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Development and validation of chromatographic method for the determination of diclofenac in water
No full textValidacija, tj. vrednovanje svih bitnih postupaka analitičkog sustava, predstavlja prvi korak kojim se određuje i dokumentira prikladnost analitičkog sustava za određenu namjenu. Kako bi validirali analitički sustav potrebno je ispitati izvedbene značajke kao što su: linearnost, točnost, specifičnost/selektivnost, granicu detekcije i granicu kvantifikacije, robusnost, radno područje, preciznost i osjetljivost. Cilj ovoga rada bio je osmisliti i validirati kromatografsku metodu za određivanje farmaceutika diklofenaka u izvorskoj i MilliQ vodi te se upoznati s izvedbenim značajkama analitičkog sustava. U ovome je radu opisana priprema otopina diklofenaka u izvorskoj i MilliQ vodi te je analiza provedena na tekućinskom kromatografu visoke učinkovitosti uz detektor s nizom dioda (HPLC-DAD). Rezultati analize potvrdili su da je ispitana kromatografska metoda valjana za određivanje diklofenaka u vodi jer su gotovo sve izvedbene značajke zadovoljile kriterij.Validation, i.e., evaluation of all relevant procedures of the analytical system, represents the first step to determining and documenting the suitability of the analytical system for a specific purpose. Performance parameters such as linearity, accuracy, specificity/selection, limit of detection and limit of quantitation, robustness, work area, precision, and sensitivity need to be examined to validate. This work aims to develop and validate a chromatographic method for the determination of diclofenac in spring water and MilliQ water and become familiar with the performance parameters of the analytical system. In this work, the preparation of diclofenac solutions in spring water and MilliQ water is described. The analysis was performed on a high-performance liquid chromatograph coupled to a diode array detector (DAD). The research results have confirmed that the tested method is acceptable for the determination of diclofenac in water because almost all parameters met the criterion
Development of a UHPLC method for the determination of elvitegravir using quality by design principles and Fusion QbD software
No full textCilj ovog rada bio je razviti i validirati analitičku metodu za određivanje aktivnog farmaceutskog sastojka, elvitegravira te njegovih poznatih onečišćenja prema načelima kvalitete ugrađene u dizajn. Razvoj analitičkih metoda svakako je važan korak u procesu razvoja i proizvodnji lijekova. On zauzima ključnu ulogu u daljnjim proizvodnim procesima kroz sve faze životnog ciklusa lijeka. Stoga je važno da razvijena analitička metoda bude pouzdana, precizna, robusna i selektivna. Princip kvalitete ugrađene u dizajn pruža nam brojne benefite nad tradicionalnim pristupom, a njegovim prihvaćanjem kontinuirano poboljšavamo robusnost proizvodnog procesa, kvalitetu proizvoda i produktivnost. U ovom radu, slijedeći principe kvalitete ugrađene u dizajn te korištenjem programa Fusion AETM uspješno je razvijena i optimirana kromatografska metoda. Razvijena metoda je validirana čime je dokazana njena prikladnost za određivanje elvitegravira.The aim of this study was to develop and validate an analytical method for the determination of the active pharmaceutical ingredient, elvitegravir and its known impurities according to the principles of quality by design. The development of analytical methods is certainly an important step in the process of drug development and production. It plays a key role in further production processes through all stages of the drug life cycle. Therefore, the developed analytical method must be reliable, accurate, robust and selective. The principle of quality by design provides us with numerous benefits over the traditional approach and by accepting it, we continuously improve the robustness of the production process, product quality and productivity. In this paper, following the principles of quality by design and using the Fusion AETM software, the chromatographic method was successfully developed and optimized. The developed method was validated, which proved its applicability for the determination of elvitegravir
