1. INTRODUCTION:
-[o-(1-hydroxy-1-methyl
ethyl) phenethyl] benzyl]thio]-methyl] cyclopropaneacetate1, as
shown in Figure (1). (MON) is an antagonist of cysteinyl leukotriene receptor, on
20/2/1998 FDA approved the utilization of MON for chronic treatment of asthma, preventing
airway edema, smooth muscle contraction and enhanced secretion of thick,
viscous mucus2. The previous researches, which were published for
the evaluation of (MON) (as individual drug or in its combination with other
drugs), were limited in some analytical techniques such as HPLC3-6,
UV spectrophotometric7-9, TLC10, capillary
electrophoresis11, Potentiometric titration12, and
voltammetric13. There was no previous ion-selective electrode method
for the analysis of MON, which encouraged us to construct a new, simple, precise,
eco-friendly and economic potentiometric method for the determination of
previously mentioned drug.
Pencil graphite electrodes are a developed form of ion-selective electrodes. It excels over the traditional ion-selective electrodes in that there is no need to an internal filling solution, the small size which enable us to use them in biological systems, their fast response time, long lifetime and simple preparation14.
Figure 1. chemical structrure of MON
2. MATERIAL AND METHODS:
2.1 Apparatus:
Radiometer analytical–Ion Check 10pH/mv meter (CEDEX- France), Crison pH meter model Glp21/EU (Spain), ultrasonic bath model Power Sonic 405(Korea), hot- plate magnetic stirrer MS 300 BANTE (CHINA). All weights were weighed by Sartorius balance design 2474 (Germany) its exactness ± 0.1mg.
2.2: Chemicals and reagents:
High pure Montelukast sodium supplied by Unipharma Pharmaceutical industry (Damascus, Syria), Strontium nitrate (BDH chemicals, England), high molecular weight PVC (SABC. KSA), tetrahydrofuran solvent (MERCK 99.5%), di- butyl phthalate (MERCK 99%).
2.3. Pharmaceutical forms samples:
Azmalir 4mg chewable tablets, 10mg film coated tablets (Unipharma pharmaceutical company), Lukast 4mg chewable tablets, 4mg granules (AL Fares pharmaceutical company).
2.4. Standard solutions:
The stock solution of pure montelukast sodium (0.1 mol/l) was prepared by dissolving accurate weight in bi-distilled water. It was found that this solution was steady for 24 hrs., at room temperature in amber flask outlying from light. Working solutions (10-2 -10-7mol/l) were prepared by diluting the stock solution with bi-distilled water in 25ml volumetric flasks.
2.5 Procedure:
2.5.1 Preparation of ion pair
The ion pair, which is considered the active part in the electrode, was prepared by mixing 1mmol of strontium nitrate with 1mmol montelukast sodium, an off-white precipitate was formed, then we filtered the precipitate and rinsed it several times by bi-distilled water, and left it to dry in room temperature for 24 hrs.
2.5.2 Fabrication of the coated graphite electrode:
The coated graphite electrode was fabricated by immersion the end of a graphite rod (2mm in diameter)- after washing it by acetone and left it to dry for 30 minutes- in the coating solution, which consists of PVC (30%) as polymeric template, DBP (60%) as plasticizer, and the ion pair was mentioned previously (10%). The three previous components were dissolved in an adequate volume of tetrahydrofuran (THF). We repeated this immersion step various times to get a suitable thickness of polymeric film that was required. The coated graphite electrode was activated before starting measurements, by dipping it in 10-3mol/l MON solution for 24 hrs.
2.5.3 Direct potentiometric determination of MON in its pure samples:
The previously constructed electrode in junction with Ag/AgCl reference electrode was used for potentiometric measurements of standard solutions (10-2-10-7)mol/l. The measured potential was plotted against the minus logarithm of (MON) concentration according to Nernstian equation
E=E0+ RT/ZF Log [MON]
Effect of pH 2.5.4:
The influence of pH on potential measurements was studied for (10-3 and 10-4) mol/l MON solutions, over pH range (2-12), this was adjusted by adding aliquots of hydrochloric acid and sodium hydroxide. The potential response at each pH value was recorded.
2.5.5 Selectivity of the electrode:
The sensitivity of the constructed sensor was determined in the presence of some obstructive ions and excipients, which may exist with the drug material. The sensitivity was calculated by the matched potential method. In this method, the selectivity coefficient is described as the activity ratio of the essential and the interfering ion that exhibit the equal potential change(15).
