2010) 1( 23مجلة ابن الھیثم للعلوم الصرفة والتطبیقیة المجلد طریقة مباشرة وطریقة غیر مباشرة لتعیین البراسیتامول في مستحضرات هیدروكسي بنزوات الصودیوم-2- امینو-باراصیدالنیة باالزدواج التأكسدي مع ليخالـد فهـد عـ، سرمد بهجت دیكران ،اسماء هاشم شاكر* جامعة تكریت، كلیة التربیة للبنات، قسم الكیمیاء* جامعة بغداد، ابن الهیثم-كلیة التربیة، قسم الكیمیاء الخالصة تعتمد الطریقة على اقترانه مع . ن لتقدیر الباراسیتامول في الوسط المائيان وحساستان سهلتان طیفیتاطریقت تطور ط ) AHB(الصودیوم هیدروكسي بنزوات-2- امینو-كاشف بارا بوجود العامل المؤكسد بیریودات الصودیوم في الوس λmax =470لون بني برتقالي ذائب في الماء التي یقاس امتصاصها عند الطول الموجي يذ مركبالحامضي لتكوین مول.لتر 3371وقد بلغت قیمة معامل االمتصاص الموالري . نانومیتر -1 سم. -1 مكغم 0.0449، وداللة ساندل تساوي سم. -2 مكغم من الباراسیتامول في حجم 500.0 – 12.5واتبعت الطریقة قانون بیر في مدى من التراكیز یتراوح بین مل.مكغم 20.0 – 0.5مل اي 25محلول نهائي -1 بینما ، % 4.70- 0.26وتراوح االنحراف القیاسي النسبي للطریقة بین مستویات من تراكیز الباراسیتامول ةولخمس% 106 - 95المئویة بین بلغت دقتها المعبر عنها بنسبة االسترجاع أما الطریقة الثانیة فتعتمد على تقدیرالباراسیتامول بصورة غیر مباشرة من خالل إجراء تحلل مائي حامضي ) AHB(ت الصودیوم هیدركسي بنزوا-2- امینو-مع كاشف بارا) امینوفینول–البارا (للباراسیتامول ثم مفاعلة ناتج التحلل إذ یتكون مركب ذو لون بنفسجي مزرق ذائب في الماء یقاس أقصى ، بوجود بیریودات الصودیوم في الوسط القاعدي λmامتصاص لها عند طول موجي ax=580 مول.لتر 11884نانومیتر وبامتصاصیة موالریة مقدارها -1 سم. -1 وداللة سم.مكغم 0.0127ساندل -2 مكغم من الباراسیتامول في حجم نهائي 500.0–12.5قانون بیر بین وكانت حدود تطبیق . مل.مكغم 20.0 -0.5مل أي 25 -1 وانحراف قیاسـي % 101.60-94.28وبمعدل نسبة اسـترجاع مئویة تراوح بین ن بنجاح على بعض المستحضرات الصیدالنیة الحاویة على الباراسیتامول تاطبقت الطریق%. 1.1- 0.6نسـبي .مستویات من التراكیز ةالطریقین المباشرة واإلضافة القیاسیة ولثالثوب IBN AL- HAITHAM J . FO R PURE & APPL. SC I VO L. 23 (1) 2010 Direct and Indirect Spectrophotometric Determination of Paracetamol in Pharmaceutical Preparations By Oxidative Coupling With p-Amino-2-hydroxy Sodium Benzoate *A. H. Shakir, S.B. Dik ran, K. F. Ali *Departme nt of Chemistry, College of Education for Women, Tik rit Unive rsity Departme nt of Chemistry, College of Education .I bn-Al-Haitham, Unive rsity of Baghdad Abstract New simple and sensitive sp ectrop hotometric methods for the determination of p aracetamol in aqueous medium were developed. The first method is based on coupling of p aracetamol with p -amino-2-hydroxy sodium benzoate (AHB) in the p resence of sodium p eriodate, as oxidizing agent, to form a brownish-orange comp ound which shows a λm ax at 470 nm. The molar absorp tivity (εm ax) of the colored p roduct was found to be (3371) l.mole - 1 .cm -1 and Sandel’s index 0.0449 μg.cm -2 . The method follows Beer’s law in the concentration range of 12.5-500.0 μg of p aracetamol in a final volume of 25 ml (0.5-20.0) μg.ml -1 with relative st andard deviation p ercent (R.S.D%) ranged between 0.26-4.71% and accuracy, exp ressed by recovery p ercent, 95-106% for five levels of p arcetamol concentration. The second method is based on indirect sp ectrop hotometric p rocedure for the determination of p aracetamol, after its hy drolysis in acidic medium and the reaction of hy drolyzed p roduct (p -aminophenol) with p -amino-2-hydroxy sodium benzoate in the p resence of sodium p eriodate in alkaline medium. A bluish-violet water soluble comp ound is formed with λm ax =580nm and εm ax =11884 l.mole -1 .cm -1 and Sandel’s index 