Povećana isporuka etopozida u Daltonov limfom u miševa pomoću micela s polisorbatom 20

The study evaluates the possibility of enhancing uptake of etoposide (topoisomerase II inhibitor) by tumor when delivered through Polysorbate 20 micelles. The micelle formation was ascertained by determining the critical micellar concentration (CMC) with a du Nouy ring tensiometer and by size measurement using dynamic light scattering. Addition of 5% ethanol decreased the CMC of Polysorbate 20 (from 5.0 x 10-5 to 4.54 x 10-5 mol L-1). Etoposide (ET) and etoposide loaded Polysorbate 20 micelles (EPM) were radiolabeled with 99mTc by the reduction method using stannous chloride. Labeling parameters were optimized to obtain high labeling efficiency. The diethylenetriamine pentaacetic acid and cysteine challenge tests showed very low transchelation of 99mTc-ET and 99mTc-EPM complexes indicating their in vitro stability. The complexes also exhibited serum stability assessed by ascending thin layer chromatography. Subcutaneous injection of EPM resulted in significantly higher tumor uptake (~ 100 folds compared to ET 6 h post injection) (p < 0.001) and prolonged tumor retention. Tumor uptake was also confirmed by gamma imaging studies. EPM exhibited relatively high brain concentrations (~7 fold 24 h post injection) compared to ET, suggesting the potential use of EPM in the treatment of brain malignancies.U radu je proučavan ulazak etopozida (inhibitora topoizomeraze II) u tumorsko tkivo iz micela s polisorbatom 20. Oblikovanje micela je potvrđeno određivanjem kritične micelarne koncentracije (CMC) pomoću du Nouy kružnog tenziometra i mjerenjem veličine čestica metodom rasapa svjetlosti. Dodatak 5% etanola smanjuje CMC polisorbata 20 (od 5,0 x 10-5 do 4,54 x 10-5 mol L-1). Etoposid (ET) i micele etoposida s polisorbatom 20 (EPM) obilježene su radioizotopom 99mTc redukcijom pomoću kositrova klorida. Parameteri markiranja su optimirani. Testovi s dietilentriamin pentaoctenom kiselinom i cisteinom pokazali su vrlo nisko transkeliranje 99mTc-ET i 99mTc-EPM kompleksa, što ukazuje na njihovu stabilnost u uvjetima in vitro. Uzlaznom tankoslojnom kromatografijom dokazana je i stabilnost kompleksa u serumu. Nakon subkutane primjene EPM isporuka etopozida u tumorsko tkivo bila je značajno veća (~ 100 puta u odnosu na ET 6 h poslije injiciranja) (p < 0,001), a dokazano je i produljeno zadržavanje EPM u tumoru. Ulazak u tumor je potvrđen i gama analizom slike. EPM je postigao relativno visoku koncentraciju u mozgu u usporedbi s ET (~ 7 puta veću 24 h poslije injiciranja), zbog čega bi se potencijalno mogao upotrijebiti u terapiji malignih tumora mozga

Utjecaj načina polimerizacije i eksperimentalnih varijabli na veličinu čestica i brzinu oslobađanja metotreksata iz poli(butilcijanoakrilata)

