DESIGN AND EVALUATION OF ALBENDAZOLE MATRIX TABLETS FOR COLON SPECIFIC DRUG RELEASE

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1 DESIGN AND EVALUATION OF ALBENDAZOLE MATRIX TABLETS FOR COLON SPECIFIC DRUG RELEASE L. Matsyagiri*, B. Prem Kumar, D. Pranitha, P. Venu Kumar Department of Pharmaceutics, Swami Vivekananda Institute of Pharmaceutical Sciences, Vangapally, Yadagirigutta, Nalgonda, Telangana, India, Pin ABSTRACT Objective: Albendazole is an Antihelmenthic agent used to treat irritable bowel diseases colon region of GIT. The present work aimed at to design and evaluation of colon specific drug release of Albendazole with the purpose of developing a release of drug at colon region for local action, which is very convenient for administration, without the problem of enzymatic degradation and effect of ph of upper part of GIT like stomach and small intestine. Materials and Methods: Colon specific matrix tablets of Albendazole were prepared using guar gum, xanthene gum and HPMC polymers as matrix. FTIR showed that there is no interaction between drug and excipients. In vitro dissolution of prepared matrix tablets of albendazole performed by using USP type II apparatus in ph 0.1N l first 2 hrs and remaining three hours in phosphate buffer ph 7.4 phosphate buffer solutions. Results and Discussion: The tablets were evaluated for various parameters like thickness, drug content uniformity, weight variation, hardness, friability and in vitro drug release, all were showed satisfactory results. Conclusion: It is concluded that colon specific drug release of Albendazole give all satisfactory results for formulation F1-F6. From the all formulations the optimized batch is F4 due to its effective results with guar gum. Key words: Albendazole; Colon specific drug release; Inflammatory bowel diseases INTRODUCTION The colon specific drug delivery is beneficial for the localized treatment of colonic diseases like inflammatory bowel diseases, irritable bowel syndrome and colonic cancer because it is relevant to bioavailability of poorly absorbed drugs from the upper parts of the GIT due to their polar nature, enzymatic degradation in the small intestine [1]. The colon targeted drug delivery is beneficial for the localized treatment of several colonic diseases mainly inflammatory bowel diseases (IBD), irritable bowel syndrome and colonic cancer. *Corresponding Author: L. Matsyagiri, Assoc. Professor, Department of Pharmaceutics, Swami Vivekananda Institute of Pharmaceutical Sciences, Vangapally, Yadagirigutta, Nalgonda, Pin , Telangana, India, Phone: , E mail: lmgiripharmacy@gmail.com To achieve clinically CSDDS relevant bioavailability of poorly absorbed drugs from Advanced Journal of Pharmacie and Life science Research 17

2 the upper parts of the gastrointestinal tract because of their polar nature and/or vulnerability to chemical and enzymatic degradation in the small intestine specifically for proteins and peptides [2]. The colonic drug delivery provide more effective therapy of colon associated diseases such as irritable bowel syndrome, IBD including Crohn s disease and ulcerative colitis, and also has potential to deliver macromolecular drugs orally [3, 4]. Figure 1: Anatomy of colon Inflammatory bowel disease like irritable bowel syndrome, Ulcerative colitis and crohn s diseases are considered serious colonic disorders. Ulcerative colitis, if not treated, leads to colon cancer. More than cases of colon cancer are reported to occur every year in India. Cancer of the large intestine accounts for about 15% of cancer death in India. The incidence is still high in western countries. The mainstay of treatment for colon cancer is still surgery. In most cases, partial colectomy (removal of the part of the colon) is performed followed by chemotherapy [5]. Benefits of colon specific drug delivery system 1. Target drug delivery 2. Decrease in dose to be administered 3. Decreased side effects 4. Improved drug utilization 5. It is a promising site for a drug which is unstable or poorly absorbed from upper GI tract Rationale for colon specific drug delivery system 1. Topical application of drugs active at the mucosal level and May reduces adverse effects in the treatment of colonic of colonic disease. 2. It is important in the treatment of colonic diseases like ulcerative colitis, crohn s disease, cancer and infections 3. It also provide opportunity to clarify the mechanism of action of some non steroidal anti- inflammatory drugs (NSAID) such as sulfide which get metabolized in the colon to the active moiety and interfere with the proliferation of colon polyps (first stage in colon cancer) probably in local mode. 4. Colon is capable of absorbing some drugs efficiently. 5. Drug absorption enhancer works better in the colon as compare to small intestine. 6. Large intestine is potential site for absorption of protein drugs [6]. Advantages of colon specific drug delivery system 1. Targeted drug delivery to the colon in treatment of colonic disease ensures direct Advanced Journal of Pharmacie and Life science Research 18