0.0127 μg.cm -2 . Beer’s law is app licable for concentration range of p aracetamol 12.5-500.0 μg p er 25 ml volume of solution (0.5-20.0) μg.ml -1 with (R.S.D %) ranged between 0.60-1.10 % and recovery p ercent 94.28-101.6% for three levels of p arcetamol concentration. The p rop osed methods were successfully app lied for the determination of p aracetamol in p harmaceutical p reparations by both direct and st andard addition method and for three levels of concentration. Introduction Paracetamole chemically known as N-(4-hy droxyp heny l)acetamide is used therap eutically as an analgesic-antip y retic agent alone or associated with other drugs[1], it is effective in treating mild to moderate p ain such as h eadache, n euralgia, and p ain of musculo-skeletal orgin[2]. IBN AL- HAITHAM J . FO R PURE & APPL. SC I VO L. 23 (1) 2010 Sever al analytical methods have been reported for the analysis of p aracetamol in p harmaceutical or biolo gical fluids, include titrimetric [3-6], fluoremetric[7-11], chromatogr aphic[12-14], sp ectop hotometric[15-19] and other p rocedures[20-23]. Some of these p rocedures are not simple for routine analysis and require exp ensive or sop histicated instruments. Oxidative couplin g reactions, which rely on the coup ling of two organic comp ounds in the p resence of oxidizing agent under suitable conditions, could be considered as a typ e amon g the most imp ortant organic reactions which have wide app lications in analytical chemist ry [24,25]. The p resent work describes a sp ectrop hotometric p rocedures for the assay of p aracetamol. The first one is based on coupling with p -amino-2-hydroxy sodium benzoate in the p resence of sodium p erchlorate, whi le the se cond depends on the o xidative couplin g of the acid hy droly zed p roduct of p aracetamol with p -amino-2-hydroxy sodium benzoate in alkaline medium. Experime ntal Apparatus All absorbance measurements were p erformed by usin g a Sp ectronic 21D Uv-visible sp ectrop hotometer, while the sp ectral measurements were carried out with Centra-5 double- beam sp ectrop hotometer using 1-cm silica match cells. The p H measurements were taken with Jenway p H-meter3310. Re agents All reagents were of analytical grade. 1. Paracetamol st ock solution (1000 µg.mL -1 ) was p rep ared by dissolving) 0.1gm of p ure p aracetamol p owder (obtained from the state comp any for drug industries and medical appliance ( S.D.I.), Samar a-Iraq)in 10 mL of ethanol and d iluted to 100 mL with distilled water. Working solutions were freshly p repared by subsequent dilutions. 2. P-amino-2-hy droxy sodium b enzoate (AHB) solution (1.0 x 10 -2 M ) was p repared by dissolving 0.2111 gm of the reagent in distilled water and diluted to 100 mL in a volumetric flask. 3. Sod ium p eriodate solution (1.0 x 10 -1 M ) was p rep ared by dissolving 2.1389 gm of the salt in 100 mL of dist illed water. 4. Acetate buffer solution (pH = 4) was p repared by dissolving 13.7 gm of sodium acetate in 6 mL of glacial acetic acid and mak ing the volume to 100 mL in a calibrated f lask. T he pH of the resulted buffer mixture was adjust ed to p H = 4 ± 0.2 via the addition of glacial acetic acid using a pH-meter. 