Procedures for recycling perovskite photovoltaic cells
No full textPerovskitne fotonaponske ćelije izazvale su interes zbog visoke učinkovitosti pretvorbe sunčeve energije u električnu. Princip kružnog gospodarstva zahtijeva definiranje postupaka zbrinjavanja i recikliranja proizvoda i prije njihove upotrebe, te će se u ovom radu opisati pojedini postupci recikliranja perovskitnih ćelija kako bi se uspješno približile tržištu. Postupci su opisani na različitim konfiguracijama perovskitnih fotonaponskih ćelija te su međusobno uspoređeni. Prikazano je kako se perovskitni sloj može ukloniti i reciklirati na nekoliko načina i iskoristiti za sintezu novih ćelija te time spriječiti ispuštanje toksičnog olova u okoliš. Prisutne skupe materijale kao što su staklena podloga s nanesenim slojem metalnog oksida ili sloj za transport šupljina moguće je ponovno upotrijebiti, dok se elektroda od zlata ili srebra može prikupljati na dva načina: iz otopine ili ljepljivom trakom. Razmotreni postupci recikliranja se temelje na upotrebi različitih otapala koja su kancerogena ili toksična te utječu na zdravlje živih organizama i na okoliš, stoga njihovo korištenje zahtijeva moguće recikliranje ili pravilno zbrinjavanje za razvoj industrijskih postupaka recikliranja.Perovskite photovoltaic cells have attracted great attention due to the high power conversion efficiency of solar energy into electricity. The principle of the circular economy requires the definition of product disposal and recycling procedures even before their use, so in this paper, the potential recycling procedures for perovskite cells are described to successfully accelerate their transition into the market. The recycling procedures are described and compared according to different configurations of the perovskite photovoltaic cells. It is shown how a perovskite layer can be removed and recycled in several ways and used for the synthesis of a new cell, which also prevents the release of toxic lead into the environment. Expensive materials such as metal-oxide-coated glass substrate or hole transport layer can be reused, while gold or silver electrodes can be collected in two ways: from solution or with adhesive tape. The recycling procedures under consideration are based on the use of various solvents that are carcinogenic or toxic and affect the health of living organisms and the environment, therefore their use requires possible recycling or proper disposal for the development of industrial recycling procedures
Coulomb's law demonstrated with augmented reality
No full textIz svakodnevnog života poznato je da se djelovanje između dva nabijena tijela odvija bez vidljivog posrednika (npr. ako se balon trlja po kosi, počet će privlačiti vlasi, na isti način natrljani komad stakla privlačit će vunu itd.), prva takva zapažanja zabilježena su 600 godina prije nove ere. Ono što se tada nije znalo, a danas je poznato, je da se takva djelovanja pripisuju postojanju dvaju električnih naboja koji su nazvani pozitivnim i negativnim. Također je poznato da se istoimeni naboji odbijaju, a raznoimeni privlače. U popunjenom atomu svakog elementa broj pozitivnih i negativnih naboja je jednak, a između njih djeluju električne sile. Tijelo je električki neutralno kada su svi atomi popunjeni elektronima, tada izvan atoma nema električnog djelovanja. Pri određenim uvjetima neki elektroni iz valentne ljuske atoma mogu se odvojiti i smjestiti se u prazni prostor između ostalih atoma. To se odvija i tijekom, već spomenutog, trljanja staklenog štapa vunom, točnije, s površine stakla neki se elektroni istrgnu i ostanu na vuni. Na taj način stakleni štap postaje pozitivno naelektriziran, jer ima višak pozitivnog naboja, a vuna negativno naelektrizirana, jer ima višak otrgnutih elektrona. Višak pozitivnog naboja na štapu miruje kao i višak negativnog naboja na vuni. Tako stvoreni višak naboja zove se statički naboj, a grana fizike koja se bavi proučavanjem pojava između električki nabijenih čestica, elektrostatika. Prva kvantitativna istraživanja između dvaju naelektriziranih tijela proveo je Charles de Coulomb, eksperimentalno na torzijskoj vagi. Te je došao do zaključka, danas poznatog kao Coulombov zakon, koji glasi: „Dva se mirna električna naboja odbijaju ili privlače silom koja je razmjerna umnošku njihovih naboja, a obrnuto je razmjerna kvadratu njihove udaljenosti.