Pastillation Technology Based Design & Development of Oral Modified Release Multiparticulate Drug Delivery System Presented by: Prof. B. Mishra Professor & Former Head, Department of Pharmaceutics, Indian Institute of Technology (Banaras Hindu University) Varanasi- 221 005 Components of Research Background • Lipid based multiparticulate drug delivery system • Doxofylline as potential anti-asthmatic agent Experimental work • Development of Immediate and controlled release pastilles • Development of pulsatile release pastilles • In vivo study 2 Lipid based multiparticulate system Nanoparticles Pellets/Beads Microparticles Granules 3 Pastillation • Pastillation is a widely used technique in chemical, petrochemical and agrochemical industries • It is used for the solidification of dusty hazardous powders of chemicals into pastilles (hemispherical solidified units of uniform size) which eases their handling. • In this process, the drops of chemical substances in molten state are deposited on a cooled stainless steel surface for rapid solidification to generate pastilles of uniform dimensions. • Depending on the size of the drops and the physical properties of the melt, the drops flatten to a certain extent. • The solidified droplet, therefore, has the typical pastille-like shape. The production process can be easily carried out at large scale with the help of specially designed equipments called ‘Rotoformer’. 4 Pastillation equipment 5 Why pastillation in DDS? • • • • • • • • • Suitable for hygroscopic drug as the processing of the ingredients is absolutely free from use of water. Environment friendly as involves no use of organic solvents. Pastilles are stable and highly uniform in shape. Pastilles can be produced in a wide range of sizes with diameters ranging from 1 to 30mm. Pastilles have higher bulk density and better packing properties than powders and therefore, ideal for handling, filling and packaging. The conversion of a bulk molten liquid directly into individual solidified units provides dust free working environment. Single step process involving one equipment (melting of lipid, mixing of drug and excipients followed by solidification). Reduced energy costs due to absence of number of processes of formulation. Ease of packaging as the pastilles of smaller dimension can be capsule filled while the larger ones can either be strip packed or filled directly in sachets/bottles. 6 Components of Research Background • Lipid based multiparticulate drug delivery system • Doxofylline as potential anti-asthmatic agent Experimental work • Development of immediate and controlled release pastilles • Development of pulsatile release pastilles • In vivo study 7 Doxofylline • • • • • Ist Marketed product in India Product: DOXOBID (Doxofylline tablets 400mg) Company: Dr. Reddy’s Labs. Label Claim: Each uncoated tablet contains: Doxofylline 400mg Indication :used as Bronchodilator in Asthma & chronic obstructive pulmonary disease(COPD) Dose : 400mg IR is given 2-3 times daily Chemical Name: 2-(7-theophyllinemethyl)-1,3 dioxolane Molecular Formula: C11H14N4O4 Formula weight: 266 Melting Point: 144-145.5°C Solubility: Freely Soluble in chloroform and Dichloromethane soluble in acetone, sparingly soluble in water and ethyl acetate Storage: Store in cool, dark and dry place. 