Određivanje Septalen® pastila primenom derivativne spektrofotometrije

In this paper, a second-derivative spectrophotometric method of assaying Septalen® pellets (Krka, Novo Mesto, Slovenia), which contain lidocaine 1 mg, and cetrimoniumbromide 2 mg, is described. Lidocaine, 2-(diethylamino)-N-(2,6-dimethyl-phenyl)-acetamide, is a local anesthetic with pronounced antiarhythmic and anticonvulsant properties. Cetrimoniumbromide, N,N,N-trimethyl-l-hexadecanaminium bromide, is a topical antiseptic and cleansing agent. Lidocaine was determined at 250 nm using the "zero crossing" technique because the signals of centrimonium bromide and the colour ingredient are zero at this wavelength. Cetrimonium bromide was determined by correction of the peak amplitude at 215 nm according to lidocaine. In choosing the optimal magnitudes for the simultaneous determination of both drugs, the following criteria were considered: (1) the linearity of the calibration graphs as given by the correlation coefficients, (2) the intercept, (3) the sensitivity as given by the regression coefficient, (4) the degree of interference in the derivative measurement by the presence of the other compound, as given by the relative percent error and by the relative recovery, and (5) the reproducibility, as given by the coefficient of variation, calculated by recording the second-derivative spectra.U ovom radu opisana je derivativna spektrofotometrija izvoda drugog reda za određivanje Septalen® pastila (Krka, Novo Mesto, Slovenija), koje sadrže lidokain 1 mg, i cetrimonijum-bromid 2 mg. Lidokain, 2-(dietilamino)-N-(2,6-dimetil-fenil)-acetamid, je lokalni anestetik sa izrazitim antiaritmičnim i antikonvulzivnim osobinama. Cetrimonijum-bromid, N,N,N-trimetil-1-heksadekanaminijum-bromid je površinski antiseptik i agens za čišćenje. Lidokain je određivan na talasnoj dužini od 250 nm korišćenjem metode "nultog preseka", jer su signali za cetrimonijum-bromid i boju bili nula na toj talasnoj dužini. Cetrimonijum-bromid je određivan metodom korekcije na 215 nm u odnosu na lidokain. Prikazani su rezultati određivanja aktivnih komponenti Septalen® pastila u prisustvu boje ili sa prethodnim obezbojavanjem. Pod izabranim eksperimentalnim uslovima određeni su i sledeći kriterijumi za optimizaciju predložene derivativne spektrofotometrijske metode: (1) linearnost kalibracione krive data je korelacionim koeficijentom, (2) presek sa ordinatom, (3) osetljivost je data regresionim koeficijentom, (4) uticaj prisustva ostalih komponenti na derivativna merenja dat je relativnom greškom i "recovery" vrednošću i (5) reproduktivnost je data koeficijentom varijacije

Određivanje sadržaja pseudoefedrina, paracetamola i askorbinske kiseline u peroralnom prašku primenom reverzno-fazne tečne hromatografije

For the simultaneous analysis of multicomponent mixture containing pseudoephedrine, paracetamole and ascorbic acid two RP-HPLC methods were developed. Separation were performed on Hewlett Packard 1100 system which consisted of HP 1100 binary pump, HP 1100 UV/VIS detector and HP ChemStation for the automatic data evaluation. Methods were developed, e. g. chromatographic conditiond settled, methods submited to method validation and then applied for the determination of content of multicomponent powder.The best separation was achived on Platinium Alltech Amino 150 x 4.6 mm, 5 mm particle size column, at 30°C. Injection volume was 20mL. Mobile phase in mehtod I was a mixture of methanol-water (30:70 V/V), pH 2.5, and in mehtod II was a mixture methanol-water (60:40 V/V), pH 2.9. pH of the mobile phases were adjusted with 85% ortophosphoric acid. Detection was performed at 214 nm in mehtod I and at 257 nm in method II. Flow rate was 1 mLmin-1. Developed methods were validated. Obtained results showed that both methods are suitable for routine analysis of pharmaceutical dosage forms which contain pseudoephedrine, paracetamole and ascorbic acid.Za istovremenu analizu trokomponentne smeše koja sadrži pseudoefedrin, paracetamol i askorbinsku kiselinu postavljene su dve metode reverzno-fazne tečne hromatografije pod visokim pritiskom (RP-HPLC). Hromatografski sistem Hewlett Packard 1100 koji čini HP 1100 binarna pumpa, HP 1100 UV-VIS detektor i HP ChemStation za automatsku obradu podataka korišćen je za hromatografsko razdvajanje. Postupak je obuhvatio definisanje hromatografskih uslova, validaciju postavljenih metoda, kao i njihovu primenu za ispitivanje sadržaja pseudoefedrina, paracetamola i askorbinske kiseline u peroralnom prašku. Optimalna separacija postignuta je u koloni Platinium Alltech Amino 150 mm x 4,6 mm, 5 mm veličine čestica, na temperaturi kolone od 30°C. Volumen injektovanja bio je 20 mL. Mobilna faza u metodi I bila je smeša metanol-voda (30:70 V/V), pH vrednost podešena na 2,5, a u metodi II smeša metanol-voda (60:40 V/V), pH vrednost podešena na 2,9. pH mobilne faze je podešavan sa 85%-tnom orto-fosfornom kiselinom. Talasna dužina detekcije bila je 214 nm u metodi I i 257 nm u metodi II. Protok mobilne faze za obe metode bio je 1 mL min-1. Postavljene metode su validirane i na osnovu dobijenih parametara procenjeno je da obe predložene metode mogu da se primene za analizu peroralnog praška koji sadrži paracetamol, pseudoefedrin i askorbinsku kiselinu

