Iraqi J Pharm Sci, Vol.28(1) 2019 Synthesis and anti-inflammatory study of new ibuprofen derivatives DOI: https://doi.org/10.31351/vol28iss1pp131-137 131 Synthesis, Characterization and Preliminary Study of the Anti-Inflammatory Activity of New Pyrazoline Containing Ibuprofen Derivatives Mayada R. Al-Nakeeb*,1 and Tagreed N-A. Omar* *Department of Pharmaceutical Chemistry, College of Pharmacy, Baghdad University, Baghdad, Iraq. Abstract New ibuprofen derivatives containing variously substituted pyrazoline have been synthesized, characterized by FT-IR and 1H-NMR spectroscopy and evaluated preliminarily for their anti-inflammatory activity. In vivo anti-inflammatory activity of the final products (5a‐f) was studied in rats using egg‐white induced edema method of inflammation. All of them showed anti-inflammatory activity compared to the control group (propylene glycol) except compound 5f that showed more anti-inflammatory activity than ibuprofen. Keywords: Ibuprofen, Pyrazoline, Anti-inflammatory على ةالمضادة لاللتهاب لمشتقات جديدة لاليبوبروفين الحاوي ةللفعالي ةاولي ةتخليق و تشخيص ودراس البيرازولين * عمر تغريد نظام الدينو 1*،رياض النقيب ميادة *فرع الكيمياء الصيدالنية، كلية الصيدلة، جامعة بغداد، بغداد،العراق. الخالصة تحت الشعةا بمطياف تشخيصها تم قد و مختلفة، بمجاميع معوض بيرازولين تحتوي لالبوبروفين جديدة مشتقات تخليق تم لاللتهاب لمضادةا الفعالية دراسة تم. لاللتهاب المضادة لفعاليتها اولي تقييم و للبروتون المغناطيسي النووي الرنين مطياف و الحمراء عاليةف اظهرت المركبات كل. المختبرية الجرذان عند البيض بزالل المستحدثة الوذمة طريقة باساستخدام( و – أ5) النهائية للمركبات .االبوبروفين من اكثر لاللتهاب مضادة فعالية اظهر الذي( و5) المركب ماعدا‘كاليكول البروبيلين بمجموعة مقارنة لاللتهاب مضادة .الكلمات المفتاحية: ايبوبروفين، بيرازولين، مضاد التهاب Introduction One of the most useful medication used in primary health care are NSAID, because of their analgesic, antipyretic and anti-inflammatory activities. Inflammation in Rheumatoid arthritis and osteoarthritis is known to be reduced by the use of NSAID, also they enhance the recovery and mobility(1). NSAID act by the same mechanism of action, through inhibiting cyclooxygenase enzymes COX that are responsible for the production of prostaglandins. Those enzymes are different in their regulation, distribution and biological functions(2). There are two isoforms of COX enzymes: COX-1 is constitutively normally expressed in most tissues, and prostaglandins controlled by COX-1 mediate cytoprotection of gastric mucosa and platelet aggregations in addition to some other physiological processes(3).COX–2 is not detected in normal tissues and selectively induced in response to pro-inflammatory stimuli such as, cytokines and growth factors(4). Classical NSAIDs, such as Ibuprofen, inhibit both isoforms of the enzymes(5). COX-3 is a splice variant/isoenzyme of COX-1 and, may have been named COX-1b. It was initially reported to be expressed in canine cerebral cortex. In humans COX-3 is found in highest concentrations in the brain and heart. The advantage of COX-3 is that it could explain the pharmacological actions of drugs such as acetaminophen and other antipyretic analgesic which are weak inhibitors of COX-1 and COX-2, but penetrate easily into the central nervous system(6). The major limitation to long term use of NSAIDs in therapy is the increased risk of gastrointestinal( GI) ulceration (7). A well-accepted fact that the GI side effect of acidic NSAIDs is a result of direct irritation of gastric mucosa, because of the carboxylic group, and indirectly because of COX-1 inhibition that reduce the levels of protective prostaglandins. Inhibition of prostaglandin synthesis in the GI tract lead to increase gastric acid secretion and decrease trophic effects on epithelial mucosa(8) . 