Page4111 Indo American Journal of Pharmaceutical Research, 2016 ISSN NO: 2231-6876 FORMULATION DEVELOPMENT OF RIVAROXABAN LIPID SOLID DISPERSION USING DIFFERENT TECHNIQUES FOR THE DISSOLUTION ENHANCEMENT M. Ganesh 1, Dr. B. Chandra Shekar 2, Prof (Dr). Y. Madhusudan 3 1 Jawaharlal Nehru Technological University, Kukatpally, Hyderabad-72, Telangana. 2 Bomma Institute of Pharmacy, Allipuram, Khammam -507318, Telangana. 3 Vagdevi College of Pharmacy, Hanmakonda, Warangal, Telangana. ARTICLE INFO Article history Received 25/01/2016 Available online 31/01/2016 Keywords Rivaroxaban, Lipid Solid Dispersion, Gelucire 50/13, Gelucire 48/16,, Compitrol ATO 888 And Dissolution. ABSTRACT Rivaroxaban drug used in acute coronary syndrome (ACS), Prevention of cardiovascular death, myocardial infarction and stent thrombosis. Rivaroxaban is a potent selective oral direct factor Xa inhibitor, Rivaroxaban BCS Class II. Depending on the choice of excipient(s) and formulation techniques, it is possible to obtain a variety of systems including physical mixtures, liquid/solid solutions, solid dispersions, and Self-Micro or Self-Nano Emulsifying Drug Delivery Systems (SMEDDS/SNEDDS).Lipid based formulations including lipid solid dispersion formulations offer the potential for enhancing the dissolution and absorption of poorly soluble and/or poorly permeable compounds. Lipid solid dispersions are prepared by three different techniques Solvent evaporation, Hot melt granulation and Spray drying method and evaluated by drug content, saturation solubility, particle size analysis and in-vitro dissolution. Comparative evaluation of three different techniques studied and Spray drying method (SDRD8) shows better dissolution profile as comparative to the other two techniques and marketed market product. Spray dried formulation was stable at accelerated condition. Corresponding author M. Ganesh Research Scholar, Pharmaceutical Sciences, JNTUH, Hyderabad, Telangana - 500072, India. ganeshsrcm@gmail.com Please cite this article in press as M. Ganesh et al. Formulation Development of Rivaroxaban Lipid Solid Dispersion Using Different Techniques for the Dissolution Enhancement. Indo American Journal of Pharmaceutical Research.2016:6(01). Copy right 2016 This is an Open Access article distributed under the terms of the Indo American journal of Pharmaceutical Research, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Page4112 INTRODUCTION Rivaroxaban drug used in acute coronary syndrome (ACS), Prevention of cardiovascular death, myocardial infarction and stent thrombosis. Rivaroxaban is a potent selective oral direct factor Xa inhibitor, Rivaroxaban BCS Class II. Depending on the choice of excipient(s) and formulation techniques Lipid based formulations including lipid solid dispersion formulations offer the potential for enhancing the dissolution and absorption of poorly soluble and/or poorly permeable compounds. Lipid solid dispersions are one of the most successful formulations to improve the in-vitro dissolution and in-vivo absorption of poorly soluble drugs and their bioavailability [1]. The dissolution of drug from Lipid solid dispersion is controlled by the relative amount of combinations of hydrophilic lipids in the formulation. To overcome biopharmaceutical challenges, versatile formulation approaches are designed which will accommodate the physicochemical properties of the individual drug while simultaneously improving the aqueous solubility