Biopharmaceutical characterization of levothyroxine sodium immediate-release tablets

Nakon oralne primene, koja za pacijente često predstavlja najprihvatljiviji put uzimanja lekovitog preparata, lek je izložen mnogobrojnim fizičkim, hemijskim i biološkim promenama koje definišu njegovu sudbinu u organizmu. Koncept biološke raspoloživosti i biološke ekvivalencije je upravo i razvijen sa ciljem da objasni i kvantifikuje ove promene. Bioekvivalencija lekova postoji u slučajevima kada su dva preparata farmaceutski ekvivalentna i kada je njihova bioraspoloživost, nakon primene u istom molarnom odnosu, slična u tolikoj meri da će njihovo dejstvo u organizmu, uzimajući u obzir efikasnost i neškodljivost, biti isto. Sa uvođenjem Biofarmaceutskog sistema klasifikacije lekova, koji se bazira na pretpostavci da su rastvorljivost, brzina rastvaranja i permeabilnost ključni faktori koji utiču na resorpciju leka, omogućeno je korišćenje testa brzine rastvaranja kao zamene za in vivo ispitivanje bioekvivalencije (biowaiver koncept). Kako je resorpcija leka veoma kompleksan proces, koji se često teško može kvantifikovati konvencionalnom farmakokinetičkom analizom, poslednjih godina je došlo do razvoja većeg broja in silico modela koji na osnovu kombinacije odgovarajućih farmakokinetičkih, fizičko-hemijskih i fizioloških parametara omogućavaju predviđanje ovog procesa. Cilj ovog rada je bila biofarmaceutska karakterizacija razvojne formulacije tableta sa trenutnim oslobađanjem levotiroksin-natrijuma i razvoj biorelevantnog testa za ispitivanje brzine rastvaranja kroz izvođenje odgovarajućih in vivo, in vitro i in silico studija. U okviru in vitro ispitivanja je sprovedena karakterizacija levotiroksin-natrijuma u pogledu rastvorljivosti i brzine rastvaranja iz tableta pri različitim eksperimentalnim uslovima. U okviru in vivo studije je sprovedeno ispitivanje biološke ekvivalentnosti izabranih preparata u grupi zdravih ispitanika oba pola, u vidu randomizovane, dvostruko ukrštene studije, nakon primene odgovarajuće doze leka. Određivanje farmakokinetičkih parametara je vršeno sa korekcijom i bez korekcije koncentracije levotiroksina u odnosu na endogeni nivo. Za in silico predviđanje resorpcije levotiroksina korišćena je metoda gastrointestinalne simulacije u okviru GastroPlusTM softvera...The oral route of drug administration is the most convenient and, for patients, the most acceptable method for administering drugs intended to have systemic effects. After oral administration, drugs are exposed to many physical, chemical and biological alterations, which define their in vivo performance. The concept of bioavailability and bioequivalence has been developed in order to describe and quantify these alterations. Bioequivalence is a comparison of the bioavailability of two or more drug products. Thus, two products or formulations containing the same active ingredient are bioequivalent if their rates and extents of absorption are the same. Utilisation of in vitro dissolution tests as a surrogate for in vivo bioequivalence studies (biowaiver) was introduced with the Biopharmaceutics classification system, based on the assumption that drug solubility, permeability and dissolution rate from the dosage form are critical factors influencing the rate and extent of oral drug absorption. Oral drug absorption is complex process which cannot be always easily evaluated by the conventional pharmacokinetic analysis. Therefore, the in silico prediction tools capable of predicting in vivo drug absorption on the basis of drug physicochemical and pharmacokinetic properties have been developed recently. The aim of this research was biopharmaceutical characterization of the levothyroxine sodium immediate-release tablets based on the results of in vivo, in vitro and in silico studies. The in vitro study included determination of levothyroxine sodium solubility and evaluation of effect of various experimental conditions on levothyroxine sodium release from immediate-release tablets. The in vivo study was conducted as randomized, single dose, two-way cross-over bioequivalence study in healthy subjects. Pharmacokinetic parameters were calculated without and with adjustment for baseline levels of endogenous levothyroxine. The drug-specific absorption model for levothyroxine was developed using mechanistic gastrointestinal simulation technology implemented in GastroPlusTM software package. The required input parameters were experimentally determined, in silico predicted and/or taken from the literature. The profile obtained was compared with the mean levothyroxine plasma concentration-time profile observed in vivo for the reference formulation..

