Multifunctional antibiotic- and zinc-containing mesoporous bioactive glass scaffolds to fight bone infection.

Bone regeneration is a clinical challenge which requires multiple approaches. Sometimes, it also includes the development of osteogenic and antibacterial biomaterials to treat the emergence of possible infection processes arising from surgery. This study evaluates the antibacterial properties of gelatin-coated meso-macroporous scaffolds based on the bioactive glass 80%SiO2-15%CaO-5%P2O5 (mol-%) before (BL-GE) and after being doped with 4% of ZnO (4ZN-GE) and loaded with both saturated and the minimal inhibitory concentrations of one of the antibiotics: levofloxacin (LEVO), vancomycin (VANCO), rifampicin (RIFAM) or gentamicin (GENTA). After physical-chemical characterization of materials, release studies of inorganic ions and antibiotics from the scaffolds were carried out. Moreover, molecular modelling allowed determining the electrostatic potential density maps and the hydrogen bonds of antibiotics and the glass matrix. Antibacterial in vitro studies (in planktonic, inhibition halos and biofilm destruction) with S. aureus and E. coli as bacteria models showed a synergistic effect of zinc ions and antibiotics. The effect was especially noticeable in planktonic cultures of S. aureus with 4ZN-GE scaffolds loaded with VANCO, LEVO or RIFAM and in E. coli cultures with LEVO or GENTA. Moreover, S. aureus biofilms were completely destroyed by 4ZN-GE scaffolds loaded with VANCO, LEVO or RIFAM and the E. coli biofilm total destruction was accomplished with 4ZN-GE scaffolds loaded with GENTA or LEVO. This approach could be an important step in the fight against microbial resistance and provide needed options for bone infection treatment. STATEMENT OF SIGNIFICANCE: Antibacterial capabilities of scaffolds based on mesoporous bioactive glasses before and after adding a 4% ZnO and loading with saturated and minimal inhibitory concentrations of levofloxacin, vancomycin, gentamicin or rifampicin were evaluated. Staphylococcus aureus and Escherichia coli were the infection model strains for the performed assays of inhibition zone, planktonic growth and biofilm. Good inhibition results and a synergistic effect of zinc ions released from scaffolds and antibiotics were observed. Thus, the amount of antibiotic required to inhibit the bacterial planktonic growth was substantially reduced with the ZnO inclusion in the scaffold. This study shows that the ZnO-MBG osteogenic scaffolds are multifunctional tools in bone tissue engineering because they are able to fight bacterial infections with lower antibiotic dosage.

Vanadium in vivo interaction with cefatoxime

Anteriormente, en estudios por HPLC, hemos demostrado in vitro, que la presencia de V (IV) en las disoluciones de penicilinas y cefalosporinas, aumentan la degradación de éstas en sus correspondientes ácidos penicilóico y cefalosporánico. Los mecanismos de la catálisis de V (IV) involucran a un complejo ternario. En este trabajo se estudia las consecuencias de esta degradación, in vivo, de Cefotaxima, en sangre, hígado, bazo, riñón, pulmón y corazón, para ver las consecuencias de la intoxicación de vanadio. Las diferencias más importantes en ratas intoxicadas con vanadio se observaron en hígado, pulmón y riñón

The presence of V(IV) in penicillin and cephalosporin solutions, has been shown previously, in vitro, to promote the degradation of the penicillins and cephalosporins studied to their corresponding penicilloic and cephalosporanic acids. HPLC studies provided an additional evidence for the reaction mechanism. The mechanisms of V(IV) catalysis involve a ternary complex. This work was undertaken to study the consequences of this degradation, in vivo, upper the pharmacokinetic and pharmacodynamic of Cefotaxime, being these consequences a lower concentracion of free cefotaxime in blood, liver, spleen, kidney, lung and heart when there was intoxication with vanadium. The differences more significant between rats with vanadium and without it were observed in liver, lung and kidney

Mesoporous SBA-15 HPLC evaluation for controlled gentamicin drug delivery.

Mesoporous silica SBA-15 was prepared to evaluate its application as gentamicin drug delivery system. Two procedures were used to evaluate the delivery: calcined powder and disk conformed. The samples were charged with gentamicin sulphate and the experiments were carried out in vitro. No significant difference between powder and disk was observed in the tests. The release profiles exhibited a pronounced initial burst release effect of 60%, followed by a very slow release pattern. A new HPLC method was employed for calculated gentamicin amount in the delivery test. This method requires a small amount of sample, very advisable in these kinds of assays.

Determinación de las constantes de la reacción de hidrólisis de Ceftriaxona por cromatografía de líquidos / Determination of ceftriaxone hydrolisis constants reaction by high pressure liquid chromatography

Hemos realizado la determinación de las constantes de la reacción de hidrólisis de la Ceftriaxona por cromatografía de líquidos, en un intervalo de pH de 2 a 7 y a temperaturas de 30 a 60ºC. Asimismo a partir de los perfiles cromatográficos obtenidos y del estudio de los espectros de U.V. de las fracciones cromatográficas eluidas, es posible deducir el mecanismo de reacción que tiene lugar en nuestras condiciones de ensayo (AU)

Preparation, characterization, and in vitro release of ibuprofen from AI2O3/PLA/PMMA composites.

The preparation, characterization, and in vitro release of Ibuprofen from Al2O3, poly(L-lactic acid) (PLLA), and polymethylmethacrylate (PMMA) composites are described. The release process of the anti-inflammatory drug after the immersion of composites in a buffered solution is analyzed. The rate of Ibuprofen release is related to the crystalline or amorphous form of the drug. The presence of a ceramic component, alpha-Al2O3, and a biodegradable polymer, PLLA, facilitates both Ibuprofen crystallization and drug release. In addition, these composite systems modulate the release of the stereoisomers R(-) and S(+) of the drug.