and oral bioavailability. These approaches include co-solvents [2], solid dispersions [3], cyclodextrin inclusion complexes [4] nanosuspensions [5], colloidal delivery systems 6 and lipid based delivery systems [7-8] MATERIALS AND METHODS Rivaroxaban drug was obtained as gift sample from MSN Laboratories, Hyderabad, India. Macrogol stearate Polyoxyl stearate (Type I) NF (Gelucire 48/16), Behenoyl polyoxyl-8 glycerides NF (Compitrol HD5), Lauroyl macrogol-32 glycerides (Gelucire 44/14), Stearoyl macrogoglycerides (Gelucire 50/13), Glyceryl dibehanate (Compritol ATO888), PEG-32 stearate (Tefose 1500) and Caprylocaproyl polyoxyl-8 glycerides NF (Labrasol ) kindly provided by Gattefosse (Saint-Priest Cedex, France).HPLC grade acetonitrile and phosphoric acid were purchased from Tedia. Co., Ltd. (Fairfield, OH, USA). Gelatin capsules (size 1) were obtained from ACG Capsules. (Mumbai, Maharashtra, India). Reagents were of analytical grade, and preparation of HPLC mobile phase was done with Millie-Q demineralized double-distilled water. FORMULATION OF RIVAROXABAN LIPID SOLID DISPERSION Rivaroxaban lipid solid dispersion prepared by three different techniques. Different lipids with the different ratios are evaluated and tabulated in table 1. Based upon the final outcome the ratio of lipids in the lipid mixture is maintained at a final concentration of 10:15:1 of Gelucire 48/16, Compritol HD5 and Labrasol. SOLVENT EVAPORATION METHOD: The preparation method includes the dispersion of Rivaroxaban in the lipid matrix consisting of Gelucire 48/16, Compritol HD5 and Labrasol at different a weight ratios. The drug dispersed lipid matrix is dissolved in the dichloromethane (DCM) to obtain a clear solution. The drug and lipid mixture solution evaporate using vaccume evaporator. The total solid contents concentration is maintained at 5 w/v%. The dried Rivaroxaban drug loaded lipid-solid dispersions are collected from the vessel, solid mass was grounded and passed through sieve no.100 and filled in the capsules. To develop free flowing fine particles by Solvent evaporation method different adsorbents were selected and evaluated. The flow propertied of resulting dried powder from the trails Gelucire 48/16 in combination with Compritol HD5 and Labrasol was found to be satisfactory. The optimum drug to excipient (s) ratio was identified on the basis of drug content, drug solubility and physical form. HOT MELT GRANULATION: The preparation method includes the Rivaroxaban drug dissolved in solvent dichloromethane (DCM) and lipid matrix consisting of Gelucire 48/16 and Labrasol, this mixture dispersed on Compritol HD5 and air dried granules at room temperature than pass this dried granules through sieve no.100 and filled in the capsules. The total solid contents concentration is maintained at 5 w/v%. SPRAY DRYING METHOD: The preparation method includes the dispersion of Rivaroxaban in the lipid matrix consisting of Gelucire 48/16, Compritol HD5 and Labrasol at different a weight ratios. The drug dispersed lipid matrix is dissolved in the dichloromethane (DCM) to obtain a clear solution. The resulting solution was subjected to spray drying using Labultima spray dryer. The total solid contents concentration was maintained at 5 w/v%. The dried Rivaroxaban lipid solid dispersion collated from cyclones and drying chamber and filled in to the capsules. The comparative evaluation of formulation with different techniques given in table 1.