5. Solutions of p harmaceutical p reparations containing p aracetamol: Different p harmaceutical p reparations from different sources containin g p aracetamo l wer e obtained from local market (T able (1)). a. Solution for tablet analysis: 10 tablets were weighted out , grinded and mixed well. A p ortion of the resulted p owder ( containing 0.1 gm of paracetamol) was used for the IBN AL- HAITHAM J . FO R PURE & APPL. SC I VO L. 23 (1) 2010 p rep aration of the solution as described before. The resulted solution was filtered off and subsequently diluted to obtain working solutions. b. Solution for supp ositories analysis: The containing of five supp ositories was mixed well and a we ight from the resulted mixture contain ing 0.1 gm of paracetamol was d issolved in 10 mL of ethanol and a little amount of hot distilled water. The solution was t hen diluted to 100 mL with hot distilled water and the volume was checked after the solution b een cooled. Workin g solutions were prepared after filtration of the p rep ared st ock solution. c. Hy drolyzed p aracetamol solution: 25 mL of concentrated hydrochloric solution was add ed to 150 mL of 1000 µ g. mL -1 of st ock p aracetamol solution in a round bottom flask. The mixture was refluxed for 1hr and after cooling the volume was diluted to 250 mL with distilled water. A 600 µg.mL -1 of the hy droly zed p aracetamol (as p -aminophenol) stock solution was obtained and workin g solution were freshly p repared after neutralizing ( p H = 7) the required aliquots of st ock solution with 20% sodium carbon ate solution before dilution with distilled water. d. Solutions of drugs for analysis by direct and st andard addition methods: To 60 mL of 1000 µg.mL -1 solution of drug ( tablet or supp ositories), which is p rep ared as described before, 10 mL of concentrated HCl solution (11.8 M) was added and the mixture was refluxed for 1 hr. Aft er cooling the mixture was d iluted with distilled water in a 100 mL volumetric f lask. Workin g solutions were freshly p rep ared for each dru g (100 µg. mL -1 ) after adjust ing the p H to 7 with 20% sodium carbonate solution. Re commended Procedures 1.Di rect Determination of Paracetamol : a.Calibration curve p rocedure: To a ser ies of 25- mL vo lumetric flasks, different volumes (0.25 – 10 mL) of st andard 50 µg.mL -1 of p aracetamol solution were added fo llowed by the addition of 1.6 mL of 0.1 M of NaIO4 solution, 0.6 mL of AHB reagent solution (1 x 10 -2 M ) and 2.0 mL of acetate buffer solution. The volume in each flask was diluted with distilled water and the absorbance of the formed colored compound was measured at 470 nm against reagent blank solution after 30 minutes. Figure (3) shows that linear calibr ation graph was obtained in the range of p aractamol solution of (0.5 – 20.0 µg.mL -1 ) while high er concentrations show negative dev iations from Beer's law. b. Standard addition p rocedure: Standard addition p rocedure was used for the assay of p aracetamol contained in p harmaceutical p reparations at t hree concentration levels (viz. 1, 5 and 10 µg.mL -1 ) as follows; to a series of f ive 25- mL calibrated flasks, a liquots of t he sought drug solution containin g (25 or 125 or 250 µg) of p aracetamol were transferred followed by the addition of ( 0, 0.5, 1.0, 1.5 and 2.0 mL) of st andard p aracetamo l solution ( 100 µ g. mL -1 ) resp ectively. The resulted mixtures were then treated as described in the calibration curve p rocedure and the absorbances were measured at 470 nm after st andin g for 30 minutes. 