DIFFERENCES IN EXPLOSIVE STRENGTH OF ELITE FEMALE HANDBALL PLAYERS DURING THE COMPETITION SEASON

The aim of our research was to determine the explosive strength of the legs i.e., the height of the jump of the top-ranked female handball players during the season. 15 female players underwent the following tests for estimating the explosive strength of the legs: SJ, CMJ, CMJ free arm, CMJ right leg and CMJ left leg. The Student’s t-test was applied for establishing the changes between the measuring sessions during the season. The results obtained show that there were statistically significant changes and better results at the end of the season in the following parameters: CMJ right leg =.002 and CMJ left leg = .018, whereas no significant changes occurred in all the other two-leg jumps. Taking into consideration the fact that in performing different throws and goal shooting the most prominent movements in handball are done on one leg, the results were expected. It is recommended that throughout the season the training process should include additional exercises for improving and maintaining the ability of the handball players to jump (plyometric, proprioceptive and the combination of the two with the common strength improving exercises), since their positive effects have been proven by quite a few studies

THE EXPLOSIVE POWER OF THE LOWER LIMBS IN BASKETBALL AND HANDBALL PLAYERS

Basketball and handball are sports which require almost the same physical abilities. Since horizontal jumps and vertical jumps are the predominant elements of the game in both sports, their successful realization depends on the explosive power of the lower limbs. The aim of this research was to determine the significance of the differences of the explosive power of the lower limbs in basketball and handball players. Thirty participants took part in the research, 15 basketball and 15 handball players, all from Niš. A set of six variables was applied for evaluating the horizontal (3 Hop Test, One Leg Triple Jump and Standing Long Jump Test) and vertical jump (Bosko-Abalakov Jump- CMJ, Vertical Jump - run up and single leg take off and Squat Jump - SJ). The results of the univariate analysis of a single variable (ANOVA) show that basketball players achieved statistically better results in the vertical jump tests, whereas handball players did better in the horizontal jump tests

An Investigation into the Influence of Experimental Conditions on In Vitro Drug Release from Immediate-Release Tablets of Levothyroxine Sodium and Its Relation to Oral Bioavailability

The aim of this study was to investigate the influence of experimental conditions on levothyroxine sodium release from two immediate-release tablet formulations which narrowly passed the standard requirements for bioequivalence studies. The in vivo study was conducted as randomised, single-dose, two-way cross-over pharmacokinetic study in 24 healthy subjects. The in vitro study was performed using various dissolution media, and obtained dissolution profiles were compared using the similarity factor value. Drug solubility in different media was also determined. The in vivo results showed narrowly passing bioequivalence. Considering that levothyroxine sodium is classified as Class III drug according to the Biopharmaceutics Classification System, drug bioavailability will be less sensitive to the variation in its dissolution characteristics and it can be assumed that the differences observed in vitro in some of investigated media probably do not have significant influence on the absorption process, as long as rapid and complete dissolution exists. The study results indicate that the current regulatory criteria for the value of similarity factor in comparative dissolution testing, as well as request for very rapid dissolution (more than 85% of drug dissolved in 15 min), are very restricted for immediate-release dosage forms containing highly soluble drug substance and need further investigation. The obtained results also add to the existing debate on the appropriateness of the current bioequivalence standards for levothyroxine sodium products

DIFFERENCES IN AGILITY AND EXPLOSIVE POWER OF BASKETBALL PLAYERS IN RELATION TO THEIR POSITIONS ON THE TEAM

Basketball is a sports game which consists of rapid changes in direction of movement, sudden stopping and starting for driving and dribbling and a great number of jumps. The various positions on a basketball team precisely determine the requirements for specific forms of movement, even though contemporary basketball strives for all players in all positions to possess the aforementioned abilities. A sample of 15 male basketball players, divided into three groups of five players each, based on their positions on the team, including the guard, forward and center position, was used to determine differences in agility (Agility T Test, Hexagon Agility Тest, Illinois Agility Test и Lane Agility Drill) and explosive power (the Squat jump, Countermovement Jump, Drop Jump and One-legged Counter Movement Jump). To determine the differences between the basketball players in relation to their positions on the team, the ANOVA analysis for independent samples was used as was a post-hoc analysis. The research results have indicated that there is a difference between the guard position compared to the forward and center position

Osobine mezenhimskih matičnih ćelija izolovanih iz periferne krvi i Vartonove sluzi pupčane vrpce

