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N Micali

Publications and source records attributed to N Micali.

At least 37 records · Page 2Linked to original sources
PubMed1994

Spectrofluorimetry at zero angle: determination of salicylic acid in an acetylsalicylic acid pharmaceutical formulation.

In this work, a solid-state spectrofluorimetric method for drug assays was developed. In particular, we report the determination of salicylic acid (SA), as a hydrolysis product, in solid pharmaceutical formulations containing acetylsalicylic acid (ASA). Recently, we described a sensitive and accurate fluorescence method that provided, through a mathematical application, the simultaneous determination of ASA and SA. By means of the spectrofluorimetric method reported herein it was possible to carry out the SA determination, without any mathematical calculation and with a sensitivity 100 times that of our previous method. The intra- and inter-day reproducibility of the spectrofluorimetric method, expressed as the relative standard deviation, ranged from 0.1 to 0.3%. The present method requires a fluorescence apparatus with the excitation and detection systems in-line (zero angle). The detection system was not sensitive to the excitation wavelength, but was highly sensitive to emission wavelengths from 350 to 800 nm. The results obtained were compared with those of our previous spectrofluorimetric method, together with those of a high-performance liquid chromatography method and a US Pharmacopeia method. The sensitivity of the method was of the order of 10(-8) g.

Aspirin↗
PubMed1992

Simultaneous spectrophotometric determination in solid phase of aspirin and its impurity salicylic acid in pharmaceutical formulations.

We report the simultaneous determination of aspirin and its hydrolysis product, salicylic acid, in solid phase by fluorescence spectrophotometry. Aspirin is often the most labile component in a combination-type analgesic compound. Therefore, its stability is often the initial concern in any formulation-screening program. Preliminary screening of a large number of potential formulations can be arduous, because most current methods of analysis generally consist of several steps: extractions or column separations followed by UV, colorimetric, or gas-liquid chromatographic assays. The method proposed here is quite suited to large numbers of assays because it is not time consuming, it is straightforward, and it is not subject to interference from the substances present in the pharmaceutical formulations. In addition, the method is nondestructive, not dependent on the sampling procedure, and, above all, quite sensitive.

Aspirin↗
PubMedDate not supplied

Evaluation of polyalkylcyanoacrylate nanoparticles as a potential drug carrier: preparation, morphological characterization and loading capacity.

Some physicochemical behaviours were investigated of polyethyl- (PECA) and polyisobutylcyanoacrylate (PICA), which, in recent years, have been proposed as nanoparticle colloidal systems for drug carrying. We observed the influence of preparation conditions, such as pH value and surfactant concentration, on parameters such as particle size and polymer molecular weight. Lower operating pH values (0-2) resulted in smaller nanoparticles than those prepared at pH 5.5. The polymer molecular weight was also a function of pH: low molecular weight at low pH and vice-versa. The surfactant concentration positively influenced main particle size and polymer molecular weight. These trends were independent of type of monomer; in fact, both ethyl- (ECA) and isobutyl-2-cyanoacrylate (ICA) showed the same behaviour. Loading capacity, as well as release profile, of the two polymers were evaluated using fluorescein as a model drug. Whereas both polymers showed almost the same release profile, there was a difference in the amount of encapsulated probe: higher aliquots for PICA than for PECA. Storage effects on such physicochemical parameters were also tested.

Chemistry, Pharmaceutical↗