Page4113 Table: 1 Comparative evaluation of formulation with different techniques. Solvent Evaporation method Formulation Composition Drug/excipient Final Product ratio dispersion SDRLD1 RVB+Tefose 1500 1:1 Wet particles SDRLD2 RVB+Gelucire 48/16 1:1 Wet particles SDRLD3 RVB+Gelucire 44/164 1:1 Wet particles SDRLD4 RVB+Gelucire 50/163 1:1 Wet particles SDRLD6 RVB+ Gelucire 48/16 + Compitrol HD5 ATO 1:1:3 Dry powder SDRLD7 HD5 ATO 1:1:1:3 Wet particles SDRLD8 HD5 ATO 1:1:0.25:3 Dry powder SDRLD9 HD5 ATO 1:1:0.5:3 Dry powder Hot melt granulation 1 HMRLD1 RVB+ Tefose 1500 1:1 Wet particles 2 HMRLD2 RVB+ Gelucire 48/16 1:1 Wet particles 3 HMRLD3 RVB+ Gelucire 48/16 1:1 Wet particles 4 HMRLD4 RVB+ Gelucire 48/16 1:1 Wet particles 5 HMRLD5 RVB+ Gelucire 48/16 + Compirol ATO 888 1:1:3 Dry powder 6 HMRLD6 RVB+ Gelucire 48/16 + 1:1:3 Dry powder 7 HMRLD7 HD5 ATO 1:1:1:3 Wet particles 8 HMRLD8 HD5 ATO 1:1:0.25:3 Dry powder 9 HMRLD9 HD5 ATO 1:1:0.5:3 Dry powder Spray drying method 1 SDRLD1 RVB+ Tefose 1500 1:1 Wet particles 2 SDRLD2 RVB+ Gelucire 48/16 1:1 Wet particles 3 SDRLD3 RVB+ Gelucire 44/164 1:1 Wet particles 4 SDRLD4 RVB+ Gelucire 50/163 1:1 Wet particles 5 SDRLD5 RVB+ Gelucire 48/16 + Compitrol ATO 888 1:1:3 Dry powder 6 SDRLD6 RVB+ Gelucire 48/16 + 1:1:3 Dry powder 7 SDRLD7 8 SDRLD8 9 SDRLD9 Wet particles HD5 ATO 1:1:1:3 HD5 ATO 1:1:0.25:3 Dry powder HD5 ATO 1:1:0.5:3 Dry powder From the above formulation prepared by three different techniques, the free flowing fine particles dried formulation selected for further evaluation. CHARACTERIZATION ph Solubility Study ph solubility study performed for the Rivaroxaban drug over the ph range of the 1.2 to 6.8. Drug content estimation The amount drug incorporated in the lipid-solid dispersions is determined by using a HPLC method. The extraction method includes dispersion of 10 mg sample in 10 ml of acetonitrile and vortexed well. The solutions are filtered through a membrane filter (0.45 mm) and suitably diluted with mobile phase before injecting to the HPLC.
Page4114 Saturation Solubility The efficacy of the formulations in improving the dissolution is preliminarily evaluated by measuring the saturation solubility of the drug from the formulations. The saturation solubility is determined for the plain drug (RVR) and formulations prepared by three different techniques. (Solvent evaporation method: SERLD5, SERLD6, SERLD8 and SERLD9; Hot melt granulation; HMRLD5, HMRLD6, HMRLD8 and HMRLD9 Spray drying; SDRLD5, SDLD6, SDRLD8 and SDRLD9).The impact of formulation prepared by three different techniques on the solubility enhancement is studied by taking plain drug as a control (RVR). The known excess amount of Rivaroxaban is added to 10 ml of ph 4.5 acetate buffer. Samples are rotated at 20 rpm in a water bath (37± 0.5 o C) for 48 hours. The samples are then filtered, suitably diluted, and analyzed by HPLC. Laser Diffraction Particle Size Analysis The particle size and particle size distribution of the developed formulations are measured using a laser diffraction size analyzer (HELOS Germany). Samples are suspended in water and two to three drops of isopropyl alcohol is added to disperse the particles and ultra-sonicated at 50% amplitude. The particle size and distribution is measured at a measurement range of 10 seconds in 500ms time base and at the optimum concentration of 10%. Differential Scanning Calorimetry (DSC): The enhanced solubility of the Rivaroxaban from the developed formulations can be attributed to the morphological conversion of the drug upon Solvent evaporation, Hot melt granulation and Spray drying method. To validate the morphological conversion of the Rivaroxaban, DSC studies are performed for the formulations using a TA instrument, Model Q200 equipped with a RCS-90(-90 C to 450 C) cooling unit. In vitro dissolution: The dissolution rate of Rivaroxaban (RVR) from the dispersions prepared by three different techniques. (Solvent evaporation method: SERLD5, SERLD6, SERLD8 and SERLD9; Hot melt