1,720,971 research outputs found
Characterization of tamoxifen in crosslinked alginate microparticles
No full textPurpose: Physical-chemical characterisation of tamoxifen (TMX) in alginate microparticles for the uptake by Peyer’s patches after oral administration.
Methods: Uncrosslinked microparticles were prepared by spray-drying of hydro-alcoholic solutions of alginate/TMX (1:0.1) mixtures. A subsequent crosslinking process by calcium ions and chitosan provides crosslinked microparticles. The obtained microparticles were evaluated for morphology and size by SEM and drug loading level. Tamoxifen physical state inside the microparticles was analysed by DSC and IR analysis. Rheological analysis was performed to detected chemical interaction between the drug and the polysaccharide.
Results: Tamoxifen citrate salt exists in two polymorphic forms, metastable form A, stable form B. Commercial product was metastable form A. The microscopic observation of the obtained microparticles revealed a size in 1-3 m range, which is considered proper to be taken up by M cells of Peyer’s patches. Following the spray-drying process, TMX was found in an amorphous state. The rheological analysis, detecting polyelectrolite electroviscous effect, demonstrated the TMX/alginate interaction leading to a suitable drug loading level and to a drug immobilisation within the microparticles.
Conclusions: Tamoxifen citrate salt is widely used as the primary hormonal therapy for metastatic estrogen receptor-positive breast cancer. However, side effects include endometrial pathologies, liver cancer and ocular effects. The designed microparticles could be taken up by Peyer’s patches and translocate the drug to the lymphatic system, so avoiding the first-pass metabolism and enzymatic degradation from cytosolic enzymes of the epithelial cells. Therefore, an improved TMX bioavailability could lead to a decrease of the therapeutic dose and, consequently, of the side effects
Preparation and in vitro characterization of lipospheres as a carrier for the cosmetic application of glycolic acid
No full textLipospheres for the cosmetic delivery of glycolic acid were prepared by the melt method using tristearin as the lipid phase and hydrogenated soybean phosphatidylcholine as the emulsifier. The lipospheres, sized from 5 to 40 micron, contained a rather high glycolic acid loading level probably due to a partial polymorphic modification of the lipid and determined glycolic acid sustained release pattern
Sperimentazione "in vivo" di liposfere contenenti acido glicolico
No full textSono state preparate e valutate liposfere contenenti acido glicolico per applicazioni cosmetiche in vivo su volontari sani per determinarne il potenziale irritante l'attività cheratomodulante a confronto con applicazioni di acido glicolico in forma liber
Valutazione in vivo di micro- e nanocarrier lipidici per uso dermocosmetologico
No full textE' stata determinata la permeazione attraverso lo strato corneo di micro- e nanoparticelle di natura lipidica (liposfere, Solid Lipid Nanoparticles) veicolanti beta-carotene e titanio biossido, quali marker, mediante stripping test. Le microparticelle non attraversano la struttura cornea, mentre le nanoparticelle sono risultate in grado di attraversare la barriera cornea
Ex-vivo evaluation of alginate microparticles for Polymyxin B oral administration
No full textA crosslinked alginate microparticle system for the targeting to the lymphatic system by Peyer's patches (PP) uptake was designed in order to improve the oral absorption of Polymyxin B (PMB). To verify mucoadhesion and PP uptake, microparticles labelled with fluorescein isothiocyanate (FITC) were prepared by spray-drying technique and crosslinking reactions with calcium ions and chitosan (CS), in vitro characterized and assayed by an ex vivo method. Microparticles showed a size less then 3 mu m, an antibiotic loading level of 11.86 +/- 0.70%, w/w, a sustained drug release behaviour in simulated gastro-intestinal (GI) fluids and a preserved biological activity throughout the manufacture. The ex vivo study was performed by a perfusion method on intestinal tracts of just sacrificed adult rats. The recovered samples were analysed by epifluorescence microscope for mucoadhesion and PP uptake and by microbiological analysis for antibiotic activity preservation, providing evidence of mucoadhesion at the level of both PP and non-PP epithelium, uptake by PP and PMB microbiological activity in PP tissue. Furthermore, the study revealed the involvement of transport pathways across villous enterocytes
Effect of the feeding condition on the urinary excretion of riboflavin dosed by a multiparticulate floating system
No full textThe floating units, composed of a calcium alginate core separated byan air compartment from a calcium alginate/PVA membrane, were tested to establish the release characteristic and the pharmacokinetics of riboflavin in different feeding conditions by urinary excretion
Applicazione delle microonde all'essiccamento di granulati farmaceutici
No full textIn numerosi campi industriali esiste attualmente un crescente interesse per le microonde a causa delle possibilità di risparmio energetico, nonché dell'opportunità di diversificazione delle fonti energetiche e del rispetto dellìambiente
Preformulative and formulative studies on inclusion complexes between cyclodextrins and ursodeoxycholic acid
No full textThree different methods (evaporation, spray-drying and lyophilisation) were used to prepare the complex between ursodeoxycholic acid and cyclodextrin (beta CD or HP beta CD). A small fraction of free drug not included into the cyclodextrin cavity along with the complex was noticed only for the complexes prepared using the evaporation method. Preformulative parameters of at least three batches of each complex were evaluated in view of the industrial preparation method selected. All the methods guarantee good reproducibility, but the surface area and the density of the complex powders were chiefly affected. Given the low-density value, the spray-dried and lyophilised complexes need to be transformed into granules before tablet preparation. The formulative parameters of the tablets were also evaluated. The disintegration test of both uncoated and coated tablets prepared with the granules obtained form the different beta CD complexes was not satisfactory. In spite of the long disintegration time, the ursodeoxycholic acid dissolution rate from the tablets was similar to that observed in the case of the inclusion complex powders.Three different methods (evaporation, spray-drying and lyophilisation) were used to prepare the complex between ursodeoxycholic acid and cyclodextrin (βCD or HPβCD). A small fraction of free drug not included into the cyclodextrin cavity along with the complex was noticed only for the complexes prepared using the evaporation method. Preformulative parameters of at least three batches of each complex were evaluated in view of the industrial preparation method selected. All the methods guarantee good reproducibility, but the surface area and the density of the complex powders were chiefly affected. Given the low-density value, the spray-dried and lyophilised complexes need to be transformed into granules before tablet preparation. The formulative parameters of the tablets were also evaluated. The disintegration test of both uncoated and coated tablets prepared with the granules obtained from the different βCD complexes was not satisfactory. In spite of the long disintegration time, the ursodeoxycholic acid dissolution rate from the tablets was similar to that observed in the case of the inclusion complex powder
Detection of solid lipid nanoparticles in human stratum corneum by EDX analys
No full textThe purpose of the work was to examine in vivo the structural modifications and the translocation ability of Solid Lipid Nanoparticles (SLN) loaded with titanium or silicon dioxides across stratum corneum (SC) by EDX analysis. Intact SLN can translocate across SC until the corneum compactum where a biodegradation process can occur suggesting an interaction with the lipid packing between the corneocyte clusters supposed as the main pathway. Conversely, lipid microparticles were retained on the skin surface preventing the loaded metal dioxides from permeating the uppermost SC layers
Evaluation of polyelectrolyte complexes by means rheological analysis
No full textThe occurrance of interaction between the polyanionic sodium alginate and polycationic compuonds (gentamicin, bovine serum albumin, chitosan) was investigated by rheological measurements. Under soluble complex conditions, the interaction was analyzed by evaluating the "electroviscous effect", whereas in the presence of solid complexes it was monitored by determining viscosity modifications in supernatant solutions after the complex removal
- …