3 treatment at the affected area with lower dose and less systemic side effects. 2. The colonic drug delivery can also be utilized as the threshold entry of the drugs into blood for proteins and peptides which degraded or poorly absorbed in upper GIT. 3. The colon targeted drug delivery can also be used for chronotherapy for effective treatment of diseases like asthma, angina and arthritis [7]. Disadvantages of colon specific drug delivery system 1. There are variations among individuals with respect to the ph level in the small intestine and colon which may allow drug release at undesired site. The pattern of drug release may differ from person to person which may cause ineffective therapy. 2. The ph level in the small intestine and caecum are similar which reduces site specificity of formulation. 3. The major disadvantage of colonic delivery of drug is poor site specificity. 4. Diet and diseases can affect colonic microflora which can negatively affect drug targeting to colon. Nature of food present in GIT can affect drug pharmacokinetics. In diseased conditions ph level of GIT differs from ph level of healthy volunteers which alters the targeted release of formulations which release the drug according to ph of desired site. 5. Enzymatic degradation may be excessively slow which can cause interruption in polymer degradation and thus alters the release profile of drugs. 6. Substantial variation in gastric retention time may cause drug release at the undesired site in case of time dependent colonic drug delivery system [8]. MATERIALS AND METHODS Materials Albendazole was a gift sample from Medrich Ltd., Bangalore India: Hydroxyl Propyl Methylcellulose, xanthane gum, guar gum was obtained as a gift sample from Zydus Cadila Healthcare Ltd. India. All other reagents used were of analytical grade. Figure 2: Chemical structure of albendazole A) Analytical methodology The preformulation parameters for Albendazole under analytical aspect are: 1. Fourier Transform Infrared(FTIR) Spectroscopy The Fourier transform infrared (FTIR) spectra of samples were obtained by using FTIR spectrophotometer. Pure drug, individual polymers and optimized formulations were subjected to FTIR study. About 2 3 mg of sample was mixed with dried potassium bromide of equal weight and compressed to form a KBr disk. 2. UV spectroscopy Advanced Journal of Pharmacie and Life science Research 19

4 20 mg of Albendazole was dissolved in 96 % formic acid and IPA. The solution was scanned between 200 nm and 400 nm. 3. Melting point The melting point of Albendazole was taken by using Thiele s apparatus. 4. Standard graph of Albendazole (formic acid and IPA) Principle: Albendazole showed maximum absorbance at 257 nm in formic acid and IPA (1: 1.5) solution and obeyed Beer s law in the concentration range of 2-12 mcg/ml. Procedure: 10 mg of pure Albendazole was accurately weighed and transferred to 10 ml of volumetric flask. 4 ml of formic acid was added to the flask to dissolve albendazole and mixed. Then diluted to 10ml with IPA (SS-I, 1000 µg/ml). 1ml of the stock solution was pipette in to 10 ml volumetric flask and diluted to 10ml with IPA (SS-II, 100 µg/ml). From this further dilution were made to give 1µg, 2 µg, 4 µg, 6 µg, 8 µg, 10 µg, 12 µg. The absorbance was measured at 257 nm against blank (1 in 500 ml formic acid in IPA) and plotted graphically to give the standard graph of Albendazole. 5. Pre compression parameters The Final blend of all formulations was evaluated for Bulk density, Tapped density, percentage Compressibility Index (CI), Hausner ratio and Angle of repose. a) Bulk Density: 30 gms of material was passed through a sieve no. 25 to break up agglomerates and introduced into a dry 100 ml cylinder. Without compacting, the powder was carefully leveled and the unsettled apparent volume V 0, was read. The bulk density was calculated, in grams per ml, using the formula [9, 10]. Pour (or Bulk) density = mass / untapped volume (or) Bulk density D b = (M) / (V 0 ) Where, M = Total mass of the material, V 0 = bulk volume b) Tapped Density: After carrying out the procedure as given in the measurement of bulk density the cylinder containing the sample was tapped using a mechanical bulk density tester that provides a fixed drop of 14±2 mm at a nominal rate of 300 drops per minute. The cylinder was tapped 500 times initially followed by an additional tap of 750 times and then tapped volume V t, was measured to the nearest graduated unit. The tapped density was calculated, in g per ml, by using the following formula [9, 10]. Tapped density = mass / tapped volume (or) Tapped density (D t) = (M) / (V t ) c) Measures of Powder Compressibility: The % Compressibility Index and Hausner Ratio are measures of the propensity of a powder to be compressed. % Compressibility Index = (D t -D b ) /D t X 100 Where, D t = Tapped density D b = Bulk density Advanced Journal of Pharmacie and Life science Research 20