1Corresponding author E-mail: mralnakeeb@yahoo.com Received: 24/12/2018 Accepted: 20/3/2019 Iraqi Journal of Pharmaceutical Sciences https://doi.org/10.31351/vol28iss1pp131-137 https://doi.org/10.31351/vol28iss1pp131-137 http://bijps.com/index.php/bijps/index Iraqi J Pharm Sci, Vol.28(1) 2019 Synthesis and anti-inflammatory study of new ibuprofen derivatives 132 In order to increase the analgesic and anti- inflammatory activity and reduce the side effects, recent researches focus on designing new compounds by derivitization of the carboxylic group of NSAID with heterocyclic systems, pyrazoline(9,10). Pyrazolines constitute an interesting class of heterocycles due to their synthetic flexibility and effective biological activities. They have been shown to possess a broad range of physiological activities such as antimicrobial, analgesic, anti- amoebic, anticancer, antidepressant, and anti- inflammatory activities (11–15) . The direction of the current work is to synthesize potent non‐steroidal anti‐inflammatory agents that are derivatives of ibuprofen by joining a group of pyrazoline ring to the carboxylate group of ibuprofen, using spacer arm glycine ester(16,17), and then evaluating them as anti‐inflammatory agents. Materials and Methods Chemicals and solvents used during synthesis were of Analar type and were purchased from (Fluka, England, India and Germany). Ibuprofen (General Company for Pharmaceuticals Industries and Medical appliances, Samarra, Iraq). The progress of the reaction and checking the purity of the products were determined by thin-layer chromatography (TLC), using silica gel GF254 (type 60) pre-coated aluminium sheets, Merck (Germany) exposed to UV-254nm light. Chromatograms were eluted by using three solvent systems: A /Ethyl acetate: Petroleum ether (1:1). B / Ethanol: toluene (4:6). C /Chloroform: Methanol (85:15). Melting points were measured by using Stuart SMP3 melting point apparatus in open capillary tubes, and are uncorrected. The Infrared spectra were performed using FT-IR (IRAffinity-1) spectrophotometer, Shimadzu, japan. 1HNMR spectra were recorded on NMReady-60 spectrometer model with tetra methylsilane as an internal standard, chemical shift were expressed as (δ= ppm) and coupling constant in (Hz). Chemical synthesis General method for synthesis of chalcones derivatives (1a-f) In a 96% ethanol (22ml) acetophenone (1.18 ml, 10 mmole) and derivatives of aromatic aldehydes (a-f) (10 mmole) were dissolved (table 1). Sodium hydroxide (40%, 10 ml) solution was added gradually. The solution was stirred in an ice bath until solidified, then kept in cold condition overnight. Then the solid was diluted with cold water and acidified with 2N HCl, filtered then recrystallized by ethanol(18). Table (1 )Aromatic aldehydes and weights used Aldehydes’ name Product R Weight (gm) benzaldehyde Ia H 1.06 4-chlorobenzaldehyde Ib Cl 1.4 4-nitrobenzaldehyde Ic NO2 1.51 4-hydroxybenzaldehyde Id OH 1.22 4- methoxybenzaldehyde Ie OCH3 1.36 4-dimethylaminobenzaldehyde If N(CH3)2 1.49 1,3-Diphenylpropenone (C15H12O) (compound 1a): Colour: pale yellow crystals. Yield: 90%. M.P.:56- 58 ºC. Rf: A=0.6. FT-IR: 3055 (CH asymmetric stretching aromatic), 3028 (CH symmetric aromatic stretching), 1662 (C=O), 1604, 1573 (C=C aromatic). 