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Alibrandi G, Micali N, Trusso S, Villari A. Hydrolysis of aspirin studied by spectrophotometric and fluorometric variable-temperature kinetics. J Pharm Sci 1996; 85:1105-8. [PMID: 8897279 DOI: 10.1021/js950506t] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Pseudo-first-order rate constants for the hydrolysis of acetylsalicylic acid as a function of temperature have been obtained by variable-temperature kinetic experiments. A method, based on a generalization of non-isothermal analysis, has been used that takes advantage of the capabilities of modern data collection and processing systems. Both spectrophotometric and, for the first time under non-isothermal conditions, fluorometric measurements have been carried out. The results obtained are identical to those obtained under the same conditions but using traditional constant-temperature kinetic runs. This provides the possibility of reducing the amounts of time and chemicals usually spent in collecting kinetic data in mechanistic studies in solution by an order of magnitude.
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Micali N, Trusso S, Vasi C, Blaudez D, Mallamace F. Dynamical properties of water-methanol solutions studied by depolarized Rayleigh scattering. PHYSICAL REVIEW. E, STATISTICAL PHYSICS, PLASMAS, FLUIDS, AND RELATED INTERDISCIPLINARY TOPICS 1996; 54:1720-1724. [PMID: 9965249 DOI: 10.1103/physreve.54.1720] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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53
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Mallamace F, Micali N, Trusso S, Scolaro LM, Romeo A, Terracina A, Pasternack RF. Experimental evidence for self-similar structures in the aggregation of porphyrins in aqueous solutions. PHYSICAL REVIEW LETTERS 1996; 76:4741-4744. [PMID: 10061369 DOI: 10.1103/physrevlett.76.4741] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
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54
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Nickolov ZS, Earnshaw JC, Mallamace F, Micali N, Vasi C. Light-scattering study of phase transitions in aqueous solutions of nonionic amphiphiles. PHYSICAL REVIEW. E, STATISTICAL PHYSICS, PLASMAS, FLUIDS, AND RELATED INTERDISCIPLINARY TOPICS 1995; 52:5241-5249. [PMID: 9964023 DOI: 10.1103/physreve.52.5241] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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55
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Fresta M, Puglisi G, Giammona G, Cavallaro G, Micali N, Furneri PM. Pefloxacine mesilate- and ofloxacin-loaded polyethylcyanoacrylate nanoparticles: characterization of the colloidal drug carrier formulation. J Pharm Sci 1995; 84:895-902. [PMID: 7562444 DOI: 10.1002/jps.2600840721] [Citation(s) in RCA: 79] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The entrapment of fluoroquinolones, perfloxacine mesilate (PFX) and ofloxacin (OFX), in polyalkylcyanoacrylate (PECA) nanoparticles could offer some advantages for their biological application; for examples, increasing their bioavailability, controlling the drug time-release in blood, and reducing the formation of bacterial resistance. To load these two drugs in PECA polymeric bulk, the incorporation or adsorption method was performed. These two methods were capable of influencing nanoparticle size, molecular weight, release profile, and drug-polymer association. The incorporation method, particularly for the OFX system, achieved PECA nanoparticle suspensions with a mean size value three times higher than that obtained in the absence of the drug. In contrast, negligible changes were observed for PFX systems. This preparation process also influenced the nanoparticle storage stability. The molecular weight values of the various nanoparticle preparations were also influenced; that is, the PFX-loaded systems showed an enhancement in the average molecular weight values, whereas a reduction was observed for OFX-loaded systems. The adsorption method showed no particular difference in particle size, molecular weight, and storage stability compared with nanoparticles prepared without the drugs. The nanoparticle loading capacity was higher for the colloidal systems obtained following the incorporation preparation procedure. The release of drug from the nanoparticles was biphasic for both preparation processes. The fluoro-quinolone-loaded nanoparticles showed an enhancement of the antimicrobial activity against standard bacteria strains from 2- to 50-fold compared with the free drugs.
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Mallamace F, Micali N, Trusso S, Chen SH. Spinodal decomposition of a three-component water-in-oil microemulsion system. PHYSICAL REVIEW. E, STATISTICAL PHYSICS, PLASMAS, FLUIDS, AND RELATED INTERDISCIPLINARY TOPICS 1995; 51:5818-5823. [PMID: 9963318 DOI: 10.1103/physreve.51.5818] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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57
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Micali N, Trusso S, Vasi C, Mallamace F, Lombardo D, Onori G, Santucci A. Rotational dynamics of water molecules in a water-short-chain-nonionic-amphiphile mixture: Depolarized light scattering. PHYSICAL REVIEW. E, STATISTICAL PHYSICS, PLASMAS, FLUIDS, AND RELATED INTERDISCIPLINARY TOPICS 1995; 51:2349-2355. [PMID: 9962896 DOI: 10.1103/physreve.51.2349] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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58
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Mallamace F, Lombardo D, Micali N, Trusso S, Vasi C. Light-scattering studies on water-nonionic-amphiphile solutions. PHYSICAL REVIEW. E, STATISTICAL PHYSICS, PLASMAS, FLUIDS, AND RELATED INTERDISCIPLINARY TOPICS 1995; 51:2341-2348. [PMID: 9962895 DOI: 10.1103/physreve.51.2341] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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59
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Villari A, Micali N, Fresta M, Puglisi G. Spectrofluorimetry at zero angle: determination of salicylic acid in an acetylsalicylic acid pharmaceutical formulation. Analyst 1994; 119:1561-5. [PMID: 7943744 DOI: 10.1039/an9941901561] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
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.