2.Indirect Determination of Paracetamol : a.Calibration curve p rocedure: To a series of 25 mL calibr ated flasks, different volumes (0.25 – 10 mL) of 50 µ g.mL -1 of the hydrolyzed p aracetamol solution were added followed by the IBN AL- HAITHAM J . FO R PURE & APPL. SC I VO L. 23 (1) 2010 addition of of 0.2 mL of NaIO4 solution (0.1 M ), 3 mL of AHB solution (1.0 x 10 -2 M ) and 2 mL of NaOH solution (1.0 M ). Dilution was made with d istilled water and the absorbance was measured after 20 minutes at λm ax = 580 nm against reagent blank. Fi gure (6 ) shows the calibr ation curve which is linear in the concentration range of (0.5 – 20 µg.mL -1 ) of p aracetamol. b. Standard addition p rocedure: The method was applied to cover three concentration levels of p aracetamol (hy drolyzed as described before) in the studied druges ( viz. 2.0, 4.0 and 10.0 µg.mL -1 ) app ly ing the following p rocedure; to a series of five 25 mL calibrated flasks aliquots of the studied drug solution (hydroly zed as described before) containin g (50 or 100 or 250 µ g) of p aracetamol were transferred, followed by the addition of (0, 1, 2, 3 and 4 mL) of st andard hy droly zed p aracetamol solution (50 µ g.mL -1 ) resepectively. The resulted mixtures were treated as described in calibration curve p rocedure and the absorbances were measured at 580nm after standing for 20 minutes. Results and Discussion 1.Di rect Determination of Paracetamol The p resent work dep ends on quantitative oxidative- coupling of p aracetamo l via reaction with 4-amino-2-hydroxy sodium benzoate followed by sp ectrop hotometric determination of the resulted colored compound. Prelimin ary invest igations showed that a brownish-orange p roduct resulted up on treating p aracetamol solution with AHB and NaIO4 in acidic medium. The absorbance of the colored p roduct was measured at 470 nm against reagent blank solution and its absorbance was found t o be stable after 30 minutes of mixing(Fi g. 1 a). A univariate st udy of the variables affectin g the color develop ment of reaction p roduct, namely the amount of reagent for the range of (0.2 – 1.2 mL) of 0.1 M , the amount of oxidizing agent for the range (0.2 – 2.0 mL) of 0.1 M , the p H of the oxidation medium by using differ ent volumes (0.2 – 6.0 mL) of acetate buffer (p H = 4.47), the order of mixing of analyte and reagent solutions and the of reaction temperature (17.5 ºC, 20 ºC, 25 ºC, 30 ºC, 40 ºC), was p erformed on a 20 µ g.mL -1 of the analyte solution. One milliliter of AHB reagent solution was selected as an op timum amount (Fig.1b), and was used subsequently . Among different typ es and amounts of oxidizing agents which were invest igated, 1.6 mL of 0.1 M solution of NaIO4 was found to be the op timum (Fig.1 c). Different types of buffer solutions ( acidic and basic) were tested to control the p H of reaction medium. The study showed that using 2 mL of acetate buffer (p H = 4.42) gave the best result (Fig.1d). Table (2) illust rates the results obtained when different orders of mixing of analy te and reagents solutions were followed. The op timum order which gave the highest absorbance was: p aracetamol solution(S) + NaIO4 solution (O) + AHB reagent solution (R) + acetate buffer solution (B). A suggested mechan ism for the reaction is p rop osed in which paracetamol oxidized in the p resence of NaIO4 to form a benzoquinon immine which in turn couples with AHB through ortho-p osition to -NH2 group in acidic med ium as shown in the followin g scheme. IBN AL- HAITHAM J . FO R PURE & APPL. SC I VO L. 23 (1) 2010 OH N H CH3 O NaIO4 O NH COONaH2N OH O N COOH NH2 HO pH=4.42 Final Absorption S pectrum Absorp tion sp ectrum of the colored p roduct formed under op timum reaction conditions shows a maximnm absorp tion at 470 nm in contrast to reagent blank Fig (2 ). Calibration Graph App ly ing the conditions described in the recommended p rocedure, a linear calibration p lot for p aracetamol concentration in the range of ( 0.5 – 20 µg.mL -1 ) against the measured absorbance is obtained (Fi g.