granulation; HMRLD5, HMRLD6, HMRLD8 and HMRLD9 Spray drying; SDRLD5, SDLD6, SDRLD8 and SDRLD9) is measured in a Disso-2000 model dissolution test system (Labindia, India) using ph 4.5 acetate buffer and USP apparatus II (paddle) method. The drug loaded dispersions are filled into hard gelatin capsule equivalent to 10mg of Rivaroxaban (RVR). The equivalent plain Rivaroxaban (RVR) is filled into capsules along with Mannitol as an inactive excipient (RVR1). In each dissolution vessel, drug filled capsules are added to 900 ml dissolution medium. Bath temperature and paddle rotation speed are maintained at 37 C and stirred at 75 rpm. Stability studies: The finalized solid dispersions SDRLD8 (based on the process feasibility and faster rate of in vitro dissolution profile as compared to that of in vitro dissolution profiles of corresponding Marketed product product eq.to 10 mg of Rivaroxaban was filled in hard gelatin capsules were packed in 40cc HDPE container (30 s count) with 1.0 gm silica gel bag and loaded for stability studies at accelerated stability conditions, i.e. 40 0 ±2 0 C/75%±5%RH maintained in thermo stability chamber (Thermo Lab, India) for 6 months period. Samples were unloaded after 1, 2, 3 and 6 months, evaluated for % drug assay and in vitro dissolution study and compared with that initial preparation. RESULTS AND DISCUSSION The Rivaroxaban incorporated solid-lipid dispersions are prepared by three different techniques. The spay drying of drug lipid solution produces fully dried drug incorporated solid lipid particles when compared to the solvent evaporation and Hot melt granulation. By preparing the Rivaroxaban incorporated solid-lipid particles prepared by Spray drying method assumed to have a higher aqueous dissolution of drug due to morphological conversion of the drug and reduced particle size. After morphological conversion to amorphous form the Rivaroxaban is stabilized by lipids and additionally by the spray drying process the particle size can be precisely controlled to lower range than other two techniques. ph solubility study: ph solubility of Rivaroxaban studied over the ph range of 1.2 to 6.8, the results are given table 2. Table: 2 ph Solubility Study. Sample Details Solvent ph (Approx.) Solubility (µg/ml) Dose/solubility (ratio) Rivaroxaban 0.1 M HCl 1.2 40 500 ph 4.5 Acetate Buffer 4.5 200 100 ph 6.8 Phosphate Buffer 6.8 30 666.6 Purified Water 6.5 20 1000 Rivaroxaban drug substance was exhibiting ph dependent solubility, from the ph solubility data ph 4.5 acetate buffer selected for dissolution study.
Page4115 Drug content and Saturation solubility HPLC analysis is used to estimate the drug content in the formulations after the complete extraction of the drug from the formulations. To evaluate the increase in solubility of Rivaroxaban formulations solubility studies are performed for the selected formulations based upon the nature of the final product. The impact on the solubility enhancement is studied by taking plain drug as a control. Drug content and Saturation solubility data given table 3. Table: 3 Comparative evaluation drug content and saturation solubility. SOLVENT EVAPOURATION METHOD S. No. Formulation Composition Assay Solubility ( % w/w) (µg/ml) 1 Plain Drug - 99.8 27.5 2 SERLD5 ATO 888 96.4 68.6 3 SERLD6 HD5 ATO 97.4 135.9 4 SERLD8 95.9 152.6 5 SERLD9 92.2 175.7 HOT MELT GRANULATION METHOD 1 HMRLD5 ATO888 97.1 74.3 2 HMRLD6 HD5 ATO 96.8 144.3 3 HMRLD8 94.6 165.6 4 HMRLD9 95.8 179.7 SPRAY DRYING METHOD 1 SDRLD5 HD5 ATO 97.9 66.3 2 SDRLD6 96.4 168.6 3 SDRLD8 HD5 ATO 96.8 174.3 4 SDRL9 94.1 195.7 Laser Diffraction Particle Size Analysis The reason for the enhancement of solubility from the lipid solid dispersion formulations can be attributed to the reduced particle size of the drug. The plain drug has larger particle size and distribution compared to the formulation prepared by three different techniques. Comparative particle size distribution of lipid solid dispersion prepared by three different techniques is given Table 4.