3-(4-Chlorophenyl)-1-phenylprop-2-en-1-one (C15H11OCl) (compound 1b): Colour: off white powder. Yield: 80%. M.P.: 112-114 ºC. Rf: A=0.5. FT-IR: 3064 (CH asymmetric aromatic stretching), 3016 (CH symmetric aromatic stretching), 1658 (C=O), 1597, 1589 (C=C aromatic), 821 (C-Cl). 3-(4-Nitrophenyl)-1-phenylprop-2-en-1-one (C15H11NO3) (compound 1c): Colour: deep yellow crystals. Yield: 75%. M.P.: 156-158 ºC. Rf: A=0.54. FT-IR: 3070 (asymmetric C-H stretching aromatic), 1654 (C=O), 1589, 1577 (C=C aromatic), 1516 (NO2 asymmetric stretching), 1334 (NO2 symmetric stretching). 3-(4-Hydroxyphenyl)-1-phenylprop-2-en-1-one (C15H12O2) (compound 1d): Colour: light yellow crystals. Yield: 60%. M.P.: 182-184 ºC. Rf: A=0.7. FT-IR: 3213 (OH stretching), 3070 (asymmetric CH stretching aromatic), 3032 (symmetric CH stretching aromatic), 1647 (C=O), 1597, 1554 (C=C aromatic), 1346 (OH bending), 1215 (C-O). 3-(4-methoxyphenyl)-1-phenylprop-2-en-1-one C16H14O2) (compound 1e): Colour: yellow crystals. Yield: 80%.M.P.: 73-75ºC. Rf: A=0.6. FT-IR: 3059(asymmetric CH stretching aromatic), 3017 (symmetric CH stretching aromatic), 2954(asymmetric CH stretching), 2839 (symmetric C-H stretching), 1654 (C=O), 1689, 1573(C=C aromatic), 1257(C-OCH3), 1257 (C-O). Iraqi J Pharm Sci, Vol.28(1) 2019 Synthesis and anti-inflammatory study of new ibuprofen derivatives 133 3-(4- (Dimethyl amino) phenyl)-1-phenylprop-2-en- 1-one (C17H17NO) (compound 1f): Colour: bright orange red needle like crystal. Yield: 85%. M.P.: 110-112ºC. Rf: A=0.7. FT-IR: 2912 (asymmetric CH stretching), 2846 (symmetric CH stretching), 1647 (C=O), 1597, 1558 (C=C aromatic), 1157 (C-N). Synthesis of ethyl amino acetate hydrochloride (C4H10NO2Cl) (compound 2): Glycine (2 g, 26.6 mmol) to be esterified was suspended in absolute ethanol (50 ml) and cooled to 5ºC. Thionyl chloride (2.3 ml, 32 mmol) was added slowly over a period of 15 minutes, and the reaction mixture was refluxed for 3 hours. The solvent was then evaporated to dryness under reduced pressure. Finally the residue was purified by recrystallization from ethanol: diethyl ether .Colour: white crystals. Yield: 92%. M.P.: (144-145) ºC, (145-146) ºC Lit.. Rf C=0.5. FT-IR: 1743 (C=O) , 1246(C-O-C), 1176 (C-N) (17). Ethyl 2-(2-(4-isobutylphenyl) propanamido) acetate chemical synthesis (C17H25NO3) (compound 3): Synthesis of ibuprofen acid chloride: Ibuprofen (1g, 4.8 mmol) was suspended in 1 ml dry chloroform and excess of thionyl chloride (1.2 ml, 16.9 mmol) was added drop wise over a period of 3-5 minutes, then refluxed for 3 hours. Evaporation under reduced pressure to remove excess gases was done. Ibuprofen acid chloride was obtained as a faint yellow oily residue(19). The reaction of ibuprofen acid chloride with glycine ethyl ester: Triethylamine (TEA) (1.35 ml, 9.6mmol) was added to a suspension of glycine ethyl ester hydrochloride (0.676g, 4.8 mmol) in dry dichloromethane (DCM) (30 ml) at 25°C. The reaction mixture was stirred for 3hours. To this mixture, ibuprofen acid chloride (prepared above) dissolved in 1 ml dry chloroform was added drop wise with continuous stirring, keeping the temperature about 5ºC and left stirring overnight. After evaporating the solvent under vacuum, ethyl acetate 30ml was added to the residue, filtration was done to remove the precipitate. The ethyl acetate layer was washed with 1N HCl, followed with distilled water, and then it was washed with 5% NaHCO3 