FORMULATION AND EVALUATION OF TASTE MASKED FAST DISSOLVING TABLETS OF TENOFOVIR

Available online at www.ijtpls.com International Journal of Trends in Pharmacy and Life Sciences Vol. 2, Issue: 3, 2016: 907-922 FORMULATION AND EVALUATION OF TASTE MASKED FAST DISSOLVING TABLETS OF TENOFOVIR S.Ibrahim Saheb*,S Habibulla, T. Shahanaz Begum,V. Lakshmana Murthy, E. Shabarish, E.Satheesh Kumar Department of Pharmaceutics, Balaji College of Pharmacy, Ananthapuramu, Andhra Pradesh. E.mail:syedibrahim1432@gmail.com ABSTRACT Tenofovir disoproxil fumarate (a prodrug of Tenofovir) In vivo Tenofovir disoproxil fumarate is converted to Tenofovir, an acyclic nucleoside phosphonate (nucleotide) analog of adenosine 5'- monophosphate. Tenofovir exhibits activity against HIV-1 reverse transcriptase. Tenofovir is water soluble drug having poor bioavailabilty and bitter taste. Thus the Purpose of this study is to formulate and evaluate taste masked fast dissolving tablets of Tenofovir. Drug and excipient compatibility studied by using FTIR studies showed that there are no interactions. These tablets of Tenofovir were prepared by using β- cyclodextrin as taste masking agent. Seven formulations (F1-F7) were prepared by varing the concentrations of super disintegrants such as cross caramellose sodium, crospovidine and sodium starch glycolate. Tablets were prepared by direct compression method. The prepared tablets were evaluated for all physical parameters, disintegration time, Invitro dispersion, weight variation, hardness, and friability and invitro dissolution studies. An Invitro dissolution study shows that formulation F6 containing sodium starch glycollate as super disintegrant showed 98% drug release when compared to the other formulations. Keywords: Tenofovir disoproxil fumarate, Taste masking, β- cyclodextrin, sodium starch glycollate, cross caramellose sodium and crospovidine *Corresponding Author: S.Ibrahim Saheb, Department of Pharmaceutics, Balaji College of Pharmacy, Ananthapuramu, Andhra Pradesh. Received: 04/03/2016 Revised: 26/03/2016 Accepted: 29/03/2016 INTRODUCTION Fast dissolving tablets (FDT) disintegrates and dissolves rapidly in saliva without need of drinking water. The FDT usually dissolve in the oral cavity in about 10 seconds to 3 minutes. Faster the drug goes into solution, the quicker absorption and onset of clinical effect. These tablets are not only indicated for the people who have swallowing difficulties, but also ideal for active people [1-3]. Tenofovir [4] which is the prodrug of Tenofovir disoproxil fumarete is a white to off-white crystalline powder with the IUPAC name ({[(2R)-1-(6-amino-9H-purin-9-yl)propan-2- yl]oxy}methyl)phosphonic acid, belongs to a class of antiretroviral drugs known as nucleotide analogue reverse transcriptase inhibitors (NtRTIs), which block reverse transcriptase, an enzyme crucial to viral production in HIV-infected people[5]. Ibrahim Saheb S et al. Int J Trends in Pharm & Life Sci. 2016: 2(3); 907-922. 907

MATERIALS AND METHODS Table 1: Materials used in the Formulation S.No. Drug/Exciepents Source 1 Tenofovir disoproxil fumarete Gift sample from CIPLA,Bengaluru 2 β-cyclodextrins [6] Baris pharma Pvt.Ltd,Hyderabad 3 Lactose S.D. Fine chemicals Pvt.Ltd,Mumbai 4 Crospovidone Global merchants,vadgadi,mumbai 5 Croscarmellose cellose Hiranya cellulose products,gandhi nagar,hyderabad 6 Sodium starch glycolate S.V. Enterprisers,Mumbai 7 Aspartame A.B. Enterprisers,Shradanand buildings, Mumbai 8 Aerosil S.D. Fine chemicals Pvt.Ltd,Mumbai 9 Talc S.D. Fine chemicals Pvt.Ltd,Mumbai FORMULATION DEVELOPMENT All ingredients were selected for formulation based on preformulation studies and literature review Brief Manufacturing Procedure of Preperation of tablets by direct compression method Weigh all the ingredients separately API and other excipients are passed through the 60 # sieve and blended for 15 minutes Compress the blend into tablet by 11 mm concave punches.bb tooling on eight station rotary tablet compression machine. Ibrahim Saheb S et al. Int J Trends in Pharm & Life Sci. 2016: 2(3); 907-922. 908

