Microsoft Word - bagpha05114 _3_ Iraqi J. Parma. Sci., Vol.14, 2005 20 --------------------------------------------------------------------------------------------------------------- FORMULATION OF ECONAZOLE NITRATE AS A TOPICAL SOLUTION LAITH HAMZA SAMIN Received: 14.01.2002 Accepted: 05.08.2002 ABST RACT : Econazole nitrate (EN) is considered as the most effective agent for the treatment of all forms of dermatomycosis caused by dermatophytes. This study was carried out to formulate a stable Econazole nitrate solution for a topical use through preparation of different formulas and selected the most suitable one. The results indicated that the use of propylene glycol and ethanol as a vehicle for EN which is very slightly soluble in water gave amore stable formula as EN topical solution, with a shelf life of about 3.15 years .The data also indicated that the light accelerated the degradation of EN, while the type of container (glass or plastic) had no effect on the rate of drug. The overall results of this study suggest that the selected formula could be used as a topical solution for EN. :الخـالصـة عالج جمیع أشكال الفطریات الجلدیة الناتجة الدواء فيیعتبر األكثر فعالھ الستخدام ھذا ) نترات االیكانازول(أن محلول عل�ى ش�كل ) لنت�رات االیكان�ازول (كان ھدف الدراسة أیج�اد ص�یغھ تركیبی�ھ مس�تقره .الفطریةعن العوامل المسببة لتلك االلتھابات .یر عدد من الصیغ التركیبیة واختیار الصیغة األكثر فعالیھ من خالل تحض محلول، وال�ذي یك�ون قلی�ل ) لنت�رات االیكان�ازول (كم�ادة ناقل�ھ ) الكح�ول االثیل�ي (و)ب�روبلین كالیك�ول (النتائج أثبت�ت أن اس�تعمال النتائج أیضا إلى أن الضوء أشارت .سنھ 3,15الذوبان في الماء أعطى صیغھ تركیبیھ اكثر استقرارا لھذا المحلول وعمر صالحیة نت�رات (ل�یس ل�ھ ت�أثیر عل�ى اس�تقراریة ) بالس�تك أو زج�اج (نوع الحاویة ا، بینم)نترات االیكانازول(ساعد في تسریع عملیھ تحلل نت���رات (أن حص���یلة نت���ائج ھ���ذه الدراس���ة أظھ���رت أن الص���یغة التركیبی���ة المخت���ارة یمك���ن اس���تعمالھا لتحض���یر ). االیكان���ازول .على شكل محلول)لاالیكانازو Iraqi J. Parma. Sci., Vol.14, 2005 21 --------------------------------------------------------------------------------------------------------------- INTRODUCTION: Econazole nitrate is (RS)-1-[2,4-dichloro-B (p-chorobezyl- oxy) phenethyl] imidazole nitrate (1) . It is a white or almost white crystalline powder.m.ρ. About 164C o , with decomposition. Very slightly soluble in water and ether: soluble 1 in 125 of ethanol (96%) 1in 60 of chloroform and l in 25 of methanol (1, 2) . Econazole nitrate is used for the topical treatment of all forms of dermatomycosis caused by Dermatophytes like trichophyton rubum, trichophyton mentagrophytes, trichophyton tonsusrans which cause tinea pedis, tinea cruris, and tinea corporis respectively(3). It is used for dermatomycosis caused by yeasts like candida albicans and candida guilliermordi (4) . Econazole nitrate is available in a variety of dosage form such as skin cream (alone or in combination with triamcinolone), skin solution, skin lotion and spray solution (3) . It has been proven to be effective in the presence of mixed infection. The antibacterial effect of the preparation offers an additional outstanding advantage. The purpose of this work is to formulate a stable Econazole nitrate solution for topical application using different types of vehicles like propylene glycol, polyethylene glycol (PEG), Glycerol and ethyl alcohol which they are inert nontoxic and maintain the solubility of drug. Furthermore, the effects of container type and light on the stability of the prepared formula are studied as well as its shelf life. MATERIALS, INSTRUMENTS AND METHODS Materials Econazole nitric powder (Alesmalia company-Iraq), methanol, polyethylene glycol, glycerol, ethanol (BDH, Chemicals, Ltd, Pool, England), hydrochloric aid (Riled DE Haen AG Seelze, Hanover, Germany). Standard buffer ( pH 4 and 7 ) . Propylene glycol (MERK Germany) . INSTRUMENTS Spectrophotometer (Pye-Unicom SP-8-100 England Model 292 MK2 England) Sartorius balance (Werke-GMBH, Type 2842, Germany – GMBH,Type 1265 NIP,W.G Autoclave (Vebstatex Jimenau , Type SD505 ) PH-meter(Schott-Geate,Type