“. Obzirom da je izvedba torzijske vage vrlo zahtjevna i teško izvediva u učionicama, što se odnosi i na mnoge druge eksperimente koji su tijekom povijesti provedeni u svrhu otkrivanja raznih fizikalnih zakona, u nastavi se koriste isključivo matematička objašnjenja. Takav način predavanja, ali i učenja je vrlo nezahvalan zbog nemogućnosti vizualizacije često apstraktnih pojmova. U svrhu boljeg razumijevanja, ali i potencijalno veće zainteresiranosti učenika i studenata za gradivo fizike, sve se više uvode aplikacije koje koriste tehnologije poput proširene stvarnosti. Takva je i aplikacija CoulombsLawAR. Vrednovanje njene korisnosti, koje je karakteristično za aplikacije te vrste, provedeno je među studentima prve godine prijediplomskog studija Fakulteta kemijskog inženjerstva i tehnologije u obliku ankete koja se sastojala od četiri dijela (SUS, HARUS, UX upitnici te otvorena pitanja), a dobiveni rezultati pokazuju zadovoljstvo ispitanika. Sveukupan dojam je pozitivan, aplikacija je pomogla studentima u razumijevanju gradiva, no potrebno je ukloniti neke tehničke poteškoće.It is known from everyday life that the action between two charged bodies takes place without a visible intermediary (e.g. if a balloon is rubbed on the hair, it will begin to attract hairs, in the same way a rubbed piece of glass will attract wool, etc.), the first such observations were recorded in 600 years BC. What was not known then, and is known today, is that such actions are attributed to the existence of two electric charges, which are called positive and negative. It is also known that charges of the same name repel, and charges of different names attract. In a filled atom of each element, the number of positive and negative charges is equal and electric forces act between them. A body is electrically neutral when all atoms are filled with electrons and then there is no electrical activity outside the atoms. Under certain conditions, some electrons from the valence shell of an atom can be separated and placed in the empty space between other atoms. This also takes place during the already mentioned rubbing of the glass rod with wool, more precisely; some electrons remain on the wool after being torn off the surface of the glass. In this way, the glass rod becomes positively electrified, because it has an excess of positive charge, and the wool becomes negatively electrified, because it has an excess of torn electrons. The excess positive charge on the stick is at rest, as is the excess negative charge on the wool. The excess charge thus created is called static charge, and the branch of physics that deals with the study of phenomena between electrically charged particles is called electrostatics. Charles de Coulomb conducted the first quantitative research between two electrified bodies, experimentally on a torsion balance. He concluded that two stationary electric charges repel or attract each other with a force proportional to the product of their charges, and inversely proportional to the square of their distance – Coulomb’s Law. Given that, the execution of the torsion balance is very demanding and difficult to perform in classrooms, which also applies to many other experiments that have been conducted throughout history for discovering various physical laws, that is the reason why in classes professors are using only mathematical explanations. This way of teaching and learning is very ungrateful due to the impossibility of visualizing often-abstract concepts. For the purpose of better understanding, but also potentially greater interest of pupils and students in physics material, more and more applications that use technologies such as augmented reality, are being introduced. Such is the application of CoulombsLawAR. The evaluation of its usability, which is characteristic for applications of this type, was carried out among first-year undergraduate students of the Faculty of Chemical Engineering and Technology in the form of a survey consisting of four parts (SUS, HARUS, UX questionnaires and open-ended questions). The obtained results show the satisfaction of the respondents. The overall impression is positive, the application helped students in understanding the material, but some technical difficulties need to be removed