Table 2: Formulation design of the fast dissolving tablets Ingredietns (mg) F-1 F-2 F-3 F-4 F-5 F-6 F-7 Tenofovir 150 150 150 150 150 150 150 β-cyclodextrin 150 150 150 150 150 150 150 Lactose 93.5 83.5 93.5 83.5 93.5 83.5 118.5 Crospovidine 25 35 - - - - - Corscaramellose sodium Sodium starch glycolate Total wt. Of 450 450 450 450 450 450 450 Tablet(mg) Table 3: Instruments / Equipment used in the Formulation and Evaluation S.No. Name of the Instrument / Equipment Make 1 Rotary tablet compression machine model-ii, Rinek 2 Friabilator USP EF-2,Friabilator,Electro Lab,Mumbai 3 Hardness tester - - 25 35 - - - - - - - 25 35 - Aspertame 20 20 20 20 20 20 20 Aerosil 1.5 1.5 1.5 1.5 1.5 1.5 1.5 Talc 10 10 10 10 10 10 10 Pfizer,Servewell instruments and equipments pvt.ltd.,banglore 4 Digital vernier scale RK Industries,Mumbai 5 Bulk Density apparatus DBK Instruments,Mumbai 6 Mettler Balance Model-AE-160,Mettler, Switzerland. 7 Digital ph meter 7007,Digisun Electronics,Hyderabad 8 Disintegration tester USP Electro Lab 9 FT-IR Model-FTIR-Bruker 10 Dissolution apparatus DBK Instruments,Mumbai 11 UV spectrophotometer Model-UV-1601, Shimadzu. 12 Hot air oven Parekh Scientifics[INDIA],Mumbai Ibrahim Saheb S et al. Int J Trends in Pharm & Life Sci. 2016: 2(3); 907-922. 909

PREFORMULATION STUDIES [1-3] Drug excipient compatibility [FTIR studies] Compatability of the drug with excipients (Beta Cyclodextrin, Lactose Crospovidone, SSG, Aspartame, aerosol and Talc) used to produce FDT was established by IR spectral analysis. IR spectral analysis of pure drug, with the excipients was carried out. This study was carried out to detect any changes on chemical constitution of the drug after combining it with the excipient. The drug and excipients were mixed in a ratio of 1:1 placed in a petri dish and kept in a hot air oven at 45 0 C RH 75% for a period of 15 days. The samples were scanned over wave number ranges of 4000-400 cm -1. Angle of repose The angle of repose was measured by passing the prepared granules through a sintered glass funnel of internal diameter 27mm on the horizontal surface. The height (h) of the heap formed was measured with a cathetometer and the radius(r) of the cone base was also determined. The angle of repose (θ) was calculated from equation [1-3] Angle of repose (θ) =Tan -1 h/r Bulk density The term bulk density referes to a measure used to describe a packing of particles. It is expressed in gm/ml and was determined using a balance and measuring cylinder. Initially the weight of the measuring cylinder was tarred, 5gm pre sieved (40#) bulk drug were poured into the measuring cylinder using a funnel and weighed(m).then volume of the powder (Vb) was taken.bulk density of the granules was calculated using the following formula[1-3] Bulk density = M/Vb Tapped density Blend was tapped for a fixed number of taps. The minimum volume (Vt) occupied in the cylinder and the weight (M) of the blend was measured. The tapped density was calculated using following formula. Tapped density = M/ Vt Compressibility (Carr s) Index An accurate weight of granules was poured into a volumetric cylinder to occupy a volume (V 0 ) and then subjected to a standard tapping procedure onto a solid surface until a constant volume was achieved (Vf). The Carr s index was calculated using equation Compressiblity index = V 0 V f X V 0 Hausner s ratio[1-3] Hausner s ratio is an indirect index of ease of powder flow. It is calculated by the following formula, Hausner s ratio = tapped density / bulk density Ibrahim Saheb S et al. Int J Trends in Pharm & Life Sci. 2016: 2(3); 907-922. 910

