Uporaba ultrazvoka za mešanje pri določanju termodinamske topnosti velikega števila modelnih spojin

Kastelic, Anže (avtor), Žakelj, Simon (mentor)

V razvoju novih učinkovin je topnost ena izmed najpomembnejših lastnosti spojine, saj se mora ta raztopiti v zadostni koncentraciji, da se lahko absorbira in doseže željen farmakološki učinek. Poznamo več izrazov za topnost, med katerimi se najpogosteje uporablja termodinamska topnost, ki opisuje topnost spojine v nasičeni raztopini v ravnotežnem stanju. Zlati standard za njeno določanje je shake-flask metoda, kjer se kot sredstvo za mešanje uporablja klasično mehansko mešanje. V začetnih fazah razvoja zdravil je pogosto na razpolago le omejena količina preiskovane učinkovine, zato moramo z njo ravnati preudarno. Da bi z nizko porabo učinkovine lahko dosegli biofarmacevtsko relevantno topnost, mora biti majhen tudi volumen medija za raztapljanje, kar pa lahko predstavlja izziv pri klasičnem mehanskem mešanju, ki je učinkovito le do spodnje meje volumna medija (~ 250 μL). Kot alternativa se ponuja ultrazvok, ki odpira možnost učinkovitega mešanja pri še veliko manjših volumnih. V okviru raziskovalnega dela smo zato pri določanju termodinamske topnosti na podlagi shake-flask metode razvili in ovrednotili posodobljen postopek mešanja z ultrazvokom in na velikem številu modelnih spojin preverili ujemanje rezultatov z referenčnimi vrednostmi, dobljenimi s klasičnim mehanskim mešanjem. Metodi smo primerjali z določanjem topnosti 34 spojin v treh pufrih s pH-ji 1,2, 4,5 in 6,8 pri biofarmacevtsko relevantni temperaturi 37 °C. Pri tem smo pokazali, da so imeli uporabljeni pufri dovolj veliko pufrno kapaciteto in da so dobro nasprotovali spremembi pH po dodatku spojin. Potrdili smo, da daje določevanje topnosti z metodo z ultrazvočnim mešanjem primerljive rezultate kot shake-flask metoda s klasičnim mehanskim mešanjem. Hkrati smo pokazali, da uporaba ultrazvoka pri raztapljanju spojin le-teh ne pripelje v območje prenasičenja, ampak le do ravnotežnega stanja. Poleg tega smo 34 modelnim spojinam določili termodinamsko topnost pri treh različnih pH pri 37 °C in tako ustvarili največjo znano zbirko eksperimentalno določenih biofarmacevtsko relevantnih topnosti zdravilnih učinkovin, kar je lahko v pomoč in referenco drugim raziskovalcem.

• Jezik: Slovenski jezik
• Ključne besede: termodinamska topnost, določanje topnosti, ultrazvok, ultrazvočno mešanje
• Vrsta gradiva: Magistrsko delo/naloga
• Organizacija: FFA - Fakulteta za farmacijo
• Leto izida: 2022
• PID: 20.500.12556/RUL-141568
• Datum objave v RUL: 01.10.2022

Sekundarni jezik

• Jezik: Angleški jezik
• Naslov: Application of ultrasonic mixing for thermodynamic solubility determination of a large number of model compounds

Izvleček

Solubility is one of the most important properties of a compound in new drug research and development, as it must dissolve in a sufficient concentration to be absorbed and to achieve the desired pharmacological effect. There are several terms for solubility, among which thermodynamic solubility is used the most. It describes the solubility of a compound in a saturated solution at equilibrium. The gold standard for its determination is the shake-flask method, where traditional mechanical mixing is used as a means of mixing. In the early stages of drug development, often only a limited amount of the active substance is available and therefore needs to be used sparingly. In order to achieve biopharmaceutically relevant solubility with a low consumption of active substance, the solvent volume must also be small, which can be a challenge with conventional mechanical mixing, because it is only effective down to a certain lower limit of the volume of the medium (~250 μL). As an alternative, ultrasound offers the possibility of effective mixing at even smaller volumes. As part of the research work, we have therefore developed and evaluated an updated sonic mixing procedure for the thermodynamic solubility determination based on the shake-flask method and compared the results to the reference values obtained by conventional mechanical mixing on a large number of model compounds. The methods were compared by determining the solubility of 34 compounds in three buffers at pH 1,2, 4,5 and 6,8 at a biopharmaceutically relevant temperature of 37 °C. We have showed that the used buffers had a sufficiently high buffer capacity and resisted well the pH change after the addition of the compounds. We have confirmed that the solubility determination using the method with sonic mixing gives comparable results to the shake-flask method with traditional mechanical mixing. At the same time, we have shown that the use of ultrasound to dissolve compounds does not lead to supersaturation, but only to the equilibrium state. In addition, we have determined the thermodynamic solubility of 34 model compounds at three different pH values at 37 °C, thus creating the largest known collection of experimentally determined biopharmaceutically relevant solubilities of active pharmaceutical ingredients, which can be of help and reference to other researchers.

• Ključne besede: thermodynamic solubility, solubility determination, ultrasound, sonic mixing