Poly(butylcyanoacrylate) nanoparticles were prepared by dispersion polymerization (DP) and emulsion polymerization (EP) of n-butyl cyanoacrylate monomer. The particles were characterized by infrared spectroscopy, differential scanning calorimetry, X-ray diffractometry and transmission electron microscopy. Particle properties such as size and zeta potential were determined for nanoparticles prepared by DP and EP techniques and compared. EP technique resulted in a low particle size compared to the DP. A high zeta potential was observed for nanoparticles prepared by the DP method. Incorporation of methotrexate resulted in a decrease in zeta potential in both types of nanoparticles, the decrease being greater in DP nanoparticles. Effect of experimental variables such as monomer concentration, polymerization time and temperature on drug entrapment and particle size was studied. Both types of nanoparticles showed an increase in drug entrapment with increased monomer concentrations. Variable polymerization time did not influence the drug entrapment of EP nanoparticles. Polymerization at 60 ± 2 °C resulted in a decrease of drug entrapment and a great increase in the particle size of both types of nanoparticles. In vitro drug release studies showed a comparatively high release of methotrexate from DP nanoparticles suggesting the channelizing effect of dextran chains incorporated into nanoparticles during polymerization. Though the release profiles of nanoparticles appeared similar, a significant difference in release rates was found for DP and EP nanoparticles in 0.1 mol L-1 HCl and pH 7.4 phosphate buffer (p < 0.01). Drug release data indicate that the release of methotrexate from DP and EP nanoparticles followed Fickian diffusion in 0.1 mol L-1 HCl, while the mechanism was found anomalous in pH 7.4 phosphate buffer. An effort was also made to critically correlate the properties of nanoparticles synthesized by the above two techniques, and emphasize the importance of these characteristics in targeted drug delivery.Priređene su nanočestice poli(butilcijanoakrilata) disperzijskom (DP) i emulzijskom polimerizacijom (EP) n-butyl-cijanoakrilata. Čestice su karakterizirane IR spektroskopijom, diferencijalnom pretražnom kalorimetrijom, difraktometrijom X-zračenjem i transmisijskom elektronskom mikroskopijom. Uspoređivana je veličina i zeta potencijal nanočestica dobivenih na oba načina. Nanočestice priređene EP metodom bile su manje nego čestice dobivene DP metodom, a čestice priređene DP metodom imale su visoki zeta potencijal. Uklapanje metotreksata smanjilo je zeta potencijal u obje vrste nanočestica, naročito u DP nanočesticama. Proučavan je utjecaj eksperimentalnih varijabli (koncentracija monomera, vrijeme polimerizacije i temperatura) na uklapanje ljekovite tvari i veličinu čestica. Povećanje koncentracije monomera kod obje vrste čestica povećalo je uklapanje ljekovite tvari. Produljenje vremena polimerizacije nije utjecalo na količinu uklopljenog metotreksata u EP nanočesticama. Povišenjem temperature na 60 2 C smanjilo se uklapanje, a povećao promjer obje vrste nanočestica. In vitro studije pokazale su značajno oslobađanje metotreksata iz DP nanočestica, što upućuje na nastanak kanalića uslijed ugradnje lanaca dekstrana u nanočestice tijekom polimerizacije. Iako se profili oslobađanja metotreksata čine sličnim, značajne razlike između DP i EP nanočestica uočene su u otopini kloridne kiseline koncentracije 0,1 mol L-1 i fosfatnom puferu pH 7,4 (p 0,01). Oslobađanje ljekovite tvari pratilo je Fickov zakon difuzije u 0,1 mol L-1 HCl, dok je u puferu pH 7,4 mehanizam bio anomalan. Pokušalo se dovesti u korelaciju svojstva nanočestica priređenih na oba načina i naglasiti važnost tih svojstava u ciljanoj isporuci ljekovitih tvari

Colon delivery of 5 – Fluoro uracil using cross-linked chitosan microspheres coated with eudragit S 100

5-Fluorouracil though recommended as a chemotherapeutic agent for colorectal cancer, suffers from severe systemic toxicity and so needs site-specific delivery. Objective of present investigation is to design slow release enteric coated solid formulations to avoid drug release in stomach and upper small intestine but slowly to build up required drug concentration in the colon. Chitosan microspheres were prepared by emulsification method using gluteraldehyde as cross linking agent. The microspheres were then coated with Eudragit S – 100 by emulsion solvent evaporation method. The coated microspheres were characterized for particle size, entrapment efficiency and surface characteristics. In-vitro drug release profile was studied by changing pH media as per USP protocol and the data was subjected to kinetic interpretations. The optimized microspheres showed particle size in the range of 62 to 65 μm with 65 ± 2% drug entrapment. Eudragit coated chitosan microspheres showed particle size increase upto 390 ± 2 μm with nearly spherical shape and smooth surface. In vitro drug release profile of uncoated microspheres was typical like conventional dosage forms with 38 %, 62 % and 88 % drug release at the end of 2 hrs, 6 hrs and 10 hrs respectively. Coated microspheres showed no drug release in SGF (2hrs), negligible release (8 %) in 6hrs but substantial release of 95% in 24 hours in simulated colon media. Drug distribution in GI following oral administration of coated microspheres in wistar rats showed 84% of the drug accumulation in colon.Keywords: 5-FU; colon-targeting; chitosan; microspheres; Eudragit S-100