Introduction. Mesenchymal stem cells (MSCs) are a promising tool for regenerative medicine, but due to the heterogeneity of their populations, different sources and isolation techniques, the characteristics defining MSCs are inconsistent. Objective. The aim of this study was to compare the characteristics of MSCs derived from two different human tissues: peripheral blood (PB-MSCs) and umbilical cord Wharton's Jelly (UC-MSCs). Methods. The PB-MSC and UC-MSC were isolated by adherence to plastic after gradient-density separation or an explant culture method, respectively, and compared regarding their morphology, clonogenic efficiency, proliferating rates, immunophenotype and differentiation potential. Results. MSCs derived from both sources exhibit similar morphology, proliferation capacity and multilineage (osteogenic, chondrogenic, adipogenic and myogenic) differentiation potential. Differences were observed in the clonogenic capacity and the immunophenotype, since UC-MSCs showed higher CFU-F (colony-forming units-fibroblastic) cloning efficiency, as well as higher embryonic markers (Nanog, Sox2, SSEA4) expression. When additional surface antigens were analyzed by flow cytometry (CD44, CD90, CD105, CD33, CD34, CD45, CD11b, CD235a) or immunofluorescent labeling (vimentin, STRO-1 and α-smooth muscle actin), most appeared to have similar epitope profiles irrespective of MSC source. Conclusion. The results obtained demonstrated that both MSCs represent good alternative sources of adult MSCs that could be used in cell therapy applications.Uvod. Mezenhimske matične ćelije (MMĆ) su posebno značajne za regenerativnu medicinu. S obzirom na heterogenost njihovih populacija, raznovrsnost izvora i tehnika izolacije, ne postoje jedinstvena obeležja koja određuju MMĆ. Cilj rada. Cilj ove studije bila je uporedna analiza bioloških karakteristika MMĆ izolovanih iz periferne krvi (PK-MMĆ) i Vartonove (Wharton) sluzi pupčane vrpce (VSP-MMĆ). Metode rada. PK-MMĆ i VSP-MMĆ su izolovane na osnovu osobine da prianjaju na plastičnu podlogu, a upoređivane su njihove morfološke odlike, klonogeni i proliferativni kapacitet, imunofenotip i potencijal diferencijacije. Rezultati. Dobijeni rezultati pokazali su da oba tipa MMĆ imaju slične morfološke osobine, sličan proliferativni kapacitet i multipotentni potencijal diferencijacije u ćelije različitih mezenhimskih tkiva (koštanog, masnog, hrskavičavog i mišićnog). Razlike su primećene u klonogenom kapacitetu i imunofenotipu, budući da su VSP-MMĆ ispoljile veći kapacitet za formiranje CFU-F (engl. colony-forming unit-fibroblasts), kao i veću ekspresiju markera tipičnih za embrionalne matične ćelije (Nanog, Sox2, SSEA4). Ispitivanje površinskih antigena tipičnih za MMĆ (CD44, CD90, CD105, CD33, CD34, CD45, CD11b, CD235a) protočnom citometrijom i imunofluorescentno obeležavanje dodatnih mezenhimskih markera (Vimentin, STRO-1 i alfa-aktina glatkih mišićnih ćelija) nije ukazalo na razlike u ekspresiji ovih markera. Zaključak. Oba tipa MMĆ su pogodan alternativni izvor adultnih MMĆ koje bi se mogle koristiti u ćelijskoj terapiji

Urokinase type plasminogen activator mediates Interleukin-17-induced peripheral blood mesenchymal stem cell motility and transendothelial migration

Mesenchymal stem cells (MSCs) have the potential to migrate toward damaged tissues increasing tissue regeneration. Interleukin-17 (IL-17) is a proinflammatory cytokine with pleiotropic effects associated with many inflammatory diseases. Although IL-17 can modulate MSC functions, its capacity to regulate MSC migration is not well elucidated so far. Here, we studied the role of IL-17 on peripheral blood (PB) derived MSC migration and transmigration across endothelial cells. IL-17 increased PB-MSC migration in a wound healing assay as well as cell mobilization from collagen gel. Concomitantly IL-17 induced the expression of urokinase type plasminogen activator (uPA) without affecting matrix metalloproteinase expression. The incremented uPA expression mediated the capacity of IL-17 to enhance PB-MSC migration in a ERK1,2 MAPK dependent way. Also, IL-17 induced PB-MSC migration alongside with changes in cell polarization and uPA localization in cell protrusions. Moreover, IL-17 increased PB-MSC adhesion to endothelial cells and transendothelial migration, as well as increased the capacity of PB-MSC adhesion to fibronectin, in an uPA-dependent fashion. Therefore, our data suggested that IL-17 may act as chemotropic factor for PB-MSCs by incrementing cell motility and uPA expression during inflammation development