EVALUATION OF TABLETS Weight variation: Twenty tablets were selected from formulated tablets at random and the average weight was calculated, individual tablet weights were compared with the average weight. Not more than two individual weights deviate from the average weight by more than the percentage. [1-3] Average weight -Tablet weight % Deviation = X Average weight Hardness: The tablet hardness, which is the force required to break a tablet in a diametric compression force. Pfizer hardness tester was used for the determination of the hardness which applies force to the tablet diametrically with the help of an inbuilt spring. For each formulation 6 tablets were determined. It is expressed in kg/cm 2 [1-3]. Friability: Friability of the tablet was checked by using Roche friabilator. This device Subjects a number of tablets to the combined effect of the abrasion and shock by utilizing a plastic chamber that revolves at 25 rpm dropping at a distance of 6 inches with each revolution. Preweighed samples of tablets were placed in the friabilator, which was then operated for revolutions. Tablets were dedusted using a soft muslin cloth and reweighed [1-3]. The friability (f) is given by the formula: f= (1-W 0 /W) W 0 is weight of the tablet before test W is weight of the tablet after test. Thickness: Thickness of the tablets was determined using digital Vernier calipers. 5 tablets from each formulation and average were calculated [1-3]. In-Vitro disintegration time: [7,8] In-vitro disintegration time of 6 tablets from each formulation was determined by using digital tablet disintegration apparatus. In-vitro disintegration test was carried out at 37 2 o C in 900 ml of distilled water. Six tablets were taken and one tablet was introduced in each tube, disc was placed and basket rack was positioned in 1 liter beaker containing water 37 2 o C and apparatus operated for 6 min and the disintegration time in seconds was noted [1-3]. In-vitro- dispersion test: Tablet was added to 6 ml of phosphate buffer solution, ph 6.8 at 37 0.5 o C time required for the complete dispersion of a tablet was determined. From each batch average of 3 tablets were selected randomly In-vitro dispersion time was Performed [1-3]. Ibrahim Saheb S et al. Int J Trends in Pharm & Life Sci. 2016: 2(3); 907-922. 911

Wetting time: This is carried out as a measure of hydrophilicity of tablets. Wetting time is a length of time required to wet the tablet. A piece of tissue paper (12x10.75) was folded twice was placed in the small petri dish (I.D = 6.5 cm) containing 6 ml of simulated saliva ph, a tablet was put on the paper and the time for complete wetting was measured. Three trials for each batch were performed and standard deviation was also determined. Water absorption ratio: Water absorption ratio, which is important criteria for understanding the capacity of disintegrants to swell in the presence of little amount of water. Weight of the tablet after and before test was taken. Water absorption ratio (R) is calculated using following formulae [1-3]. W a R = W a -W b W b X = Weights of the tablets after water absorption test. W b = Weights of the tablets before water absorption test. Dissolution studies: [7-8] Dissolution rate was studied by using USP type II paddle apparatus at 50 rpm. Phosphate Buffer of ph 6.8, 900 ml used as dissolution media. Temperature was maintained at 37 0 C 0.5 0 C. Aliquots of dissolution media was withdrawn at specific time intervals and it was filtered. Same amount of the fresh dissolution media was replaced. The filtered solution was determined for drug content spectrometrically at 260 nm. Dissolution rate studies were carried for all designed formulations [1-3]. RESULTS AND DISCUSSION Table 4: Observation for Physical Incompatibility S. No Name of the Excipient Category Ratio API: Excipient At 40 0 C/ 75%RH (30 days) 1. Tenofovir-API Drug 1 NCC 2. API+β-Cyclodextrin Complexing agent 1 : 1 NCC 3. API+ Lactose Diluent 1 : 1 NCC 4. API+ Crospovidone Disintegrent 1 : 1 NCC 5. API+Croscarmellose sodium Disintegrent 1 : 1 NCC 6. 7. API+ Sodium starch glycolate API+ Saccharin Disintegrent 1 : 1 NCC Sweetener 1 : 1 NCC 8. API+ Aerosil Glidant 1 : 1 NCC 9. API +Talc Lubricant 1 : 1 NCC Ibrahim Saheb S et al. Int J Trends in Pharm & Life Sci. 2016: 2(3); 907-922. 912