5 Table 1: Compressibility index specifications Compressibility Index Properties 5-12 Free flowing Good Fair Poor Very poor >40 Extremely poor Hausner ratio: It indicates that the flow properties of the powder and measured by the ratio of taped density to bulk density [9, 10]. Hausner ratio = tapped density / pour density (or) Hausner ratio = D t / D b Where, D t = Tapped density; D b = Bulk density Table 2: Hausner ratio specifications Hausner Ratio Property Free flowing Cohesive powder Carr s index: It indicates that the flow properties of the powder and measured by the ratio of taped density to bulk density [9, 10]. Carr s Index = (tapped density bulk density) x 100 / tapped density Table 3: Carr s index specification Carr s index Property 5-11 Excellent Good Fair >23 Poor d) Angle of Repose (A): The angle of repose was measured by fixed funnel method. A funnel was secured with its tip at a given height h above a graph paper that was placed on a flat horizontal surface. The blend was carefully pored through the funnel until the apex of the conical pile just touched the tip of the funnel. The radius, r of the base of the conical pile was measured [9, 10]. Α= tan 1 (h/r) Table 4: Specifications of angle of repose Angle of repose Powder flow < 25 Excellent Good Passable > 40 Very poor Formulation of Albendazole Matrix Tablets Technology Applied: Direct compression. The matrix tablets containing 200 mg albendazole were formulated with different proportions of natural polysaccharides such as guar gum, xanthum gum and synthetic polymer HPMC K200M. Albendazole was passed through the sieve no.16; polymers, microcrystalline cellulose and Lactose (DC) were passed through the sieve no.40separately and mixed homogeneously. The drug blend was lubricated with a mixture of talc, Colloidal silica and magnesium stearate which were previously passed through the sieve no.60. Finally the lubricated powders were compressed into tablets containing 200 mg Advanced Journal of Pharmacie and Life science Research 21

6 albendazole using 11 mm round flat punch [14, 15]. Table 5: Composition of different formulations of Albendazole matrix tablet varniear caliper. Three tablets of each formulation were picked randomly and thickness was measured individually [12, 13]. Hardness test: Tablet hardness was measured using a Monsanto hardness tester. The crushing strength of the 10 tablets with known weight and thickness of each was recorded in kg/cm 2 and the average hardness, and the standard deviation was reported [12, 13]. Weight variation test: Twenty (20) tablets from each batch were individually weighed in grams on an analytical balance. The average weight and standard deviation were calculated, individual weight of each tablet was also calculated using the same and compared with average weight [12, 13]. Friability test: The friability of tablets was determined using Roche friabilator. It is expressed in percentage (%). Ten tablets were initially weighed (W initial ) and transferred into friabilator. The friabilator was operated at 25rpm for 4 min or run up to 100 revolutions [12, 13]. The tablets were weighed again (W final ). The % friability was then calculated by: = Table 6: Weight variation tolerances for uncoated tablets Maximum % of weight difference allowed Average weight of tablets(mg) USP IP 10 <130 < >324 >250 Tablet dimensions: The thickness in millimeters (mm) was measured individually for 10 pre weighed tablets by using digital Vernier Calipers. The average thickness and standard deviation were reported. Thickness and diameter were measured using a calibrated % Friability of tablets less than 1% are considered acceptable. Drug content: One tablet was selected randomly and weight was taken. The tablet was mixed with 20 ml of 96 % formic acid in 100 ml of volumetric flask and heated on a steam bath for 15 minutes. Cooled and soaked for 24 hrs and IPA was added to volume and mixed [12, 13]. The drug content was calculated using fallowing formula. Drug content = (sample abs/slope) x Dilution factor Aliquot volume x 1000 Advanced Journal of Pharmacie and Life science Research 22