Analitika hidrokortizon-acetata u mastima za oči primenom reverzno-fazne tečne hromatografije pod visokim pritiskom

In this paper the reversed-phase high performance liquid chromatographic method (RP-HPLC) was applied for the determination of hydrocortisone acetate in eye ointment. Analysis were performed on the chromatographic system Hewlett Packard 1100 which consisted of a HP 1100 pump, HP 1100 UV-VIS Detector and HP ChemStation integrator. Separations were performed on a Bio-Sil C18 250 mm x 4,6 mm, 5µm particle size column at 30.5 °C. The samples were introduced through a Rheodyne injector valve with a 20 µL sample loop. Methanol - water (75:25 V/V) was used as a mobile phase, at flow rate 1.15 mL/min and pH was adjusted to 4.0 with ortophosphoric acid. UV detection was performed at 254 nm. Mometasone furoate was used as an internal standard. Developed RP-HPLC method was validated and all the validation parameters of the method are given. The proposed method is rapid, accurate, selective and because of its sensitivity and reproducibility, it may be used in routine control of pharmaceutical dosage forms which contain hydrocortisone acetate.Postavljena je metoda reverzno-fazne tečne hromatografije pod visokim pritiskom (RP-HPLC) za analizu hidrokortizon-acetata u mastima za oči. Analiza je izvršena na hromatografskom sistemu Hewlett Packard 1100 koji čine HP 1100 binarna pumpa, HP 1100 UV-VIS detektor i HP ChemStation za automatsku obradu podataka. Postupak je obuhvatio izbor odgovarajućih hromatografskih uslova, izbor pogodnog postupka ekstrakcije hidrokortizon-acetata iz masti, kao i validaciju metode. Za hromatografsku analizu odabrana je kolona Bio-Sil C18 250 mm x 4,6 mm, 5µm veličine čestica, termostatirana na 30,5°C. Volumen injiciranja bio je 20 µL. Mobilnu fazu činila je smeša metanol?voda (75 : 25 V/V) čiji je pH podešen na 4,0 sa 85%-tnom ortofosfatnom kiselinom. Protok mobilne faze bio je 1,15 ml/min., a talasna dužina detekcije 254 nm. Kao interni standard korišćen je mometazon-furoat. Postavljena RP-HPLC metoda je validirana, tj. ispitana je robusnost, selektivnost, linearnost, tačnost, preciznost - ponovljivost i određeni su limit detekcije i limit kvantifikacije. Kako je predložena metoda pouzdana i robusna može se koristiti u rutinskoj analizi doziranih oblika koji sadrže hidrokortizon-acetat

Razvoj hromatografskih metoda za analizu sulfametoksazola, trimetoprima, njihovih degradacionih proizvoda i konzervanasa u sirupu

