Reproduction of the Caramote prawn, Melicertus kerathurus (Forskål, 1775) (Decapoda, Penaeidae) in Boka Kotorska bay, Montenegro (South-eastern Adriatic)

The aim of this study was to investigate for the first time some aspects of the reproductive activity of the Caramote prawn, Melicertus kerathurus, in Montenegrin waters. This species is considered a target species in the small-scale fishery in Boka Kotorska Bay, being a species of high commercial value. Sampling was carried out on a monthly basis from April 2019 to December 2019 by trammel nets. The spawning season was estimated based on monthly changes in the gonadosomatic index, condition factor and gonadal maturity stages. The main spawning season for females extends from April-May to September, with a clear peak in June. The total sex ratio (males/females) was 1:1. Sexual differences related to the length-weight relationship were noted

pH-Dependent solubility profile of desipramine hydrochloride

pH-dependent solubility profile of Desipramine hydrochloride (Ds.HCl) was studied using pH-ramp shake flask method. First, the pH value of DsHCl stock solution in 0.15 M phosphate buffer was adjusted to 11.7 in order to minimize supersaturation effect. Then, the pH value in separate samples was adjusted downwards with HCl, to prepare solutions in the pH 1.7-11.7 region. After stirring (6 h) and sedimentation (18 h), PTFE (hydrophobic, pore size 0.22 µm) filters or centrifugation were used for phase separation. Concentration was measured using HPLC with UV/Vis detection. The computer program pDISOL-X was used for data processing and refinement of equilibrium constants. Different techniques were used for solid phase characterization

pH-Dependent solubility profile of desipramine hydrochloride

pH-dependent solubility profile of Desipramine hydrochloride (Ds.HCl) was studied using pH-ramp shake flask method. First, the pH value of DsHCl stock solution in 0.15 M phosphate buffer was adjusted to 11.7 in order to minimize supersaturation effect. Then, the pH value in separate samples was adjusted downwards with HCl, to prepare solutions in the pH 1.7-11.7 region. After stirring (6 h) and sedimentation (18 h), PTFE (hydrophobic, pore size 0.22 µm) filters or centrifugation were used for phase separation. Concentration was measured using HPLC with UV/Vis detection. The computer program pDISOL-X was used for data processing and refinement of equilibrium constants. Different techniques were used for solid phase characterization

Razmnožavanje brgljuna, Engraulis encrasicolus (Linnaeus, 1758) u Bokokotorskom zaljevu (Crna Gora, južni Jadran)

The annual alteration of gonad morphology in anchovy, Engraulis encrasicolus (Linnaeus,1758), caught in the period from July 2006 to June 2007 using beach seines in the region of Boka Kotorska Bay (Montenegro, southern Adriatic) was studied. Samples were taken each month. Total length of individuals ranged from 6.6 to 12.2 cm, while weight ranged from 1.58 to 11.27 g, Their ovaries were extracted and weighed, and a piece of female gonad tissue was sampled for histological analysis. The length–weight relationship of all anchovy specimens was described by the equation: (W = 0.0032) (L_T^3.2537; (r^2 = 0.9528)). The lowest GSI values were found in November and remained at low levels until April, which corresponded to the gonad rest stage. The GSI increased gradually during April and May, which coincides with the begining of spawning period. Although primary oocytes (stage I) were present during all months, their percentage increased from October and was the highest during the winter months (November-March 100%). Mature cells, stage IV, were present during April – October period, with highest value in May when they comprised 12.3% of total oocyte number. An increase in the percentage of oocytes in the yolk vesicle (II) and yolk (III) stages occurred in April, remaining almost unchanged until October. Smallest average oocyte size was noticed in period November – February with an average of 59.69 μm, while greatest size was recorded in April 2007, 185.84 μm.U radu su predstavljeni rezultati proučavanja godišnje promjene morfologije gonada kod brgljuna, Engraulis encrasicolus (Linnaeus, 1758) uhvaćenog obalnim mrežama potegačama u razdoblju od srpnja 2006 do lipnja 2007na području Bokokotorskog zaljeva (Crna Gora, južni Jadran). Uzorci inćuna uzimani su mjesečno, sredinom mjeseca. Ukupna dužina jedinki kretala se od 6,6 do 12,2 cm, dok je masa jedinki kolebala od 1,58 do 11,27 g. Kod ženki, jajnicima je nakon vađenja izmjerena masa, a dio tkiva jajnika odvojen za histološku analizu. Dužinsko-maseni odnos svih jedinki brgljuna opisan je jednadžbom (W = 0.0032) (L_T^3.2537; (r^2 = 0.9528)). Najniža vrijednost gonadosomatskog indeksa (GSI), manja od 1, zabilježena je u studenom, a ostala je niska sve do travnja, što odgovara razdoblje odmora gonada. GSI se postupno povećava tijekom travnja i svibnja, što se poklapa sa početkom perioda mrijesta. Iako su primarni oociti (stadij I) bili prisutni u svim mjesecima, njihova postotna zastupljenost u porastu je od listopada, a najviša tijekom zimskih mjeseci (u razdoblju od studenog do ožujka zastupljenost je iznosila 100%). Zrele stanice (stadij IV) bile su prisutne u razdoblju od travnja to listopada, sa najvećom zastupljenošću u svibnju, kada su činile 12,3% ukupnog broja oocita. U travnju se javlja povećanje postotne zastupljenosti oocita u stadijima žumanjčane kesice (II) i žumanjca (III) i ostaje gotovo nepromijenjeno do listopada. Najmanja prosječna veličina oocita zabilježena je tijekom razdoblja od studenog do veljače, kad je iznosila 59.69 μm, dok je najveća zabilježena u travnju 2007., 185.84 μ