7 Dissolution profile of Albendazole tablet formulation [11, 18] : The in vitro release study for all the formulations was carried out in dissolution apparatus conforming to USP type II (paddle method). The water bath was thermo stated at 37 C ± 0.5 C. The paddle was set to rotate at 75 rpm. One tablet previously weighed was kept in the dissolution media. Three dissolution medias-acidic buffer ph 1.2 for 2 hrs, Sorenson s phosphate buffer ph 7.4 for 3 hrs and phosphate buffer ph 6.8 for nineteen hrs were used. 1ml of dissolution media was pipette out at every hour into a 10 ml volumetric flask and 1 ml of formic acid was added and volume made up to mark with the IPA and analyzed by UV Visible spectrophotometer against blank. Each time 1ml of respective fresh dissolution media was replaced into the bowel [11, 16]. Specifications of dissolution procedure Bowel temperature: 37 C ± 0.5 C Bath temperature: 37 C ± 0.5 C Regression equation: Y = mx + C = 0.029x Dissolution media: Simulated Gastric fluid ph 1.2 Dissolution media: Sorenson s phosphate buffer ph 7.4 Dissolution media: Phosphate buffer ph 6.8 Volume of dissolution media: 900 ml Volume pipetted: 1 ml Volume replaced: 1 ml of respective dissolution media Dissolution apparatus: USP Type II (paddle) Revolutions per minute: 75 (For 2-hours ph 1.2 buffers, for 3-hours Sorenson s phosphate buffer ph 7.4 and for 19 hours phosphate buffer ph 6.8) Drug release studies in presence of galactomannase enzyme Drug release studies were carried out using USP dissolution apparatus II at 75 rpm and 37 C. The tablets were placed in dissolution media and tested in acidic buffer ph 1.2 (900 ml) for 2 hours as the average gastric emptying time is about 2 hours. The dissolution medium was replaced with ph 6.8 Sorensen phosphate buffer (900 ml) and tablets were tested for 3 hours as the average small intestinal transit time 3 hours. Samples each of 1 ml were taken separately, suitably diluted and analyzed for Albendazole content at 257 nm. The studies simulating the drug release in colon were carried out in USP dissolution test apparatus II at 75 rpm and 37 C with slight modification. A beaker of capacity 500 ml containing 200 ml dissolution medium as ph 6.8 phosphate buffer with galactomannase enzyme (0.1 mg/ml) was kept in water bath of dissolution test apparatus. The experiment was carried out with continuous CO 2 supply into beakers. The drug release study was carried out for 24 hours since the colonic transit time is hours. 1ml of dissolution media was pipette out at every hour into a 10 ml volumetric flask and 1ml of formic acid was added and volume Advanced Journal of Pharmacie and Life science Research 23

8 made up to mark with the IPA and analyzed by UV Visible spectrophotometer against blank. Each time 1ml of respective fresh dissolution media was replaced into the bowel [17, 18]. Table 8: Cumulative percentage drug release profile of guar gum formulated RESULTS AND DISCUSSION Evaluation of post compression parameters: Table 7: Post compression evaluation of All values are expressed as Mean ± SD, n = 3 All the prepared formulations were tested for Physical parameters like Hardness, thickness, Weight Variation, Friability and found to be within the Pharmacopoeias limits. The hardness of the tablets for all the formulations was in the range of kg/cm 2. The uniformity weight of tablets of all the formulations was within the prescribed limits. The thickness of the tablets for all formulations was in the range of 3.65 to 3.98 mm. The friability of all the formulation was less than 1%. Drug content of all the formulations were found to be in the range of 96.5 to %. All the results were within the prescribed limits. In vitro dissolution studies All values are expressed as Mean ± standard deviation (SD), n = 3 In vitro release studies of matrix tablets (F1- F9) shows drug release in the first 5 hours (ph 1.2 for first two hours and ph 7.4 for next three hours mimicking stomach and small intestine) was found to be in the range 14.1% to 3.85 %. The dissolution studies were further carried out in the simulated colonic fluid (phosphate buffer ph-6.8 with and without rat caecal medium) for next 19 h. From the studies it was observed that the formulation of F1, F2, F3 (guar gum 20 %, 25 % and 30 % ) found to release the albendazole in the range of 70.05% to 53.01% at the end of 24 h in the absence of galactomannase enzyme. But the same formulation found to release the albendazole in the range of 84.53% to 68.71% at the end of 24h in the presence of galactomannase enzyme. Further it was observed that the formulations of F4, F5, F6 (xanthum gum 20%, 25% and 30% ) found to release the albendazole in the range of 72.22% to 56.1% at the end of 24 h Advanced Journal of Pharmacie and Life science Research 24

