EVALUATION OF SOME BIOPOLYMERS FOR VARIOUS PHARMACEUTICAL APPLICATIONS BY SHAZMA MASSEY ROLL NO. 105-Ph.D-Chem-2009 SESSION: 2009-2014 1 DEPARTMENT OF CHEMISTRY GC UNIVERSITY, LAHORE EVALUATION OF SOME BIOPOLYMERS FOR VARIOUS PHARMACEUTICAL APPLICATIONS A thesis submitted to the GC University Lahore in partial fulfillment of the requirements for the award of the degree of DOCTOR OF PHILOSOPHY IN CHEMISTRY BY SHAZMA MASSEY ROLL NO. 105-Ph.D-Chem-2009 SESSION: 2009-2014 2 DEPARTMENT OF CHEMISTRY GC UNIVERSITY, LAHORE IN THE NAME OF THE MOST MERCIFUL AND GRACIOUS GOD “WHO EVER BELIEVES IN HIM WILL NOT BE DISAPPOINTED” Romans 10: 11 DEDICATED TO MY DEAREST AND LOVING PARENTS PROF. ISAAC MASSEY (Late) AND MRS SHAKUNTALA MASSEY (Late) 3 RESEARCH COMPLETION CERTIFICATE This is to certify that the research work contained in the thesis titled “Evaluation of some biopolymers for various pharmaceutical applications” has been carried out and completed by Ms.Shazma Massey, Roll No. 105-PhD -Chem-2009, Reg. No. 46 -PhD-Chem-2009 under my supervision during her PhD (Chemistry) studies in the laboratories of the Department of Chemistry. The quantum and the quality of the work contained in this thesis is adequate for the award of degree of Doctor of Philosophy. Dated: June27, 2014 __________ __________ Prof. Dr. Mohammad Saeed Iqbal Dr. Irfana Mariam Supervisor Co-Supervisor Submitted through ______________________ _____________________ Prof. Dr. Adnan Ahmad Controller of Examination 4 Chairman GC University, Lahore Department of Chemistry, GC University, Lahore. DECLARATION I, Ms. Shazma Massey, Reg. No. 046-PhD-Chem-2009 student of PhD in the subject of Chemistry, session 2009-2014, hereby declare that the matter printed in the thesis titled “Evaluation of some biopolymers for various pharmaceutical applications” is my own work and has not been printed, published and submitted as thesis or publication in any form in any university, research institute etc. in Pakistan or abroad. Dated: June27, 2014 _____________________ Shazma Massey CONTENTS ACKNOWLEDGEMENT I - II ABSTRACT III - IV LIST OF ABBREVIATIONS V - VII LIST OF FIGURES VIII - XIV 5 LIST OF TABLES XV – XVI 1. Introduction 1-30 1.1. General 1 1.2. Polymers in pharmaceuticals 2 1.2.1. Binders 2 1.2.2. Thickners 2 1.2.3. Suspending agents 3 1.2.4. Film coating agents 3 1.2.5. Drug delivery 3 1.3. Polymers from plant materials 4 1.3.1. Materials in use 4 1.3.2. Materials used in the present work 5 1.4. Some important properties of carbohydrate polymers 18 1.4.1. Structure 18 1.4.2. Surface morphology 19 1.4.3. Rheology 19 1.4.4. Thermal behavior 20 1.4.5. Monosaccharide analysis and protein analysis 20 1.4.6. NMR analysis 21 1.4.7. Swelling behavior and water retention 22 1.4.8. Time-of-flight secondary ion mass spectrometry (ToF-SIMS) 23 6 1.4.9. Gel Permeation Chromatography (GPC) 23 1.4.10. Mechanical strength 24 1.4.11. Drug release models and mechanism 24 1.4.12. Empirical/Semi-Empirical models 27 1.4.12.1. Power law 27 1.4.12.2. Zero and First order models 28 1.4.12.3. Mechanistic realistic theories 29 2. Materials and methods 31-46 2.1. Materials 31 2.2. Methods 31 2.2.1. Isolation of biopolymers 31 2.2.2. Characterization 32 2.2.2.1. Elemental analysis 32 2.2.2.2. Moisture content 33 2.2.2.3. FT-IR spectroscopy 33 2.2.2.4. Thermal analysis 33 2.2.2.5. Scanning electron microscopy 35 2.2.2.6. Atomic force microscopy 35 2.2.2.7. Monosaccharide analysis by HPLC 35 2.2.2.8. Protein analysis 36 2.2.2.9. NMR study 37 2.2.2.10. Rheology 38 2.2.2.11. Determination of molar mass 39 7 2.2.2.12. ToF-SIMS 41 2.2.2.13. Mechanical strength 42 2.2.2.14. Swelling index 42 2.2.2.15. Water retention 42 2.2.3. Evaluation of biopolymers as drug carriers 43 2.2.4. Evaluation as binders in tablets 45 2.2.5. Evaluation as suspending agents 45 2.2.6. Evaluation as thickening agents 46 2.2.7. Evaluation as film coating materials 46 3. Results and discussion 47- 151 3.1. Isolation of biopolymers 47 3.2. Characterization 48 3.2.1. Elemental analysis 48 3.2.2. Moisture content 48 3.2.3. FT-IR spectroscopy 48 3.2.4. Thermal analysis 51 3.2.5. Electron microscopy 61 3.2.6. Atomic force microscopy 61 3.2.7. Monosaccharide analysis by HPLC 66 3.2.8. Protein analysis 66 3.2.9. NMR study 71 8 3.2.10. Rheology 76 3.2.11. Determination of molar mass 76 3.2.12. Mechanical strength 81 3.2.13. Swelling index 84 3.2.14. Water retention 84 3.3. Evaluation of biopolymers as drug carriers 84 3.3.1. Electron microscopy 86 3.3.2. ToF-SIMS 86 3.3.3. Dissolution study 91 3.3.3.1. Release profile of diclofenac sodium loaded polymer films in phosphate buffer 97 3.3.3.2. Release profile of diclofenac sodium loaded polymer films in 0.1 N HCl 98 3.3.3.3. Release