1,721,218 research outputs found
Microparticulate powders for temporary suspensions
No full textL'oggetto dell'invenzione comprende polveri microparticellari per sospensioni temporanee dei farmaci caratterizzati da un sapore particolarmente sgradevole, in particolare acidi biliari
PLA microparticles for nimesulide prolonged release: effect of the preparative variables.
No full textPLA microparticles for nimesulide prolonged release: effect of the preparative variables
A theoretical model for the calculation of the drug distribution profile in matrices of different shape to achieve the desired drug release kinetics
No full textThe drug release kinetics from a matrix is often affected by the matrix geometry. To compensate for the influence of the matrix geometry on the drug release, a nonhomogeneous drug distribution has been suggested. Keeping in mind this approach, a theoretical mathematical model to calculate the drug distribution profile according to The matrix geometry is proposed. This approach could be useful in achieving the desired drug release kinetics without varying the matrix geometry
Can kinetic analysis be a tool for evaluating pore characteristics?
No full textAs the pore morphology influences drug release, the purpose is to study pore characteristics by comparing bead performances. Casein/gelatin beads have been prepared by the emulsification extraction method, cross-linked with D,L-glyceraldehyde in acetone:water mixture 3:1 (v/v) and loaded with sodium fluorescein as a model drug. The beads with higher casein percentage have a higher matrix porosity, a wider average pore diameter and a higher cross-linking degree. The higher casein percentage causes a lower drug release rate. The kinetic analysis shows that the drug release occurs bq diffusion and that the diffusion coefficient is affected by the casein percentage and the cross-linking degree. It can be hypothesized that the pore and channel morphology (tortuosity.), due to the casein percentage in the matrix and the cross-linking treatment, can he evaluated by kinetic analysis of the release data
Surface treatment on sodium alginate matrices
No full textThe soaking of sodium alginate matrices with solutions of an inorganic calcium salt produced a film of calcium alginate on the matrix surface that was evaluated by EDX analysis
Microparticelle di PLGA per la somministrazione intrapleurica di Cidofovir
No full textMicroparticelle di PLGA per la somministrazione intrapleurica di Cidofovi
A DELIVERY SYSTEM FOR THE CONCURRENT ADMINISTRATION OF HYDROCHLOROTHIAZIDE AND CAPTOPRIL
No full textA delivery system for the concurrent administration of drugs was prepared inserting a conventional hydrochlorothiazide tablet in the hole of a perforated matrix of captopril coated on all the surfaces except the hole surface. The influence of both the hole diameter and the drug/polymer ratio on the release process was evaluated. According to the system design, hydrochlorothiazide was promptly liberated from the tablet inserted in the hole, whereas captopril was gradually released following a linear release profile. No significant differences were pointed out between the release behavior of both drugs in de-ionized water and in simulated gastrointestinal fluids
Influence of drug loading level on drug release and dynamic swelling of crosslinked gelatin microspheres
No full textThe effect of drug loading level both on dynamic swelling and drug releae was evaluated using crosslinked gelatin microspheres. Owing to water penetration the microsphere diameter went first to a maximum value, wich was not affected by the payload; the diameter gradually approached to an equilibrium swollen value, which was affected by drug loading level. Water absorption increases and drug diffusion decreases the microsphere diameter. Obviolusly, the diameter variation depends on the factor (water absorption and drug diffusion) predominating in the process. As the payload affected only the equilibrium swollen level it is reasonable to hypothesize that drug loading level has a greater effect on drug diffusion than on polymer relaxation. This rationale could explain the increase of the diffusion component of the drug release process as the payload increased
ANALYSIS OF RELEASE DATA IN THE EVALUATION OF THE PHYSICAL STATE OF PROGESTERONE IN MATRIX SYSTEMS
No full textEthylene-vinyl acetate microspheres were prepared by an emulsion solvent-evaporation method as sustained delivery carriers of progesterone. Physical state of the drug in the microspheres was affected by drug loading level. As thermal analysis and mathematical release models showed, low payloads of the matrix supported the molecularly dispersed drug. Crystalline drug appeared only as the drug loading level increased. The release process of the crystalline drug produced a porosity increase in the polymeric system; thus, the drug could diffuse through pores and channels. Hence, the porosity of the matrix structure was affected by the payload. This hypothesis could justify the increasing goodness-of-fit of the release data to the square-root model as the drug loading level of the microspheres increase
Role de l'agent de reticulation sur la liberation de matrices spheriques de carboxy methylcellulose reticulee
No full textOn a prepare des matrices spheriques de carboxymethylcellulose reticulee en utilisant une technique de "in liquid curing coating" ou AlCl3 etait l'agent de reticulation. L'influence de la fraction de l'agent de reticulation libre a ete evalue sur les processus de gonflement des matrices et de liberation du principe actif
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