Title Hidrogelovi s intrinzičnom antimikrobnom aktivnosti Author Ana Čačić Mentor Željka Vanić (mentor)Mentor Maja Šegvić Klarić (mentor)Committee member Anita Hafner (predsjednik povjerenstva)Committee member Željka Vanić (član povjerenstva)Committee member Josipa Vlainić (član povjerenstva)Granter University of Zagreb Defense date and country 2020-12-22, Croatia Scientific / art field, BIOMEDICINE AND HEALTHCARE Abstract Cilj istraživanja
Jedan od ciljeva ovog istraživanja bio je ispitati intrinzični antimikrobni učinak izvornih kitozanskih hidrogelova koji su korišteni kao polučvrste podloge za uklapanje liposomskih disperzija azitromicina. Kako bi se utvrdilo utječe li kitozan na antibakterijsku aktivnost liposomski uklopljenog antibiotika te doprinosi li fosfolipidni sastav liposoma antimikrobnoj aktivnosti, ispitan je antibakterijski učinak kitozanskih hidrogelova s liposomski uklopljenim azitromicinom, a dobiveni rezultati uspoređivani su s antibakterijskom aktivnosti: liposoma s azitromicinom, otopine azitromicina, kitozanskih hidrogelova s azitromicinom te izvornih kitozanskih hidrogelova.
Materijali i metode
Eksperimentalni dio rada obuhvaćao je izradu kitozanskih hidrogelova iz kitozana različitih molekularnih masa, pripravu nekoliko tipova liposoma s uklopljenim azitromicinom, te izradu liposomskih hidrogelova umješavanjem liposoma u kitozanske hidrogelove. Ispitivanja intrinzičnog antimikrobnog učinka izvornih kitozanskih hidrogelova provedena su tako da su hidrogelovi inokulirani određenim test mikroorganizmima (Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Candida albicans i Aspergillus brasiliensis) i čuvani u propisanim uvjetima, a redukcija broja mikroorganizama praćena je kroz određene vremenske intervale tijekom 28 dana. Ispitivanje utjecaja kitozana na antibakterijsku aktivnost različitih liposoma s azitromicinom provedeno je primjenom in vitro agar-difuzijskog testa na bakterijskom soju Staphylococcus aureus ATCC 6538.
Rezultati
Neovisno o tipu kitozana iz kojeg su pripravljeni, svi izvorni kitozanski hidrogelovi su pokazali intrinzičnu antimikrobnu aktivnost na ispitivane mikroorganizme, čime je potvrđeno da nije
potrebno dodatno konzerviranje topikalnih formulacija koje sadrže kitozanske hidrogelove kao polučvrste podloge. Nadalje, čvrstoća/elastičnost liposomskih dvoslojeva utjecala je na antibakterijsku aktivnost ispitivanih liposoma s azitromicinom i liposomskih hidrogelova. Pritom je najjači učinak postignut s liposomima karakteriziranim izrazito čvrstim (rigidnim) dvoslojevima (konvencionalnim liposomima). Svi kitozanski hidrogelovi potencirali su antibakterijski učinak liposomski uklopljenog azitromicina, što je potvrđeno većim zonama inhibicije u odnosu na one postignute otopinom azitromicina.
Zaključak
Rezultati svih provedenih ispitivanja ukazuju na mogućnost primjene kitozanskih hidrogelova kao podloga za topikalne lijekove i nanoterapeutike namijenjene liječenju infekcija kože. Međutim, neophodno je provesti daljnja in vivo ispitivanja kako bi se dokazala njihova terapijska učinkovitost.
Abstract (english) Objectives
One of objectives of this study was to examine the intrinsic antimicrobial activity of the chitosan hydrogels, which were used as vehicles (bases) for incorporation of the azithromycin liposomes. To determine whether chitosan hydrogels could potentiate antibacterial activity of the incorporated azithromycin liposomes and to examine the effect of bilayer fluidity on the antibacterial activity of encapsulated azithromycin, the studies were performed with chitosan hydrogels containing incorporated azithromycin liposomes and the results were compared with azithromycin liposomes (liquid dispersions), solution of azithromycin, hydrogels containing azithromycin solution and the plain chitosan hydrogels.
Material and Methods
The experimental part of this study included preparation of the plain chitosan hydrogels from the different molecular weight chitosans as well as preparation and characterization of the several types of liposomes encapsulating azithromycin, which were incorporated into the chitosan hydrogels (liposomal hydrogels). Intrinsic antimicrobial activities of the plain chitosan hydrogels were examined by the reduction of number of the test microorganisms (Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Candida albicans and Aspergillus brasiliensis), which were inoculated into the hydrogels, stored for 28 days and tested at determined time intervals. In vitro antibacterial activity of the different azithromycin containing liposomal hydrogels toward Staphylococcus aureus ATCC 6538 was performed by agar well diffusion method.
Results
All the plain chitosan hydrogels have shown intrinsic antimicrobial activities, confirming that there is no need for the use of preservatives in the topical formulations based on the chitosan
hydrogels. Furthermore, the elasticities/rigidities of the different azithromycin liposomes have influenced their antibacterial activities as well as antibacterial activities of the liposomal hydrogels. Conventional liposomes, characterized by rigid bilayers, have demonstrated the most pronounced antibacterial activity. All the chitosan hydrogels contributed the antibacterial activity of the incorporated azithromycin liposomes, what was confirmed by a larger inhibition zones formed, compared to those obtained by hydrogels containing azithromycin solution and the zones formed by the free drug.
Conclusion
Considering all the results, it can be assumed that the chitosan hydrogels could be used as vehicles for topical formulations and liposomes aimed for the treatment of skin infections. However, further in vivo studies should be carried out to confirm the efficacy of the innovative formulations.
Keywords
kitozanski hidrogelovi
liposomski hidrogelovi
liposomi
azitromicin
antimikrobna aktivnost
infekcije kože
Keywords (english)
chitosan hydrogels
liposome hydrogels
liposomes
azithromycin
antimicrobial activity
skin infections
Language croatian URN:NBN urn:nbn:hr:163:364065 Study programme Title: Drug development Type of resource Text File origin Born digital Access conditions Open access Terms of use Created on 2021-04-15 14:39:57
