Vrednotenje stabilnosti in sproščanja peptidne učinkovine iz liotropnih tekočih kristalov za subkutano aplikacijo

Kodrič, Sara (author), Gosenca Matjaž, Mirjam (mentor), Roškar, Robert (comentor)

Subkutana aplikacija predstavlja aktualen način aplikacije zdravil zaradi številnih prednosti tako za bolnika kot zdravstveni sistem. Vezano na zdravilne učinkovine omogoča podaljšano sproščanje peptidnih učinkovin, kot je timozin alfa 1, za katere je značilen kratek razpolovni čas. Na področju razvoja dostavnih sistemov za subkutano aplikacijo z namenom podaljšanega sproščanja izkazujejo liotropni tekoči kristali velik potencial, zlasti tekoči kristali s heksagonalnimi in/ali kubičnimi mezofazami. V okviru magistrske naloge smo proučevali osem sistemov liotropnih tekočih kristalov na osnovi glicerol monooleata in glicerol monolinoleata. V prekurzorske formulacije, ki ob stiku s fiziološkim medijem tvorijo gel in situ z mikrostrukturo tekočih kristalov, smo vgradili peptidno učinkovino timozin alfa 1 in vrednotili sproščanje in vitro tekom 28 dni. Z namenom izbire optimalnega medija smo izvedli tudi stabilnostne študije timozina alfa 1 v izbranih medijih. Rezultate stabilnostne študije in študije sproščanja smo analizirali z validirano metodo tekočinske kromatografije ultra visoke ločljivosti. V sklopu stabilnostnih študij je bil cilj izbrati ustrezen medij, kjer timozin alfa 1 izkazuje ustrezno stabilnost tekom izvedbe sproščanja, tj. 28 dni. Testirali smo 10 različnih medijev pri štirih različnih temperaturah (-20 °C, 8 °C, 25 °C in 37 °C). Timozin alfa 1 je bil najstabilnejši v 5 % etanolni raztopini v fosfatnem pufru, ki smo ga uporabili kot medij za sproščanje. Pred študijami sproščanja smo izvedli preliminarne študije z namenom optimizacije pogojev sproščanja. Za študije sproščanja smo tako določili brezmembranski model, kjer smo v 15 mL izbranega medija injicirali 1000 µL prekurzorske formulacije z vgrajenim timozinom alfa 1 (1,6 mg/g formulacije). V drugem delu naloge smo vrednotili sproščanje timozina alfa 1 in vitro iz osmih sistemov tekočih kristalov. Vse prekurzorske formulacije so takoj po injiciranju v medij tvorile gel in situ. Sproščanje je bilo odvisno od mikrostrukture tekočih kristalov. Hitrejše sproščanje je bilo iz tekočih kristalih z lamelarnimi mezofazami, podaljšano sproščanje pa iz tekočih kristalih z izkazanimi heksagonalnimi in kubičnimi mezofazami. Kot potencialna sistema za podaljšano sproščanje timozina alfa 1 s subkutano aplikacijo sta se za najbolj obetavna izkazala sistema (E/L)GL50* in (E/L)GO50*, kjer so se tvorile heksagonalne in kubične mezofaze. *Črke označujejo E-etanol, L-lecitin, GL-glicerol monolinoleat, GO – glicerol monooleat; številka označuje odstotek lipida.

• Language: Slovenian
• Keywords: timozin alfa 1, heksagonalni tekoči kristali, kubični tekoči kristali, subkutana aplikacija, stabilnost, sproščanje, UHPLC metoda
• Work type: Master's thesis/paper
• Organization: FFA - Faculty of Pharmacy
• Year: 2024
• PID: 20.500.12556/RUL-160268
• Publication date in RUL: 24.08.2024

Secondary language

• Language: English
• Title: Evaluation of peptide drug stability and release profile from lyotropic liquid crystals for subcutaneous application

Abstract

Subcutaneous administration is recognized as a valuable route of administration due to numerous advantages for both the patient and the healthcare system. In terms of active pharmaceutical ingredients, it enables the prolonged release of peptide drugs, such as thymosin alpha 1, characterized by a short half-life. Within the field of novel delivery systems for subcutaneous application aiming prolonged release, lyotropic liquid crystals have great potential, especially liquid crystals with hexagonal, and/or cubic mesophases. Within the Master's thesis, we investigated eight lyotropic liquid crystal systems based on glycerol monooleate and glycerol monolinoleate. In precursor formulations, which upon contact with physiological media form an in situ gel with liquid crystal microstructure, we incorporated the peptide drug thymosin alpha 1 and evaluated its in vitro release over 28 days. To select the optimal medium, stability studies of thymosin alpha 1 in the chosen media were also conducted. The results of the stability study and release study were analyzed using validated ultra-high-performance liquid chromatography. As part of the stability studies, the goal was to select an appropriate medium where thymosin alpha 1 demonstrates sufficient stability throughout the 28-day release period. We tested 10 different media at four different temperatures (-20 °C, 8 °C, 25 °C, and 37 °C). Thymosin alpha 1 stability was the highest in a 5 % ethanol solution in phosphate buffer, which was used as the release medium. Prior to the release studies, preliminary studies were conducted to optimize the release conditions. For the release studies, a membrane-free model was chosen, where 1000 µL of the precursor formulation containing thymosin alpha 1 (1,6 mg/g formulation) was injected into 15 mL of the selected medium. In the second part of the thesis, we evaluated the in vitro release of thymosin alpha 1 from eight liquid crystal systems. All precursor formulations immediately formed an in situ gel upon contact with the medium. Release was dependent on the liquid crystal microstructure. The faster release was from liquid crystals with lamellar mesophases and the prolonged release was from liquid crystals exhibiting hexagonal and cubic mesophases. Two systems, (E/L)GL50* and (E/L)GO50*, showing hexagonal and cubic mesophases, emerged as the most promising candidates for sustained release of thymosin alpha 1 via subcutaneous application. *The letters indicate E – ethanol, L – lecithin, GL – glycerol monolinoleate, GO – glycerol monooleate; number indicate percentage of lipid.

• Keywords: thymosin alpha 1, hexagonal liquid crystals, cubic liquid crystals, subcutaneous application, stability, release, UHPLC method