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Lombardo D, Mallamace F, Micali N, D'Arrigo G. Dynamic critical phenomena in water-butoxyethanol mixtures studied by viscosity and light-scattering measurements. PHYSICAL REVIEW. E, STATISTICAL PHYSICS, PLASMAS, FLUIDS, AND RELATED INTERDISCIPLINARY TOPICS 1994; 49:1430-1438. [PMID: 9961353 DOI: 10.1103/physreve.49.1430] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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61
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Micali N, Vasi C, Mallamace F, Bansil R, Pajevic S, Sciortino F. Light-scattering studies in cross-linked gels: Evidence of a microphase separation. PHYSICAL REVIEW. E, STATISTICAL PHYSICS, PLASMAS, FLUIDS, AND RELATED INTERDISCIPLINARY TOPICS 1993; 48:4501-4509. [PMID: 9961132 DOI: 10.1103/physreve.48.4501] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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62
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Micali N, Vasi C, Mallamace F, Corti M, Degiorgio V. Raman scattering and water structure in nonionic amphiphile solutions. PHYSICAL REVIEW. E, STATISTICAL PHYSICS, PLASMAS, FLUIDS, AND RELATED INTERDISCIPLINARY TOPICS 1993; 48:3661-3666. [PMID: 9961023 DOI: 10.1103/physreve.48.3661] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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63
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Panico A, Pignatello R, Mazzone S, Cardile V, Bindoni M, Cordopatri F, Villari A, Micali N, Mazzone G. Lipid vesicles loaded with thymopentin: characterization and in vitro activity on tumoral cells. Int J Pharm 1993. [DOI: 10.1016/0378-5173(93)90036-f] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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64
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Puglisi G, Giammona G, Fresta M, Carlisi B, Micali N, Villari A. Evaluation of polyalkylcyanoacrylate nanoparticles as a potential drug carrier: preparation, morphological characterization and loading capacity. J Microencapsul 1993; 10:353-66. [PMID: 8377093 DOI: 10.3109/02652049309031525] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
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.
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Majolino D, Mallamace F, Migliardo P, Aliotta F, Micali N, Vasi C. Spectral evidence of connected structures in liquid water: Effective Raman density of vibrational states. PHYSICAL REVIEW. E, STATISTICAL PHYSICS, PLASMAS, FLUIDS, AND RELATED INTERDISCIPLINARY TOPICS 1993; 47:2669-2675. [PMID: 9960297 DOI: 10.1103/physreve.47.2669] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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66
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Villari A, Micali N, Fresta M, Puglisi G. Simultaneous spectrophotometric determination in solid phase of aspirin and its impurity salicylic acid in pharmaceutical formulations. J Pharm Sci 1992; 81:895-8. [PMID: 1432636 DOI: 10.1002/jps.2600810911] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
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.
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Mallamace F, Micali N, Vasi C, D'arrigo G. Large supramolecular structures in water-alcohol mixtures evidenced by elastic light scattering. ACTA ACUST UNITED AC 1992. [DOI: 10.1007/bf02457392] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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68
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Mallamace F, Micali N, D'Arrigo G. Dynamical effects of supramolecular aggregates in water-butoxyethanol mixtures studied by viscosity measurements. PHYSICAL REVIEW. A, ATOMIC, MOLECULAR, AND OPTICAL PHYSICS 1991; 44:6652-6658. [PMID: 9905793 DOI: 10.1103/physreva.44.6652] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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69
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D'Arrigo G, Mallamace F, Micali N, Paparelli A, Vasi C. Molecular aggregations in water-2-butoxyethanol mixtures by ultrasonic and Brillouin light-scattering measurements. PHYSICAL REVIEW. A, ATOMIC, MOLECULAR, AND OPTICAL PHYSICS 1991; 44:2578-2587. [PMID: 9906238 DOI: 10.1103/physreva.44.2578] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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70
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Mallamace F, Micali N, Vasi C, D'Arrigo G. Viscoelastic properties of dense microemulsions: Hypersound results. PHYSICAL REVIEW. A, ATOMIC, MOLECULAR, AND OPTICAL PHYSICS 1991; 43:5710-5713. [PMID: 9904889 DOI: 10.1103/physreva.43.5710] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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71
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Mallamace F, Micali N, Vasi C. Viscoelastic properties of charged colloids, polystyrene, and silica-water suspensions. PHYSICAL REVIEW. A, ATOMIC, MOLECULAR, AND OPTICAL PHYSICS 1990; 42:7304-7311. [PMID: 9904045 DOI: 10.1103/physreva.42.7304] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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72
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Majolino D, Mallamace F, Venuto S, Micali N. Viscosity measurements in dense microemulsions. PHYSICAL REVIEW. A, ATOMIC, MOLECULAR, AND OPTICAL PHYSICS 1990; 42:7330-7339. [PMID: 9904047 DOI: 10.1103/physreva.42.7330] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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73
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Maisano G, Mallamace F, Micali N, Vasi C, Caponetti E, Triolo R. Correlation spectroscopy in molten and supercooled antimony trichloride. PHYSICAL REVIEW. A, ATOMIC, MOLECULAR, AND OPTICAL PHYSICS 1990; 41:3245-3249. [PMID: 9903480 DOI: 10.1103/physreva.41.3245] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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74
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Majolino D, Mallamace F, Migliardo P, Micali N, Vasi C. Elastic and quasielastic light-scattering studies of the aggregation phenomena in water solutions of polystyrene particles. PHYSICAL REVIEW. A, GENERAL PHYSICS 1989; 40:4665-4674. [PMID: 9902711 DOI: 10.1103/physreva.40.4665] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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75
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Magazú S, Majolino D, Maisano G, Mallamace F, Micali N. Large structural order in dense microemulsions studied by light scattering. PHYSICAL REVIEW. A, GENERAL PHYSICS 1989; 40:2643-2648. [PMID: 9902450 DOI: 10.1103/physreva.40.2643] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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