Določanje topnosti kurkumina v različnih topilih z metodo tekočinske kromatografije visoke ločljivosti

Tratar, Alja (author), Tavčar, Eva (mentor)

Polifenol kurkumin pridobivamo iz korenike kurkume (Curcuma longa L.), ki se že tisočletja uporablja v tradicionalni medicini in kot začimba. V zadnjih desetletjih je pritegnil veliko pozornosti zaradi svojega terapevtskega potenciala. Vendar pa slaba topnost in slaba biološka uporabnost omejujeta njegovo terapevtsko uporabo. Topnost je pomembna lastnost substance za razvoj novih formulacij, vendar je v literaturi malo podatkov, ki opisujejo topnost kurkumina v različnih topilih. Kurkumin je občutljiv na svetlobo in se na njej hitro razbarva, zato smo najprej preverili njegovo stabilnost na svetlobi. Ene vzorce smo izpostavili svetlobi, druge pa smo postavili v temo. Analizirali smo vsebnosti kurkumina v različnih časovnih točkah z metodo HPLC in jih primerjali med sabo. Najprej sta bili vsebnosti v vzorcih izpostavljeni svetlobi in temi približno enaki, po devetih dneh pa se je na svetlobi vsebnost v nasprotju s pričakovanji povečala. Določali smo topnost kurkumina v različnih topilih z metodo prenasičenja. Pripravili smo suspenzije pri sobni temperaturi. En vzorec smo analizirali takoj po pripravi in nato po 30 minutah, 1 uri, 2 urah, 4 urah in 24 urah, ostale pa smo stresali na stresalniku 24 ur. Vzorci so bili zaščiteni pred svetlobo. Shranili smo jih v temi in jih kasneje ponovno analizirali. Po določenem času se je koncentracija kurkumina začela zmanjševati, kar kaže na njegovo nestabilnost. Najvišjo doseženo vrednost v posameznem topilu smo določili kot topnost kurkumina. Kurkumin je bil najbolje topen v DMSO (47,18 mg/100 mg raztopine) in podobno tudi v dimetilformamidu (44,45 mg/100 mg raztopine). Zelo dobro topen je bil tudi v acetonu (9,52 mg/100 mg raztopine), v PEG 400 (9,31 mg/100 mg raztopine), trietil citratu (1,52 mg/100 mg raztopine) in triacetinu (0,97 mg/100 mg raztopine). Topen je bil tudi v diklorometanu (0,55 mg/100 mg raztopine), etanolu (0,385 mg/100 mg raztopine) in metanolu (0,370 mg/100 mg raztopine). Nekoliko slabše topen je bil v n butanolu (0,132 mg/100 mg raztopine), dietil etru (0,130 mg/100 mg raztopine), izopropanolu (0,120 mg/100 mg raztopine), propilenglikolu (0,116 mg/100 mg raztopine) in v olju srednjeverižnih trigliceridov (0,117 mg/100 mg raztopine). Najslabše topen je bil v konopljinem olju (0,052 mg/100 mg raztopine), v olivnem olju (0,030 mg/100 mg raztopine) in sončničnem olju (0,030 mg/100 mg raztopine). V heksanu in izo-oktanu pa je bil netopen. Ugotovili smo, da je kurkumin topen v večini organskih topil.

• Language: Slovenian
• Keywords: kurkumin, topnost, saturacijska metoda
• Work type: Master's thesis/paper
• Organization: FFA - Faculty of Pharmacy
• Year: 2024
• PID: 20.500.12556/RUL-162753
• Publication date in RUL: 27.09.2024

Secondary language

• Language: English
• Title: Determination of the curcumin solubility in various solvents by high-performance liquid chromatography

Abstract

The polyphenol curcumin is obtained from the rhizomes of turmeric (Curcuma longa L.), which has been consumed as a dietary spice and used in a traditional medicine for thousands of years. It has attracted a lot of attention in recent decades due to its therapeutic potential. However, poor solubility and bioavailability, limit curcumin’s therapeutic usage. Solubility is an important property of substance for the development of new formulations, but there is little data in the literature describing the solubility of curcumin in different solvents. Curcumin is sensitive to light and quickly discolours, so we first checked its photostability. Some samples were exposed to light, while others were placed in the dark. The curcumin content was analysed at different time points by the HPLC method and compared with each other. Initially, the contents in the samples exposed to light and darkness were approximately the same, but after nine days of light exposure, the content increased, contrary to expectations. Solubility of curcumin was determined in various solvents by the supersaturation method. Suspensions were prepared at room temperature. One sample was analysed immediately after preparation and then after 30 minutes, 1 hour, 2 hours, 4 hours, and 24 hours, while the others were shaken for 24 hours. The samples were protected from light. They were stored in the dark and later reanalysed. After a certain time, the concentration of curcumin started to decrease, which indicates its instability. The highest concentration achieved in each solvent was determined as the solubility of curcumin. Measured solubility was highest in DMSO (47,18 mg/100 mg solution) and similarly in dimethylformamide (44,4 mg/100 mg solution). It was also very soluble in acetone (9,52 mg/100 mg solution), PEG 400 (9,31 mg/100 mg solution), triethyl citrate (1,52 mg/100 mg solution) and triacetin (0,97 mg/100 mg solution). Curcumin was soluble in dichloromethane (0,55 mg/100 mg solution), ethanol (0,384 mg/100 mg solution) and methanol (0,370 mg/100 mg solution). It was slightly less soluble in n-butanol (0,132 mg/100 mg solution), diethyl ether (0,130 mg/100 mg solution), isopropanol (0,120 mg/100 mg solution), propylene glycol (0,116 mg/100 mg solution) and medium-chain triglyceride oil (0,117 mg/100 mg solution). Curcumin was the least soluble in hemp seed oil (0,052 mg/100 mg solution), olive oil (0,030 mg/100 mg solution) sunflower oil (0,030 mg/100 mg solution) and insoluble in hexane and isooctane. We found that curcumin is soluble in most organic solvents.

• Keywords: curcumin, solubility, saturation method