Povećana isporuka etopozida u Daltonov limfom u miševa pomoću micela s polisorbatom 20

The study evaluates the possibility of enhancing uptake of etoposide (topoisomerase II inhibitor) by tumor when delivered through Polysorbate 20 micelles. The micelle formation was ascertained by determining the critical micellar concentration (CMC) with a du Nouy ring tensiometer and by size measurement using dynamic light scattering. Addition of 5% ethanol decreased the CMC of Polysorbate 20 (from 5.0 x 10-5 to 4.54 x 10-5 mol L-1). Etoposide (ET) and etoposide loaded Polysorbate 20 micelles (EPM) were radiolabeled with 99mTc by the reduction method using stannous chloride. Labeling parameters were optimized to obtain high labeling efficiency. The diethylenetriamine pentaacetic acid and cysteine challenge tests showed very low transchelation of 99mTc-ET and 99mTc-EPM complexes indicating their in vitro stability. The complexes also exhibited serum stability assessed by ascending thin layer chromatography. Subcutaneous injection of EPM resulted in significantly higher tumor uptake (~ 100 folds compared to ET 6 h post injection) (p < 0.001) and prolonged tumor retention. Tumor uptake was also confirmed by gamma imaging studies. EPM exhibited relatively high brain concentrations (~7 fold 24 h post injection) compared to ET, suggesting the potential use of EPM in the treatment of brain malignancies.U radu je proučavan ulazak etopozida (inhibitora topoizomeraze II) u tumorsko tkivo iz micela s polisorbatom 20. Oblikovanje micela je potvrđeno određivanjem kritične micelarne koncentracije (CMC) pomoću du Nouy kružnog tenziometra i mjerenjem veličine čestica metodom rasapa svjetlosti. Dodatak 5% etanola smanjuje CMC polisorbata 20 (od 5,0 x 10-5 do 4,54 x 10-5 mol L-1). Etoposid (ET) i micele etoposida s polisorbatom 20 (EPM) obilježene su radioizotopom 99mTc redukcijom pomoću kositrova klorida. Parameteri markiranja su optimirani. Testovi s dietilentriamin pentaoctenom kiselinom i cisteinom pokazali su vrlo nisko transkeliranje 99mTc-ET i 99mTc-EPM kompleksa, što ukazuje na njihovu stabilnost u uvjetima in vitro. Uzlaznom tankoslojnom kromatografijom dokazana je i stabilnost kompleksa u serumu. Nakon subkutane primjene EPM isporuka etopozida u tumorsko tkivo bila je značajno veća (~ 100 puta u odnosu na ET 6 h poslije injiciranja) (p < 0,001), a dokazano je i produljeno zadržavanje EPM u tumoru. Ulazak u tumor je potvrđen i gama analizom slike. EPM je postigao relativno visoku koncentraciju u mozgu u usporedbi s ET (~ 7 puta veću 24 h poslije injiciranja), zbog čega bi se potencijalno mogao upotrijebiti u terapiji malignih tumora mozga

Vincristine-sulphate-loaded liposome-templated calcium phosphate nanoshell as potential tumor-targeting delivery system