8 Pharmacokinetic profile Absorption • Absorption Bioavailability : 62.6% Therapeutic Drug Concentration • Chronic Bronchitis : 8-20 µg/ml • Time to peak concentration (tmax) : 1.19 hours • The steady state is reached within 6hrs : 9.43 µg/ml • Area under the curve, AUC : 69.5 hr×µg/ml Distribution • Protein Binding : 48% • Distribution Half Life : 0.19 hr • Volume of distribution : 1 L/kg Metabolism • Metabolism sites & kinetics: Liver >90% • Metabolites: Hydroxyethyltheophylline (inactive) Excretion • Kidney: Less than 4% of an administered dose of doxofylline is excreted unchanged in the urine • Total Body Clearance: 444-806µg/ml • Elimination Half life: Parent compound – 7 to 10hrs 9 Objectives of the research work To explore pastillation to design a platform technology for the development of novel and unique modified release drug delivery system PART I To design a immediate and controlled release formulation of doxofylline using pastillation technology PART II To design a pulsatile release formulation of doxofylline using pastillation technology PART III To evaluate pharmacokinetic behavior of the developed formulations in animal model 10 In-house laboratory scale device for pastillation Transformer Heating coil Ceramic insulation Glass syringe Needle Pastilles Shaft Cold plate Ice tray 11 Operating parameters Factorial design using MINITAB® Sl No. Factors Low (-) High (+) 1. Needle dimensions (X1) 16G 20G 2. Dropping height (X2) 1 cm 3 cm 3. Temperature of plate (X3) 4 °C 25 °C 12 Evaluating parameter Contact angle measurement Method of analysis (Photographic method) The photographs of the pastilles were taken from the horizontal side at their contact with the plate and the snaps were then proportionally magnified and processed using Adobe Photoshop® software. The angle of contact was determined manually and confirmed mathematically using the following equation: θ = 2tan−12h/d Where h is the height of the drop from the plate and d is the diameter of the drop. Both of these dimensions can be measured from the photograph for calculating the contact angle. 13 Contact angle of pastilles 14 Formulation batches (for optimization) Sl. No. Batches X1 X2 X3 1. A1 16G 1 cm 4 °C 2. A2 16G 1 cm 25 °C 110° 3. A3 16G 3 cm 4 °C 100° 4. A4 16G 3 cm 25 °C 80° 5. A5 20G 1 cm 4 °C 120° 6. A6 20G 1 cm 25 °C 115° 7. A7 20G 3 cm 4 °C 95° 8. A8 20G 3 cm 25 °C 85° Avg. Contact angle (Y1) 121° 15 Effect of needle size and dropping height on contact angle (A) Response Surface 3D plot (B) Contour plot 16 Effect of temperature of plate and dropping height on contact angle (A) Response Surface 3D plot (B) Contour plot 17 Effect of needle size and temperature of plate on contact angle (A) Response Surface 3D plot (B) Contour plot 18 Flow property of pastilles based on their contact angle Flow property Contact Angle Poor 60-85° Fair 85-105° Good 105-125° 19 Optimized parameters for highest achievable (desirable) contact angle Sl No. Optimized parameters 1. Needle dimensions (X1) 20 G 2. Dropping height (X2) 1 cm 3. Temperature of plate (X3) 4 °C 20 Formulation chart Composition B-1 B-2 B-3 B-4 g/batch B-5 B-6 DOX 0.5 0.5 0.5 0.5 0.5 0.3 0.4 0.5 0.5 0.5 2.0 2.0 2.0 2.0 2.0 2.0 1.7 1.7 1.7 - - - - - - 0.3 1.5 0.75 - 0.3 - - 0.3 0.3 - - - PEG 6000 - - 0.3 - - - - - - PEG 400 Colloidal 75 silicon dioxide Drug content 100.56 Uniformity (%) ± 0.93 - - - 0.3 - - - - - Stearic acid Benefat PEG 4000 2.0 B-7 B-8 B-9 B-10 98.89 ± 1.23 21 Evaluation • Drug content uniformity (20 ml water added to pastilles eq. to 10 mg drug and heated at 75°, sonicated, cooled and volume made upto 25 ml. 5 ml filtered and measured spectrophotometrically) • Drug release study (USP Appt. II, 500 ml of 0.1 N HCl, 50 rpm, 37±0.5°C for 2 h followed by pH 6.8 phosphate buffer for next 22 h) • Scanning electron microscopy (The morphological structure of the prepared pastilles was observed using scanning electron microscope (FEI Quantum 200E Instrument) • Stability studies (pastilles packed in 30 ml