3382.99 1033.25 1272.16 1759.89 1636.05 65 70 75 80 85 90 95 1096.27 1683.81 2900.69 894.36 2986.19 2933.71 787.96 3686.41 3655.38 1270.90 1760.43 984.98 1681.38 1033.61 2939.05 1102.08 1625.13 892.89 Transmittance [%] 30 40 50 60 70 80 90 789.48 3226.95 2986.61 834.36 655.42 3676.81 RESEARCH ARTICLE e-issn: 2454-7867 3500 3000 2500 2000 Wavenumber cm-1 1500 0 D:\IR DATA\.1039 TEMOLOVIR SOLID 1/6/2016 Page 1/1 Fig.1: FTIR spectra of pure drug Tenofovir 3500 3000 2500 2000 Wavenumber cm-1 1500 0 D:\IR DATA\.1035 T LACTOSE SOLID 1/6/2016 Page 1/1 Fig.2: FTIR spectra of pure drug Tenofovir+ Lactose Ibrahim Saheb S et al. Int J Trends in Pharm & Life Sci. 2016: 2(3); 907-922. 913

1654.28 1274.94 3422.06 1761.21 1422.11 1031.35 Transmittance [%] 60 70 80 90 3643.53 2984.97 2926.65 3738.61 3670.40 892.54 654.41 2345.70 1030.77 3384.32 1271.44 1156.78 1760.85 1684.86 Transmittance [%] 20 30 40 50 60 70 80 90 2985.44 2928.63 892.89 789.67 834.88 578.21 3733.12 2345.60 RESEARCH ARTICLE e-issn: 2454-7867 3500 3000 2500 2000 1500 0 Wavenumber cm-1 D:\IR DATA\.1037 T BCYCLODELTRIN SOLID 1/6/2016 Page 1/1 Fig.3: FTIR spectra of Tenofovir + betacyclodextrin 3500 3000 2500 2000 1500 0 Wavenumber cm-1 D:\IR DATA\.1036 T CROSPOVIDONE SOLID 1/6/2016 Page 1/1 Fig. 4: FTIR spectra of Tenofovir + Crospovidone Ibrahim Saheb S et al. Int J Trends in Pharm & Life Sci. 2016: 2(3); 907-922. 914

1272.49 985.18 1761.01 1032.25 1685.08 3423.96 2936.11 1102.17 Transmittance [%] 60 70 80 90 2986.13 893.12 789.59 1508.15 834.43 655.59 3756.91 2345.42 65 70 75 80 85 90 95 1273.44 1760.89 2986.57 2925.36 2854.87 3747.69 3678.13 RESEARCH ARTICLE e-issn: 2454-7867 3500 3000 2500 2000 Wavenumber cm-1 1500 0 D:\IR DATA\.1033 T CROSEARMELLOSE SOLID 1/6/2016 Page 1/1 Fig.5: FTIR spectra of Tenofovir + Croscarmellose sodium 3500 3000 2500 2000 Wavenumber cm-1 1500 0 D:\IR DATA\.1040 T SODIUM STARCH SLYCOLYTE SOLID 1/6/2016 Page 1/1 Fig.6 : FT-IR spectra of Tenofovir + Sodium starch glycolate Ibrahim Saheb S et al. Int J Trends in Pharm & Life Sci. 2016: 2(3); 907-922. 915

