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Biomedical subjects

F Bottari

Publications and source records attributed to F Bottari.

18 recordsLinked to original sources
PubMed1993

Bactericidal activity of two different dosage regimens of imipenem in an in-vitro dynamic model.

The antimicrobial activity of imipenem was tested in an in-vitro model mimicking human serum pharmacokinetics after either 1000 mg im once daily or 500 mg im twice daily. Six recent clinical isolates of Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, Proteus mirabilis, Klebsiella pneumoniae and Salmonella group B were used as test strains. Our results suggest that a single daily dose of imipenem 1000 mg im exerts an antibacterial action comparable to that obtained with two divided doses of 500 mg.

Dose-Response Relationship, Drug↗
PubMed1980

Vehicle effects in percutaneous absorption: in vitro study of influence of solvent power and microscopic viscosity of vehicle on benzocaine release from suspension hydrogels.

The release through silicone rubber membranes of benzocaine suspended in carbomer hydrogels containing different concentrations of low molecular weight polysols (ethylene glycol, propylene glycol, glycerol, and sorbitol) was studied to establish general principles and procedures for control of the effects on percutaneous absorption caused by changes in drug solubility and/or diffusivity in the vehicle. The effect of the additives on the release is expressed in terms of the relative released amount, i.e., the ratio, Q/Qw, of the amount of drug released from each additive-containing gel to the amount released at the same time from the additive-free gel. The experimental Q/Qw values are correlated with values calculated by a simple equation involving known or readily measurable parameters such as the drug concentration in the gel, the drug solubility in the pure liquid phase, and the viscosity of this phase. Derivation of such a relationship from a known equation describing the vehicle-controlled relase of suspended drugs was possible because an inverse proportionality was observed between drug diffusivity in the gels and the viscosity of the respective solvents. This relationship is interpreted with respect to current theories on drug diffusion in diluted gels.

Benzocaine↗
PubMed1977

Release of drugs from ointment bases II: In vitro release of benzocaine from suspension-type aqueous gels.

The in vitro release of benzocaine, suspended in an aqueous gel, through silicone rubber membranes was studied to test an extension of existing mathematical models. The theoretical treatment proposed is intended for experimental systems involving release, through a non-porous membrane, of a drug whose concentration is a few times (larger than or equal to 3) greater than its solubility in the vehicle. For either micronized (2micrometer) or macrosize (125 micrometer) drug, the Q (amount released) versus t1/2 (time1/2) plots were not linear until substantial time had elapsed. Excellent agreement was found between the experimental points and theoretical plots, generated by a computer fit to experimental data of an equation derived from a reported vehicle-boundary diffusion layer model. The values of the solubility and of the diffusion layer model. The values of the solubility and of the diffusion coefficient of benzocaine in the gel, calculated by the present mathematical treatment from release data, were in agreement with literature data. The particle size of released benzocaine did not influence the release pattern, thus confirming release in the present conditions to be diffusion rather than dissolution controlled. The present method is applicable for determining the solubility and diffusion coefficient of drugs in vehicles in cases not contemplated in current release theories.

Benzocaine↗
PubMed1975

Evaluation of a dynamic permeation technique for studying drug-macromolecule interactions.

The applicability of a permeation rate technique to the determination of drug-macromolecule interactions was tested by measuring the extent of interaction of methylparaben with polyvinylpyrrolidone and polysorbate 80. Results were in agreement with literature data obtained by other techniques. The present method, although restricted to permeant molecules that diffuse readily through nonporous nylon membranes, is of potential value for investigations of drug binding by macromolecules not retained by porous dialysis membranes.

Binding, Competitive↗