solution and distilled water. The ethyl acetate layer was dried over anhydrous magnesium sulphate, filtered, and the filtrate was evaporated under vacuum to an oily residue, that represents the compound (3). Colour: yellow oil. Yield: 80%. Rf: B=0.6. FT-IR: 3309 (NH amide) , 1739 (C=O ester) , 1654 (C=O amide) (20). N- ( 2 – hydrazinyl – 2 – oxoethyl ) -2- (4- isobutylphenly) propanamide chemical synthesis (C15H23N3O2) (compound 4): Compound (3) (0.8 g, 3 mmol ) was dissolved in 10 ml methanol, then hydrazine hydrate ( 1.5 ml ,30 mmol) was added, the reaction mixture was refluxed for 9 hours, then left over night with continuous stirring, then the solvent was evaporated under reduced pressure. White precipitate appeared upon the addition of iced water, filtered washed with cold water, dried and washed with ether for further purification. Colour: white powder. Yield: 80%. M.P.: 100-112ºC. Rf: B=0.5. FT-IR: 3305 (NH amide) , 3228 and 3190 (NHNH2) , 1678 (C=O 2º amide) (21). N-(2- ( 3 ,5 – diphenyl – 4 ,5-dihydro-1H-pyrazol- 1-yl)-2-oxoethyl ) – 2 - ( 4 – isobutylphenyl ) propanamide (compounds 5 ( a – f ) ) chemical synthesis: Compound (4) (0.4gm, 1.44 mmol) was dissolved in absolute ethanol, together with chalcones (1a-f) of (1.44 mmol) , then few drops of glacial acetic acid (GAA) was added. The reaction mixture was refluxed for 24 hours and followed by using TLC, till single spot is obtained. The solvent was evaporated to dryness under reduced pressure; the residue was triturated with petroleum ether. Then ether was added, white precipitate appeared, filtered and collect the filtrate, evaporate to dryness(22). N-(2-(3,5-diphenyl-4,5-dihydro-1H-pyrazol-1-yl)- 2-oxoethyl)-2-(4-isobutylphenyl) propanamide (C30H33N3O2) compound 5a: Colour: off white powder. Yield: 60%. M.P.: 66-88ºC. Rf A= 0.62. FT-IR: 3278 (NH amide), 1647 (C=O), 1593 (C=N). 1HNMR (60 MHz, DMSO-d6, ppm): 0.75-0.85 (6H, d, two CH3 ibuprofen), 1.22-1.33 (3H, d, CH3 ibuprofen), 1.76-1.86 (m, CH ibuprofen), 2.3 (2H, d, CH2 ibuprofen), 3.63 (3H, m, CH ibuprofen and CH2 pyrazoline), 4.21 (3H, m, CH2 glycine and CH of pyrazoline ring), 6.94-7.44 (14H, m, Ar-H), 8.10 (1H, br. s, NH amide). N-(2-(5-(4-chlorophenyl)-3-phenyl-4,5-dihydro- 1H-pyrazol-1-yl)-2-oxoethyl)-2-(4- isobutylphenyl)propanamide (C30H32ClN3O2) compound 5b: Colour: off white powder. Yield: 62%. M.P.: 62-65ºC. Rf A=0.65. FT-IR: 3294 (NH amide), 1647 (C=O), 1593 (C=N), 813 (C-Cl). 1HNMR (60 MHz, DMSO-d6, ppm): 0.75-0.85 (6H, d, two CH3 ibuprofen), 1.21-1.33 (3H, d, CH3 ibuprofen), 1.76-1.86 (1H, m, CH ibuprofen), 2.3 (2H, d, CH2 ibuprofen), 3.63 (3H, CH ibuprofen and CH2 pyrazoline), 4.25 (3H, m, CH2 glycine and CH of pyrazoline ring), 6.94-7.15 (13H, m, Ar-H), 8.12 (1H, br. s, NH amide). 2- ( 4 – isobutylphenyl ) – N - ( 2 -(5-(4- nitrophenyl)-3-phenyl – 4 , 5 – dihydro - 1H – pyrazol – 1 – yl )-2-oxoethyl) propanamide (C30H32N4O4) compound 5c: Colour: yellow powder. Yield: 70%. M.P.: 76-78ºC. Rf A=0.55. FT- IR: 3305 (NH amide), 1651 (C=O), 1620 (C=N), 1514 (NO2 asymmetric stretching), 1334 (NO2 symmetric stretching). 1HNMR (60 MHz, DMSO- d6, ppm): 0.74-0.84 (6H, d, two CH3 ibuprofen), 1.19-1.32 (3H, d, CH3 ibuprofen), 1.75-1.85 (1H, m, CH ibuprofen), 2.29 (2H, d, CH2 ibuprofen), Iraqi J Pharm Sci, Vol.28(1) 2019 Synthesis and anti-inflammatory study of new ibuprofen derivatives 134 3.63 (3H, m, CH ibuprofen and CH2 pyrazoline) ,4.36 (3H, m, CH2 glycine and CH of pyrazoline ring) , 6.93-7.82 (13H, m, Ar-H) , 8.18 (1H, br. s, NH amide). N-(2-(5-(4-hydroxyphenyl)-3-phenyl-4,5 -dihydro- 1H-pyrazol-1-yl)-2-oxoethyl)-2-(4-isobutylphenyl ) propanamide ( C30H33N3O3 ) compound 5d: Colour: light brown powder. Yield: 70%. M.P.: 82-84ºC. Rf A=0.7. FT-IR: 3232 (NH amide), 3217 (phenolic OH), 1647 (C=O), 1604 (C=N). 