pH-Dependent solubility profiles of imipramine and amitriptyline hydrochlorides

The aim of this study was to examine solubility-pH behavior of desipramine structural analogues: imipramine and amitriptyline hydrochlorides. Appearance of aggregates (trimer, around pH 4 in imipramine case), which lead to slow sedimentation, and oil forms make solubility determination extremely challenging. Oils which are more soluble than crystalline forms are formed in alkaline solutions (above pH 7.8 in imipramine case). Sometimes in such cases, pH adjustment in that pH region can be unpredictable. Furthermore, oil sticks to electrode making pH measurement difficult, especially in amitryptiline case. Concentration was measured using HPLC with UV/Vis detection. Different techniques were used for solid phase characterization. Solid phase characterization is particularly important in complicated systems like this

Solubility-pH profile of desipramine hydrochloride in saline phosphate buffer: Enhanced solubility due to drug-buffer aggregates

Although solubility-pH data for desipramine hydrochloride (DsHCl) have been reported previously, the aim of the present study was to critically examine the aqueous solubility-pH behavior of DsHCl in buffer-free and buffered solutions, in the presence of physiologically-relevant chloride concentration, using experimental practices recommended in the recently-published “white paper” (Avdeef et al., 2016). The computer program pDISOL-X was used to design the structured experiments (pH-RSF method), to process the data, and to refine the equilibrium constants. Low-to-high and high-to-low pH assays (using HCl, H 3 PO 4 , or NaOH to adjust pH) were performed on phosphate-buffered (0.12‑0.15 M) saturated solutions of DsHCl in the pH 1.3–11.6 range. After equilibration (stirring 6 h, followed by 18 h stir-free sedimentation), filtration or centrifugation was used for phase separation. Concentration was measured using HPLC with UV/VIS detection. The 2:1 drug-phosphate solubility product (K sp 2:1 = [DsH + ] 2 [HPO 4 2− ]) was determined from data in the pH 4–9 region. The free base of desipramine was prepared and used to determine the K sp 1:1 ([DsH + ][H 2 PO 4 − ]) in chloride-free acidified suspension. In addition, phosphate-free titrations were conducted to determine the intrinsic solubility, S 0 , and the 1:1 drug-chloride solubility product, K sp DsH [rad] Cl = [DsH + ][Cl − ]. Under the assay conditions, only the phosphate-free solutions showed some supersaturation near pH max 8.0. In phosphate-containing solutions, pH max was indicated at higher pH (8.8–9.6). Oils mixed with solids were observed to form in alkaline solutions (pH > 11). Notably, soluble drug-phosphate complexes appeared to form below pH 3.9 and above pH max in saturated phosphate‑containing saline solutions. This was indicated by the systematic pH shift to higher values in the log S-pH curve in alkaline solution than expected from the Henderson-Hasselbalch equation. For pH < 3.9, saturated phosphate-containing saline solutions exhibited elevated solubility, with drug-hydrochloride as the sole precipitate. Salt solubility products, intrinsic solubility, and complexation constants, which rationalized the data, were determined. Elemental, thermogravimetric (TGA), differential scanning calorimetric (DSC), and powder X-ray diffraction (PXRD) analyses were used to characterize the precipitates isolated from suspensions at different pH.This is the peer-reviewed version of the following article: Marković, O. S.; Pešić, M. P.; Shah, A. V.; Serajuddin, A. T. M.; Verbić, T. Ž.; Avdeef, A. Solubility-PH Profile of Desipramine Hydrochloride in Saline Phosphate Buffer: Enhanced Solubility Due to Drug-Buffer Aggregates. European Journal of Pharmaceutical Sciences 2019, 133, 264–274. [https://doi.org/10.1016/j.ejps.2019.03.014]Supplementary material: [http://cherry.chem.bg.ac.rs/handle/123456789/2926

Dnevni naraštajni prstenovi u otolitima i stopa rasta juvenilnog inćuna, Engraulis encrasicolus (Linnaeus, 1758), u jugoistočnom Jadranu