CG820,W.Germany. METHOD Assay of Econozole nitrate topical solution: A simple and fast procedure for the determination of (EN) based on the UV spectrophotometry (5) , was applied as follows. .HNO3 Iraqi J. Parma. Sci., Vol.14, 2005 22 --------------------------------------------------------------------------------------------------------------- Test solution: 5ml was measured and diluted with pure methanol to 100ml. Reference solution: 50mg of pure (EN) was exactly weighted and transferred into 100ml volumetric flask. About 50 ml of pure methanol was added, shacked well until it was dissolved, completed the volume to 100ml with methanol and mixed. The UV absorbency was then recorded in 1cm quartz cell for the reference and test solutions against pure methanol. The quantity of Econazole nitrate in topical solution was calculated using the following equation. % Econazole nitrate = (Acorr sample X mg standard) / (Acorr standard Xmg sample X 10) (Acorr= A271.5 _ A278.5) Formulation of Econazole nitrate as a topical solution. Different formulas of Econazole nitrate for topical solution (1%w/v) were prepared as shown in Table-1. Formu la Econazole nitrate (gm) Propylen glycol (ml) Polyethylere glycol (ml) Glycerol (ml) Ethanol a.s.to (ml) A 1 ---- 75 ---- 100 B 1 ---- 35 40 100 C 1 50 12 13 100 D 1 50 25 ---- 100 E 1 75 ---- ---- 100 Table-1 Schedule of Different formulations of Econazole Nitrate as a topical Solution All formulas (A,B,C, Dand E ) were composed of Econazole nitrate (1%) and completed to 100 ml volume with ethanol(95%). Stability Study Stability of (EN) in a normal and accelerated conditions was carried out by incubating samples of formula E in ovens at 40,45 and 50 o C for 120 days. Samples were taken and assayed for their drug content at suitable time intervals (2 weeks) using spectrophotometry method. Effect of light This factor was studied by placing formula E in a clear glass container and subjected to light at room temperature for 2 months (6, 7) . Samples were taken every two weeks and analyzed for their drug content. Effect of containers The functions of container are to maintain the quality, safety and stability of its content (8, 9). Various samples of formulaE were stored at different conditions (room temperature, 40 o C) in glass bottles and plastic bags for 120 days. Samples were taken and assayed for their drug content every one month using spectro photometric method. Quality control The concept of total quality control refers to the process of striving to produce perfect product by a series of measurements. The quality control tests that were done, included density, pH, drug content and appearance of solution Iraqi J. Parma. Sci., Vol.14, 2005 23 --------------------------------------------------------------------------------------------------------------- RESULTS AND DISCUSSION Method of Assay In this study the ultraviolet spectrophotometry was used for the quantification of (EN) as a topical solution, the data indicated that the method gave acceptable results since a good standard curve with a correlation of 0.996 was obtained as seen in fig.1. Iraqi J. Parma. Sci., Vol.14, 2005 24 --------------------------------------------------------------------------------------------------------------- The U.V. spectrum of (EN) is shown in Fig.2. The profile indicates that, the drug has maximum absorbance at 271.5 nm and minimum absorbance at 278.5nm in methanol as it has been reported. Fig 2 UV spectrum of Econazole Nitrate in solvent Methanol at 25 C Formulation of Econazole nitrate Table –2 shows the percent remaining after 4 months and rate of hydrolysis of the five formulas calculated from the slope of first-order kinetic plots in order to select the most stable one. Formula Method of Assay Remaining (90-110)% K40C (X10 -3 )day -1 A UV 90.3 0.81 B UV 85 1. 3 C UV 83 1. 