1HNMR (60 MHz, DMSO-d6, ppm): 0.75-0.85 (6H, d, two CH3 ibuprofen) , 1.22-1.32 (3H, d, CH3 ibuprofen), 1.8 (1H, m, CH ibuprofen), 2.31 (2H, d, CH2 ibuprofen), 3.66 (3H, CH ibuprofen and CH2 pyrazoline ring), 4.10 (3H, CH2 glycine and CH pyrazoline ring) , 6.81-7.43 (13H, m, Ar-H) , 8.03 (1H, br. s, NH amide), 9.82 (1H, br. s, OH). 2- ( 4- isobutylphenyl ) – N - ( 2 - ( 5 - ( 4- methoxyphenyl)-3- phenyl – 4 , 5 – dihydro - 1H – pyrazol – 1 -yl)-2-oxoethyl) propanamide (C31H35N3O3) compound 5e: Colour: off white powder. Yield: 60%. M.P.: 60%. Rf A=0.6. FT-IR: 3294 (NH amide), 1647 (C=O), 1604 (C=N). 1HNMR (60 MHz, DMSO-d6, ppm): 0.75-0.85 (6H, d, two CH3 ibuprofen), 1.22-1.33 (3H, d, CH3 ibuprofen), 1.78-1.86 (1H, m, CH ibuprofen) , 2.3- 2.4 (2H, d, CH2 ibuprofen), 3.73 (6H, m, CH ibuprofen and -OCH3 overlapped with CH2 pyrazoline), 4.21 (3H, CH2 glycine and H of pyrazoline ring), 6.94-7.44 (13H, m, Ar-H) , 8.05 (1H, br. s, NH amide),. N-(2-(5-(4-(dimethyl amino) phenyl)-3-phenyl-4,5 - dihydro-1H-pyrazol-1-yl)-2-oxoethyl)-2-(4- isobutylphenyl) propanamide (C32H38N4O2) compound 5f: Colour: red powder. Yield: 65%. M.P.: 60-62ºC. Rf A=0.55. FT-IR: 3298 (NH amide), 1647 (C=O), 1600 (C=N), 1168 (N-CH3). 1HNMR (60 MHz, DMSO-d6, ppm): 0.74-0.85 (6H, d, two CH3 ibuprofen), 1.2-1.3 (3H, d, CH3 ibuprofen), 1.78-1.86 (1H, m, CH ibuprofen) , 2.4 (2H, d, CH2 ibuprofen), 2.9 (6H, s, N(CH3)2), 3.56 (3H, CH ibuprofen and CH2 pyrazoline), 4.2 (3H, CH2 glycine and CH pyrazoline), 6.73-7.43 (m, 13H Ar- H), 8.11 (1H, br. s, NH amide). Pharmacology Anti-inflammatory assessment study In vivo, anti‐inflammatory effects of the chemically synthesized products (5a‐f) were assessed using egg‐white induced paw oedema. Measuring the decrease of paw thickness is the basis for the evaluation of the ant‐inflammatory activity of the desired compounds(23). Albino rats of either sex weighing (170±10 g) were supplied by Iraqi centre for cancer and Medical genetic research and were housed in University of Technology under standardized conditions for 10 days for acclimatization. Animals were fed commercial chow and had free access to water. Animals were taken to the laboratory, one hour before the experiment, and were separated into eight groups (each group consist of 6 rats) as follows(24): Group A: Six rats considered as control and injected with the vehicle intra peritoneally (i.p.) (propylene glycol 50% v/v). Group B: Six rats treated with ibuprofen as reference substance in a dose of 50mg/kg suspended in propylene glycol. Group C‐H: Six rats for each group injected with the tested compounds (5a‐f), also suspended in propylene glycol(25), in doses that are illustrated in table 2. The paw width was measured by vernier calliper at seven time periods (0, 30, 60, 120, 180, 240, and 300 min.) after drug delivery. Potent inflammation can be created by injecting of 0.05ml of undiluted egg-white subcutaneously into the planter side of the hind paw of the rats 1/2 hr. after i.p. delivery of the target compounds including standard and control . The data was stated as the mean ± standard error of mean (SEM) and results were investigated for statistical significance using student t‐test (Two sample assuming equal variances) for comparison between mean values. However, comparisons between different groups were made using ANOVA: Two factors without replication. Probability (P) value of less than 0.05 was considered significant. Ibuprofen which is given in a dose of 50mg/kg, so; the doses of synthesized compounds are calculated as in table 2: M. Wt. of Ibuprofen = 206.29 (50mg / kg) / M. Wt. of reference drug = Dose /M. Wt. of the tested compound (25). Table (2) Compounds with their molecular weight and dose Compound Molecular Wt. Weight Dose (mg/ kg) Ibuprofen 206.29 50.00 5a 467.60 113.335 5b 502.05 121.685 5c 512.60 124.242 5d 483.60 117.21 5e 497.60 120.61 5f 510.67 123.77 Results and Discussion Chemistry Chalcones (1a-f) were synthesized based on aldol condensation by reacting aromatic aldehydes with acetophenone in ethanol with NaOH 40% solution. Chalcones were characterized by FTIR that shows appearance of C=O stretching at (1662- 1647). Glycine ethyl ester HCl (2) was prepared by refluxing glycine with thionyl chloride in absolute Iraqi J Pharm Sci, Vol.28(1) 2019 Synthesis and anti-inflammatory study of new ibuprofen derivatives 135 ethanol. FTIR shows characteristic band of ester C=O stretching at (1743). Compound (3) was synthesized from reacting ibuprofen acyl chloride with compound (2), and was characterized by FTIR to show NH stretching at (3305), C=O stretching of ester at (1739) and C=O stretching of amide at (1654). Compound (4) was prepared by refluxing compound (3) with hydrazine hydrate in methanol. FTIR shows characteristic band of hydrazide of NHNH2 stretching at 3224 and 3190. The final product (5) was synthesized by refluxing chalcones with compound (4) in ethanol using glacial acetic acid as a catalyst. The appearance of bands C=N stretching at (1620-1593), were characteristic of pyrazoline derivatives. All the steps involved in synthesis of targets compound were shown in (Scheme 1). Iraqi J Pharm Sci, Vol.28(1) 2019 Synthesis and anti-inflammatory study of new ibuprofen derivatives 136 The anti‐inflammatory activity evaluation of the tested compounds The anti‐inflammatory activity of the tested compounds has been evaluated in comparison with their vehicle (control group) and ibuprofen. Table 3 explains the effect of tested compounds 5a‐f in comparison to control and ibuprofen. Discussion All tested compounds employed imperative reduction of paw oedema in comparison to the effect of propylene glycol 50%v/v (control group). The effect of Ibuprofen and all tested compounds started at time 120 min except 5f which has started at 60 min. indicating rapid onset of action. The effect of target compounds and Ibuprofen continued till the end of experiment. Compound 5d and 5e showed comparable effect to Ibuprofen at all experimental time while compounds 5a, 5b and 5c produced significantly lower inhibitory effect than Ibuprofen at time 120‐240 minutes. Remarkably, compound 5f exerted significantly higher paw edema reduction than ibuprofen at 60‐240 min. All tested compounds have showed comparable effect to that of ibuprofen at time 300 minutes. Table( 3 )The anti‐inflammatory effect of control, ibuprofen and compounds 5a‐f on egg‐white induced paw edema in rat # #Non‐identical superscripts (a, b and c) among different tested compounds are regarded significantly different (p < 0.05);*significantly different compared to control (p < 0.05). Data are expressed in mm paw thickness as mean ± SEM. n= number