Interleukin 17 inhibits myogenic and promotes osteogenic differentiation of C2C12 myoblasts by activating ERK1,2

The present study evaluated the role of interleukin (IL) 17 in multilineage commitment of C2C12 myoblastic cells and investigated associated signaling pathways. The results concerning the effects on cell function showed that IL-17 inhibits the migration of C2C12 cells, while not affecting their proliferation. The data regarding the influence on differentiation demonstrated that IL-17 inhibits myogenic differentiation of C2C12 cells by down-regulating the myogenin mRNA level, myosin heavy chain expression and myotube formation, but promotes their osteogenic differentiation by up-regulating the Runt-related transcription factor 2 mRNA level, cyclooxygenase-2 expression and alkaline phosphatase activity. IL-17 exerted these effects by activating ERK1,2 mitogen activated protein kinase signaling pathway, which in turn regulated the expression of relevant genes and proteins to inhibit myogenic differentiation and induce osteogenic differentiation. Additional analysis showed that the induction of osteogenic differentiation by IL-17 is independent of BMP signaling. The results obtained demonstrate the potential of IL-17 not only to inhibit the myogenic differentiation of C2C12 myoblasts but also to convert their differentiation pathway into that of osteoblast lineage providing new insight into the capacities of IL-17 to modulate the differentiation commitment

Enkapsulacija nanolipozoma bioaktivnim proteinima magarećeg mleka i mogućnost primene u dermatologiji i kozmetologiji

Nanoliposomes represent natural or synthetic nanoparticles made of phospholipids, which may spontaneously aggregate in an aqueous medium. Their use in dermatology and for cosmetic purposes may offer facilitated delivery in skin via enhanced opening of the tight junctions between the epithelial cell monolayers. As far as their use in dermatology is concerned, both transdermal and local application may offer successful release profile. Donkey milk may have special therapeutic properties when used in cosmetology for skin treatment. The aim of our study was to establish encapsulation efficacy of nanoliposome loaded with skimmed donkey milk and to explore the efficiency of encapsulation of different skimmed donkey milk concentrations in nanoliposomes. In our experimental study, it was documented that 1%, 2% and 5% solutions of skimmed donkey milk were almost equally effectively encapsulated, more than 80% in 1% solution of nanoliposomes, while 10% solution of skimmed donkey milk was encapsulated more efficiently, with 88.9% in 1% of nanoliposome solution. Encapsulation can lead to greater efficiency by enabling the use of lower administration doses and preventing the corresponding side effects, which may be the result of higher doses. Skimmed donkey milk is a suitable encapsulation solution.Nanolipozomi predstavljaju prirodne ili sintetske nanočestice sačinjene od fosfolipida koje mogu spontano da agregiraju u vodenoj sredini. Njihova upotreba u dermatologiji i u kozmetičke svrhe može omogućiti ubrzanu aplikaciju i prodiranje u kožu jer dolazi do lakšeg otvaranja spojeva između epitelnih ćelija. Kada je u pitanju korišćenje u dermatologiji, i transdermalna i lokalna aplikacija su veoma efikasne. Magareće mleko se pokazalo kao potencijalno veoma korisno kada se koristi u kozmetičke svrhe za tretman kože. Cilj ove studije bio je da se ispita efikasnost enkapsulacije nanolipozoma, koji su tretirani obezmašćenim magarećim mlekom, kao i da se ispita koliki je kapacitet enkapsulacije u uslovima različitih korišćenih koncentracija mleka. U našoj eksperimentalnoj studiji pokazano je da je 1%, 2% i 5% rastvora obezmašćenog magarećeg mleka gotovo jednako efikasno enkapsulirano i to više od 80%, kada se koristila koncentracija od 1% nanolipozoma, dok je 10% rastvora obezmašćenog magarećeg mleka bilo još efikasnije enkapsulirano i to čak 88,9%, kada se koristila koncentracija nanolipozoma od 1%. Enkapsulacija supstanci u nanolipozome je proces koji omogućava korišćenje manjih doza potrebnih supstanci, što dovodi do manje šanse da se pojave štetni efekti u poređenju sa većim dozama. Obezmašćeno magareće mleko je rastvor koji je veoma pogodan za metodu enkapsulacije nanolipozoma