Vgrajevanje težko topne učinkovine v liposome in nanostrukturirane lipidne nosilce

Prašnikar, Monika (author), Zupančič, Špela (mentor)

Večina novo odkritih zdravilnih učinkovin ima slabo topnost in posledično nižjo učinkovitost. Nanodostavni sistemi omogočajo večjo učinkovitost delovanja učinkovin, saj se lahko zaradi svoje nanometrske velikosti skupaj z učinkovino razporedijo po telesu, jo zaščitijo pred razgradnjo in tarčno dostavijo na mesto delovanja. Z namenom izboljšanja učinkovitosti delovanja lipofilne modelne učinkovine A smo jo v sklopu magistrskega dela vgradili v tri različne na lipidih osnovane nanodostavne sisteme (liposome, trdne lipidne nanodelce in nanostrukturirane lipidne nosilce (NLC)) in jih ovrednotili. Liposome iz HSPC, PEG2000-DSPE in holesterola smo pripravili s filmsko metodo in njihovo velikost s sonikacijo zmanjšali na 100 nm ter vanje vgradili modelno učinkovino A s 30 % učinkovitostjo vgradnje. Količina učinkovine A v liposomih je po 24 h upadla zaradi fizikalne in/ali kemijske nestabilnosti, po nekaj dneh pa je v liposomih ni bilo več. V trdne lipidne nanodelce iz HSPC in Compritola 888 ATO nismo uspeli vgraditi učinkovine A, zato smo jim dodali tekoče lipide in s tem formulirali NLC. Pri razvoju NLC smo optimizirali metodo priprave in proučili vpliv sestave, pri čemer smo spreminjali (i) razmerje trdni lipid:fosfolipid, (ii) masni delež tekočega lipida, (iii) vrsto trdnega lipida, (iv) dodatek steričnega stabilizatorja in (v) masni delež lipidov v vodni disperziji. Razvili smo uspešno formulacijo NLC iz trdnega lipida Compritola 888 ATO, tekočega lipida Captex 200, fosfolipida in stabilizatorja PEG2000-DSPE ter modelne učinkovine A, ki smo jih izdelali s homogenizacijo z visoko ponovljivostjo. Nastali so 211,3 nm veliki NLC, v katere smo vgradili modelno učinkovino A s 85,6 % učinkovitostjo vgradnje in 2,13 % dejansko vsebnostjo. S pomočjo diferenčne dinamične kalorimetrije in termogravimetrične analize ter infrardeče spektroskopije s Fourierjevo transformacijo smo opredelili izdelane NLC in jih pregledali z vrstičnim elektronskim mikroskopom. Ker se je količina učinkovine A tudi v NLC s časom zmanjševala, smo njeno stabilnost skušali izboljšati z dodajanjem antioksidantov, kombinacijo stabilizatorjev in liofilizacijo, vendar neuspešno. V magistrskem delu smo uspešno razvili NLC z visoko učinkovitostjo vgradnje učinkovine A, potrebne pa bodo nadaljnje raziskave za povečanje stabilnosti te formulacije.

• Language: Slovenian
• Keywords: nanodostavni sistemi, liposomi, nanostrukturirani lipidni nosilci, slaba topnost, stabilnost
• Work type: Master's thesis/paper
• Organization: FFA - Faculty of Pharmacy
• Year: 2022
• PID: 20.500.12556/RUL-137683
• Publication date in RUL: 26.06.2022

Secondary language

• Language: English
• Title: Incorporation of a poorly soluble drug into liposomes and nanostructured lipid carriers

Abstract

Poor solubility of drugs under development presents an important limitation in their clinical use. A novel solution are nano-drug delivery systems (NDDSs) that are absorbed along with the active ingredient, which enables distribution control, drug protection or even targeted therapy. This work presents the incorporation of a lipophilic model drug A into three different lipid-based NDDSs, liposomes, solid lipid nanoparticles and nanostructured lipid carriers (NLCs), and their evaluation with the aim of increasing the drug’s efficacy. Liposomes made of HSPC, PEG2000-DSPE and cholesterol were prepared with the thin film method and then sonicated for size reduction to 100 nm. Model drug A was incorporated with up to a 30% encapsulation efficiency but was unstable either for physical or chemical reasons. Its content in the liposomes decreased in 24 h and was reduced to zero after a few days. Solid lipid nanoparticles were prepared from HSPC and Compritol 888 ATO, but were unable to incorporate drug A. Therefore, NLCs were designed by adding a liquid lipid. The preparation method and NLC composition were further optimised, where variations of (i) ratio solid lipid:phospholipid, (ii) liquid lipid mass fraction, (iii) solid lipid type, (iv) addition of a steric stabilizer and (v) lipid mass fraction in the dispersion of water were studied. A successful formulation was developed including solid lipid Compritol 888 ATO, liquid lipid Captex 200, phospholipid and stabilizer PEG2000-DSPE and model drug A. NLC produced by homogenisation with high repeatability had a mean diameter of 211,3 nm and incorporated model drug A with a 85,6% encapsulation efficiency and 2,13% drug loading. They were evaluated with differential scanning calorimetry, thermogravimetric analysis and Fourier-transform infrared spectroscopy and visually assessed with scanning electron microscopy. In addition, an attempt to increase NLC stability was made through inclusion of antioxidants, stabilizers combination and lyophilization, however, unsuccessfully. This master thesis presents a successful incorporation of model drug A into NLC and points at the necessity to further improve the stability of the formulation in the future.

• Keywords: nanodelivery systems, liposomes, nanostructured lipid carriers, poor solubility, stability