Page4116 Table: 4 Comparative evaluation of particle size. SOLVENT EVAPOURATION METHOD S.No. Formulation/Drug 1 Rivaroxaban 95.72 124.3 141.2 2 SERLD5 34.5 72.3 122.3 3 SERLD6 35.4 78.2 118.8 4 SERLD8 27.4 66.2 88.8 5 SERLD9 31.2 66.7 81.2 HOT MELT GRANULATION METHOD 1 HMRLD5 48.3 86.5 108.8 2 HMRLD6 56.3 96.5 119.8 3 HMRLD8 41.3 84.3 104.9 4 HMRLD9 45.3 88.5 112.3 SPRAY DRYING METHOD 1 SDRLD5 11.2 36.2 48.2 2 SDRLD6 14.4 33.1 45.4 3 SDRLD8 18.4 42.4 52.8 4 SDRLD9 21.2 41.5 58.4 The particle size distribution of formulations prepared by solvent evaporation method lager than the Hot melts granulation than the spray drying method. The size of the particle in the formulations prepared by spray drying method is precisely controlled by atomization pressure and feed rate during the spray drying process. Differential Scanning Calorimetry (DSC) The absence of Rivaroxan DSC thermogram peak (231.4 C) in the thermogram of the solid-lipid dispersion formulation prepared by spray drying method indicates that the drug substance was converted into an amorphous form indicate the DSC thermogram peak absence at 231.4 C instead observed at 181.6 C, whereas solid-lipid dispersion formulation prepared by solvent evaporation Rivaroxaban DSC thermogram peak observed at 228.9 C and hot melt granulation method shows Rivaroxaban DSC thermogram peak observed at 219.5.9 C. The faster dissolution rate of the drug from the solid dispersion is attributed to the presence of amorphous form of Rivaroxaban within solid dispersion. The DSC thermograms of three techniques are given fig 1-4.
Page4117. In-vitro dissolution: In order to evaluate the performance of the solid-lipid dispersions prepared by three different techniques in-vitro dissolution testing is conducted under sink conditions. Comparative dissolution profile of Rivaroxaban plain drug, Marketed product (Xarelto) and Rivaroxaban solid-lipid dispersion formulation prepared by solvent evaporation method performed in ph 4.5 acetate buffer in 900 ml, USP II for 90 min. The release of Rivaroxaban from the lipid solid dispersion shows enhancement of dissolution is approximately 2-3 times higher until 90 minutes compared to plain drug and release less than the Marketed product.
Page4118 % drug release % drug release 120 100 80 60 40 20 0 Comparative dissolution profile of Rivaroxaban drug,marketed product and Lipid solid dispersions prepared by Solvent evopouration method 0 50 100 Time (min) Rivaroxaban (Plain drug) Marketed Product (Xarelto) SERLD6 SERLD8 SERLD9 Fig5: Comparative dissolution profile of Rivaroxaban Lipid solid dispersion formulations (Solvent evaporation method) vs Plain drug and Marketed product. Comparative dissolution profile of Rivaroxaban plain drug, Marketed product (Xarelto) and Rivaroxaban solid-lipid dispersion formulation prepared by Hot melt granulation method performed in ph 4.5 acetate buffer in 900 ml, USP II for 90 minutes. The release of Rivaroxaban from the lipid solid dispersion shows enhancement of dissolution is approximately 3-4 times higher until 90 minutes compared to plain drug and release less than the Marketed product. 120 100 80 60 40 20 0 Comparative dissolution profile of Rivaroxaban drug, Marketed product and Lipid solid dispersions prepared by Hot melt granulation method 0 50 100 Time (min) Rivaroxaban (Plain drug) Marketed Product (Xarelto) HMRLD6 HMRLD8 HMRLD9 Fig6: Comparative dissolution profile of Rivaroxaban Lipid solid dispersion formulations (Hot melt granulation method) vs Plain drug and Marketed product. Comparative dissolution profile of drug from solid-lipid dispersion prepared by spray drying method shows 5-6 times higher until 90 minutes compared to plain drug and release profile slightly higher than the Marketed product.