profile of caffeine loaded polymer films in distilled water 98 3.3.3.4. Release profile of diclofenac sodium loaded polymer tablets in phosphate 120 3.3.3.5. Release profile of diclofenac sodium loaded polymer tablets in 0.1 N HCl 120 3.3.3.6. Release profile of caffeine loaded polymer tablets in distilled water 121 3.3.4. Targeted delivery 146 3.3.5. Disintegration study 146 3.4. Evaluation as binders in tablets 146 3.5. Evaluation as suspending agents 146 3.6. Evaluation as thickening agents 149 3.7. Evaluation as film coating materials 149 3.8. Concluding remarks 152 3.9. Research publication by the author from this work 153 9 1. Introduction 1.1. General Polymers are extensively used in formulation of various dosage forms of pharmaceuticals. They play their roles as binders, viscosity enhancers, suspending agents, retarded release materials, targeted delivery devices and scaffolds in tissue engineering. The polymers employed for these applications are mostly synthetic or semi-synthetic materials [1, 2]. Early research was focused on synthetic non-biodegradable materials such as polyethylene glycol (PEG) copolymers, which are used in cardiovascular devices. Similarly polyvinyl alcohol (PVA) gels are used for contact lenses, lining for artificial hearts and in drug delivery devices. The synthetic devices need to be implanted and then removed by surgery. Thus for biomedical applications it is desirable that the materials should preferably be biocompatible and biodegradable. The synthetic polymers are made up of highly toxic monomers and as such lack biocompatibility. Natural sources of very useful polymers, also known as biopolymers, are abundantly available, which can be developed as important pharmaceutical ingredients. Biopolymers have been isolated from animal or plant sources. Gelatin, collagen and chitosan are among the extensively used biopolymers from animal sources. Gelatin is widely used for fabrication of capsule shells. Plants produce large quantities of polysaccharides; the most important are starches, celluloses and hemicelluloses. In pharmaceutical applications the use of natural hydrogels such as guar gum, pectin, cellulose ether, chitosan, carrageenan, hyaluronic acid and alginic acid is quite common. Polylactide (PL), polyglycolide (PG) and their copolymer polylactide-co-glycolide 10 (PLGA), being biodegradable, have long been used for designing controlled drug delivery devices. These degrade into glycolic and lactic acids in the body and are easily handled via normal body metabolism. 1.2. Polymers in pharmaceuticals The polymers being used as inactive ingredients (adjuvants) in pharmaceutical formulations are described as follows. 1.2.1. Binders The most commonly used polymers as binders for tablets are synthetic and include polyvinyl pyrolidone (PVP), hydroxypropylmethyl cellulose (HPMC), hydroxypropyl cellulose (HPC), hydroxyethyl cellulose (HEC) and carboxy methyl cellulose (CMC) [3, 4]. They produce harder granules with greater stability, higher binding, low friability and good flowability [5,6]. Among the natural polymers guar gum, pectin, high methoxy pectin [7- 10] have found their way in this application. These are biocompatible, low cost, environmentally friendly and easily available materials. Some of the natural materials including Lallemantia royleana (LR) and Astragalus tragacantha (AT) are subject of several studies to evaluate their potential in this respect [11]. 1.2.2. Thickeners Different grades of synthetic polymers described as binders are also used thickening or viscosity enhancing agents in formulation of oral liquids and ophthalmic solutions. 11 Among the natural materials gum Arabic, guar gum, xanthan gum and gum tragacanth are in common use in formulation of oral liquids. Glucomannan, a food additive, is used as an emulsifier and thickener with the E number E425(ii) [12] in candies and cosmetics. 1.2.3. Suspending agents PVP and PVA are synthetic suspending agents mostly used in formulation of oral liquids and ophthalmic solutions [13, 14]. But now these polymers are being replaced by natural polymers such as guar gum and Acacia nilotica (AN) which are used as stabilizers, emulsifier, thickening, and suspending agent in liquid formulations [15]. AN has been listed as edible material with E number as E 414. 1.2.4. Film coating agents Film coating of pharmaceutical tablets is generally being carried out by use of synthetic polymers including PVP and HPMC. Now film coating materials are undergoing a transition from synthetic or semi-synthetic to natural products. Hypromallose-pectin and ethyl cellulose aqueous dispersion also as mixtures with chitosan are becoming popular for film coating the tablets [16].