HDPE bottles kept in 40°C/75%RH for 3 months storage conditions in stability chamber (Narang Scientific Works Pvt. Ltd., New Delhi, India)) 22 Analytical method • UV–VIS spectrophotometry (Hitachi U-1800) • Standard curves of doxofylline were prepared in water, 0.1 N HCl (pH 1.2) and phosphate buffer solutions (pH 6.8) in the concentration range of 5–35 μg/ml. • A UV visible spectrum of doxofylline showed a characteristic peak at 273 nm in all the solutions. • The standard curve was plotted as drug concentration (μg/ ml) vs. absorbance plot. Curve fitting was done by linear regression analysis using Microsoft Excel program 23 Standard Curves of Doxofylline 24 Effect of pore former & type of buffer media on drug release 25 Effect of drug load on drug release 26 Effect of benefat (lipid pore former) concentration on drug release behavior R2=0.983 27 Scanning electron microscopy (A) Batch B1 (B) Batch B1 at higher magnification (C) Batch B10 (D) Batch B10 at higher magnification 28 Drug release profiles of initial and 3 months stored samples Drug content uniformity 1M-98.66% 2M- 97.12% 3M-96.46% Stability study at 40°C/75%RH indicate stable formulation with no change in physical appearance, drug release and drug content 29 Components of Research Background • Drug delivery system • Therapeutic application Experimental work • Development of immediate, controlled and pulsatile release pastilles • In vivo animal study 30 Formulation chart Ingredients DOX (mg) PEG 4000 (mg) Colloidal silicon dioxide (mg) Enteric coat 1 P-I P-II P-III 500 500 500 2000 2000 2000 75 150 - - - P-IV 500 2000 75 P-V 500 2000 75 P-VI 500 2000 75 10 ± 5 %* - - (5 g Eudragit L100 55 and 0.25 g triethyl citrate (plasticizer) & 2% talc in 100ml methanol Enteric coat 2 (5 g Eudragit L100 55 and 0.5 g triethyl citrate (plasticizer) & 2% talc in 100ml methanol Floating layer 10 ± 5 %* 10 ± 5%* - - - - - 20 ± 5%# (1g HPMC K15M, 0.1 g triethyl citrate (plasticizer) in 100 ml IPA DCM mixture (60:40 v/v). NaHCO3 crushed and passed through #100 mesh & 2% talc was dispersed in the above solution * Amount of enteric coat applied was calculated in terms of percentage weight gain with respect to the weight of uncoated pastilles # Amount of floating coat applied was calculated in terms of percentage weight gain with respect to the weight of enteric coated pastilles 31 Evaluation • Assay • Drug content uniformity • Drug release study (USP Appt. II, 500 ml of 0.1 N HCl, 50 rpm, 37±0.5°C for 2 h followed by 2 h followed by pH 6.8 phosphate buffer for next 2 h) • Scanning electron microscopy • Stability studies (40°C/75%RH for 3 months) 32 Contact angle Pastilles with A) desired contact angle (above 85°), B) with contact angle ≤ 45°, C) with contact angle above 70° 33 Explanation for formation of flat pastilles Contact angle improvement of PEG pastilles at large scale Friability B-I :0.596% B-II :0.104% 34 Assay and drug content uniformity Assay (%) Drug content uniformity P-I 100.12 ± 1.11 100.19 ± 2.13 P-II 100.09 ± 1.91 99.98 ± 2.21 P-III 99.61 ± 2.17 98.89 ± 1.81 P-IV 98.12 ± 1.21 99.01 ± 0.91 P-V 98.08 ± 2.19 98.21 ± 1.27 P-VI 99.06 ± 1.98 99.12 ± 2.12 35 Drug release profile 36 Scanning electron microscopy Surface morphology of coated pastilles using SEM A) Batch P-IV, B) Batch P-V, C) Batch P-VI 37 Coated PEG pastilles floating in dissolution medium 38 Dissolution of initial and three months stored samples 39 Conclusion A novel technology ‘pastillation’ was successfully employed for the development of immediate release pastilles. This dosage form after coating with enteric and floating coat were also found to be effective to achieve the required delay in drug release for treatment of nocturnal asthma. The prepared formulations showed desired drug release profile with an initial lag phase in the in vitro drug release study. The in vivo pharmacokinetic study would be helpful in further evaluating the potential of this formulation in the chronotherapeutic treatment of nocturnal asthma. 