Title Priprava mikroemulzija Title (english) Preparation of microemulsions Author Marinela Jelačić Mentor Anamarija Rogina (mentor)Committee member Anamarija Rogina (predsjednik povjerenstva)Committee member Hrvoje Ivanković (član povjerenstva)Committee member Leonard Bauer (član povjerenstva)Granter University of Zagreb Defense date and country 2022-09-21, Croatia Scientific / art field, TECHNICAL SCIENCES Abstract Mikroemulzije se sve češće koriste kao metode priprave nanočestica, a posebno nanosfera, zbog svojih svojstava kao što su termodinamička stabilnost, optička prozirnost i niska viskoznost. Mikrosfere su sferične čestice veličine od 1 do 1000 μm, a odlikuju se velikom specifičnom površinom te su biorazgradljive što ih čini dobrim potencijalnim nosačima za lijekove te kontrolirano otpuštanje lijekova u manjim količinama. Mikrosfere se mogu pripremiti raznim postupcima, a u ovom je radu opisan postupak priprave mikrosfera na temelju kitozana metodom emulzije, odnosno mikroemulzije. Kao vodena (dispergirana) faza je korištena otopina kitozana, prirodnog polimera, uz dodatak bakrovih (II) iona (Cu2+) kao fizikalnog umreživala (otopina kompleksa CHT‒Cu). Kao uljna (kontinuirana) faza su korišteni izooktan, odnosno smjesa lakog i teškog parafina, uz dodatak emulgatora SPAN 85. Ispitivan je utjecaj različitih uljnih faza, omjer vodene i uljne faze te vrsta reaktora na sastav, izgled, morfologiju i veličinu dobivenih čestica. FTIR analiza je pokazala da su dobivene mikročestice kitozanske, a budući da nije detektirana pojava novih apsorpcijskih vrpci, interakcije funkcionalnih skupina polimera s bakrovim ionima su elektrostatske prirode. SEM analizom je utvrđeno da su dobivene mikročestice neporozne i glatke površine za sustav dobiven primjenom aparature s reaktorom ravnog dna, uz omjer vodene i uljne faze 1/5 te izooktanom kao uljnom fazom. Također, taj sustav je pokazao i najužu raspodjelu veličinu čestica. Čestice koje su nastale u emulziji sa smjesom lakog i teškog parafina kao uljnom fazom bile su nepravilnog oblika.
Abstract (english) Microemulsions are increasingly being used as methods of preparation of nanoparticles, especially nanospheres, due to their properties such as thermodynamic stability, optical transparency and low viscosity. Microspheres are spherical particles ranging in size from 1 to 1000 μm, characterized by a large specific surface area and biodegradability, which makes them suitable drug carriers for controlled release of drugs in smaller dosages. Microspheres can be prepared by various methods, and this work describes the preparation of chitosan-based microspheres using the emulsion, specifically the microemulsion method. A solution of chitosan, a natural polymer, was used as aqueous (dispersed) phase with the addition of copper (II) ions (Cu2+) as a physical crosslinker (solution of the CHT‒Cu complex). Isooctane and a mixture of viscous and highly liquid paraffin were used as the oil (continuous) phase, with the addition of the SPAN 85 as an emulsifier. The influence of different oil phases, the water-to-oil phase ratio and type of a reactor were examined on the composition, appearance, morphology and size of the particles. FTIR analysis showed that the obtained particles are chitosan-based, and the absence of new absorption bands indicated electrostatic nature of the interactions between chitosans’ functional groups and copper. SEM analysis showed that the obtained particles are non-porous and have smooth surface when prepared using the flat bottom reactor, with the ratio of water-to-oil phase of 1/5 and isooctane as the oil phase. Also, that system showed the narrowest particle size distribution. The particles formed in the emulsion with a mixture of viscous and highly liquid paraffin as the oil phase were irregular in shape.
Keywords
mikroemulzije
mikrosfere
kitozan
FTIR
SEM
Keywords (english)
microemulsions
microspheres
chitosan
FTIR
SEM
Language croatian URN:NBN urn:nbn:hr:149:924170 Project Number: UIP-2020-02-6201 Study programme Title: Chemical Engineering - Undergraduate study Type of resource Text File origin Born digital Access conditions Access restricted to students and staff of home institution Terms of use Created on 2023-03-01 10:12:37