Vincristine-sulfate-loaded liposomes were prepared with an aim to improve stability, reduce drug leakage during systemic circulation, and increase intracellular uptake. Liposomes were prepared by the thin-film hydration method, followed by coating with calcium phosphate, using the sequential addition approach. Prepared formulations were characterized for size, zeta potential, drug-entrapment efficiency, morphology by transmission electron microscopy (TEM), in vitro drug-release profile, and in vitro cell cytotoxicity study. Effect of formulation variables, such as drug:lipid ratio as well as nature and volume of hydration media, were found to affect drug entrapment, and the concentration of calcium chloride in coating was found to affect size and coating efficiency. Size, zeta potential, and TEM images confirmed that the liposomes were effectively coated with calcium phosphate. The calcium phosphate nanoshell exhibited pH-dependent drug release, showing significantly lower release at pH 7.4, compared to the release at pH 4.5, which is the pH of the tumor interstitium. The in vitro cytotoxicity study done on the lung cancer cell line indicated that coated liposomes are more cytotoxic than plain liposomes and drug solution, indicating their potential for intracellular drug delivery. The cell-uptake study done on the lung cancer cell line indicated that calcium-phosphate-coated liposomes show higher cell uptake than uncoated liposomes

Tumoricidal effects of etoposide incorporated into solid lipid nanoparticles after intraperitoneal administration in Dalton's lymphoma bearing mice

The tumoricidal effects of etoposide incorporated into lipid nanoparticles after single-dose administration were investigated in Dalton's lymphoma ascites bearing mice. Etoposide and its nanoparticle formulations were administered intraperitoneally, and the cell cycle perturbation, cytogenetic damage, cell death (apoptosis), tumor regression, and animal survival were investigated as parameters of response with time. The tumor burden of mice treated with etoposide and its nanoparticle formulations decreased significantly (P<.001) compared with the initial up to 4 to 6 days, followed by an increase at later time intervals. Of the 3 different formulations, the survival time of mice was higher when treated with etoposide-loaded tripalmitin (ETP) nanoparticles, followed by etoposide-loaded glycerol monostearate (EGMS) (27.3%) and etoposide-loaded glycerol distearate (EGDS) (27.3%) compared with free etoposide. Cell cycle analysis revealed the hypodiploid peak (sub G0/G1 cell population) as well as G2 arrest in mice treated with etoposide and its nanoparticle formulations. The frequency of dead cells treated with the nanoparticle formulations remained high even after 8 days of treatment compared with free etoposide. The mice treated with nanoparticle formulations exhibited hypodiploid peaks and reduced S phase even 8 days after treatment, whereas the free etoposide-treated mice showed decrease in apoptosis after 3 days of treatment. The apoptotic frequency in cells 17 days after treatment was in the order of ETP>EGMS>EGDS> etoposide. The experimental results indicated that among the 3 nanoparticle formulations studied, the ETP nanoparticles showed greater and prolonged apoptotic induction properties, resulting in the higher increase in survival time of tumor bearing mice

Etoposide-incorporated tripalmitin nanoparticles with different surface charge: Formulation, characterization, radiolabeling, and biodistribution studies

Etoposide-incorporated tripalmitin nanoparticles with negative (ETN) and positive charge (ETP) were prepared by melt emulsification and high-pressure homogenization techniques. Spray drying of nanoparticles led to free flowing powder with excellent redispersibility. The nanoparticles were characterized by size analysis, zeta potential measurements, and scanning electron microscopy. The mean diameter of ETN and ETP nanoparticles was 391 nm and 362 nm, respectively, and the entrapment efficiency was more than 96%. Radiolabeling of etoposide and nanoparticles was performed with Technetium-99m (99mTc) with high labeling efficiency and in vitro stability. The determination of binding affinity of99mTc-labeled complexes by diethylene triamine penta acetic acid (DTPA) and cysteine challenge test confirmed low transchelation of99mTc-labeled complexes and high in vitro stability. Pharmacokinetic data of radiolabeled etoposide, ETN, and ETP nanoparticles in rats reveal that positively charged nanoparticles had high blood concentrations and prolonged blood residence time. Biodistribution studies of99mTc-labeled complexes were performed after intravenous administration in mice. Both ETN and ETP nanoparticles showed significantly lower uptake by organs of the reticuloendothelial system such as liver and spleen (P<.001) compared with etoposide. The ETP nanoparticles showed a relatively high distribution to bone and brain (14-fold higher than etoposide and ETN at 4 hours postinjection) than ETN nanoparticles. The ETP nanoparticles with long circulating property could be a beneficial delivery system for targeting to tumors by Enhanced Permeability and Retention effect and to brain