Daily growth rate of juvenile anchovy, Engraulis encrasicolus (Linnaeus, 1758), was estimated in the south-eastern Adriatic Sea. Samples were taken by a commercial beach seine net and the size range of 100 sampled individuals was 5.0-6.8 cm total length. Age was estimated by counting growth increments of sagittal otoliths, which are formed with daily periodicity. Estimated ages were 41- 90 days and hatch date for each age class was back-calculated from the date of capture. The calculated instantaneous growth rate was 0.41 mm day-1. Fish size at metamorphosis from late larva to juvenile was estimated to 3.2 cm total length. Parameters of the von Bertalanffy’s growth function were L∞ = 10.41 and K = 3.36Dnevna stopa rasta juvenilnog inćuna, Engraulis encrasicolus (linnaeus, 1758), procijenjena je u jugoistočnom Jadranu. Uzorci su sakupljani komercijalnom obalnom mrežom potegačom, a raspon veličine kod 100 uzorkovanih jedinki iznosio je 5.0-6.8 cm ukupne dužine. dob je procijenjena brojenjem dnevnih naraštajnih prstenova na sagitalnim otolitima. Procijenjena starost kolebala je između 41- 90 dana, a nadnevak izvaljivanja ličinke za svaki starosni razred bio je naknadno izračunat prema datumu ulova. Izračunata trenutna stopa rasta iznosila je 0.41 mm dan -1. Veličina ribe za vrijeme metarmofoze iz kasnog stadija ličinke u juvenilni stadij procijenjena je na 3.2 cm ukupne dužine. Parametri u von Bertalanffy-jevoj jednadžbi rasta bili su L∞ = 10.41 i K = 3.36

Primena postupka elektrostatičke ekstruzije pri dobijanju alginatnih čestica malih dimenzija sa imobilisanim ćelijama pivskog kvasca

In beer brewing with immobilized yeast cells it is very important to minimize the mass transfer resistance, problem associated with large diameter beads, because the mass transfer limitations may force the cells to alter their metabolic states and thus, impact the efficiency of fermentation process and quality of final beer. Internal mass transfer can be optimized by adjusting the immobilization matrix size, texture and porosity. The classical dripping method, that is commonly used to produce gel beads, has a limitation in the large diameter of the produced beads, which is typically 2 to 3 mm. In recent time other techniques have been developed to produce smaller particles of equal size. The major objective of this study was to optimize the bead size by using the new technique, electrostatic droplet generation. We have obtained promising results since in this way it was possible to produce very small uniform microbeads (in the diameter range of several hundreds of micrometers to 2 mm) under stable conditions. The size of beads was strongly influenced by applied potential, needle size and electrode distance.Pri primeni imobilisanih ćelija kvasca u fermentaciji piva važno je, kako sa aspekta produktivnosti sistema, tako i sa aspekta hemijskog sastava piva, da se otpori prenosu mase supstrata i proizvoda metabolizma ćelija unutar matrice nosača svedu na najmanju moguću meru. Ovo se može postići podešavanjem veličine, teksture i poroznosti matrice nosača. Obzirom da klasična tehnika imobilizacije kvasca u matrici Ca-alginata daje čestice većih dimenzija (prečnika od 2 do 3 mm), danas je razvijeno vise različitih tehnika koje pružaju mogućnost dobijanja čestica malih dimenzija. Jedna od novih tehnika, čije su mogućnosti primene u cilju optimizacije veličine alginatnih čestica ispitivane u sklopu ovog istraživanja, je postupak elektrostatičke ekstruzije. Dobijeni rezultati su pokazali daje primenom ove tehnike moguće dobiti kontrolisanu i stabilnu proizvodnju mikro čestica uniformne veličine, čiji se prečnik kretao u rasponu od nekoliko stotina mikrometara do 2 mm, u zavisnosti od primenjene razlike potencijala, prečnika igle i rastojanja između elektroda

Study of equilibria in heterogeneous systems of tricyclic antidepressant amitriptyline

Cilj ovog rada bio je proučavanje ravnoteža u heterogenim sistemima tricikličnog antidepresiva amitriptilina (Am) koji sadrže hloride i/ili fosfate. Rastvorljivost Am u uslovima povećane jonske sile određena je pH–Ramp shake–flask metodom. Veća rastvorljivost Am u kiseloj sredini od očekivane, posledica je agregacije – analiza eksperimentalnih podataka pomoću programa pDISOL–XTM ukazuje na verovatno građenje pentamera Am5H5 5+. Kritična micelarna koncentracija i stepen disocijacije agregata određeni su primenom konduktometrijskih titracija. U baznoj sredini primećena je delimična degradacija Am. Eksperimentalno dobijeni podaci o rastvorljivosti biološki aktivnih supstanci i postojećim ravnotežama u heterogenim sistemima važni su u svim fazama dizajna i razvoja lekova.The aim of this work was to study the equilibria in tricyclic antidepressant amitriptyline (Am) heterogeneous systems containing chloride and/or phosphate ions. Solubility of Am in high ionic strength conditions was determined using pH–Ramp shake–flask method.1, 2 Higher solubility of Am than expected in an acidic media is a consequence of self-aggregation – pentamer formation (Am5H5 5+) according to pDISOL–XTM analysis. Critical micelle concentration and the degree of the aggregate dissociation were determined by conductometric titrations. Partial degradation of Am in alkaline suspensions was observed. Experimental studies of solubility as well as the existing equilibria in heterogeneous systems of biologically active compounds are important at all stages of drug design and development