Page4119 % drug release % drug release 120 100 80 60 40 20 0 Comparative dissolution profile of Rivaroxaban drug,marketed product and Lipid solid dispersions prepared by Spray drying method 0 50 100 Time (min) Rivaroxaban (Plain drug) Marketed Product (Xarelto) SDRLD6 SDRLD8 SDRLD9 Fig7: Comparative dissolution profile of Rivaroxaban Lipid solid dispersion formulations (Spray drying method) vs Plain drug and Marketed product. Comparative dissolution profile of formulations prepared by three different techniques Performed in ph 4.5 acetate buffer in 900 ml, USP II for 90 minutes. The dissolution profile of formulation prepared by spray drying method shows better dissolution profile than the hot melt granulation than solvent evaporation method respectively. Dissolution profile of spray drying method formulation (SDRLD8) shows better dissolution profile as compared to marketed product. 120 100 80 60 40 20 0 Comparative dissolution profile of Rivaroxaban drug,marketed product and Lipid solid dispersions prepared by different tecniques 0 50 100 Time (min) Rivaroxaban (Plain drug) Marketed Product (Xarelto) SERLD8 HMRLD8 SDRLD8 Fig8: Comparative dissolution profile of Rivaroxaban Lipid solid dispersion formulations (Spray drying method, Hot melt granulation and Solvent evaporation) vs Marketed product. Stability studies: The description, Assay and drug release was evaluated at initial, 1 month, 2 months, 3 months and 6 months of stability loading. Based on the results, it was concluded that Solid lipid dispersion formulation SDRLD8 was found to be stable in HDPE with 1.0 gm silica gel bag container pack at accelerated stability conditions for 6 months period. Based on the results it was concluded that the test product SDRLD8 was found to be stable during a 6-months period. CONCLUSION The Rivaroxaban incorporated lipid solid dispersions are prepared by three different techniques i.e. solvent evaporation method, hot melt granulation and spray drying. Formulations of spray drying technique shows better dissolution profiles as compared to the solvent evaporation and hot melt granulation. Rivaroxaban solid lipid dispersion prepared by spray drying method the particles size distribution study has shown the lower particle size of the drug and the size distribution is very narrow than other two techniques and the DSC thermograms revealed the morphological conversion of the Rivaroxaban to amorphous form after spray drying. Based on the in vitro drug release profile formulations prepared by spray drying technique shows there was a significant improvement in the rate of dissolution as compared to the other two techniques and marketed product. The finalized formulation was loaded for stability and the formulation was stable at accelerated conditions, 6 months period.
Page4120 ACKNOWLEDGMENT I am very thankful to the MSL Laboratories for providing drug and Gattefosse, France for proving lipid excipients. REFERENCES 1. G.L. Amidon, H. Lennernas, V.P. Shah, and J.R. Crison. A Theoretical Basis for a Biopharmaceutic Drug Classification: The Correlation of In Vitro Drug Product Dissolution and In Vivo Bioavailability, Pharm Res. 1995, 12: 413 420. 2. J.W. Millard, N. Alvarez, S.H. Yalkowsky. Solubilization by cosolvents. Establishing useful constants for the log-linear model. Int J Pharm. 2002, 245:153 166. 3. A.T.M.Serajuddin, Solid dispersion of poorly water-soluble drugs: early promises, subsequent problems, and recent breakthroughs. J. Pharm. Sci. 1999, 88:1058-1066. 4. V.J. Stella, R.A. Rajewski, Cyclodextrins: their future in drug formulation and delivery, Pharm. Res. 1997, 14: 556 567. 5. K.Sigfridsson, S.Forssen, P. Hollander, U.Skantze, J.D. Verdier. A formulation comparison, using a solution and different nanosuspensions of a poorly soluble compound European Journal of Pharmaceutics and Biopharmaceutics, 2007, 67: 540 547. 6. R.Langer, New methods of drug delivery, Science, 1990, 249: 1527-1533. 7. A.J. Humberstone, W.N.Charman, Lipid-based vehicles for the oral delivery of poorly water soluble drugs, Adv. Drug Deliv. Rev. 25 (1997) 103 128. 8. J.David Hauss, Oral lipid-based formulations Advanced Drug Delivery Reviews, 2007, 59:667 676. 54878478451160135