5 D UV 94.9 0.41 E UV 98.6 0.16 Table-2 The Percent Remaining after 4 months and Degredation Rate Constant (K) Of Econazole nitrate in Formulas A, B, C, D and E at 40oC Iraqi J. Parma. Sci., Vol.14, 2005 25 --------------------------------------------------------------------------------------------------------------- The data indicate that minimum rate of hydrolysis of (EN) was achieved using 75% propylene glycol as a solvent (formula E) since it has the lowest rate constant (0.16x0-3day-1). This may suggest that propylene glycol is the most suitable vehicle for the formulation of (EN) topical solution. It acts as a solvent for many dermatological drug and ensure homogenous dispersion of drugs used in low concentration (10) . Stability study Stability Study in normal and accelerated conditions was carried out (11) . Table-3- shows the percent remaining of (EN) at room temperature for formula E after storage. Formula E Storage time Appearance Method of Assay % Remaining (90-110)% Zero time Clear liquid UV 100.1 2 months = UV 100 4 months = UV 100.1 6 months = UV 99.0 Table-3 The percent Remaining of Econazole Nitrate (Formula E) At Room Temperature after 4 months. The effect of temperature on the rate of hydrolysis of (EN) was also studied using different accelerated temperatures (40,45and 50 o C) for 120 days. The degradation of (EN) in formula (E) follows a first-order kinetics, since straight lines were obtained when the logarithm of percent remaining of (EN) was plotted versus time as shown in fig.3. X A t4 0 o C ^ A t4 5 o C . A t5 0 oC Iraqi J. Parma. Sci., Vol.14, 2005 26 --------------------------------------------------------------------------------------------------------------- The degradation rate constants (K). at (40, 45 and 50 o C) were calculated from the slopes of lines as illustrated in table 4. Temp K X10 -3 day –1 40oc 0.200 45 o c 0.268 50 o c 0.420 25oc 0.9 Table-4 Degradation Rate Constants (K) of Econazole Nitrate in Formula E at Different temperatures To determine the expiration date (t10%) at 25 o C, Arrhenius plot (12) was constructed to predict the degradation rate constant at 25 o C (k25) for formula E as shown in Fig.4. Iraqi J. Parma. Sci., Vol.14, 2005 27 --------------------------------------------------------------------------------------------------------------- Since the degradation of drug follows first-order kinetics, therefore, the expiration date can be calculated using the following equation. t10%= 0.104/ K25 It appears from the results that the drug in formula E. (Selected formula) has a t10% value of about 3.15 years. Effect of light: The effect of light on hydrolysis of Econazole nitrate was studied by placing the selected formula (formula E) in clear and dark containers at room temperature for 2 months. As shown in figure 5, there is a linear relation ship for logarithmic plot of the percent remaining of Econazole nitrate versus time when the drug was stored in clear and dark containers, indicating that the degradation of drug follows first order kinetics figure5. Fig- 5- The effect of light on the rate of hydrolysis of Econazole Nitrate in formula E at room temperature. X Light X X X X 15 30 45 60 Time (day) Dark Iraqi J. Parma. Sci., Vol.14, 2005 28 --------------------------------------------------------------------------------------------------------------- The results indicate that the percent remaining of drug was 95.91% when exposed to light at room temperature after 2 months. This is in consistent with the reference which state that EN is known to be affected by light and should be stored in a well closed container protected from light(13). On the other hand, the samples which were stored in dark containers showed no detectable change in the percent remaining when exposed to the same condition Effect of container Table 5 shows the percent remaining of EN when placed in glass and plastic container at different conditions (room temperature, 40 o C) ,for 4 months. The result showed that no detectable change in percent remaining especially when stored at room temperature. Formula E %Remaining K 40 oC (X10-3)day-1 Glass container 97.7 0.20 Plastic container 97.8 0.20 Table-5 The effect of containers on the stability of Econazole nitrate at 40 o C after 4 months . Quality control