Mechanochemical modification of drug properties
No full textDjelatna tvar X koristi se za ciljanu terapiju zloćudnih bolesti i pokazuje svojstvo slabe topljivosti u vodenom mediju i niske bioraspoloživosti. Navedeno rezultira usporenim farmakološkim djelovanjem i nedovoljnom efikasnošću pri liječenju zloćudnih novotvorevina. S ciljem povećanja njezine topljivosti pripravljene su čvrste disperzije djelatne tvari u matrici hidrofilnog polimera, poli(vinil-pirolidona), zelenom metodom mehanokemijske priprave mljevenjem u vibracijskom kugličnom mlinu. Pripremljene čvrste disperzije karakterizirane su metodama analize koje mogu ukazati na potencijalan pomak u topljivosti djelatne tvari: diferencijalnom pretražnom kalorimetrijom, infracrvenom spektroskopijom s Fourierovim transformacijama, rendgenskom difrakcijskom analizom praha te metodom kontaktnog kuta. U pripravi tableta promjera 8 mm korištene su pripravljene čvrste disperzije, a kao pomoćne tvari korišteni su manitol, natrijeva kroskarmeloza te poli(etilen-glikol). Karakterizacija tableta podrazumijevala je ispitivanje tvrdoće, testiranje njihove raspadljivosti te određivanje sadržaja djelatne tvari. In vitro ispitivanjima testirano je otapanje djelatne tvari te su utvrđeni profili njezina oslobađanja iz tableta. Mehanokemijskim tretmanom ostvarena je amorfizacija svih uzoraka. Rezultati ovog istraživanja pokazuju da se ova specifična djelatna tvar X može mehanokemijski aktivirati u smislu poboljšanja njezinih svojstva topljivosti.Drug X is used for the targeted therapy of malignant diseases and shows the property of low aqueous solubility and thus low bioavailability. The aforementioned results in slowed down pharmacological action and insufficient efficiency in the treatment of malignant neoplasms. To increase its solubility, solid dispersions of the drug in a matrix of hydrophilic polymer poly(vinyl pyrrolidone) were prepared using the principles of green chemistry by co-grinding in a vibrational ball mill. The prepared solid dispersions were characterized by methods that can indicate improved dissolution properties: differential scanning calorimetry, Fourier-transformed infrared spectroscopy, X-ray powder diffraction analysis and by the method of contact angle. Tablets with 8 mm in diameter were prepared using solid dispersions, and mannitol, sodium croscarmellose and poly(ethylene glycol) as excipients. Characterization of tablets implied testing hardness, its disintegration and detecting the drug content. Drug dissolution and its release profiles were detected as well using in vitro dissolution tests. Amorphization was achieved by mechanochemical treatment for all samples. The results of this research show that this specific drug X can be activated mechanochemically in terms of improving its solubility properties
Fatty acid ethyl ester production in microreactor systems
No full textU ovom radu, postavljeni ciljevi su usmjereni na 3D-ispis mikroreaktora sa statičkim miješalicama, s namjerom potvrde njihove primjenjivosti u proizvodnji biodizela i dokazivanja prednosti upotrebe statičkih miješalica u poboljšanju procesa miješanja i, sukladno tome, uspješnosti reakcije. U tu svrhu, aditivnom proizvodnjom tj. tehnologijom digitalne obrade svjetlom izrađeni su mikroreaktori sa statičkim miješalicama te je provedena analiza utjecaja različitih geometrija kanala i vremena zadržavanja na konverziju, kojom je definirana uspješnost reakcije. U eksperimentalnom dijelu, 3D-ispisana su dva tipa mikroreaktora: jedan sa statičkim miješalicama u obliku dva srca, a drugi sa statičkim miješalicama u obliku srca i pregradama. Reakcijom transesterifikacije provela se sinteza etilnih estera viših masnih kiselina, a protok reaktanata bio je osiguran korištenjem dviju injekcijskih pumpi. Identifikacija i karakterizacija dobivenih produkata izvršena je metodom toplinske analize, odnosno diferencijalnom pretražnom kalorimetrijom i metodom infracrvene spektroskopije s Fourierovim