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Vrednotenje mikrostrukture liotropnih tekočih kristalov za dermalno in subkutano aplikacijo z diferenčno dinamično kalorimetrijo
ID Glavič, Urša (Avtor), ID Gosenca Matjaž, Mirjam (Mentor) Več o mentorju... Povezava se odpre v novem oknu, ID Planinšek, Odon (Komentor)

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Izvleček
Molekule površinsko aktivnih snovi, ki tvorijo liotropne tekoče kristale, se v raztopini pri določenih koncentracijah spontano združujejo in urejajo v strukture ali mezofaze, kot so lamelarna, heksagonalna in kubična. Sisteme z mikrostrukturo tekočih kristalov v farmaciji raziskujemo za različne načine aplikacije, vključujoč dermalno in subkutano. Pomembne informacije o mikrostrukturi liotropnih tekočih kristalov lahko dobimo z diferenčno dinamično kalorimetrijo, ki je termična analiza, s katero prek preučevanja faznih prehodov dobimo vpogled v stanje vode kot sestavine tekočih kristalov. Voda, ki se v sistemu tekočih kristalov nahaja v bližini polarnih glav površinsko aktivnih snovi, ima namreč zaradi interakcij, ki zmanjšajo njene prostostne stopnje, drugačne termične lastnosti od vode, ki je v sistemu tekočih kristalov od polarnih glav bolj oddaljena. V sklopu magistrske naloge smo najprej vrednotili formulacije za dermalno aplikacijo na osnovi lanenega ali konopljinega olja, za katere so v okviru predhodnega razvoja s polarizacijsko mikroskopijo potrdili prisotnost lamelarnih mezofaz. V formulacije smo vgradili zdravilno učinkovino betametazondipropionat in opazovali njen vpliv na mikrostrukturo. Pri preučevanju DSC krivulj tekočih kristalov za dermalno aplikacijo smo ugotovili, da se v formulacijah s 30 % vode le-ta nahaja v bližini polarnih glav površinsko aktivnih snovi in je vezana, pri formulacijah z več kot 50 % vode pa so polarne glave zasičene z molekulami vode in je v sistemu prisotna tudi prosta voda. Pri primerjavi posameznih formulacij brez in z vgrajeno zdravilno učinkovino smo sklenili, da se v formulacijah s 30 % vode zdravilna učinkovina vgrajuje med lamele, v formulacijah z 80 % vode pa se vgrajuje v oljne kapljice, ki so poleg lamelarnih faz prisotne ločeno. V nadaljevanju smo vrednotili prekurzorske formulacije za subkutano aplikacijo na osnovi glicerol monooleata ali glicerol monolinoleata in gelske formulacije, ki nastanejo po injiciranju nizko viskozne prekurzorske formulacije v podkožje in situ. Za nastale gele so pri razvoju s polarizacijsko mikroskopijo potrdili prisotnost kubičnih oz. heksagonalnih faz tekočih kristalov. Pri preučevanju DSC krivulj smo ugotovili, da se pri gelih nastalih iz prekurzorske formulacije s 50 % lipidne faze večina vode nahaja v bližini polarnih glav in je vezana, pri gelih nastalih iz prekurzorske formulacije z 20 % lipidne faze pa so polarne glave površinsko aktivnih snovi že zasičene in je v sistemu prisotna tudi prosta voda.

Jezik:Slovenski jezik
Ključne besede:liotropni tekoči kristali, dermalna aplikacija, subkutana aplikacija, diferenčna dinamična kalorimetrija, prosta voda/vezana voda
Vrsta gradiva:Magistrsko delo/naloga
Organizacija:FFA - Fakulteta za farmacijo
Leto izida:2024
PID:20.500.12556/RUL-155910 Povezava se odpre v novem oknu
Datum objave v RUL:24.04.2024
Število ogledov:133
Število prenosov:126
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Sekundarni jezik

Jezik:Angleški jezik
Naslov:Evaluation of microstructure of lyotropic liquid crystals for dermal and subcutaneous application with differential scanning calorimetry
Izvleček:
Molecules of lyotropic liquid crystal forming surfactants at certain concentrations in solution spontaneously associate and organize into structures or mesophases, such as lamellar, hexagonal, and cubic lyotropic liquid crystal. These systems are studied in the field of pharmacy as delivery systems for various applications, including dermal and subcutaneous. Important information regarding lyotropic liquid crystals’ microstructure can be obtained through differential scanning calorimetry, a thermal analysis technique that provides insights into the state of water, a liquid crystals’ component, through the study of phase transitions. Water, located near the polar heads of surfactants in the liquid crystal system, exhibits different thermal properties due to interactions that reduce its degrees of freedom compared to water that is more distant from the polar heads. As part of the Master's thesis, we first evaluated formulations for dermal application based on linseed or hemp oil, in which the presence of lamellar phases was previously confirmed during development phase with polarizing microscopy. Betamethasone dipropionate as active ingredient was incorporated into the formulations and its impact on the microstructure was also studied. Based on obtained results, within formulations with 30 % water, the water molecules are located near the polar heads of surfactants are bound, while in formulations with more that 50 % water, the polar heads are saturated with water molecules, and free water is also present in the system. Comparing individual formulations without and with the incorporated betamethasone dipropionate, we concluded that in formulations with 30 % water, the active pharmaceutical ingredient is incorporated between the lamellae, while in formulations with 80 % water, it is incorporated into oil droplets present separately in addition to lamellar phases. Furthermore, we evaluated precursor formulations for subcutaneous application based on glycerol monooleate or glycerol monolinoleate and gels that are formed in situ after injection of the precursor formulation into the subcutaneous tissue. During development, the presence of cubic and hexagonal phases of liquid crystals was confirmed using polarizing microscopy for gels formed in situ. Based on obtained results, we found that in gels with 50 % lipid phase in the precursor formulation, most of the water is located near the polar heads of the surfactants and is bound, while in gels with 20 % lipid phase in the precursor formulation, the polar heads of the surfactants are already saturated with water molecules and free water is present in the system.

Ključne besede:lyotropic liquid crystals, dermal application, subcutaneous application, differential scanning calorimetry, free/bound water

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