(3)) with correlation coefficient of 0.9995. The cond itional molar absorptivity was found to be 3.371 x 10 3 liter. mo le -1 . cm -1 and Sandle's index 0.0449 µ g. cm -2 . Inte rferences To assess the p ossibility of the analy tical app lication of the p rop osed method, the effect of the p resence of some foreign substances (viz. talk, glucose, lactose, st arch) was studied by addin g different amounts of t he mentioned compounds t o 15 µg.mL -1 of p aracetamol solution and app ly ing the recommended p rocedure for color d evelopment. Each of the st udied comp ounds was considered not t o interfere if its addition causes a relative error less than 5%. It was found the p resence of 200 µg.mL -1 of each of the comp ounds is tolerated in the determination of p aracetamol. Precision and Accuracy To check the p recision and accuracy of the prop osed method, three replicate of paracetamol solution were determined under the established conditions at five concentration levels. The results are list ed in Table 3. Anal ytical Applications Five typ es of commercially available p aracetamo l containin g p harmaceutical p reparations were analyzed. On app ly ing the recommended p rocedure, good recoveries were obtained (Table 4). Comparison with Other Methods To assess the validity of the prop osed method which was checked by comp aring the results with those obtained by standard methods ( T able 5 ). M oreover, F-t est and t-test show that there were no sign ificant difference between the p rop osed and standard methods. IBN AL- HAITHAM J . FO R PURE & APPL. SC I VO L. 23 (1) 2010 2.Indirect Determination of Paracetamol In this p rocedure, the acid hy drolysis p roduct of p aracetamol ( i.e. p -aminophenol) is oxidized by sodium periodate and coupled with AHB in sodium hy droxide medium to y ield a brownish-violetwater soluble dye which absorbs at 580 nm. The exp erimental conditions for the color p roducing reaction were op timized by following the same st ep s mentioned in the direct method starting with arbitrary conditions ( i.e. mixing 1.0 mL of 0.1 M of NaIO4 solution, 1.0 mL of 1 x 10 -2 M of AHB solution and 1.0 mL of NaOH solution in a volumetric flask containin g 300 µ g of the analyte) and measuring the absorbance of the colored p roduct after 20 minutes at 580 nm against reagent blank solution(Fig. 4 a). The effect of using different volumes of coupling reagent solution(1.0 x 10 -2 M ) was invest igated, and the results show that 3.0 mL gave the highest absorbance (Fi g.4 b ) whi ch was used as a subsequent work. The results obtained from using v arious volumes (0.1 – 2.0 mL) of 0.1M of NaIO4 (Fig.4 c), indicate that 0.2 mL of the oxidizing reagent was the optimum. The st udy shows that a st able color p roduct could only be obtained in alkaline medium, therefore, the reaction was carried out in the p resence of ammonium buffer (p H range 9 – 12 ) and in the presence of NaOH. Figure (4 d) shows t hat using 2.0 mL of 1.0 M NaOH solution resulted in obtainin g the best results. The order of addition of the reacting solutions shows that the following order : (S) + (O) + (R) + (B) must be followed to obt ain the highest absorbanc (Table 6). Finally, the effect of temp erature on the color reaction was invest igated in at the given values (20 ºC, 25 ºC, 30 ºC, 40 ºC and 50 ºC). The invest igation shows that the colored p roduct is not stable at elevated temp eratures, therefor, the reaction was carried out at room temp erature (i.e. 20 ºC). A mechanism was suggested for the o xidation of the hy drolysis p roduct of p aracetamol via NaIO4 and coup lin g with AHB to form the coloed p roduct in alkaline medium as follows: OH OH NH2 N H CH3 O c onc . HCl NaIO4 O NH COONaH2N OH O N COONa NH2 HO NaIO4/Na OH Final Absorption S pectrum The absorp tion sp ectrum of the colored p roduct was recorded, for the range (400 – 700 nm), under established op timum conditions a gainst reagent blank solution. Fi gure (5) shows a sp ectrum with wavelength of maximum absorp tion(λm ax) at 580. IBN AL- HAITHAM J . FO R PURE & APPL. SC I VO L. 23 (1) 2010 Calibration Graph Emp loying the recommended p rocedure, Beer's law is oby ed over the ran ge of ( 12.5 – 500 µg.mL -1 ) of p aracetamol per 25 mL of solution with correlation coeff icient of 0.9956 (Fig. 6). The conditional molar absorp tivity for the colored p roduct was found to be 11884 liter. mo le - 1 .cm -1 and Sandl's index was 0.0127 µ g.cm -2 . Inte rferences The presence of 250 µg.mL -1 of foreign substances (talk, lactose and starch) can be tolerated in the analysis of 12 µg. mL -1 of p aracetamo l solution since it would cause relative error p ercent less t han 5%. Precision and accuracy The precision of the prop osed method was calculated in term of R.S.D.% and its accuracy in term of relative error p ercent for t hree replicates of solution at three concentration levels (2, 10 and 20 µg. mL -1 ). Satisfactory results were obtained under op timum conditions (T able 7). Anal ytical application Table ( 8 ) shows the results obtained up on app lication of the p rop osed method in the determination of five dru gs contain ing p aracetamol. Comparison with other methods Table (9) shows the results obt ained by the prop osed and other st andared methods. Both F- test and t-test were app lied and showed that there were no si gnificant diff erences between the results obtained in comp arison with standard methods. Re ferences 1. M artindal, "The Complete Drug Reference"(2002)., 33 rd edition , Pharmaceutical press, London, 2. " British Pharmacop oeia on –CD-ROM "(2005)., 3 rd Ed. , Copy right by Sy st em Simulation Ltd., The Stationery Office , London, 3." Indian Pharmacop oeia " (1996)., Thecontroller of Publication , Delhi, 4. Parimoo, P. ;Sethuraman, Amalarj, A. and Seshadari, N. (1989). Indian. Drugs. , 26 : 704 5. Ding, T. ; Wang, j. and Zhongguo Yaovue Zazhi (1989) 24:295-296 ; Anal. Abst . , 52, 2E11 (1990). 6. M ahendra, K. ; Ahmed, S. ; Singh, D. and Shukla, I. (1985)Ana lyst , 110 : 735 7. Oztunc, A. (1982) Analyst, 107:585 8. Kaito, T . Kazuhiko, S. , Yuji, I. and Tsuguchila, Y. (1974) J. Pharm. Soc. , 94:633 9. Tsunetoshi, k. and Kazunhka, S. (1974).J. Pharm. Soc . , 94:639 10. Kaito, T . ;Kazuhiko, S. and Yuji, I. (1976) Bunski. Ka gaku, 25:776. Throgh anal. Abst . , 33:1E53 (1977). 