1,720,994 research outputs found
Alginate-prednisolone controlled delivery systems: design and in vitro characterization
No full textPurpose. The current study aimed to develop a controlled release formulation for the oral
administration of prednisolone (P), potentially useful for the treatment of chronic inflammatory
diseases.
Methods. Prilling was selected as micro-encapsulation technique to produce drug loaded
hydrophilic microparticles (gel-beads). The influence of process parameters such as composition
and viscosity of the aqueous feed solutions (sodium alginate 2.0-2.75% w/v in different ratio with
P 1:10-1:4), aqueous bulks for ionotropic gelation and cross-linking time (5-10 min) on the
obtained particles was evaluated. Beads morphology, size and solid state characteristics were
analysed (SEM microscopy, FTIR, DSC). In vitro release study was assessed in conditions
simulating the gastrointestinal environment (USP XXVII).
Results. Particles morphology as well as release kinetics of alginate formulations were strongly
related to the amount of alginate and P loaded into the feed solutions. Best results were
obtained increasing alginate and P content in order to achieve a compact polymeric matrix able
to better retain the drug. The best formulation, F6 released around 20% of P in simulated gastric
fluid (SGF, pH=1); complete drug release is achieved after pH change in simulated intestinal fluid
(SIF, pH=6.8) in about 3.5 h. This behavior may be explained by a combination of alginate pHdependent
solubility, cross-linking properties of Zn2+ and polymeric matrix density in #F6; beads
did not swell or erode in SGF and still keep intact matrix, whereas in SIF (at pH 6.8) they started
to swell and further erode due to the ion-exchange. Moreover, in order to further improve the
release kinetic, the formulation F6 has been insert into suitable capsules able to protect the drug
in acidic medium and to extend anti-inflammatory activity.
Conclusions. Conventional therapies of chronic inflammatory diseases (such as arthritis
arthrosis) consists of multiple daily administrations of prednisolone leading to a variable drug
blood level and ineffective therapy. This study suggested that prilling is an appropriate
technological approach to manufacture drug delivery systems able to control prednisolone
release. The best formulation F6 could be proposed as self-consistent formulation or as a dosage
form hosted into suitable capsules for the treatment of inflammatory chronic diseases
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Prilling-based Tandem Techniques: applications in the development of NSAIDs controlled delivery systems
Full text linkPost-manufacture loading of filaments and 3D printed PLA scaffolds with prednisolone and dexamethasone for tissue regeneration applications
No full textStrategies to load prednisolone or dexamethasone in preformed poly(L-lactic acid) (PLA) filaments and 3D printed scaffolds were explored as a way of personalizing the drug, the dose and the release profile for regenerative medicine purposes. Instead of starting from a PLA filament preloaded with a given content of drug, we explored two more versatile strategies. The first one involved the soaking of PLA filaments into a drug solution prepared in a solvent that reversibly swelled PLA; during 3D printing the melting of PLA contributed to the efficient integration (encapsulation) of the drug inside the printed strand. The second strategy consisted in first printing the 3D PLA scaffolds followed by soaking in a suitable drug solution in order to exploit the higher specific surface of the printed strands compared to the filament. Sustained release profiles were recorded when either prednisolone or dexamethasone were loaded in preformed PLA filaments, while rapid release was recorded for 3D PLA scaffolds loaded after printing. The combination of the two proposed methods reported here opened the possibility of creating concentration gradients of different drugs in the same scaffold exhibiting distinct release patterns. Namely, the strand core contained an active ingredient to be slowly released, while the surface was covered with other active ingredient that could be rapidly delivered. The feasibility of this approach was confirmed through dual loading of dexamethasone in the filament and of prednisolone on the preformed scaffold. Drug-loaded scaffolds were characterized in terms of printability, structural characteristics (DSC, XRD), mechanical properties, biodegradation, and ability to promote cell attachment and proliferation. Finally, anti-inflammatory response and osteoinductive properties were verified in cell cultures
Gentamicin and particle engineering: from an old molecule to innovative drug delivery systems
Full text linkSpray-dried versus supercritical fluids gentamicin microparticles for locoregional drug controlled release
Get PDFDesign of Alginate Based Aerogel for Nonsteroidal Anti-Inflammatory Drugs Controlled Delivery Systems using Prilling and Supercritical-Assisted Drying Tandem Technique
Full text linkGentamicin and leucine inhalable powder: What about antipseudomonal activity and permeation through cystic fibrosis mucus?
