The impact of surfactants on the particle size of dexamethasone in nanosupsensions

Tijekom ovog istraživanja pripremljeni su koncentrati deksametazona s različitom vrstom surfaktanta (tyloxapola, poloksamera 188 te polisorbata 20), te dodatno evaluirane različite koncentracije deksametazona i surfaktanta tyloxapola. Isti koncentrati podvrgnuti su visokotlačnoj homogenizaciji - mikrofluidizaciji u različitom broju ciklusa. Vrijednosti temperature i tlaka bile su konstantne. Temeljem rezultata pripremljene su i uspoređene finalne suspenzije deksametazona (0.1% ), te surfaktanta (0.05%). Usporedba se temelji na njihovim veličinama čestica i brzini oslobađanja deksametazona. Ispitivanjem veličine čestica provedenim LALLS metodom (Low Angle Laser Light Scattering) na instrumentu Malvern Mastersizer 3000, dobiveni su profili volumne raspodjele veličine čestica. Brzina oslobađanja mjerena je pomoću Enhancer difuzijskih ćelija i kvantitativo određivanje oslobođenog lijeka uz pomoć HPLC uređaja. Rezultati su pokazali da se povećanjem broja ciklusa homogenizacije koncentrata i koncentracije deksametazona smanjuje veličina čestica u pripadajućim finalnim suspenzijama. Povećanje koncentracije surfaktanta nije imalo povoljan utjecaj na smanjenje veličine čestica. Metoda IVRT s Enhancer difuzijskom ćelijom pokazala je brže oslobađanje deksametazona iz nanosuspenzija u odnosu na nehomogeniziranu suspenziju.In this study dexamethasone concentrates were prepared with different types of surfactants (tyloxapol, poloxamer 188 and polysorbate 20). Concentrates with variable amounts of dexamethasone and tyloxapol were further evaluated. The same concentrates were subjected to high pressure microfluidization with variable cycles. The values of temperature and pressure were kept constant. Using results of these concentrates, final dexamethasone suspensions (dexamethasone 0.1%), and surfactant 0.05% were prepared and compared. The comparison is based on their particle sizes and the release rate of dexamethasone. Particle size was examined using LALLS method (Low Angle Laser Light Scattering), Malvern Mastersizer 3000 instrument. Results were obtained in the form of particle size volume distribution profiles. The release rate was measured using the Enhancer diffusion cells and quantified using HPLC equipment. Results showed that by increasing the number of homogenization cycles and dexamethasone concentration in the concentrates, smaller particles are found in corresponding final suspensions. Increasing the concentration of the surfactant did not have a favorable effect on the particle size reduction. IVRT method with Enhancer diffusion cells has shown faster release of dexamethasone from nanosuspensions in comparison with non-homogenised suspensions