of rats. Time (0) is the time of i.p. injection of ibuprofen, tested compounds and propylene glycol. Time (30) is the time of injection of egg white to induce edema. Percent of inhibition in paw oedema thickness The percent of inhibition of paw oedema thickness at each time interval was calculated from the mean effect in control and tested animals according to the equation(26): % Inhibition= [Vc ‐Vt /Vc] ×100 Where Vc and Vt are the mean paw thickness of the control group and tested group (at t‐time zero) respectively. The comparison among the ibuprofen, compounds 5a‐f was presented in table 4. Table (4 )Percent of inhibition of inflammation for ibuprofen and compounds 5a‐f on egg‐white induced paw oedema in rats. Time (min.) Ibuprofen 5a 5b 5c 5d 5e 5f 60 4.6% 2.9% 4% 5% 2.3% 3.5% 45% 120 56% 32% 34% 32% 50% 50% 72% 180 69% 57% 53% 53% 66% 70% 88% 240 81% 70% 62% 65% 79% 81% 97% 300 83% 68% 72% 64% 51% 62% 92% Conclusion New pyrazoline containing ibuprofen derivatives have been synthesized and characterized successfully. All of the synthesized compounds demonstrated anti-inflammatory activity in the control group of rats. Out of them, compound 5f showed better anti-inflammatory activity than that of ibuprofen, since it has electron donating group N(CH3)2. References 1. Al-Shidhani A, Al-Rawahi N, Al-Rawahi A, Murthi P S. Non-steroidal anti-inflammatory drugs (NSAIDs) use in primary health care centers in A’Seeb, Muscat: A clinical audit. Oman Med J. 2015;30(5):366–371. 2. Croff LJ. Use of NSAIDs in treating patients with arthritis. arthritis Res Ther. 2013;15(3):1– 10. 3. Badrey MG, Abdel-Aziz HM, Gomha SM, P a w T h ic k n e ss ( m m ) / n = 6 Compoun d Time (min) 0 30 60 120 180 240 300 Control 4.80±0.05 5.79±0.06 6.52±0.06 6.90±0.03 6.78±0.06 6.65±0.02 5.33±0.01 Ibuprofen 4.78±0.04 5.70±0.05 6.42±0.05 5.70±0.05 *a 5.39±0.06*a 5.13±0.06*a 4.87±0.02*a 5a 4.84±0.06 5.70±0.02 6.51±0.06 6.27±0.01 *b 5.69±0.03*b 5.39±0.02*b 5.01±0.04*a 5b 4.77±0.03 5.71±0.06 6.42±0.01 6.16±0.04 *b 5.70±0.06*b 5.47±0.02*b 4.92±0.05*a 5c 4.78±0.02 5.71±0.01 6.41±0.03 6.21±0.06 *b 5.71±0.05*b 5.42±0.06*b 4.97±0.06*a 5d 4.76±0.01 5.75±0.06 6.44±0.04 5.81±0.03 *a 5.43±0.02*a 5.14±0.05*a 5.02±0.06*a 5e 4.79±0.06 5.70±0.02 6.45±0.03 5.83±0.02 *a 5.38±0.04*a 5.13±0.01*a 4.99±0.06*a 5f 4.81±0.01 5.79±0.02 5.75±0.04 * 5.40±0.05*c 5.05±0.06*c 4.87±0.03*c 4.84±0.08*a Iraqi J Pharm Sci, Vol.28(1) 2019 Synthesis and anti-inflammatory study of new ibuprofen derivatives 137 Abdalla MM, Mayhoub AS. Design and synthesis of imidazopyrazolopyridines as novel selective COX-2 inhibitors. Molecules. 2015;20(8):15287–15303. 4. Tagreed O. Synthesis and Preliminary Pharmacological Evaluation of Esters and Amides Derivatives of Naproxen as Potential Anti-Inflammatory Agents. Iraqi J Pharm Sci. 2013;22(1):120–127. 5. Abdellatif KRA, Elsaady MT, Amin NH, Hefny AA. Design, Synthesis and biological evaluation of some novel indole derivatives as selective COX-2 inhibitors. J Appl Pharm Sci. 2017;7(8):069–77. 6. Chandrasekharan N V., Dai H, Roos KLT, Evanson NK, Tomsik J, Elton TS, et al. COX-3, a cyclooxygenase-1 variant inhibited by acetaminophen and other analgesic/antipyretic drugs: Cloning, structure, and expression. Proc Natl Acad Sci U S A. 2002;99(21):13926– 13931. 7. Lolli ML, Cena C, Medana C, Lazzarato L, Morini G, Coruzzi G, et al. A new class of ibuprofen derivatives with reduced gastrotoxicity. J Med Chem. 2001;44(21):3463– 3468. 