In this paper the experimental conditions for optimal reversed-phase liquid chromatographic (RP-HPLC) determination of sulfamethoxazole, trimethoprim and preservatives, as well as degradation products of sulfamethoxazole and trimethoprim in syrup were defined. The determination of active compounds and preservatives was carried out on Zorbax Eclipse XDB-C18, 150 mm × 4.6 mm, 5 μm particle size column, mobile phase flow rate was 1.5 mL min-1, and detection at 235 nm for the active compounds and 254 nm for preservatives. Mobile phase A consisted of 150 mL of acetonitrile, 850 mL of water and 1 mL of triethanolamine (pH 5.90 adjusted with diluted acetic acid), while mobile phase B was acetonitrile. The mobile phase ratio was defined by the gradient program. For the determination of degradation products Zorbax Eclipse Plus C18, 100 mm x 4.6 mm, 3.5 μm particle size column was used, the mobile phase flow rate was 0.5 mL min-1 and detection at 210 nm for 3,4,5-trimethoxybenzoic acid and 254 nm for sulfanilic acid and sulfanilamide. Mobile phase A was 50 mM potassium dihydrogenphosphate (pH 5.60 adjusted with a 0.5 mol L-1 potassium hydroxide), while mobile phase B was acetonitrile. The mobile phase ratio was defined by the gradient program. Through the validation of the developed methods their efficiency and reliability is confirmed and consequently the adequacy for the routine control.U ovom radu prikazano je definisanje eksperimentalnih uslova i optimizacija metoda reverzno-fazne tečne hromatografije (RP-HPLC) za određivanje sulfametoksazola, trimetoprima i konzervanasa, odnosno degradacionih proizvoda sulfametoksazola i trimetoprima u sirupu. Određivanje sadržaja aktivnih komponenti i konzervanasa vršeno je na koloni Zorbax Eclipse XDB-C18, 150 mm × 4,6 mm, 5 μm veličine čestica, protok mobilne faze bio je 1,5 mL min-1, dok je detekcija vršena na 235 nm za aktivne komponente i 254 nm za konzervanse. Mobilna faza A sastojala se od smeše 150 mL acetonitrila, 850 mL vode i 1 mL trietanolamina (pH 5,9 podešen razblaženom sirćetnom kiselinom), a kao mobilna faza B korišćen je acetonitril. Odnos mobilnih faza tokom analize definisan je programom gradijenta. Određivanje sadržaja degradacionih proizvoda vršeno je na koloni Zorbax Eclipse Plus-C18, 100 mm × 4,6 mm, 3,5 μm veličine čestica, uz protok mobilne faze od 0,5 mL min-1 i detekciju na 210 nm za 3,4,5-trimetoksibenzojevu kiselinu i 254 nm za sulfanilnu kiselinu i sulfanilamid. Mobilna faza A bila je 50 mM kalijum-dihidrogenfosfat (pH 5,60 podešen sa 0,5 mol L-1 kalijum-hidroksidom), a mobilna faza B bio je acetonitril. Odnos mobilnih faza tokom analize definisan je programom gradijenta. Validacijom postavljenih metoda potvrđeno je da su efikasne i pouzdane, i kao takve pogodne za rutinsku kontrolu

Teachers’ views of inclusive education in Serbian schools

This study was conducted to determine the attitudes of teachers concerning inclusion in schools all over Serbia. The respondents were teachers of different subjects who were tasked to anonymously complete the provided closed-type questionnaire (970 respondents). Primary and secondary school teachers from urban and rural areas of the Republic of Serbia participated in the research. The results indicate that the teachers are supportive of inclusion. Despite significant differences in respondents’ answers, the results of the research show that there are many similarities in teacher responses toward inclusive education. The results show that it is still necessary to work on the implementation of inclusive education in Serbia, especially to educate the teaching staff and involve experts in the planning and development of individual educational plans.Keywords: attitudes; inclusive education; Serbia; teacher

Central Composite Design with/without Artificial Neural Networks in Microemulsion Liquid Chromatography Separation Robustness Testing

In past few years, for overcoming some analytical problems in liquid chromatography, the microemulsion as eluent was employed. Due to the strict regulatory requirements, robustness testing became important especially when proposing completely new method such as microemulsion liquid chromatography (MELC). In this paper robustness testing of MELC method, proposed for carbamazepine and its impurities (iminostilben and iminodibenzyl) separation, was done using two different approaches both based on experiments defined using central composite design (CCD). Input and output data from CCD were either handled as second order polynomials and tested with Analysis of variance (ANOVA), or as variables in Artificial Neural Networks (ANN). From both approaches appropriate conclusions about system robustness were distinguished, e. g. that the influence of surfactant content on chromatographic retention was the largest for all analytes, meaning that small changes in its concentration will strongly influenced on chromatographic retention. On the other hand influence of the pH of the mobile phase proved to be negligible, meaning that the substances are mainly distributed in the interfacial layer. ANN gave better results and proved to be better tool for explanation and understanding of investigated factors effects on the chromatographic system and for definition of the robustness limits

Pharmacy students' perspectives on online lectures during the COVID – 19 pandemic – case study from the University of Belgrade.