40 Components of Research Background • Drug delivery system • Therapeutic application Experimental work • Development of controlled release pastilles • Development of pulsatile release pastilles • In vivo animal study 41 In-vivo animal study Animal study protocol were approved by the Animal Ethical Committee of Banaras Hindu University. (No. 2010-11/153) Male albino rats of 250 ± 20 g 12 h fasting prior to dosing 5.70 mg drug/kg body weight administered orally Pastilles were administered with 5.0 ml of 1.0% aqueous polyvinyl alcohol solution Blood (0.5 mL) was collected via retro-orbital vein 0, 0.25, 0.50, 1, 1.5, 2, 3, 4, 6, 8, 12 and 24 h Blood samples were allowed to clot They were centrifuged for 10 min at 3000 rpm The serum obtained was transferred to clean tube for storage at −20 °C until analysis 42 Study design of pharmacokinetic studies For controlled release pastilles PEG Pastilles (IR) Stearic acid pastilles (CR) For pulsatile release pastilles PEG Pastilles (uncoated) PEG Pastilles (enteric coated) PEG pastilles (enteric coated with floating layer) 43 Serum drug estimation Drug separation from serum by liquid-liquid extraction method Serum (containing drug) (500 μl) + methanol (400 μl) Vortexed (8 min) & centrifuged at 3500 rpm for 10 min Supernatant (400 μl) Evaporated in vacuum oven at 40°C Residue + mobile phase (200 μl) Reconstituted Reconstituted sample (20 μl ) injected for HPLC analysis 44 Serum drug estimation Serum drug estimation by Reverse phase HPLC method Chromatographic conditions: Column: C18 reverse-phase 250×4.6 mm 5 μm ODS2 column (Waters, Ireland) Mobile phase: 18:82 acetonitrile–12.5 mM potassium dihydrogen orthophosphate buffer (pH adjusted to 3.0 with orthophosphoric acid) Flow rate: 1 ml/min Injection volume: 20 μl λmax: 275 nm Retention Time: 9.75 min 45 Pharmacokinetic estimation Cmax peak serum concentration Tmax time to reach peak concentration AUC0-t area under the curve from time zero to last measured concentration HVD t50% Cmax time span during which the serum concentrations were at least 50% of the Cmax R∆ ratio between the HVD t50% Cmax values of the test formulation and the drug suspension Kinetica® software GraphPad Prism® software 46 Chromatographic Area under the peak HPLC chromatograms and Calibration curve of doxophylline extracted from serum 500000 450000 400000 350000 300000 250000 200000 150000 y = 188.19x - 628.05 R² = 0.9999 100000 50000 0 0 500 1000 1500 2000 Doxofylline concentration (ng/ml) 2500 47 Pharmacokinetic profile of PEG and lipid based pastilles 48 Pharmacokinetic data of PEG and lipid based pastilles Pharmacokinetic PEG based Lipid based parameters pastilles pastilles Cmax (ng/ml) 31.83 ± 1.28 16.32 ± 3.69 Tmax (h) 0.75 ± 0.06 6.0 ± 1.58 AUC last (ng/ml*h) 182.56 ± 19.98 210.39 ± 59.6 HVD (h) 3.18 ± 0.21 11.43 ± 1.52 $R∆ - 3.59 $ R∆ =of 1.5, 2 and >3 indicates, low, intermediate and strong sustained release effect, respectively Data are shown as mean + SEM 49 Pharmacokinetic profile of uncoated and coated PEG pastilles 50 Pharmacokinetic data of uncoated and coated PEG pastilles P-II (Uncoated pastilles) P-V (Enteric coated pastilles) P-VI (Enteric & floating coated pastilles) Cmax (ng/ml) 31.83 ± 1.28 30.92 ± 2.12 25.12± 2.41 Tmax (h) 0.75 ± 0.06 3.0 ± 0.27 6.0 ± 0.82 182.56 ± 19.98 201.47 ± 