K= (à-αA)\αB
K: selectivity coefficient
à: activity of essential ion
αB: activity of interfering ion
αA: fixed activity of primary ion
2.5.6 Application the proposed method to pharmaceutical dosage forms:
The proposed method was applied for the determination of montelukast sodium in some local pharmaceutical preparations that were mentioned in (2.3 section). Twenty tablets of each medication were finely powdered; exact weight proportionate to one tablet was taken (in case of tablets, and the content of one sachet in the case of granules), and dissolved with water and sonicate the solution in the ultrasonic bath for 5 minutes. Then the solution was filtered, an appropriate volume was taken from the filtrate and diluted with bi-distilled water in a 25ml volumetric flask to get 10-4mol/l of drug solution.
3. RESULTS AND DISCUSSION:
Ion selective electrodes have attracted the interest of researchers in recent years(16–25), the main objective for the pencil graphite electrodes is to develop the quality of traditional ion selective electrodes. The most important advantage of the pencil graphite electrode is that there's no need for the internal filling solution, which offers many points of interest such as simplicity, better mechanical adaptability, and the probability of miniaturization.
3.1 Calibration of the constructed graphite sensor:
The constructed graphite electrode was dipped into a standard series solutions; their concentration ranging (10-1–10-7)mol/l, the potential of each solution was measured, then a calibration graph was plotted between the potential and the minus logarithm of concentration as shown in Figure (2)
Figure 2. calibration curve of (MON.Sr) graphite electrode
3.2 Effect of pH:
The effect of pH on the measured potential was studied using two concentrations (10-3,10-4)mol/l. The pH of these solutions was adjusted between (2-12), using a little volume of HCl and NaOH, and the potential was measured against each pH value. We found that the electrode works effectively in pH range (5-9.5) with no change in the estimated potential as shown in Figure (3).
Figure 3. effect of pH on the electrode response using (0.001, 0.0001)M MON solutions
3.3 The electrode lifetime:
To estimate the lifetime of the constructed electrode, we calculated the slope of the linear range of montelukast sodium solutions over several days. The electrode was kept dipped into 10-3mol/l solution when not used. The results showed that the graphite electrode keeps working effectively for 35 days, in that the slope remained almost constant over these days, which reveals the robustness of the proposed sensor.
3.4 Validation of the method:
The validation of the method was studied according to ICH protocol(26):
3.4.1 Linearity and the range:
The linearity was estimated using 10 standard solutions of the drug; their concentrations range between (10-2- 10-7) mol/l as shown in Figure (4). The results are displayed in the Table (1)
Table 1.parameter data obtained from the linear equation.
|
Parameter |
Results |
|
Linear range (mol/l) |
(10-2-10-5) mol/l |
|
Slope±SD (mV.decade-1) |
28.563±0.07 |
|
Correlation coefficient |
0.9999 |
|
Intercept (mV.decade-1) |
-64.62 |
Figure 4. the linearity range of MON.Sr graphite electrode
3.4.2 Accuracy:
The accuracy of the method was verified by calculating the recovery for three concentrations, chosen among the linear range, each concentration was measured three times. It was observed that the proposed method is accurate according to the recovery values as appeared in the Table (2)
Table 2. Direct potentiometric determination of MON in bulk solutions.
|
C taken (mol/l) |
C taken (PC) |
C found (mol/l) |
R%± SD |
|
5*10-3 |
2.301 |
5.01*10-3 |
100.16±0.81 |
|
5.05*10-3 |
|||
|
4.96*10-3 |
|||
|
5*10-4 |
3.301 |
5.03*10-4 |
101.40±0.70 |
|
5.07*10-4 |
|||
|
5.10*10-4 |
|||
|
5*10-5 |
4.301 |
4.96*10-5 |
99.40±0.80 |
|
4.93*10-5 |
|||
|
5.01*10-5 |
3.4.3 Precision:
The precision of the method was studied at two levels, repeatability, and intermediate precision. For that test three concentrations (5*10-3,5*10-4,5*10-5)mol/l were measured separately three times daily and on two different days. RSD% was calculated, the results that we got are exhibited in the table (3).
Table 3. the precision values of the established method.
|
Concentration mol/l |
repeatability |
Intermediate precision |
||||
|
R% a |
SD |
RSD% |
R% b |
SD |
RSD% |
|
|
5*10-3 |
100.32 |
1.01 |
1.01 |
99.96 |
1.295 |
1.296 |
|
5*10-4 |
||||||
|
5*10-5 |
||||||
a and b: average of recovery of 3 concentration each concentration repeated for 3 times intraday and interday respectively.
3.4.4 Selectivity:
The selectivity of the constructed graphite electrode was estimated as mentioned in (2.5.5) paragraph. The selectivity coefficients showed high selectivity toward montelukast sodium in the presence of multi obstructive ions and excipients, which demonstrates the sensitivity of the method, as shown in the Table (4).
