Utjecaj koncentracije i površinskog naboja liposoma na reološka svojstva kitozanskih liposomskih gelova

master's thesis

• Title (english): Influence of liposome concentration and surface charge on the rheological properties of chitosan liposomal gels
• Author: Jelena Bočkaj
• Mentor: Zora Rukavina (mentor)
• Committee member: Zora Rukavina (predsjednik povjerenstva)
• Committee member: Laura Nižić Nodilo (član povjerenstva)
• Committee member: Kristina Radić (član povjerenstva)
• Granter: University of Zagreb; Faculty of Pharmacy and Biochemistry; (Department of pharmaceutical technology); Zagreb
• Defense date and country: 2024-09-06, Croatia
• Scientific / art field, discipline and subdiscipline: BIOMEDICINE AND HEALTHCARE; Pharmacy; Pharmacy

Abstract

Liposomski gelovi (CL-CHG, PGL-CHG, CATL-CHG) pripremljeni su uklapanjem različitih vrsta AZT-liposoma u CHG pri 3 različite koncentracije (10, 20 i 30 %, m/m), Uklopljeni su liposomi bili srednjeg promjera ˂ 130 nm (CL i PGL), odnosno 330 nm (CATL). Zeta potencijal CL i PGL bio je izrazito negativan (− 43 mV, − 48 mV), dok su CATL pokazali izrazito pozitivnu vrijednost zeta potencijala (+ 59 mV). Krivulje viskoznosti dobivene za liposomske gelove pokazuju da fosfolipidni sastav liposoma, tj. površinski naboj, ima određeni utjecaj na viskoznost formulacije, koji više dolazi do izražaja pri nižim koncentracijama liposoma u sustavu. Naime, negativno nabijeni liposomi CL i PGL pri koncentraciji od 10 % ili 20 % uzrokuju povećanje viskoznosti u odnosu na izvorni CHG, dok je za pozitivno nabijene CATL pri 10 % i 20 % uočen suprotan efekt (smanjenje viskoznosti). Pri najvećoj koncentraciji liposoma u gelu (30 %), dolazi do smanjenja viskoznosti formulacije neovisno o površinskom naboju liposoma, što je vjerojatno rezultat značajnog smanjenja koncentracije kitozana u gelu uslijed razrjeđivanja dodatkom tekuće faze. Tijekom oscilacijskih testova promjene amplitude, izvorni CHG i svi liposomski gelovi pokazuju širok LVR s modulom skladištenja (G') većim od modula gubitka (G''), što predstavlja viskoelastično ponašanje karakteristično za gelove i potvrđuje da dodatak liposoma u CHG u koncentraciji ≤ 30% (m/m) ne narušava strukturu gela. Očuvana struktura gela može osigurati produljeno zadržavanje na mjestu primjene i produljeno oslobađanje lijeka, a uzorci sa širokom LVR regijom ujedno se mogu smatrati dobro dispergiranima i stabilnima.

Abstract (english)

Liposomal gels (CL-CHG, PGL-CHG, CATL-CHG) were prepared by incorporating different types of AZT-liposomes into CHG at three different concentrations (10, 20, 30%, w/w). The incorporated liposomes had an average diameter ˂130 nm (CL, PGL) or 330 nm (CATL). The zeta potential of CL and PGL liposomes was strongly negative (-43 mV, -48 mV), while CATL exhibited strongly positive zeta potential (+59 mV). The viscosity curves obtained for the liposomal gels indicate that the phospholipid composition/surface charge of the liposomes, has an impact on the viscosity of the formulation, which is more pronounced at lower liposome concentrations in the formulation. Specifically, negatively charged CL and PGL liposomes at 10% or 20% cause an increase in viscosity compared to the original CHG, while for positively charged CATL at 10% and 20%, an opposite effect (viscosity decrease) was observed. At the highest liposome concentration in the gel (30 %), the viscosity of the formulation decreases regardless of the surface charge of the liposomes, which is likely the result of a significant reduction in the chitosan concentration in the gel due to dilution by the added liquid phase. During oscillatory amplitude tests, the original CHG and all liposomal gels show a wide LVR with a storage modulus (G') greater than the loss modulus (G''), which represents viscoelastic behavior characteristic of gels and confirms that the addition of liposomes to CHG at a concentration ≤ 30% (w/w) does not compromise the gel structure. The preserved gel structure can ensure prolonged retention at the site of application and extended drug release. Moreover, samples with a broad LVR region can also be considered well-dispersed and stable.

• Keywords: deformabilni liposomi; azitromicin; karbopolski gel; kitozanski gel; biokompatibilnost; HaCaT stanice
• Keywords (english): deformable liposomes; azithromycin; carbopol gel; chitosan gel; biocompatibility; HaCaT cells
• Language: croatian
• URN:NBN: urn:nbn:hr:163:346550
• Study programme: Title: Pharmacy - integrated undergraduate and graduate - university study; Study programme type: university; Study level: integrated undergraduate and graduate; Academic / professional title: sveučilišni magistar farmacije (sveučilišni magistar farmacije)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2024-10-11 11:23:15