No full textThe aim of this study was to evaluate the permeation properties of gentamicin (G) in a novel dry powder form for inhalation through an artificial mucus model. Moreover, since respiratory infections sustained by Pseudomonas are a major cause of sickness and death in CF patients, the susceptibility of P. aeruginosa to engineered G powders was investigated. Micronized G and G/leucine (85:15) formulations were produced by co-spray-drying, using process parameters and conditions previously set. Powders were characterized in terms of yield, drug content and aerodynamic profiles, analyzed by Andersen Cascade Impactor. Different mucus models were prepared, showing composition and viscosity similar to those of the native CF mucus. To investigate the impact on drug permeation, Franz-type vertical diffusion cells were used; the powders were applied directly on a synthetic membrane with or without the interposition of the artificial mucus layer. In buffer, gentamicin showed a diffusion controlled release; the presence of leucine reduced powder wettability and, consequently, the permeation rate. Otherwise, mucus delayed drug permeation from both G and G/leucine formulations, with a faint influence of the aminoacid. Antimicrobial tests revealed that G/leu engineered particles are able to preserve the antipseudomonal activity, even in presence of the mucus
Application of a new green protocol in solid-phase peptide synthesis: identification of a new green solvent mixture compatible with TBEC/ETT
No full textSolid Phase Peptide Synthesis (SPPS) is the preferred technique for synthesizing bioactive peptides. However, traditional SPPS generates significant waste and employs hazardous solvents like DMF and DCM. The aim of this research is to investigate solvents and agents of coupling that align with the green chemistry and are suitable for all stages of SPPS. Some solvents, such as p-cymene and anisole, taken into consideration in this work, can be derived from renewable sources like plants and biomass, rendering them environmentally sustainable choices. However, many of these alternative solvents possess different physicochemical properties compared to DMF. To overcome this challenge, solvent mixtures are employed. In this study, we identified a novel green solvent mixture by combining anisole with NOP; its ability to swell different resins and its capability to solubilize all Fmoc protected amino acids was investigated. The same mixture was also assessed with a green coupling agent, TBEC, in combination with ETT as additive. Model peptides Aib-enkephalin and Aib-ACP were synthesized resulting in favorable outcomes in terms of peptide synthesis efficiency, 97.81% and 98.86%, respectively.Abbreviations: SPPS: Solid Phase Peptide Synthesis; DMF: N, N-dimethylformamide; DCM: dichloromethane; APIs: Active Pharmaceutical Ingredients; 2-MeTHF: 2-methyltetrahydrofuran; THF: tetrahydrofuran; CPME: cyclopentyl methyl ether; GVL: gamma-valerolactone; NFM: N-formylmorpholine; PC: propylene carbonate; DMI: 1,3-Dimethyl-2-imidazolidinone; NBP: N-butyl pyrrolidone; DMC: dimethyl carbonate; DMM: dipropylene glycol dimethyl ether; NOP: N-octylpyrrolidone; ETT: 5-(ethylthio)-1H-tetrazole; TBEC: N-tert-butyl-N'-ethylcarbodiimide; TFA: trifluoroacetic acid; DIC: N,N '-Diisopropilcarbodiimmide; CM: ChemMatrix; PS: polystyrene; PEG: polyethylene glycol; TG: TentaGel; SEM: scanning electron microscopy; HOBt: hydroxybenzotriazole; HBTU: N,N,N ',N '-Tetramethyl-O-(1H-benzotriazol-1-yl) uronium hexafluorophosphate
- …