Table 4. selectivity coefficients of (MON.Sr) graphite sensor by the matched potential method
|
Interfering B |
K fex,B |
selectivity |
|
CaCl2 |
1.9*10-2 |
52.6 |
|
KCl |
3.4*10-2 |
29.4 |
|
Nh4Cl |
5.1*10-2 |
19.6 |
|
NaCl |
2.5*10-2 |
40 |
|
Dextrose |
1.3*10-2 |
76.9 |
|
Mg stearate |
1.7*10-2 |
58.8 |
|
Avicel |
8.4*10-3 |
119 |
3.5 potentiometric determination of montelukast in pharmaceutical forms:
The proposed electrode was utilized for the assaying of MON in the pharmaceutical formulations. The results indicated the affectability of the electrode for the determination of montelukast drug forms, which affirmed by recovery values, and by a comparative study between the submitted, and spectrophotometric reference method27, the statistical analysis using t-test and f-test demonstrated that there is no critical difference among the proposed and reference method as presented in the Table (5).
Table 5. determination of (MON) in pharmaceutical preparations using the proposed method and a spectrophotometric reference method.
|
Drug |
R% ± SD (proposed method) |
R% ± SD (reference method)(27) |
t- valuea |
f-valueb |
|
Azmalir 4 mg chew. tab. |
99.75±0.86 |
99.83±0.75 |
3.27 |
1.30 |
|
Azmalir 10mg f.c.tab. |
100.53±1.70 |
100.16±1.15 |
3.50 |
2.19 |
|
Lukast 4mg chew.tab. |
100.75±1.56 |
100.66±0.77 |
2.73 |
4.04 |
|
Lukast 4 mg granules |
100.04±0.32 |
99.69±0.44 |
2.19 |
1.89 |
a: t critical 4.302 (0.05)
b: f critical 19 (0.05), n=3.
4. CONCLUSION:
This study provides a novel, simple, and eco-friendly method for the determination of montelukast sodium in its pure and pharmaceutical dosage forms, unlike our constructed method, all the previous analytical studies for the determination of this drug are complicated and acquire a lot of steps and apparatuses for analysis. The advantages of the graphite electrode were observed as mentioned previously in this article. So we recommend using this type of electrodes as an alternative method for the analysis of drugs.
5. REFERENCES:
1. The United States Pharmacopeia. in: USP38-NF33 ed. United States Pharmacopeial Convention INC; 2015. p. 4444.
2. Sweetman SC. Martindale: The Complete Drug Reference. in: 37th ed. Pharmaceutical Press; 2011. p. 1240.
3. Shakya AK, Arafat TA, Hakooz NM, Abuawwad AN, Al-Hroub H, Melhim M. High-performance Liquid Chromatographic determination of montelukast sodium in human plasma: Application to bioequivalence study. Acta Chromatogr. 2014; 26(3): 457–72.
4. Naaz A, Vani R. Simultaneous Estimation of Montelukast and Levocetirizine in Its Bulk and Liquid Dosage form by RP-HPLC. 2015; 5(10).
5. Shrikrishna B, Nisharani R. Analytical Method Development and Validation for Simultaneous Estimation of Montelukast and Ebastine by HPLC. Res J Pharm Technol. 2015; 8(1): 651–8.
6. Chauhan B, Rani S, Nivsarkar M, Padh H. A new liquid-liquid extraction method for determination of montelukast in small volume human plasma samples using HPLC with fluorescence detector. Indian J Pharm Sci. 2009; 68(4): 517.
7. Humaira S, Munde MR, Road OJ. Validated UV Spectroscopic Method for Estimation of. 2010; 01(11): 4–8.
8. Muralidharan S, Jia Qi L, Ting Yi L, Kaur N, Parasuraman S, Kumar J, et al. Newly Developed and Validated Method of Montelukast Sodium Estimation in Tablet Dosage Form by Ultraviolet Spectroscopy and Reverse Phase - High Performance Liquid Chromatography. Pharmacol Toxicol Biomed Reports. 2016; 2(2): 27–30.
9. Patel NK, Chouhan P, Paswan SK, Prakash K. Development and validation of a UV spectrophotometric method for simultaneous estimation of combination of Montelukast sodium in presence of Levocetirizine Dihydrochloride. Paswan [Internet]. 2014; 6(3): 313–21. Available from: http://www.scholarsresearchlibrary.com/articles/development-and-validation-of-a-uv-spectrophotometric-method-for-simultaneous-estimation-of-combination-of-montelukast-s.pdf
10. Tandulwadkar SS, More SJ, Rathore AS, Nikam AR, Sathiyanarayanan L, Mahadik KR. Method Development and Validation for the Simultaneous Determination of Fexofenadine Hydrochloride and Montelukast Sodium in Drug Formulation Using Normal Phase High-Performance Thin-Layer Chromatography. ISRN Anal Chem. 2012; 2012: 1–7.