1017.70 669.55 Transmittance [%] 20 40 60 80 1629.82 1270.74 3677.55 3426.14 2937.58 1761.65 1663.01 2986.81 3775.97 1104.91 75 80 85 90 95 3445.35 Transmittance [%] 1636.79 3749.04 3674.06 2924.56 2854.83 2345.27 RESEARCH ARTICLE e-issn: 2454-7867 3500 3000 2500 2000 1500 0 Wavenumber cm-1 D:\IR DATA\.1038 T AEROSIL SOLID 1/6/2016 Page 1/1 Fig. 7: FT-IR spectra of Tenofovir + Aerosil 3500 3000 2500 2000 Wavenumber cm-1 1500 0 D:\IR DATA\.1041 T TALC SOLID 1/6/2016 Page 1/1 Fig. 8: FT-IR spectra of Tenofovir + Talc Ibrahim Saheb S et al. Int J Trends in Pharm & Life Sci. 2016: 2(3); 907-922. 916

Absorbance(nm) RESEARCH ARTICLE e-issn: 2454-7867 Table 5: Calibration Curve of Tenofovir Conc.( g/ml) 2 0.119 4 0.155 6 0.193 8 0.232 Absorbance at 260 (nm)x 0.3 0.25 0.2 0.15 0.1 0.05 0 Calibration curve of Tenofovir 0 2 4 6 8 10 12 concentration(μg/ml) 10 0.271 Fig.9: Calibration Curve of Tenofovir Table 6: In-vitro - disintegration test S.No. Formulation No Disintegration Time(sec) 1 F-1 206±2 2 F-2 237±1 3 F-3 228±3 4 F-4 334±2 5 F-5 289±3 6 F-6 302±1 7 F-7 340±1 Ibrahim Saheb S et al. Int J Trends in Pharm & Life Sci. 2016: 2(3); 907-922. 917

1 2 20 SECONDS 80 SECONDS 3 4 130 SECONDS 160 SECONDS 5 6 240 SECONDS 302 SECONDS Fig. No. 10: Process of disintegration of FDTS Ibrahim Saheb S et al. Int J Trends in Pharm & Life Sci. 2016: 2(3); 907-922. 918

Table 7: Evaluation of the blend Formulation Code Bulk density (g/cm 3 ) Tapped density (g/ cm 3 ) Hausner s Ratio Compressibility Index % Angle of Repose(θ) F-1 0.55±0.01 0.90±0.03 1.63±0.01 38±0.02 23.3±0.01 F-2 0.52±0.02 0.58±0.02 1.16±0.03 13.7±0.01 28.14 ±0.03 F-3 0.51±0.01 0.625±0.03 1.25±0.01 20.01±0.03 30.39±0.01 F-4 0.58±0.03 0.769±0.02 1.32±0.03 24.5±0.02 28.76±0.03 F-5 0.66±0.02 0.833±0.03 1.262±0.01 36.2±0.01 27.5±0.01 F-6 0.71±0.03 0.90±0.01 1.267±0.02 21.1±0.03 26.8±0.02 F-7 0.58±0.01 0.66±0.03 1.13±0.01 24.24±0.01 29.43 ±0.01 The blends were evaluated for the tapped density, bulk density, % compressibility and angle of repose. The result reveals that Compressibility was in the range of 13.7 to 38.0 which indicates good to fair Compressibility of the powdered material. Angle of repose ranging from 23.30 to 30.39 shows fair flow ability. Hausner s ratio was found in the range of 1.13-1.63, which indicates good flow properties as reported in the table. Table 8: Dissolution drug release data of formulations F1-F4 S. No Time (mins) % Drug Release F1 F2 F3 F4 1 5 35.61±2 66.52±2.5 59.96±1.5 40.05±1.5 2 10 56.18±1.5 79.83±1.5 88.34±1 63.31±2 3 15 69.34±2 90.01±1 93.10±1.5 77.82±1.5 4 30 88.62±2.2 98.22±1 101.54±0.5 92.76±1.5 5 45 95.01±1 99.77±1.5 101.78±0.3 96.43±1 6 60.97±1.5.87±0.5 102.11±0.4 97.94±1 Ibrahim Saheb S et al. Int J Trends in Pharm & Life Sci. 2016: 2(3); 907-922. 919