29.7 241.68 ± 42.7 3.18 ± 0.21 4.23 ± 0.15 6.70 ± 0.13 - 1.33 2.11 Pharmacokinetic parameters AUC last (ng/ml*h) HVDt50% Cmax (h) R∆ Data are shown as mean + SEM 51 Gamma scintigraphic method Radiolabeling of Pastilles Technetium (99mTc) was chosen for radio-labeling of the pastilles because of its short half-life of 6 hrs and very less amount of electron emission 5 mg stannous chloride dihydrate (1 mg/ml in 10% acetic acid) of pH 7.5 (adjusted with 0.5M NaHCO3 TLC (Silica Gel) After 99% reduction 5 mg stannous chloride dihydrate (1 mg/ml in 10% acetic acid) of pH 7.5 (adjusted with 0.5M NaHCO3 After 2 min radiolabeling efficiency was evaluated by TLC-SG strips as stationary phase & acetone as mobile phase 52 Gamma scintigraphic method Stability of radiolabeled pastilles pH 1.2 0.1N HCl 1g pastilles pH 6.8 buffer pH 7.2 buffer Kept under stirring in a water bath maintained at 37° C for 6 hr 0.2 ml filtered solution checked for radioactivity by auto gamma counter 53 Study design of gamma scintigraphy For pulsatile release pastilles Male albino rats of 250 ± 20 g, 12 h fasting prior to dosing 5.70 mg drug per kg body weight administered orally After light anaesthetization serial scintigraphic examination was done at 0.5, 1, 1.5, 2, 3, 4 and 5, 6 hrs depending on type of formulation using a large field view gamma camera Images were recorded for a preset time of 1 min/view to include the 140 keV photopeak of 99mTc PEG Pastilles (uncoated) PEG Pastilles (enteric coated) PEG pastilles (enteric coated with floating layer) 54 Gamma scintigraphic set up A B C D 55 Stability data of radiolabeled pastilles P-II (Uncoated pastilles) P-V (Enteric coated pastilles) P-VI (Enteric & floating coated pastilles) 1.2 0.13 0.21 0.16 6.8 0.25 0.32 0.27 7.2 0.36 0.34 0.31 pH 56 Gamma scintigraphy study of uncoated PEG pastilles A B Gamma Scintigraphy study of uncoated PEG pastilles on rats at time point (A) 0.5 hr and (B) 1 hr 57 Gamma scintigraphy study of uncoated PEG pastilles OBSERVATION: Attenuation of radioactivity within 0.5 hrs. INFERENCE: In the presence of gastric fluid, PEG matrix dissolved completely and behaved as an immediate release dosage form. 58 Gamma scintigraphy study of enteric coated PEG pastilles B A D C E Gamma Scintigraphy study of enteric coated PEG pastilles on rats at time 59 point (A) 0.5 hr and (B) 1 hr, (C) 1.5 hr, (D) 2 hr and (E) 3 hr Gamma scintigraphy study of enteric coated PEG pastilles OBSERVATION: The pastille maintained its matrix integrity till 1.5 hrs in the gastric region. At 2 hrs the pastille was located in the jejunum area where it started to dissociate. INFERENCE: No influence of gastric fluid on the enteric coating applied on the pastilles. 60 Gamma scintigraphy study of pastilles with floating coat A B C D E F Time point (A)1 hr, (B) 2 hr and (C) 3 hr, (D) 4 hr, (E) 5 hr and (F) 6 hr 61 Gamma scintigraphy study of pastilles with floating coat OBSERVATION: The pastille was retained in the stomach for 2 h. In the next hour, the intact pastille migrated into the jejunum. Further, in the 4th hour the dosage form was found to reach the ileum region where it started to disperse. The image of 6th hour shows complete disintegration of the dosage form. INFERENCE: This indicates that the floating coat is not only valuable to retain the dosage form in the stomach for more than two hours but also to protect the enteric coat from alkali environment for an hour. 62 Conclusion • The pharmacokinetic and gamma scintigraphic imaging confirms the ability of the formulations to release the drug only after a desired period of time as specifically required for the treatment of noctural asthma. • The results are also in agreement with the in vitro drug release study which indicates the efficiency of the coating system. • The present study also confirms the ability of PEG based pastilles to act as an immediate release dosage forms. • Further coating of the PEG pastilles with appropriate polymers can significantly impart functional properties to modify the release of the drug in a pre-determined fashion. 