11. Shakalisava Y, Regan F. Determination of montelukast sodium by capillary electrophoresis. J Sep Sci. 2008 Apr 1; 31:1137–43.
12. Aslan N, Erden PE, Canel E, Kilic E. Development and validation of a potentiometric titration method for the determination of montelukast sodium in a pharmaceutical preparation and its protonation constant. Bulg Chem Commun. 2014; 46(3): 497–502.
13. Alsarra I, Al-Omar M, Gadkariem EA, Belal F. Voltammetric determination of montelukast sodium in dosage forms and human plasma. Farmaco. 2005; 60(6–7): 563–7.
14. Khattab FI, Ramadan NK, Hegazy MA, Ghoniem NS. Microsized Graphite Sensors for Potentiometric Determination of Metronidazole and Spiramycin. Port Electrochim Acta. 2011; 29(2): 79–90.
15. Ion-Selective Electrodes: Recommended Kri. Union Int Pure Appl Chem. 1995; 67(3): 507–18.
16. Haroun M, Nashed D, Sakur AA. New electrochemical methods for the determination of Prasugrel using drug selective membranes. 2017; 5(3): 30–6.
17. Sakur AA, Nashed D, Haroun M, Noureldin I. Determination of prasugrel hydrochloride in bulk and pharmaceutical formulation using new ion selective electrodes. Res J Pharm Technol. 2018; 11(2): 631–6.
18. Mansour O, Nashed D, Sakur AA. Determination of Clopidogrel bisulphate Using Drug Selective Membranes. Res J Pharm Technol. 2018; 11(5).
19. Dabbeet H, Sakur A, Noureldin I. Novel Drug Selective Sensors for Simultaneous Potentiometric Determination of both Ciprofloxacin and Metronidazole in Pure form and Pharmaceutical Formulations. Res J Pharm Technol. 2019 Aug 27; 12: 3377–84.
20. Nashed D, Sakur AA. New Electrochemical Method for Determination of a Compound Derivative from Thienopyridine Using Drug Selective Membranes. has. M.Sc. Thesis in applied analytical chemistry, Faculty of Pharmacy, Aleppo University; Supervisor A.A. Sakur; 2018.
21. Dabbeet HA, Sakur AA. Development of an Electrochemical Method for the Determination of a Compound Derivative from Fluroquinolone. M. Sc. Thesis in applied analytical chemistry, Faculty of Pharmacy, The University of Aleppo; Supervisor A.A. Sakur.; 2016.
22. Nasser B, Mandil H, Sakur AA. Determination of Some Antibiotic (Ciprofloxacin, Norfloxacin and Gatifloxacin) in Pure Form and Pharmaceuticals Formulations Using Electrochemical Titrations. Ph.D. Thesis in applied analytical chemistry, Faculty of Pharmacy, Aleppo University; Supervisor H. Mandil. A.A. Sakur; 2013.
23. Sakur Aa, Bassmajei S, Dabbeet HA. Novel Moxifloxacin Ion Selective Electrodes for Potentiometric Determination of Moxifloxacin in Pure Form and Pharmaceutical Formulations. Int J Acad Sci Res. 2015;3(4): 66–75.
24. Mandil H, A.A. Sakur, Nasser B. New ion selective electrode for potentiometric determination of gatifloxacin in pure form and pharmaceutical formulations. Int J Pharm Pharm Sci. 2013;5(2).
25. Mandil H, Sakur AA, Nasser B. Use of cerium (IV) in potentiometric titration of norfloxacin in pharmaceutical preparations. Asian J Chem. 2012;24(7): 2985–8.
26. International Conference on Harmonization (ICH), Validation of Analytical Procedures: Text and Methodology, Q2(R1), IFPMA, Geneva. 2005.
27. Babu KP and PS, Department. Validated UV Spectroscopic Method for Estimation of Montelukast Sodium from Bulk and Tablet Formulations. International J Adv Pharmacy, Biol Chem Res. 2012; 1(4): 450–3.
Received on 28.02.2020 Modified on 18.04.2020
Accepted on 11.05.2020 © RJPT All right reserved
Research J. Pharm. and Tech 2021; 14(3):1279-1283.
DOI: 10.5958/0974-360X.2021.00226.2