% Drug Release % drug Release RESEARCH ARTICLE e-issn: 2454-7867 120 80 60 40 20 F1-F4 0 0 20 40 60 80 Time(mins) Fig.11: Dissolution drug release data of formulations F1-F4 Table 9: Dissolution drug release data of formulations F5-F7 S. No Time (mins) % Drug Release F5 F6 F7 1 5 33.00±2 72.82±1.5 35.01±1.5 2 10 62.82±1.5 92.86±1 38.62±2 3 15 73.34±2 97.72±1.5 41.65±1.5 4 30 94.09±2.2 99.63±0.5 43.54±1.5 5 45 98.18±1 101.61±0.3 44.53±1 6 60 98.75±0.5 102.01±0.5 48.67±1 120 F5-F7 80 60 40 20 0 0 10 20 30 40 50 60 70 Time(mins) Fig.12: Dissolution drug release data of formulations F5-F7 Ibrahim Saheb S et al. Int J Trends in Pharm & Life Sci. 2016: 2(3); 907-922. 920

SUMMARY The objective of the study was to formulate and evaluate the fast dissolving tablets of the Tenofovir. The study results are summarized below. The Preformulation studies of the Tenofovir were performed and drug excipients compatibility studies showed that there was no interaction between the drug and excipients chosen for the formulation as evident from FTIR. Tenofovir is a good water solubility drug but possess poor bioavailability hence its bioavailability was enhanced by complexation with Beta Cyclodextrin(1:1), for fast onset of the clinical action and to have better bioavailability. Tenofovir is a drug with slightly bitter taste in nature. So bitter taste of the drug is almost being reduced by using the sensory approaches like by the use of the sweeteners (aspartame). Crosscarmellose sodium and Crospovidone showed good compressibility, good compatibility, flowability & stability. Tablets formulated by using super disintegrants crospovidone and crosscarmellose sodium showed minimum In-vitro disintegration, dispersing time and wetting time. Crosprovidone and Sodium starch glucolate has good water absorption ratio. Dissolution studies indicated that 69.34% of the drug was released from F-1,90.01%drug release from F-2,93%drug release from F-3, 77.82 %drug release from F-4, 73.34 %drug release from F-5 and 98% of drug was released from the formulation F-6 with in 15 min. F-3 and F-6 formulations have sown no significant difference in their physical and chemical integrity. CONCLUSION It concluded that beta cyclodextrins were useful for enhancing the solubility of the poorly soluble drugs. Super disintegrants were helpful in formulation of the Fast dissolving tablets. Croscarmellose sodium and sodium starch glycolate are suitable for the formulation of the FDTs of among the three disintegrants used in the formulations. References 1. Reddy LH, Bijaya Ghosh, Rajneesh. A review of literature: Fast dissolving drug delivery system. Ind J Pharma Sci. 2002: 64 (4); 331-336. 2. Shirwaikar A.A and Ramesh A. Fast disintegrating tablets of Atenolol by dry granulation method. Ind J Pharma Sci. 2004: 66 (4); 422-426. 3. Vasavi Reddy D, Srilatha U, Rama Krishna M, and Srinivas Reddy Devireddy, Formulation And Evaluation Of Emtricitabine AndTenofovir Disoproxil Fumarate Film Coated Tablets, International Journal Of Research In Pharmacy And Chemistry. IJRPC. 2015: 5(1); 116-125. 4. www.drugbank/drugsdb00300(aprd01248) browsed on 08 th November 2015. Ibrahim Saheb S et al. Int J Trends in Pharm & Life Sci. 2016: 2(3); 907-922. 921

5. The safety of tenofovir disoproxil fumarate for the treatment of HIV infection in adults: the first 4 years MR Nelson, C Katlama, JS Montaner, DA Cooper - Aids, 2007 - journals.lww.com 6. http://www.betadexcyclodextrin.com/html/2.html 7. Shah.FIP/AAPS Guidelines for Dissolution/ Invitro Release Testing of Novel/Special Dosage Forms. Dissolution Technologies. May 2003 8. James Klancke. Dissolution Testing of Orally Disintegrating Tablets. Dissolution Technologies. May 2003. Ibrahim Saheb S et al. Int J Trends in Pharm & Life Sci. 2016: 2(3); 907-922. 922