transformacijama, koja je omogućila određivanje konverzije. Dobiveni rezultati potvrđuju da su 3D-ispisani mikroreaktori prikladni za proizvodnju biodizela, s najvećom konverzijom postignutom u mikroreaktoru sa statičkim miješalicama u obliku dva srca pri najdužem definiranom vremenu zadržavanja. Ovim istraživanjem ostvareni su zadani ciljevi, a istodobno je pružen detaljniji uvid u primjenu statičkih miješalica u mikroreaktorskim sustavima za proizvodnju biodizela.In this study, the set objectives were focused on 3D printing of microreactors with static mixers, with the intention of confirming their applicability in biodiesel production and demonstrating the benefits of static mixers in improving the mixing process and, consequently, reaction efficiency. To achieve these goals, microreactors with static mixers were made by additive manufacturing, i.e. digital light processing technology, while analyzing the impact of different channel geometries and retention times on conversion, which defined the success of the reaction. In the experimental part, two types of microreactors were 3D printed: one with static mixers shaped like two hearts, and the other with static mixers and baffles. Synthesis of fatty acid ethyl esters was carried out by the transesterification reaction, and the flow of reactants was ensured using two syringe pumps. Identification and characterization of the obtained products were performed using thermal analysis, particularly differential scanning calorimetry, and Fourier-transform infrared spectroscopy, allowing for determination of conversion. The results obtained confirm that the developed microreactors are highly suitable for biodiesel production, with the highest conversion achieved in the microreactor with static mixers shaped like two hearts at the longest defined retention time. This research accomplishes the outlined objectives and provides insight in the understanding of the application of static mixers in microreactor systems for biodiesel production
Investigation of photocatalytic removal of amoxicillin by Fe2O3/TiO2 immobilized on glass support
No full textPrisutnost farmaceutika u vodenom okolišu negativno utječe na ekosustav te je potrebno pronaći efikasan način uklanjanja istih. Fotokatalitička razgradnja onečišćivala na poluvodičima je napredna oksidacijska tehnologija koja omogućuje potpunu mineralizaciju tvari. Uz prisutnost energije u obliku vidljive svjetlosti, fotokatalizator u vodenoj otopini generira radikalne vrste koje ulaze u procese oksidacije onečišćenja. U ovom radu ispitano je uklanjanje amoksicilina kao onečišćenja iz vodene otopine. Amoksicilin je farmaceutik koji se zbog prekomijernog korištenja akumulirao u okolišu i teško se uklanja. Fotokatalizator korišten za ispitivanje uklanjanja amoksicilina je kompozit Fe2O3 i TiO2 imobiliziran na stakleni nosač. Pripravljeni su fotokatalizatori različitog masenog udjela Fe2O3 (1%-20%), provedena je karakterizacija strukture fotokatalizatora XRD metodom, a zatim je ispitan utjecaj omjera njihovih masa na proces razgradnje amoksicilina. Kao najefikasniji, pokazao se 5% - Fe2O3/TiO2 koji nakon 3 900 minuta postiže 99% razgradnju amoksicilina. Kako bi se smanjilo vrijeme trajanja reakcije, isti eksperiment proveden je uz dodatak oksidansa peroksodisulfata. Za određivanje utjecaja razgradnih produkata na okoliš, proveden je test toksičnosti na bakteriji Vibrio fischeri.The presence of pharmaceuticals in the aquatic environment negatively affects the ecosystem and it is necessary to find an efficient way to remove them. Photocatalytic degradation of pollutants on semiconductors is an advanced oxidation technology that enables complete mineralization of substances. Visible light can activate the photocatalyst in water solution and non-selective radicals are formed that are starting reaction of oxidation of amoxicillin. The photocatalyst used is a composite of Fe2O3 and TiO2 immobilized on a glass plate. Photocatalysts consist of a different mass fraction of Fe2O3 (1%-20%). Characterization of photocatalyst structures was carried out using the XRD method. Also, the influence of their mass ratio on the process of amoxicillin degradation was examined.
