Research Pharmaceutica, 1(2), 2017, Santosh V. Gandhi *, Ravina S. Mutha, Mangesh R. Bhalekar, Atul P. Chaudhari

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1 Research Pharmaceutica, 1(2), 2017, RESEARCH Pharmaceutica Research Article ISSN No: (Online) OPTIMIZATION OF CRYSTALLO CO AGGLOMERATES OF FENOFIBRATE TO IMPROVE FLOW PROPERTIES AND DISSOLUTION Santosh V. Gandhi *, Ravina S. Mutha, Mangesh R. Bhalekar, Atul P. Chaudhari 1 AISSMS College of Pharmacy, Kennedy Road, Near R. T. O., Pune , Maharashtra, India 2 Smt. S. S. Patil Institute of Technology (Pharmacy), Chopda , Dist. Jalgaon, Maharashtra, India An Official Publication of SKB College of Pharmacy, Kamptee ARTICLE I NFO Date of Submission: 03 Oct 2017 Date of Revision: 20 Nov 2017 Date of Acceptance: 20 Dec 2017 *Corresponding Author: ID: mrbhalekar@gmail.com K E YWORDS Fenofibrate; crystallo-co-agglomeration; dissolution; flowability; compaction. ABSTRACT The purpose of this research was to obtain directly compressible agglomerates of fenofibrate using a crystallo-co-agglomeration technique.crystalloid-co-agglomeration is an extension of the spherical crystallization technique, which enables simultaneous crystallization and agglomeration of 2 or more drugs or crystallization of a drug and its simultaneous agglomeration with another drug or excipient. Acetone - water system containing polyethylene glycol (PEG) 6000 was used as the crystallization system. Acetone acted as a good solvent for fenofibrate, water acted as bad solvent and dichloromethane acted as bridging liquid for agglomeration. The agglomerates were characterized by powder x-ray diffraction (PXRD) which showed that there is decrease in crystallinity or partial amorphization of the drug in its agglomerated form, FTIR which showed that there is no interaction between drug and polymer and were evaluated for tableting properties. Micromeriticand compressional properties of the 3 agglomerates were affected by incorporated polymer. 2 factorial design was used for optimization wherein the factors were speed of rotation, polymer: drug ratio and amount of bridging liquid. The responses evaluated were dissolution, MYP and Carr index. Dissolution of agglomerates increased 8 fold as compared to pure drug. Also there was an increase in flow property which was indicated by Carr index of drug (40.81) and optimized batch of agglomerates (13.33). 1. INTRODUCTION In the field of powder technology attempts to design of pharmaceutical substances are undertaken in order to impart various desirable properties, such as enhancement in solubility, obtaining suitable polymorph, improvement in micromeritic and compression properties, and modification of bioavailability. Particle size enlargement has become an important tool in modifying the primary and secondary 1,2 properties of pharmaceuticals. Spherical crystallization is a non conventional particle-size enlargement technique which involves crystallization and agglomeration using bridging liquid. Spherical crystallization has been used mainly to obtain directly compressible agglomerates of a single, water-insoluble large-dose drug, and rarely in combination with a diluent. Most of the excipients, such as diluents and disintegrating agents being hydrophilic cannot be incorporated in the agglomerates using organic bridging liquid thus limiting use of spherical crystallization to obtain agglomerates of low- 3,4,5 dose or poorly compressible materials. Kadam et al developed the crystallo-co-agglomeration (CCA) 6,7 technique a modification of the spherical crystallization technique in which a drug is crystallized and agglomerated with an excipient or with another drug, which may or may not be crystallized in the system. The agglomeration is performed using bridging liquid which is not soluble in good solvent also the difference in the physicochemical properties of the drug molecules and the excipients becomes the major challenge in the selection of a solvent system for the crystallo-coagglomeration. The present work involves use of CCA technique to obtain the agglomerates of fenofibrate having good dissolution, compression and flow behavior. The effect of parameters such as stirring speed, concentration of polymer and amount of bridging liquid was evaluated. Properties 3 mentioned above ware studied by a 2 factorial design using desirability function. The statistical model was developed and validated to explain the interplay between formulation variables on performance properties of agglomerates. 21