8. Sharma N. Synthesis , Characterization & Biological Evaluation of Mutual Prodrugs of Some Selected NSAIDs conjugated with different antioxidant via different amino acids. Org Med Chem Int J. 2017;4(4):1–5. 9. Shroff M, Sj D. Newer Substituted Indolyl- Pyrazoline Derivatives as Anti-Inflammatory Agents. iMebPub Journals. 2017;5(1):1–7. 10. Saud KS, Shihabaldain NL, Shareef AA. Synthesis and characterization of some new pyrazolines derivatives and their biological activity. J Chem Pharm Res. 2015;7(12):1042– 1055. 11. Chisti S, Singh DCP, Gupta S, Khan MA. Synthesis of some novel pyrazoline derivatives and evaluation of their biological activity. Pharma Innov J. 2018;7(7):796–801. 12. Jadhav SA, Kulkarni KM, Patil PB, Dhole VR, Patil SS. Design, Synthesis and Evaluation of some Novel Pyrazoline derivatives. Der Pharma Chem. 2016;8(3):38–45. 13. Jainey PJ, Bhat IK. Antitumor, Analgesie, And Anti-Inflammatory Activities Of Synthesized Pyrazolines. J Young Pharm. 2012;4(2):82–87. 14. Marella A, Rahmat Ali M, Tauquir Alam M, Saha R, Tanwar O, Akhter M, Et Al. Pyrazolines: A Biological Review. Mini- Reviews Med Chem. 2013;13(6):921–931. 15. Salian V V., Narayana B, Sarojini BK, Byrappa K. A Comprehensive Review On Recent Developments In The Field Of Biological Applications Of Potent Pyrazolines Derived From Chalcone Precursors. Vol. 15, Letters In Drug Design & Discovery. 2018. 516-574 P. 16. Monther F. Mehdi, Ayad M. R.Raauf FAHK. Design , Synthesis and Acute Anti- Inflammatory Evaluation of New Non-Steroidal Anti-Inflammatory Agents Having 4- Thiazolidinone Pharmacore. J Nat Sci Res. 2015;5(6):21–28. 17. Mahdi MF, Dawood AH, Hantoush AM. Synthesis and Characterization of New Ligands attached to NSAIDs Moiety. Int J Adv Res. 2015;3(6):172–192. 18. Attarde M, Vora A, Varghese A, Kachwala Y. Synthesis and evaluation of chalcone derivatives for its alpha amylase inhibitory activity. Org Chem An Indian J. 2014;10(5):192–204. 19. Abdellatif KRA, Chowdhury MA, Dong Y, Das D, Yu G, Velázquez CA, Et Al. Dinitroglyceryl And Diazen-1-Ium-1,2-Diolated Nitric Oxide Donor Ester Prodrugs Of Aspirin, Indomethacin And Ibuprofen: Synthesis, Biological Evaluation And Nitric Oxide Release Studies. Bioorganic Med Chem Lett. 2009;19(11):3014–3018. 20. Al-azzawi AM, Alwan SM, Saud MD, Shaker AG. Dexamethasone / Ibuprofen Prodrug Synthesis and Preliminary Kinetic Study. Nat Prod Chem Res. 2013;1(2):2–6. 21. Kansara SG, Pandit RD, Bhawe VG. Synthesis of some new Ibuprofen derivatives containing chief heterocyclic moiety like s-Triazine and evaluated for their analgesic activity. Rasayan J Chem. 2009;2(3):699–705. 22. Sharshira EM, Hamada NMM. Synthesis and antimicrobial evaluation of some pyrazole derivatives. Molecules. 2012;17(5):4962–4971. 23. MAHDI MF, NASER NH, HAMMUD NH. Synthesis and Preliminary Pharmacological Evaluation of New Naproxen Analogues Having 1,2,4-Triazole-3-thiol. Int J Pharm Pharm Sci. 2017;9(7):66–71. 24. Naser NH, Mahdi MF, Omar TNA, Fadhil AA. Synthesis and Preliminary Pharmacological Evaluation of New Analogues of Diclofenac as Potential Anti-inflammatory Agents. Iraqi J Pharm Sci. 2011;20(1):25–32. 25. Faisael MMI. Synthesis , Characterization and Anti-Inflammatory Activity Assessment of New Ibuprofen Analogues Containing Imidazole-4- One Derivatives. J Glob Pharma Technol. 2018;10(03):134–141. 26. Verma S, Jain A, Gupta Vb, Stract Ab. Synergistic And Sustained Anti-Inflammatory Activity Of Guguul With The Ibuprofen : A Preliminary Study. Int J Pharma Bio Sci. 2010;1(2):1–7.