PubMed Health⌕ Search

Biomedical subjects

P De Filippis

Publications and source records attributed to P De Filippis.

11 recordsLinked to original sources
PubMed2002

Photodegradation studies on lacidipine in solution: basic experiments with a cis-trans reversible photoequilibrium under UV-A radiation exposure.

The photostability of Lacidipine, a dihydropyridine drug used in the treatment of mild and moderate hypertension, was studied in solutions exposed to UV-A radiations. The effects of the solvent (ethanol, acetone, dichloromethane), drug concentration and radiation wavelength on the drug photostability were evaluated. Lacidipine and its photoproducts were separated by a selective liquid chromatographic (HPLC) method, under normal phase conditions (CN-column), using n-hexane:ethanol 97:3 (v/v) as mobile phase, at a flow rate of 2.0 ml/min. The main photodegradation products were isolated and characterised and a photodegradation pathway was proposed for Lacidipine in solution. The cis-isomer and a photocyclic isomer proved to be the main photodegradation products.

Calcium Channel Blockers↗
PubMed1998

Polyorganophosphazene microspheres for drug release: polymer synthesis, microsphere preparation, in vitro and in vivo naproxen release.

Microsphere preparation for naproxen slow release was investigated using two newly prepared biodegradable polyorganophosphazenes, derivatized at the phosphorus atoms with phenylalanine ethyl ester and imidazole at molar ratios of 71/29 and 80/20. The polymers were prepared by substitution of the chloride atoms of polydichlorophosphazene with a phenylalanine ethyl ester-imidazole mixture followed, after 7 or 48 h reaction, by the addition of excess imidazole. Three methods of microsphere preparation have been considered: spray-drying, emulsion/solvent evaporation and emulsion/solvent evaporation-extraction. Microparticles obtained by spray-drying were found to possess a narrow distribution size with a mean diameter of 2-5 microm. Their internal structure consisted of a porous or empty core depending upon the solvent used for the preparation. Furthermore the microspheres prepared with this technique rapidly released the entrapped naproxen independently of the used polymer, the drug loading or the preparation process. On the other hand microspheres prepared by solvent evaporation or solvent evaporation-extraction showed a distribution size ranging between 10 and 100 microm. By the appropriate choice of pH and solvent composition of the external phase, naproxen could be entrapped, in these microspheres, with a yield higher of 80%. The polymer composition dictates the in vitro release rate of naproxen from the particles, which was faster when the microspheres were prepared with the polymer at higher imidazole content. In vivo experiments, carried out by subcutaneous implantation in rats of microspheres prepared by solvent evaporation, demonstrated that a constant level of naproxen in plasma could be maintained up to 400 h at a suitable concentration for antinflammatory activity.

Animals↗
PubMed1990

Identification of enteroviruses isolated from sea-water: indirect immunofluorescence (IIF).

In this research the Enteroviruses presence in sea water was studied. In previous studies presumptive Enteroviruses were revealed in 43% and in 77% of sea water samples analyzed. It was necessary to identify viral particles isolated from marine water because the detection of this kind of virus was performed only on the basis of cytopathic effect appearance on cell cultures. The aim of this research was to verify the suitability of Indirect Immunofluorescence for identification of presumptive Enteroviruses isolated from marine waters. 13 field strains from RC 37 cells (Cercopithecus Kidney cell line) were tested. Pools of Horse immune sera against COXS, POLIO and ECHO, and anti-horse antibodies conjugated with fluorescein were used. The results revealed the presence of Coxsackie virus and Echo virus. There were many problems related with ECHO identification for the presence of cross-reactions with COXS. The IIF method cannot be performed routinely, because it did not show high level of specificity and sensibility, and it is expensive. This methodology can be used only in particular cases and in laboratories with competent virologists and related facilities. In the future, the only suitable methodology for identification of Enteroviruses isolated from field samples is based on the use of RNA and DNA probes.

Antigens, Viral↗
PubMed1987

Detection of hepatitis A virus in the stools of healthy people from endemic areas.

One-hundred-ninety-two stool samples were tested for the presence of human Hepatitis A antigen. Sixteen of these were also evaluated for the presence of infectious virus. All samples were obtained from young and apparently healthy people from endemic areas for Hepatitis A disease. The isolation of the infectious virus from these stools demonstrates clearly the wide diffusion of the virus in these areas, and its transmission by the oral-fecal route.

Adolescent↗
PubMed1987

Indirect immunofluorescence application in the epidemiological study of hepatitis A.

We used IIF test for seroepidemiological study on 531 sera divided in age-groups obtained from apparently healthy subjects of Rome. Our results confirm the endemicity of HAV (Hepatitis A virus) infection in Rome with a prevalence of more than 50%. The application of the anti-HAV IIF (Indirect Immunofluorescence) test to a large number of sera demonstrated its usefulness as a quantitative and qualitative test in the epidemiological field.

Adolescent↗
PubMedDate not supplied

HAV recovery from tap water: evaluation of different types of membranes.

A cytopathic strain of hepatitis A virus (HAV) has been used to evaluate the absorption-elution of several membranes. Filters were obtained from four different manufactures: Sartorius, Millipore, Gelman and Cuno. Only the electronegative HAWP (Millipore) and the electropositive (Cuno-Div.) filters appear to absorb HAV with a high efficiency.

Adsorption↗