for 10 min., then, the sample was filtered on the filter paper and the leach ate put in suitable volumetric flask and the volume completed with Mg +2 to gained the concentration of solution at (0.1-0.0001M), each concentrations were injected simultaneously and recorded the average of five readings.

3-1-1 Selection the best concentration of magnesium
Magnesium ion was selected as best metallic ion to the drug determination, and has ability to oxidizing luminol with hydrogen peroxide .table (2) show the relationship between concentrations of series standard solution that prepared from Mg +2 ion at concentration 110-150 ppm with increasing of chemiluminescence intensity.150 ppm was selected as best concentration to give it the highest chemiluminescence intensity, where sharp values in regular manner were obtained.
While, at low concentration, the broad and not sharp were recorded, that mean , no irregularity of bands .

Table (2) the relationship between Mg +2 concentration and the intensity of chemical luminescence emission
Mg +2 concentration (ppm) The

Figure (1) relationship between the intensity of chemiluminescence emission and Mg +2 concentration 3-1-2 Selection the best concentration of Luminol
After the selection best concentration of Mg +2 ion, the effect of Luminol concentration on the emission intensity of chemiluminescence was studied by changing the luminol concentration at range (5x 10 -4 -10 -6 M) and the results were obtained as shown in table (3) recorded after fixing all chemical variables.it was observed that the luminescence increase with the increasing of luminol concentration (the donor molecule to luminesce) and the recorded that, 5x10 -4 M was the best concentration to give it the highest intensity.according to the previous studies [8] the decrease may be happened in chemiluminescence intensity duo to the increasing in luminol concentration.That may be leading to increasing in the numbers of donor molecules as luminescence light in surrounding that leading to free collisions between the reacting molecules, some of it which entered in collision and producing excited molecules and the excess of it will reacting with molecules of reactants in surrounding, and luminol excited molecules causing loss in energy as thermal energynon radioactive -and thus chemiluminescence emission reduce.The effect of hydrogen peroxide on chemiluminescence emission intensity was studied after fixing the concentration of ion catalyst and luminol at range (10 -3 -10 -6 M), the (10 -3 M) was selected as the optimum concentration to give it the highest chemiluminescence intensity with peaks , and noticed that a weak emission of chemiluminescence was obtained at low concentration of hydrogen peroxide due to the lack of light emittingparts because to the concentration of oxidizing substances.the obtained results show in table (4).5) shows the acidity effect for the solution that Mg +2 ions dissolved in it, so that at several concentration of hydochloric acid (10 -3 -10 -5 M) were selected to dissolving Mg +2 ion in range 110-150 ppm with fixing the concentration of luminol and hydrogen peroxide.the 10 -3 M was selected as optimum concentration to give it the highest intensity with sharp peaks that due to ability of hydochloric acid to releasing protons more than other acids, leading to increase the ability of ion catalyst to oxidizing the luminol and thus increasing the intensity of chemilumienscence emission [9].

Figure (4) the effect of acidity on Chemilumeinscence intensity 3-1-5 effect of injected sample volume of ion catalyst
Effect of injected ion volume was studied after fixing all variables by changing the length of loop and noticed that the response was increase with increasing the volume of injected sample but the response represented at boarded peaks (more response) time, that result, of continuous emission, due to the length of sample part in the reaction phase versus the sensor (a saturation state happened for photo multiplying tube PMT), according to that, volume 350 µl was selected because it give the response with sharp and regular peaks but with sensitivity less than that resulting from larger volumes, therefore, the volume selection must be based on balance between the shape of response and it's intensity and the measured sensitivity, as well as the economy in the chemicals consumption.The dilution degree was calculated in presence and absent the ion exchanger columns because the flow injection technique is effects by dilution degree , all results that obtained from our study shown in table (8).

3-1-9 Measurment of accurcy and precision in drug detremination
After fixing the optimum conditions to determination the drug , the accuracy and precision were calculated by calculation the recovery and recovery rate was (97-99%), the relative standard deviation (RSD) ranging at (2.2-2.9 %) , while the relative error was (0.9 -0.18).

3-1-10 Applications
The optimum conditions for drug determination were applied and series of concentrations were prepared and the relative error, recovery, and relative standard deviation were calculated, the results shown in table (11).where the concentration of hydrogen peroxide was higher than luster intensity and was linear at concentration (0.905), while the relative standard deviation (2.3), the detection unit (0.0001) M, the relative error (0.018), the retrieval rate of less than 97%.

3
Figure (2) relationship between luminol concentration and intensity of chemiluminescence figure (3) relationship between hydrogen peroxide concentration and Luminescence intensity3-1-4 Effect of catalyst acidity on the luminescence intensityTable(5) shows the acidity effect for the solution that Mg +2 ions dissolved in it, so that at several concentration of hydochloric acid (10 -3 -10 -5 M) were selected to dissolving Mg +2 ion in range 110-150 ppm with fixing the concentration of luminol and hydrogen peroxide.the 10 -3 M was selected as optimum concentration to give it the highest intensity with sharp peaks that due to ability of hydochloric acid to releasing protons more than other acids,

Figure ( 5 )
Figure ( 5) effect of injected volume on chemiluminescence intensity3-1-6 Effect of ions flow rateEffect of flow rate for solution on the intensity of chemical luminescence emission was studied, after fixing all chemical variables, by changing the flow rate from 2 to 4 ml/min for hydrogen peroxide and luminol, and noticed that the increasing of emission intensity happened with increasing the flow rate at beginning 2-4 ml/min because the high flow rate leading to rapidity lightness segment that exit from measurement cell (there was a little to recording a signal), therefore, 3-5 ml/min was selected because

Table ( 8 ) 3 - 1 - 8
figure (8) the obtained results from measurment of dilution degree ( after placing the column of exchanger ion ) flow injection process Picture showing flow injection device Conclusions A simple and accurate method for estimating Montelukast sodium was developed by flow injection chemiluminescence technique.150 ppm was tested as the highest concentration of magnesium ion 5 × 10 -4 and as the best concentration of luminol (0.001) M