magistrsko delo
Karmen Pirc (Author), Igor Plazl (Mentor), Marjan Marinšek (Thesis defence commission member), Aleš Ručigaj (Thesis defence commission member)

Abstract

Tehnologija iztiskanja talin se v farmaciji uporablja za izboljšanje hitrosti raztapljanja v vodi slabo topnih učinkovin. Pri tem nastali iztiskanec vsebuje zdravilno učinkovino v amorfni obliki dispergirano v polimernem nosilcu, ki preprečuje ponovno kristalizacijo. Mletje je ključni korak v postopku obdelave iztiskanca, saj z njim nadzorujemo velikost delcev, ki pomembno vpliva na pretočne lastnosti in hitrost sproščanja učinkovine iz končnega izdelka. Z namenom določitve ustreznih procesnih parametrov mletja smo izvedli mletje na treh različnih kladivnih mlinih. Mletje je potekalo na dveh laboratorijskih mlinih, HammerWitt in FreDrive ter proizvodnem mlinu MFH-6. Za mletje smo uporabili iztiskanec, sestavljen iz kopolimera vinil pirolidona in vinil acetata v razmerju 6:4, Polisorbata 80 in koloidnega silicijevega dioksida. Ugotavljali smo, kako tip mlina, vrsta mlevnih teles, hitrosti mletja, velikosti odprtin mreže in hitrosti doziranja materiala vplivajo na porazdelitev velikosti delcev, njihovo obliko in pretočne lastnosti. Porazdelitev velikosti, razmerje med dolžino in širino ter okroglost delcev smo določili z dinamično slikovno analizo z uporabo naprave Camsizer XT. Določili smo tudi pretočne lastnosti in vzorce slikali z uporabo vrstičnega elektronskega mikroskopa. Pripravili smo tri eksperimentalne načrte in rezultate obdelali v računalniškem programu Umetrics MODDE. Pokazali smo, da na velikost delcev najbolj vplivata hitrost mletja in velikost mreže. Pri višjih hitrostih in manjših odprtinah mreže dobimo manjše delce. Vpliv hitrosti mletja je opaznejši pri uporabi mreže z večjimi odprtinami. Hitrost mletja in velikost mreže vplivata tudi na obliko delcev. Pri višjih hitrostih mletja so delci bolj okrogli, razmerje med širino in dolžino pa je višje. Na obliko delcev vpliva tudi uporaba različnih mlevnih teles, saj z uporabo nožev dobimo bolj podolgovate delce. Procesni parametri mletja vplivajo tudi na pretočne lastnosti, ki so boljše pri nižjih hitrostih mletja in večjih odprtinah mreže. Dokazali smo, da so pretočne lastnosti prahov z večjimi delci boljše. Z uporabo računalniškega programa MODDE smo izdelali tri modele, s katerimi smo določili potrebne procesne parametre za dosego optimalne porazdelitve velikosti ter ustreznih pretočnih lastnosti.

Keywords

trdne disperzije;tehnologija iztiskanja talin;mletje;parametri mletja;porazdelitev velikosti delcev;pretočne lastnosti;eksperimentalni načrt;magistrska dela;

Data

Language: Slovenian
Year of publishing:
Typology: 2.09 - Master's Thesis
Organization: UL FKKT - Faculty of Chemistry and Chemical Technology
Publisher: [K. Pirc]
UDC: 66.02(043.2)
COBISS: 86508291 Link will open in a new window
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Other data

Secondary language: English
Secondary title: Impact of milling process on properties of extrudate prepared by hot melt extrusion
Secondary abstract: Hot melt extrusion is used in pharmacy to improve dissolution rate of poorly water-soluble active ingredients. The extrudate contains amorphous active ingredient dispersed in polymer carrier which prevents recrystallisation. Milling is a key step in the extrudate processing since it controls particle size, which has an important influence on flow properties and dissolution rate of the active ingredient from the final product. In order to determine the appropriate milling process parameters, milling was performed on three different hammer mills. Milling was carried out on two laboratory mills, HammerWitt and FreDrive and on the production mill MFH-6. For milling used extrudate consisted of a 6:4 copolymer of vinyl pyrrolidone and vinyl acetate, Polysorbate 80 and colloidal silica. We have investigated how the type of mill, milling elements, milling speeds, mesh size and dosing speeds affect the particle size distribution, particle shape and flow properties. The particle size distribution, aspect ratio and sphericity were determined by dynamic image analysis using a Camsizer XT. The flow properties were also determined and the samples were imaged using scanning electron microscope. Three designs of experiments were prepared and the results were processed using the computer program Umetrics MODDE. It was demonstrated that particle size is most affected by milling speed and mesh size. Higher speeds and smaller mesh openings produce smaller particles. The effect of milling speed is significant when using a mesh with larger openings. Milling speed and mesh size also impact on the particle shape. At higher milling speeds the particles are rounder and the aspect ratio is higher. The shape of the particles is also influenced by the use of different milling elements, since the use of knives results in more elongated particles. Milling process parameters also impact on the flow characteristics, which are better at lower milling speeds and larger mesh openings. It was shown that powders with larger particles have better flow properties. Using the MODDE computer program, three models were built to determine the optimal process parameters to achieve the optimum size distribution and the appropriate flow properties.
Secondary keywords: hot melt extrusion;milling;design of experiments;particle size distribution;flow properties;
Type (COBISS): Master's thesis/paper
Study programme: 1000376
Embargo end date (OpenAIRE): 1970-01-01
Thesis comment: Univ. v Ljubljani, Fak. za kemijo in kemijsko tehnologijo, smer Kemijsko inženirstvo
Pages: 72 str.
ID: 13595011