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Phd Dissertation De Zordi Nicola.Pdf UNIVERSITÀ DEGLI STUDI DI TRIESTE XXIV CICLO DEL DOTTORATO DI RICERCA IN Scienze e Tecnologie Chimiche e Farmaceutiche MODIFIED RELEASE OF PHARMACEUTICAL DOSAGE FORMS Settore scientifico-disciplinare CHIM/09 DOTTORANDO NICOLA DE ZORDI COORDINATORE PROF. ENZO ALESSIO RELATORE / SUPERVISORE / TUTORE PROF. MARIAROSA MONEGHINI CORRELEATORE PROF. IRENEO KIKIC Solid dispersion : ANNO ACCADEMICO 2010/ 2011 Abstract 1 Solid dispersion : Abstract 2 Abstract During these three years, the research was focused on the preparation of pharmaceutical solid oral dosage forms with the aim to improve the dissolution behaviors and bioavailability of poor soluble drugs, or preparing sustained release systems for water- soluble drugs. In order to improve the bioavailability of poor soluble drugs, we adopted two strategies: 1) the micronization of the drug to increase their surface area, 2) preparing solid dispersions (SDs) using hydrophilic carrier. As known in the SDs the drug is dispersed or solubilized in an inert excipient or matrix where the active ingredient could exist in finely crystalline or amorphous state. When the system is exposed to aqueous media, the carrier dissolved and the drug is released as a very fine colloidal particles. This greatly reduction in particles size and the following surface area increase, results in an improvement of the dissolution rate. In addition to bioavailability enhancement, SDs systems were also directed towards the development of extender-release dosage forms using lipophilic carriers. For both the formulative approaches, we investigated the application of microwave (MW) and supercritical fluids (SCF) as preparative methods. In particular, MW ware employed for the preparation of solid dispersion either for immediate or sustained release of drugs, while SCF were investigated for the micronization and preparation of solid with the aim to prepare immediate release systems. Moreover, were investigated the thermodynamic aspect involved in the drug processing developing mathematical approaches able to predict the best operative conditions. Beside the preparation of these systems the physicochemical characterization of the compounds were investigated in order to understand the influence of the above technologies on the solid state of the materials. The goal of these behaviors was investigated trough the dissolution profile. From the obtained results these two technologies can be considered innovative and promising way to design particles. Solid dispersion : Abstract 3 Table of contents Abstract ............................................................................................................................. 3 1. Introduction ............................................................................................................... 8 1.1. Solid dispersion ................................................................................................... 9 Amorphous vs. crystalline ........................................................................................ 10 1.2. Particle size reduction ........................................................................................ 14 1.2.1. Bottom up process ...................................................................................... 14 1.2.2. Chemical reactions ..................................................................................... 16 1.2.3. Top-down approaches ................................................................................ 16 1.2.4. Combination technology............................................................................. 17 2. Aim of the research .................................................................................................. 18 3. Generality of Microwave irradiation ........................................................................ 19 3.1. Modes [64] ........................................................................................................ 22 3.1.1. Single-mode apparatus ............................................................................... 22 3.1.2. Multi-mode apparatus ................................................................................. 23 3.2. Microwave advantages ...................................................................................... 23 3.3. Microwave applications ..................................................................................... 24 3.3.1. Microwave assists drug extraction .............................................................. 24 3.3.2. Microwave digestion .................................................................................. 25 3.3.3. Microwave in chemistry synthesis .............................................................. 25 3.3.4. Microwavein drying ................................................................................... 26 3.3.5. Microwave in pharmaceutical dosage forms development .......................... 27 3.4. Active pharmaceutical ingredients (API) for SDs microwave approach ............. 29 3.4.1. Poorly soluble drugs ................................................................................... 29 Solid dispersion : 3.4.2. Slightly soluble drug .................................................................................. 30 Abstract 3.4.3. Preparation method .................................................................................... 30 4 3.4.4. Physicochemical characterizations .............................................................. 31 3.5. Nimesulide MW solid dispersions ...................................................................... 33 3.6. Itraconazole MW solid dispersions..................................................................... 41 3.7. Ibuprofen MW solid dispersions ........................................................................ 52 3.8. Conclusion of MW application research ............................................................. 67 4. Supercritical fluids applications ................................................................................ 68 4.1. Properties of supercritical fluids ......................................................................... 68 4.2. Applications of supercritical fluids ..................................................................... 72 4.2.1. Supercritical Extraction............................................................................... 72 4.2.2. Supercritical Chromatography .................................................................... 73 4.2.3. Impregnation .............................................................................................. 73 4.2.4. Powder technology ..................................................................................... 74 4.2.5. Fractional crystallization and solvents elimination ...................................... 75 4.2.6. Other applications ....................................................................................... 75 4.3. The techniques of precipitation .......................................................................... 75 4.3.1. RESS (Rapid Expansion of Supercritical Solutions) .................................... 76 4.3.2. GASR (Gas Anti-Solvent Recrystallization)................................................ 77 4.3.3. Process Variables ........................................................................................ 81 4.4. Solubility in supercritical fluids ......................................................................... 84 4.4.1. Method ....................................................................................................... 84 4.4.2. Results and Discussion ............................................................................... 91 4.5. Infinite–fugacity coefficient of volatile organic compounds and pharmaceutical compounds in Cyclic Olefin Copolymer and polyvinyl pyrrolidone. ............................. 97 4.5.1. Materials ..................................................................................................... 97 4.5.2. Method ....................................................................................................... 99 4.5.3. Results and discussion .............................................................................. 102 Solid dispersion : 4.6. Solubility estimation of drugs in ternary systems for the antisolvent precipitation process ....................................................................................................................... 125 Abstract 4.6.1. Materials ................................................................................................... 125 5 4.6.2. Physicochemical characterizations ............................................................ 125 4.6.3. Phase equilibria calculation ...................................................................... 127 4.6.4. Model description ..................................................................................... 128 4.6.5. Parameter determination ........................................................................... 129 4.6.6. Results: Ternary Systems ......................................................................... 131 4.7. Recrystallization of Vitamin B6 by means of supercritical antisolvent technology . ........................................................................................................................ 139 4.7.1. Materials .................................................................................................. 139 4.7.1. Vitamin
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