11. Pulgarian, J. A. M . and Bermcgo, I. F. G. (1996) Anal. Chimi. Acta. , 333: 59 12. Gop inath, R.; Rajan, S. ;M eyyanatnan, S. N.; Krishnaveni, N.and Sur esh, B. (2007). Indian J. of Pharmaceutical Sciences, 6a(1):137-140, 13. Senthamil Selvan, P.; Gop inath, R.; Saravanan,V. S.; Gop al, N.; Sarvana Kumar, A. and Periyasamy , K. (2007) Asia J. of Chemist ry , 19(2): 1004-1010 IBN AL- HAITHAM J . FO R PURE & APPL. SC I VO L. 23 (1) 2010 14. Emre, D.and Ozaltin, N. (2007). J. of Chromatography B: Analytical Technologies in the Biomedical and life Sciences, 847(2):126-132, 15. Lavorante, A. F.;Pires, C. K.and Reis, B. F. (2006).J. of Pharmaceutical and b iomedical analysis, 42(4): 423-429, 16. De Los, A.; Oliva, M .;Olsina, R. A.and M asi, A. N. (2005)T alanta, 66(1): 229-235, 17. Burakham, R.; Duanhthon g, S. ; Patimap ornlert, L.; Len ghor, N.; Kasiwad, S. ;Srivichai, L.; Lap anantnopp akhum, S.; Jakmun ee, J.and Grudp an, K. (2004) Analytical Sciences, 20(5): 837-840, 18. Abbas, A.; Nahid, S.and Ali, R.Z. (2006)Acta Chim. Slov., 53:357-362 19. Wafaa, S. H. (2008).American Journal of Ap p lied Sciences, 5(8):1005-1012, 20. Walash, M . I. ; Elbrashy , A. M . and Sultan, M . A. (1994) M ikrochim, Acta , 113:113-124 21. Danet, A. F. ; David, V. and David, I. (1998).Rav. Roum. Chim. , 43:811-816 22. Easwaramoorthy , D. ;Ya, Y. C. and Huang, H. J. (2001). Anal. Chim , Acta. 439:95-100 23. Az hagvuel, S.and Sekar, R., (2007) J. of Pharmaceutical and Biomedical Analysis, 43(3):873-878, 24. Russel, J. A. (1944) J. Biol. Chem. , 156:165 25. Lubochinsky , B. and Zalta, J. P. (1954).Bulls. Soc. Chem. Biol. 36: 1363 IBN AL- HAITHAM J . FO R PURE & APPL. SC I VO L. 23 (1) 2010 Fig. (1): O ptimization of experimental conditions. Fig. (2): Final absorption spectrum. Fig. (3): Calibration graph of paracetamol IBN AL- HAITHAM J . FO R PURE & APPL. SC I VO L. 23 (1) 2010 Fig. (4): O ptimization of experimental conditions. Fig.(5): Final absorption spectrum. Fig. (6): Calibration graph of paracetamol . IBN AL- HAITHAM J. FO R PURE & APPL. SC I VO L. 23 (1) 2010 Table (1): Pharmaceuti cal preparations used Company Contains Pharmaceutical p rep aration S.D.I -Iraq 500 mg p aracetamol Paracetamol tablets S.D.I -Iraq 350 mg p aracetamol 50 mg caffeine 10 mg codeine phosp hate Algesic tablets U.K- London 500 mg p aracetamol Paramol tablets M .P.K- Sy ria 450 mg p aracetamol 35 mg orp henadrine citrate Kanagesic tablets S.A.R 250mg p aracetamol Panatol delta Sup p ositories Table (2): Effect of order of mixing Table( 3): Precision and accuracy of the method Absorbance Order of addition 0.466 S+O+R+B 0.465 O+S+R+B 0.459 R+S+O+B 0.389 B+S+O+R 0.431 O+R+B+S 0.445 R+O+S+B Taken Conc. (pp m) Found Conc. (pp m) Average Recovery (%) Error (%) R.S.D (%) 0.5 0.4909 0.4507 0.4839 0.4751 95.0202 -4.9798 4.5156 1 1.1261 1.0334 1.0456 1.0684 106.8377 +6.8377 4.7155 5 5.0876 5.1125 5.0904 5.0968 101.9363 +1.9363 0.2681 10 9.6469 9.8640 9.8092 9.7734 97.7341 -2.2659 1.1549 20 20.1984 20.0394 20.7091 20.0863 100.4315 +0.4315 0.2796 IBN AL- HAITHAM J . FO R PURE & APPL. SC I VO L. 23 (1) 2010 Table (4): Anal ytical application of the direct and standard additi on me thods. Pharmaceutical p rep aration Procedure Amount Recovery (%) Certified value (mg) Conc. Of Paracetamol (µg/ml) Found Valu e(mg) Each assay Average Paracetamol tablets S.D.I –Iraq Calibration curve 500 10 522.8460 104.5690 101.2435 5 509.0640 101.8120 1 486.7421 97.3484 Standard addition 10 507.591 101.5182 99.3506 5 490.675 98.1350 1 492.00 98.4000 Algesic tablets S.D.I –Iraq Calibration curve 350 10 365.5990 104.456 102.0797 5 364.2092 104.059 1 342.0296 97.7226 Standard addition 10 351.583 100.4523 100.2193 5 351.344 100.3840 1 349.376 99.82172 Paramol