5% - Fe2O3/TiO2 is proved to be the most effective one. After 3900 minutes of reaction,
it converts 99% of amoxicilin. For reducing the duration of the reaction, the same experiment was carried out with the addition of peroxodisulfate as an oxidant. To determine the impact of degradation products on the environment, a toxicity test was tested on Vibrio fischeri
The influence of the crystal shape on the properties of the active pharmaceutical ingredient
No full textVećina djelatnih tvari proizvodi se u krutom obliku te je kristalizacija od iznimnog značaja za farmaceutsku industriju. Jedna od metoda koja poboljšava granulometrijska svojstva kristala je sferična kristalizacija u kojoj nastaju sferični kristali što smanjuje broj koraka pri formulaciji lijeka. Svrha ovog rada bila je različitim procesima odrediti sustav otapala za provedbu sferične kristalizacije te ispitati utjecaj različitih hidrodinamičkih uvjeta na granulometrijska svojstva dobivenih kristala. Uvjeti za provedbu sferične kristalizacije određeni su za djelatnu tvar ceritinib koja se koristi u liječenju raka pluća nemalih stanica. Kao dio preliminarnih eksperimenata, za odabir kapljevine za premoštenje koristio se programski sustav Dynochem. Odabrani sustav sadrži otapalo THF, vodu koja se koristi kao antiotapalo, kapljevinu za premoštenje heptan i polimer PVP (polivinilpirolidon) kao dodatak. Kako bi se ispitao utjecaj procesnih uvjeta na granulometrijska svojstva dobivenih kristala, provedena je njihova karakterizacija tijekom procesa te nakon sušenja. Analiza granulometrijskih svojstava određena je raspodjelom veličine čestica koja je dobivena metodom laserske difrakcije, morfologija kristala ispitana je optičkim elektronskim mikroskopom, a njihova struktura metodom difrakcije rendgenskih zraka.Most of the active substances are produced in solid form, and crystallization is extremely important for the pharmaceutical industry. One of the methods that improves the granulometric properties of crystals is spherical crystallization, in which spherical crystals are formed, which reduces the number of steps in drug formulation. The purpose of this work was to determine the solvent system for spherical crystallization using different processes and to examine the influence of different hydrodynamic conditions on the granulometric properties of the obtained crystals. The conditions for the implementation of spherical crystallization are determined for the active substance ceritinib, which is used in the treatment of non-small cell lung cancer. As part of the preliminary experiments, the Dynochem software system was used to select the bridging fluid. The chosen system contains the solvent THF, water used as an antisolvent, the bridging liquid heptane and the polymer PVP (polyvinylpyrrolidone) as an additive. In order to examine the influence of process conditions on the granulometric properties of the obtained crystals, their characterization was carried out during the process and after drying. The analysis of granulometric properties was determined by the particle size distribution obtained by the laser diffraction method, the morphology of the crystals was examined by an optical electron microscope, and their structure by the X-ray diffraction method
Monitoring of enzyme stability by measuring protein size distribution
No full textN-acetilneuraminska kiselina (Neu5Ac) je sijalična kiselina čiju sintezu katalizira enzim N-acetilneuraminat sintaza. N-acetilmanozamin (MaNAc) kondenzacijom s fosfoenolpiruvatom (PEP) daje N-acetilneuraminsku kiselinu (Neu5Ac). Za potrebe ovog rada enzim je pripremljen i pročišćen. Prekomjerna ekspresija proteina neuB, koji kodira N-acetilneuraminat sintazu, postignuta je ubacivanjem plazmida u genetski modificirane stanice Escherichia coli. Bakterijske stanice razbijene su ultrazvukom i pročišćene centrifugiranjem. Dobiveni enzim pročišćen je u koloni s niklom i nitrilotrioctenom kiselinom i skladišten u odgovarajućem puferu na 4°C. Stabilnost enzima sintaze N-acetilneuraminske kiseline (NeuS) je praćena preko specifične aktivnosti, raspodjele veličina čestica i koncentracije proteina.N-acetylneuraminic acid (Neu5Ac) is a sialic acid whose synthesis is catalyzed by the enzyme N-acetylneuramine synthase. N-acetylmannosamine (MaNAc) by condensation with phosphoenolpyruvate (PEP) gives N-acetylneuraminic acid (Neu5Ac). For the purposes of this work the enzyme was prepared and purified. Overexpression of the protein neuB, which encodes N-acetylneuramine synthase, was achieved by inserting the plasmid into genetically modified Escherichia coli cells. Bacterial cells were disrupted by ultrasound and purified by centrifugation. The resulting enzyme was purified in a column with nickel and nitrilotriooctenoic acid and stored in the appropriate buffer at 4°C. The stability of N-acetylneuraminate synthase (NeuS) enzyme was monitored through specific activity, particle size distribution and protein concentration