63 Major findings • Use of pastillation technology for the first time in pharmaceutical field • Novel drug delivery system “PASTILLES” were successfully formulated as: immediate release dosage form pulsatile release dosage form sustained release dosage form 64 Important references •Cheboyina, S. and Wyandt, C.M., Wax-based sustained release matrix pellets prepared by a novel freeze pelletization Technique . I. Formulation and process variables affecting pellet characteristics, Int J Pharm, 359, 158166, 2008. •Reitz, C. and Kleinebudde, P., Spheronization of solid lipid extrudates, Powder Technol, 189 238-244, 2009. •Van G.F., Rao Y.M., Modified No.WO2009/112436A1, 2009. release composition comprising doxofylline, Patent application •Huang, H.F., Lu, Y., He, H.B., and Tang, X., Preparation and bioavailability of sustained-release doxofylline pellets in beagle dogs, Drug Dev Ind Pharm, 34, 676-682, 2008. •Gils, P.S., Ray D., Sahoo P.K., Controlled release of doxofylline from biopolymer based hydrogels, Am J Biomed Sci, 2, 373-383, 2010. •Gannu, R., Bandari S,. Sudke S.G., Rao, M. and Shankar, B.P., Development and validation of a stability-indicating RP-HPLC method for analysis of doxofylline in human serum. Application of the method to a pharmacokinetic study, Acta Chromatographica, 9,149-160, 2007 •Sandvik Materials Technology. Available at:http://www.processsystems.sandvik.com/ •Rxlist. Available at: www.rxlist.com •Cipla Therapeutic Index, Respiratory drugs, Zordox. CiplaDoc. http://www.cipladoc.com/therapeutic/admin.php?mode=prod&action=disp&id=650 Available at: •Aulton, M.E., Dyer, A.M. and Khan, K.A., The strength and compaction of millispheres, Drug Dev Ind Pharm, 20, 3069-3104, 1994. •Breitenbach, J., Melt extrusion: from process to drug delivery technology, Eur J Pharm Biopharm, 54, 107-117, 65 2002. Publications from research work S. No Publication Details 1. Shukla D, Chakraborty S, Singh S, Mishra B. Doxofylline: a promising methylxanthine derivative for the treatment of asthma and chronic obstructive pulmonary disease. Expert Opin Pharmacother. 10(14): 2343-2356, 2009. Shukla D, Chakraborty S, Singh S, Mishra B. Lipid based oral multiparticulate formulations – Advantages, technological advances and industrial applications. Expert Opin Drug Deliv. 8(2):207-224, 2011. Shukla D, Chakraborty S, Singh S, Mishra B. Pastillation: A novel technology for development of oral lipid based multiparticulate controlled release formulation. Powder Technol. 209 (1-3): 65-72, 2011. Shukla D, Chakraborty S and Mishra B. In vitro and in vivo evaluation of multilayered pastilles for chronotherapeutic management of nocturnal asthma. Expert Opin Drug Deliv 9(1):9-18, 2012 Shukla D, Chakraborty S and Mishra B. Evaluation of in vivo behavior of controlled and pulsatile release pastilles using pharmacokinetic and γ-scintigraphic techniques. Expert Opin Drug Deliv 9(11): 1333-1345, 2012. 2. 3. 4. 5. Impact Factor 3.205 4.896 2.080 4.896 4.896 66 Dr. (Mrs) Dali Shukla This Presentation is taken from the Ph.D. Thesis of Mrs Dali Shukla who has worked under my direct supervision. Varanasi Ghats Lord Vishwanath (Varanasi) BHU Gate Vishwanath Temple (in BHU) IIT(BHU), Varanasi Department of Pharmaceutics THANK YOU