9 in the simulated colonic fluid without galactomannase enzyme. But the same formulations found to release the albendazole in the range of 94.62% to 74.13%at the end of 24 th h in the presence of galactomannase enzyme. Further it was observed that the formulations of F7, F8, F9 (HPMC 20 %, 25 %, and 30%) found to release the albendazole in the range of % to % at the end of 24 h in the simulated colonic fluid without galactomannase enzyme. These results showed that the formulated matrix tablets were able to restrict the release in the stomach and small intestine and able to target the drug release in the colon. From the above results, it was found that the present drug released from albendazole tablets were less in phosphate buffer (ph 1.2 and ph 7.4) than the percentage drug released in phosphate buffer (ph 6.8) containing galactomannase enzyme. Table 9: Cumulative percentage drug release profile of xanthan gum formulated All values are expressed as Mean ± standard deviation (SD), n = 3 Figure 4: Cumulative percentage drug release profile of xanthane gum formulated Table 10: Cumulative percentage drug release profile of HPMC formulated Figure 3: Cumulative percentage drug release profile of guar gum formulated All values are expressed as Mean ± standard deviation (SD), n = 3 Advanced Journal of Pharmacie and Life science Research 25

10 Drug release profile in presence of galactomannase enzyme Galactomannase enzyme was used because of the similarity with human intestinal microflora. Figure 5: Cumulative percentage drug release profile of HPMC formulated Table 12: Cumulative percentage drug release in acidic buffer (P H 1.2 for 2 hrs) and phosphate buffer (P H 7.4 for 3 hrs) from without galactomannase enzyme Table 11: Cumulative percentage drug release profile of all formulations of All values are expressed as Mean ± standard deviation (SD), n = 3 Table 13: Cumulative percentage drug release in phosphate buffer (P H 6.8 for 19 hrs) from with galactomannase enzyme Figure 6: Cumulative percentage drug release profile of all formulations of Advanced Journal of Pharmacie and Life science Research 26

11 All values are expressed as Mean ± standard deviation (SD), n = 3 Figure 7: Cumulative percentage drug release profile of formulations (F1-F6) of in presence of galactomannase enzyme in phosphate buffer P H 6.8 for 19 Hours. From all the above formulations (F1, F2, F3, F4, F5, F6, F7, F8, and F9) of albendazole matrix tablets F4 considered as the optimized formulation as it is targeting the drug to the colon and it is releasing 94.6% of albendazole at the end of 24 hrs. CONCLUSION The guar gum matrix tablets satisfied the drug content as they contained to % of Albendazole. The mean percent of drug released from colon targeted tablet was found to be less than 17 % after 5 hrs of testing in simulated gastric and intestinal fluids. On exposure to the dissolution fluid, the guar gum becomes hydrated and forms a viscous gel layer that slows down further sweeping-in of dissolution fluids towards the core tablets. The hydration of guar gum seems not to be affected by the ph of the dissolution medium. Thus guar gum in the form of matrix tablet coat is capable of protecting the drug from being released in the physiological environment of stomach and small intestine. The guar gum based colon targeted drug delivery systems should not only protect the drug from being released in the physiological environment of stomach and small intestine, but also have to release the drug in colon by colonic bacteria. Hence in vitro release studies were carried out in ph 6.8 phosphate buffer containing 4 % (w/v) of rat caecal content obtained after 7 days of pre-treatment of rats with 1 ml of 1% (w/v) aqueous dispersion of guar gum. The present study was to achieve a colon specific release of albendazole consisting of guar gum as a microbially triggered polymer, from the results F4formulation considered as optimized batch. ACKNOWLEDGEMENTS The authors are grateful to the management of Swami Vivekananda Institute of Pharmaceutical Sciences, Vangapally for providing all the necessary facilities for the successful completion of this work. REFERENCES 1. Jain NK. Advances in controlled and novel drug delivery system. New Delhi: CBS; Reddy SM, Sinha VR, Reddy DS. Novel oral colon-specific drug delivery system for Pharmacotherapy of peptide and non peptide drugs.drugstar.1999: 35: Advanced Journal of Pharmacie and Life science Research 27

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