2 2. MATERIALS AND METHODS Materials: Fenofibrate was a kind gift from Lupin Ltd. Polyethylene glycol (PEG 6000), Dichloromethane (DCM)(Merck Ltd, Mumbai, India) ware purchased locally and all chemicals were of analytical grade. Crystalloid-Co-Agglomeration: In a crystallization vessel, fenofibrate (6 g) was dissolved in required amount of acetone (good solvent)to make saturated solution. This was added to aqueous solution of PEG 6000(bad solvent), with stirring using a mechanical stirrer (Remi motors, Mumbai) for 15 min, following which dichloromethane (DCM) was added slowly which acted as bridging liquid. The temperature of the crystallization system was maintained below 5 C. The stirring was continued to obtain agglomerates, which were then filtered and dried overnight at room temperature. Selection of optimization model: 3 A three factor two level 2 factorial design was selected for optimization wherein the 3 factors were stirring speed (A), polymer: drug ratio(b) and amount of bridging liquid(c). The responses to be optimized were % dissolution, Mean yield pressure (MYP) and Carr index.(table 1 and 2) The data obtained was further analysed using Design Expert software. Coded level Actual value in % A B C rpm 0.5:1 1ml rpm 1.5:1 2ml Evaluation: FTIR: Table 1. Coded levels translated in actual units. Formulation code Stirring speed (rpm) A FTIR studies were carried out to check whether there are any changes in the pure drug after spherical crystallization. FTIR spectra were obtained using a JascoFTIR (460 Plus) spectrophotometer. The samples of pure drug and physical mixture were prepared into KBr disks. The scanning range was kept from 4000 to 500 cm 1. Polymer:drug ratio (g) B Amount of bridging liquid (ml) C Table 2. Optimization batches for fenofibrate. 8 Saturation solubility studies: Fenofibrate selected in the present work has poor aqueous solubility characteristics. To determine the aqueous solubility of Fenofibrate, saturation solubility study has been carried out. Saturation solubility studies were performed in phosphate buffer ph 7.4 in triplicate according to the method reported by Higuchi and Connors. Excess of Fenofibrate (50 mg) and agglomerates of optimized equivalent to 50 mg were added to 20 ml of phosphate buffer ph 7.4 were taken in screw cap tube and shaken for 24 h in rotary flask shaker at 37±0.50C to achieve the equilibrium. Appropriate aliquots were then withdrawn and filtered through Whatman filter paper no. 41 and analyzed spectrophotometrically at 290 nm. The results obtained from saturation solubility studies were statistically validated. 9 Determination of drug content: Drug content was determined by dissolving samples of optimized batch Crystalloid-co-agglomerates of PEG 6000 equivalent to 10 mg of Fenofibrate in 10 ml of methanol. The solution was filtered through Whatman filter paper no. 41, were suitably diluted to get a concentration of 10 g/ml. and absorbance was measured at 290 nm using double beam UV spectrophotometer (Jasco 550, Japan). Micromeritic Studies: The flow properties of fenofibrate bulk and agglomerates were determined in terms of angle of repose, bulk density, Carr's Index and Hausnar's ratio. Angle of repose was determined by fixed funnel method whereas Carr's Index and Hausnar's ratio were calculated from bulk and tapped densities using methods described in literature. Dissolution studies: The dissolution rate studies were conducted in 900 ml of 0.05M sodium lauryl sulphate at 100 rpm maintained at 37±0.5 C in a dissolution apparatus (Model TDT- 08L,Electrolab) using USP type I apparatus (Basket type). Fenofibrate 80 mg and agglomerates equivalent to fenofibrate 80 mg were added to separate dissolution vesselsand the aliquots were withdrawn at appropriate time intervals. The aliquots were immediately filtered through 0.45 membrane filter, suitably diluted and analysed spectrophotometrically at 290nm. The data obtained from dissolution studies were statistically validated. Similarly 14,15 samples for agglomerates were analysed. Heckel Analysis: Heckel equation is expressed as: m 22