tablets U.K- London Calibration curve 500 10 485.3933 97.0787 98.7492 5 501.5730 100.314 1 494.2322 98.8464 Standard addition 10 502.4390 100.4878 100.5014 5 502.7851 100.5570 1 502.2971 100.4594 Kanagesic tablets M .P.K- Sy ria Calibration curve 450 10 453.7079 100.823 100.3779 5 458.1573 101.812 1 443.1236 98.4969 Standard Addition 10 452.1344 100.4743 100.5266 5 453.4599 100.7688 1 451.5152 100.3367 Panatol delta S.A.R Calibration curve 250 10 261.4232 104.569 104.3645 5 260.1498 104.059 1 261.1610 104.464 Standard addition 10 249.2453 99.69812 100.3144 5 250.9978 100.3991 1 252.1151 100.8460 Table (5): Comparison with other methods Recovery % Drug samples Standard method The prop osed method 101.000 * 100.394 Paracetamol Pure 99.000 * 101.243 Paracetamol tablets S.D.I –Iraq 97.970 ** 102.079 Algesic tablts S.D.I –Iraq 100.501 *** 98.749 Paramol tablts U.K- London 100.526 *** 100.377 kanagesic tablts M .P.K- Sy ria 100.314 *** 104.364 Panatol delta S.A.R * British Pharmacop oeia B.P, ** S.D.I standard methods , *** Oxidative coupling v ersus standard addition value. IBN AL- HAITHAM J . FO R PURE & APPL. SC I VO L. 23 (1) 2010 Table (6): Effect of order of mixing Absorbance Order of Addition 1.062 S + O + R + B 1.026 S + R + O + B 0.872 S + B + O + R 0.950 R + O + S + B 0.954 R + S + B + O 0.898 B + S + O + R 1.020 O + S + R + B 0.794 O + R + B + S Table (7): Precision and accuracy of the method. Taken Conc. (pp m) Found Conc. (μg. ml -1 ) Average Recovery (%) Error(%) R.S.D(%) 2 1.8651 1.8899 1.9022 1.8857 94.2863 -5.7137 1.0025 10 10.0582 10.1448 10.2809 10.1613 101.6130 + 1.6130 1.1052 20 19.9839 19.8601 20.1077 19.9839 99.9196 -0.0804 0.6193 IBN AL- HAITHAM J . FO R PURE & APPL. SC I VO L. 23 (1) 2010 Table (8): Anal ytical application of the direct and standard additi on me thods. Pharmaceutical p rep aration Procedure Amount Recovery (%) Certified value (mg) Conc. of Paracetamol (µg/ml) Found Valu e(mg) Each assay Average Paracetamol tablets S.D.I –Iraq Calibration curve 500 10 506.8948 101.3789 99.7617 4 493.2985 98.6597 2 496.2322 99.2464 Standard addition 10 504.8823 100.9764 100.9449 4 504.9708 100.9941 2 504.3217 100.8643 Algesic tablets S.D.I –Iraq Calibration curve 350 10 336.4066 96.1161 99.2741 4 348.4753 99.5643 2 357.4970 102.1421 Standard addition 10 356.9930 101.9980 101.5203 4 354.3256 101.2359 2 354.6450 101.3271 Paramol tablets U.K- London Calibration curve 500 10 486.9397 97.3879 99.3166 4 491.4631 98.2926 2 511.3459 102.2692 Standard addition 10 505.4348 101.1087 101.0055 4 502.8191 100.5638 2 506.7203 101.3440 Kanagesic tablets M .P.K- Sy ria Calibration curve 450 10 458.2759 101.8391 100.8003 4 448.0397 99.5644 2 454.4884 100.9474 Standard Addition 10 453.9413 100.8758 99.6598 4 450.9009 100.2002 2 440.4731 97.8829 Panatol delta S.A.R Calibration curve 250 10 257.7771 103.1108 103.6618 4 264.0131 105.6052 2 255.6730 102.2692 Standard addition 10 246.2356 98.4942 100.3073 4 252.5189 101.0076 2 253.5550 101.4220 Table( 9): Comparison with other methods. Recovery % Drug samples Standard method The prop osed method 101.0000 * 99.7617 Paracetamol Pure 99.0000 * 98.6000 Paracetamol tablets S.D.I –Iraq 97.9700 ** 99.2741 Algesic tablts S.D.I –Iraq 100.5014 *** 99.3165 Paramol tablts U.K- London 100.5260 *** 100.8002 kanagesic tablts M .P.K- Sy ria 100.3140 *** 103.6617 Panatol delta S.A.R * British Pharmacop oeia B.P, ** S.D.I standard methods , *** Oxidative coupling v ersus standard addition value.