The selected formula (formula E) was subjected to many types of product control test for topical solution these tests include appearance of solution , drug content ,pH, and density. The prepared product passed all these tests successfully as shown in table 6. Type of Test Results Formula E Requirement Drug content 100.1% 90 –110 % PH 3.5 – 4.5 ----- Clarity of Solution Clear colorless Solution Clear colorless solution Density(20 ºC) 0.975 – 0.995 g/ml 0.995 g/ml Table-6 Results of the Quality Control Test for the selected Formula (formula E) of Econazole Nitrate This indicates that the method of preparation is efficient and effective. CONCLUSIONS (EN) is a novel antimycotic preparation for topical use. After conducting this investigation on Econazole nitrate as a solution dosage form for topical application, one can conclude the followings: 1. formula E consider the most stable formula since log percent remaining for this formula was 1.995(99%) after incubation in 40ºc for 4 months 2. propylene glycol is an excellent vehicles used to increase the solubility of medicament, it also act as a solvent for EN to ensure homogeneous dispersal of drug used in low concentration (10,14) . 3. It was noticed that there was a significant effect of light on degradation of Econazole nitrate 4. Econazole nitrate show a good linearity of UV response which is simple and fast procedure for determination of Econazole nitrate in the drug substance based on UV. 5. The use of plastic or glass container for Econazole nitrate drug had no effect since the same percent remaining were seen when drug solution was stored the drug at different temperature. Iraqi J. Parma. Sci., Vol.14, 2005 29 --------------------------------------------------------------------------------------------------------------- 6. The product passed all the quality control tests successfully which indicate the efficiency of the method of preparation. 7. The expiration date of EN drug was found to be 3.15 years. 8. Further study will be done to formulate Econazole nitrate as a topical cream with triamcenolone Iraqi J. Parma. Sci., Vol.14, 2005 30 --------------------------------------------------------------------------------------------------------------- REFERENCES: 1- British Pharmacopoeia, P.245, 1998. 2- Clark’s, isolation and identification of drug, 2th. Ed, the pharmaceutical press, London; P.579, 1986. 3- Physician Desk References 1999. 4- Scholar-M; Prediel-H; Korting –HC, Light and Electron Microscopic finding in amodel of Human Coetaneous Candidacies, Journal of Drug Targeting, 1999; 6(5) 361 – 372. 5- Sastry, B.S; Rao, J.V, spectrophotometric method for determining of Econazole nitrate, Indian Drug, 1992; 29 (Mar) ,277,280. 6- The Arab Good Manufacturing Practice guilders “GMP” 1995 by the Arab Union of the Manufacturers of pharmaceutical and Medical Appliances (AUPAM). 7- Guidance for industry (Q.B photo stability testing of new drug substances and products).November 1999. 8- Marcie, K.N., “Utilization of Nicotinamide as a complexing agent in the formulation of diazepam oral solution,” PhD. Thesies Baghdad University, college of pharmacy, 1996. 9- Remingtin’s pharmaceutical science 7 th . Ed. Mark publishing company, Easton, Pennsylvania. chap.80,87, 1985. 10- Carter, S.J, the ointment, pastes and jellies, chap.13 in “dispensing for pharmaceutical students “12 th ed. Churchill Livingstone 1987. 11- Wolfgang Grim, Extension of the International Conference on Harmonization Tripartite Guideline for Stability Testing of New Drug Substance and Product to Countries of Climatic, Zones III and IV. Drug development and industrial pharmacy, 1998; 24(4), 313 – 325. 12- Lachman, L., liberman, H.A. and. Change J.L., “the theory and practice of industrial pharmacy” 3 rd ,er., Lea and Febiger Publishing Company, Philadelphia (1986). 13- The United States Pharmacopoeia, VOL 32,p.1189. 14- Ford, J.L., parenteral product, chap. 21in” pharmaceutics, the science of dosage form design, by Alton ,N.E, Churchill Livingstore, 1988. ABSTRACT : الخـلاصـة: Formula Method of Assay