3 Where D is the relative density of a powder compact at pressure P, Constant k is a measure of the plasticity of a compressed material; Constant A is related to the die filling and particle rearrangement before deformation and bonding of the discrete particles. k is the slope of the linear portion of the plot, and A is a function of the initial bulk volume (intercept on a Heckel plot). The slope (k) of the Heckel equation provides information about the compaction mechanism of a substance. The Heckel analysis was made using tablets prepared at compaction pressure between 2 tonnes to 12 tonnes in KBr press using mm flat faces punches for both pure drug and agglomerates at every pressure applied, the diameter, height, and weight of the tablets were measured. Mean yield pressure (Py) was calculated as the inverse of the 14,16 slope (1/K) expressed in tonnes. Powder X-Ray Diffraction (PXRD): Crystallinity of the drug and optimized batch was determined using Bruker XRD (Model: D 8 Advance) with copper target. The conditions were: 40 kv voltages; 40 ma current; at room temperature. The samples were loaded on to the difffractometer and scanned over a range of 2θvalues form 10 to 800 at a 17 scan rate of /min. 3. RESULTS AND DISCUSSION: Preparation of Spherical agglomerates: Fenofibrateis an antihyperlipidemic which is a BCS Class II drug poorly water soluble and processes poor 14 compaction and flow properties. The agglomerates o f fenofibr ate were pre pared using a cr ystallocoagglomeration technique. Fenofibrate was crystallized from acetone-water-dcm system and agglomerated with hydrophilic polymer PEG Fenofibrate is freely soluble in acetone, but practically insoluble in water. Also it is soluble in DCM (bridging liquid) which is immiscible with water. Hence, these solvent systems were selected for the present study. In this process, crystallization of drug was performed by the addition of the anti-solvent phase (water) to drug solution. The addition of bridging liquid (DCM) promotes the formation of liquid bridges between the drug crystals to form spherical agglomerates. The spherically agglomerated crystals ware formed by coalescence of these dispersed crystals. The effect of different variables on formulation of agglomerates of fenofibrate was studies with help of a three factor two level design. (Table 3) The response variables chosen were MYP which indicated compression behavior, dissolution at end of 2 hrs and Carr index to predict changes in flow behavior. Infrared Spectroscopy (FTIR): FTIR spectra of pure drug and spherical agglomerate were shown in Fig 1. FTIR studies were carried out to check whether there are any changes in the pure drug after spherical crystallization. The major peaks of Fenofibrate are observed at 3040, , , , , , , , , , , , , , , , , , , , , , and cm-1. Upon comparison between FTIR spectra of pure drug and spherical agglomerates all the characteristic peaks were retained which indicate absence of significant interaction 18 between the excipients used in process with fenofibrate. Micromeritic properties: Micromertic properties of the crystallo-co-agglomerates was studied in terms of bulk density, tapped density, Carr's index, Hausnar ratio and angle of repose. Fenofibrate bulk had a significantly higher angle of repose (>400) which indicates irregular shape of the crystals whereas that of crystallo-co-agglomerates were seen to have angle of repose between ( ) (Table 3). The Carr's index and Hausner ratio of agglomerates ranged between( ) and ( ) respectively compared to that of bulkfenofibrate (40.81% and 1.68). This indicates improvement in the flowability of the agglomerated crystals. The reason for the improved flow of agglomerates is the significant reduction in the interparticle friction because of the nearly spherical shape (fig 2) and the larger size of the 19 crystals. Fig 1: FTIR Spectra of A: Fenofibrate B: Agglomerates of fenofibrate. Fig 2: Photomicrograph (40x) of A: Bulk Fenofibrate B: Agglomerates of Fenofibrate. 23