Synchronous lectures tend to be used as the prevalent method of online instruction, irrespective of notable differences and obvious limitations when compared to their in-person delivery. Study aim was to assess students’ perspective on online lectures held during the emergency remote teaching (ERT) due to COVID-19 pandemic. Method: Students were invited to take part in online survey related to their experience with ERT. Survey included 25 items related to: satisfaction (14 items), motivation (3 items), interaction with peers and lecturers (4 items), and perceived challenges (4 items). A 5-point Likert scale was employed. Statistical analysis was performed using the SPSS software. Results: A total of 387 students participated in the survey. Majority of respondents (79.3%) were junior students. Among them, 72.6% reported no previous experience with online learning. Although relatively high level of satisfaction was reported (mean score 3.91±0.75), challenges were also scored relatively high (3.05±0.99), while interaction was scored somewhat lower (2.98±0.73), and the least mean score was observed for motivation (2.73±0.58). Students reported having trouble to keep motivation, concentration and focus during online lectures, which usually took long hours per day. Interaction with peers was reported as unsatisfactory (2.48±1.46), whereas it was more feasible with lecturers (3.24±1.42). Students were quite satisfied with the possibility to organize their time flexibly (71.4%), and with respect to the workload (54.5%), while they were less convinced that online sessions provide enough opportunities to reflect on what has been learnt (50,1% agree, 25,1% neither agree nor disagree). Conclusions: The results obtained indicate that students are somewhat hesitant with respect to online lectures as the main mode of instruction. Lectures, generally, place students in a passive role, which is further increased in online delivery. In order to support students’ engagement and success, online lectures should be combined with more active instructional strategies.ORAL PREVIEW (usmena prezentacija)Link to the Pharmacy Education version [https://farfar.pharmacy.bg.ac.rs/handle/123456789/4381

Modeling the Geography Class through Problem-Based Teaching: a Case Study from Novi Sad, Serbia

The idea of problem-based teaching, i.e. learning through solving problems, is not a new one, but has been fairly neglected in the teaching process. The aim of this research is to consider the possibility of applying this learning model in teaching geography in primary and grammar schools. This teaching model was proposed for the presentation of the teaching unit Australia and Oceania, in the framework of the thematic unit Political/Geographic, Demographic and Economic/Geographic Features of Certain Parts of the World. The model implies group work. The expected successful outcome of the applied teaching model has been verified by the results of a survey and the scores achieved in the knowledge test. The study contains the entire course of the experimental teaching of the unit Australia and Oceania by applying problem-based teaching, and presents and analyzes the results achieved. The classes were modelled by relying on Hill-Slater′s model. A t-test was used for the statistical analysis of data in order to test the hypothesis on differences in the arithmetic mean. The choice and application of the statistical mathematical procedure are determined by the nature of the phenomenon which is the subject of this research. The software packages Mathematica and Excel were used in order to statistically analyze data and to draw tables and graphs

Evaluation of Seven Chromatographic Response Functions on Simulated and Experimentally Obtained Chromatograms in Hydrophilic Interaction Liquid Chromatography System

This paper investigates the ability of seven chromatographic response functions to measure the quality of chromatograms obtained in hydrophilic interaction liquid chromatography (HILIC). First, the functions were tested on a set of simulated chromatograms and differences in their mathematical design were discussed. Second, the functions were evaluated on the experimentally obtained chromatograms in HILIC analysis of model mixture consisted of beta agonists and antagonists. The ranking of chromatograms obtained by different functions was significantly different, implying that the accuracy of the optimization procedure is strongly dependent on the function that was selected as an output. Investigation of potential drawbacks of each function was conducted and general recommendations concerning the use of chromatographic response functions in optimization strategies are proposed.This is peer-reviewed version of the following article: Rakić, T.; Stojanović, B. J.; Jovanović, M.; Malenović, A.; Ivanović, D.; Medenica, M. Evaluation of Seven Chromatographic Response Functions on Simulated and Experimentally Obtained Chromatograms in Hydrophilic Interaction Liquid Chromatography System. Anal. Lett. 2013, 46 (8), 1198–1212. [https://doi.org/10.1080/00032719.2012.755689