4 Determination of Drug Content: Drug contents in Crystalloid-co-agglomerates of optimized batch was found to be 98.5% Saturation Solubility Study Fenofibrate shows poor aqueous solubility (0.08 mg/ml). Crystalloid-co-agglomeration technique shows significant improvement in the aqueous solubility of Fenofibrate. The s o l u b i l i t y o f a g g l o m e r a t e s w a s f o u n d t o b e 0.66mg/ml.Incorporation of hydrophilic polymer PEG 6000 enhances wettability of Fenofibrate by the process of hydrophillization which may increases the aqueous solubility of Fenofibrate.There was 8.04 fold increase found in the aqueous solubility of Fenofibrate from the Crystalloid-coagglomerates of PEG Heckel analysis: Heckel analysis has been used to classify powders as their compaction behaviour and for the interpretation of the mechanism of bonding. Mean yield pressure (Py) is the pressure required to deform a powder or granules and to obtain compacts and is defined as the inverse of slope of the linear portion of the Heckel plot. The slope (k) is an indication of the deformation behaviour of the material. With low values of Py, the amount of plastic deformation increases and when high values of Py is an indication of the material compressing behaviour is mainly fragmentation. The values obtained from Heckel equation as shown in Table 3 indicated significant low mean yield pressure (Py) of spherical agglomerates( ton) than plain fenofibrate (5.95 tonns) indicating improvement in compaction 14,16 behaviour of spherical agglomerates. Dissolution studies: In In-vitro dissolution study of spherical agglomerates showed significantly faster drug release profile (64.64 %) as compared with plain Fenofibrate (8.72%) in 2 hrs. The reason for this faster drug dissolution was linked to the increase in surface area and wetting. Fenofibrate agglomerates showed better wettability due to addition of hydrophilic polymer and the porous internal structure resulted in faster 14,15 dissolution. Optimisation: The results of optimization runs were analysed using Design Expert software. The mean yield pressure values of cystallo-co-agglomerates were found to be higher at high polymer and high bridging liquid concentration, whereas at low values of polymer the increase in bridging liquid reduced MYP sharply which may be due to porous agglomerates whereas PEG being soft and plastic in nature gives better compressibility to the formed 20 agglomerates as it undergoes plastic deformation. The stirring speed did not have appreciable effect on MYP hence was excluded from equation. The combination of low bridging liquid and high stirring speed reduced the MYP as the particle collisions increase at high speed which resulted in smaller particle size and smaller MYP. The binary combination of variables as well as all the three demonstrated a good effect on reducing the MYP. (Fig 3) Dissolution = A+0.80B+1.21C-6.26AB -0.44AC+9.42BC-3.50ABC Carr Index= A+0.069B-0.76C-2.29AB +1.46AC ABC Dissolution= A+0.80B+1.21C-6.26AB -0.44AC+9.42BC-3.50ABC The dissolution is most coveted characteristic of a drug material; dissolution of fenofibrate was highly reduced by increasing polymer content as agglomerates formed were sticky in nature. The low stirring speeds which produce bigger agglomerates may also reduce the dissolution. The higher polymer: drug ratio and low bridging lead to significant reduction in dissolution. High bridging liquid and high stirring speed show increase in dissolution.also a combination of low polymer: drug ratio and high stirring Run Table 3: Trial runs for optimization of Fenofibrate agglomerates and the response variables. X1 Polymer:drug ratio X2 Amount of Bridging liquid (ml) X3 Stirring speed (rpm) R1 MyP R2 Dissolution (%) R3 Carr index (%) Angle of Repose Hauners's Ratio Bulk density 1 0.5: : : : : : : : Fenofibrate >

5 speed lead to increase in dissolution. ( Fig 5)Incorporation of PEG causes faster consolidation and yields particles with lower tortuosity and hence batches containing PEG at higher 21 levels exhibit slower release of drugs. Fig 6: PXRD graphs of A: Bulk Fenofibrate B: Agglomerates of Fenofibrate. Fig 3: 3 D Response Surface Plots for MYP Fig 4: 3 D Surface plot for Carr Index Fig 5: 3 D Surface plot for dissolution The XRD scan of plain Fenofibrate showed intense peaks of crystallinity, whereas the XRD pattern of agglomerates exhibited halo pattern with less intense and denser peaks compared with plain fenofibrate indicating (Fig 6) the decrease in crystallinity or partial amorphization of the drug 17 in its agglomerated form. 4. CONCLUSION The crystalloid-co-agglomeration process was optimized with respect to the variables such as polymer drug ratio, speed of rotation and bridging liquid. It was seen dissolution increases with polymer content, decreases with stirring speed, and increases with bridging liquid. The required Carr index could be achieved at lower polymer, high speed and low bridging liquid. The MYP was increased the most bypolymer, bridging liquid and decreased with rotation speed. 5. ACKNOWLEDGMENT Authors are thankful to Principal, AISSMS College of Pharmacy, and Pune, India for providing necessary facilities in the college. 6. REFERENCES 1. Pawar A, Paradkar A, Kadam S, Mahadik K. Crystalloid-coagglomeration: A Novel Technique to Obtain Ibuprofen- Paracetamol Agglomerates. AAPS Pharm Sci Tech. 2004; 5: Jadhav N,Pawar A, Paradkar A.Design and Evaluation of Deformable Talc Agglomerates Prepared by Crystallo-Co- Agglomeration Technique for Generating Heterogeneous Matrix. AAPS Pharm Sci Tech. 2007;8: Sarfaraz Md., Khan A, Doddayya H, Reddy S, Udupi R. Particle Design of Aceclofenac-Disintegrant Agglomerates for Direct Compression by Crystallo-Co-Agglomeration Technique, Asian J. Pharm. Tech. 2010; 1: Pawar A, Paradkar A, KadamS, Mahadik K. Agglomeration of Ibuprofen With Talc by Novel Crystallo-Co-Agglomeration Technique. AAPS Pharm Sci Tech, 2004; 5:

6 5. Paradkar A, Pawar A, Jadhav N. Crystalloid-Co- Agglomeration: A Novel Particle Engineering Technique. Asian Journal of Pharmaceutics. 2010; 4: Kadam S, Mahadik K, Paradkar A, inventors. A process for making agglomerates for use as or in a drug delivery system. Indian patent February 14, Kadam S, Mahadik K, Paradkar A. A process for making agglomerates for use as or in a drug delivery system. Indian patent February 14, Yadav V, Yadav A. Enhancement of Solubility and Dissolution Rate of Fenofibrate by Melt Granulation Technique. International Journal of PharmTech Research. 2009;1: Kumar S, Mishra D and Singh S. Enhancement of Dissolution and Bioavailability of Fenofibrate by Solid Dispersion with Sodium Citrate, HPMC and Sugar Derivatives. Der Pharmacia Lettre. 2015; 7: Lachman L, Lieberman H. The Theory and Practice of Industrial Pharmacy, Third Edition(special edition 2009), CBS Publishers and distributors; ;66-70, Aulton M. Particle Science and Powder Technology. In Aulton's Pharmaceutics the design and manufacturing of medicines. 3rd ed, China; Churchill Livingstone Elsevier; 2007; Subrahmanyam C V S.,Micromeritics, Textbook of Physical Pharmaceutics, 2ndedn, Delhi: VallabhPrakashan; 2000; Hari Krishna E, Gupta V, Jyothi S. Spherical Crystallisation A Modern Technique for Direct Compression of Pharmaceutical Substances. Asian Journal of Pharmaceutical and Clinical Research,2012; 5: Patil S, Bhokare K. Preparation and Evaluation of Direct Compressible Fenofibrate Spherical Agglomerates. Current Pharma Research. 2012; 2: Jamzad S, Fassihi R. Role of Surfactant and ph on Dissolution Properties of Fenofibrate and Glipizide - A Technical Note, AAPS Pharm Sci Tech. 2006;7: E1-E6 16. PatilP, Gupta V, Udupi R, K. Srikanth, Pati Nikunja, Prasad S. Spherical Agglomeration- Direct Tableting Technique. IRJP. 2011; 2: Md. Yousaf A, Dong Wuk Kim, Yu-KyoungOh, Chu Soon Yong, Jong Oh Kim, Han-Gon Choi. Enhanced Oral Bioavailability of Fenofibrate Using Polymeric Nanoparticulated Systems: Physicochemical Characterization and In Vivo Investigation. International Journal of Nanomedicine. 2015;10: Md. Faruki Z, Razzaque E, Rishikesh, Akhter R, Ahmed Bhuiyan M.Design, Formulation Development and Solubility Enhancement of Fenofibrate, A Water Insoluble Drug by Solid Dispersion Technique; World Jour nal of Pharmaceutical Research.2014; 3: Londhe S, Thenge R, Mahajan N, Adhao V. Preparation and Characterization of Spherical Agglomerates of Gliclazide. Ind J. Pharm Edu Res.2013;47: Rahate N, Bodhankar M, Dhoke P.Crystallo-Co- Agglomeration: A Novel Technique to Improve Flow and Compressibility. Journal of Drug Delivery & Therapeutics. 2013; 3: Pawar A, Paradkar A, Kadam S, Mahadik K. Effect of Polymers on Crystallo-Co-Agglomeration of Ibuprofen- Paracetamol: Factorial Design. Indian J. Pharm. Sci. 2007; 69 (5):