Biomedical subjects

Paola Bertocchi

Publications and source records attributed to Paola Bertocchi.

4 recordsLinked to original sources

PubMed2006

Development and validation of a reversed-phase LC method for analysing potentially counterfeit antimalarial medicines.

Pharmaceutical counterfeiting is more and more a public health problem, especially in developing countries where the most counterfeit drugs are antibiotics, antimalarials and other life-saving drugs. The evaluation of the phenomenon extent is of great concern to the World Health Organization for carrying out a global strategy to combat the phenomenon. To this purpose, a reversed-phase liquid chromatographic method to perform the separation and simultaneous determination of three different kinds of antimalarial drugs (chloroquine, quinine and mefloquine) was developed. The method was validated by using both commercial and in-laboratory produced tablets and was then verified on various in-laboratory produced formulations differing in excipient composition. Finally, the method was successfully applied to the analysis of medicinal samples purchased from the informal market in Congo, Burundi and Angola.

Antimalarials↗

PubMed2005

Physico-chemical characterisation and intrinsic dissolution studies of a new hydrate form of diclofenac sodium: comparison with anhydrous form.

Diclofenac sodium is a non-steroidal anti-inflammatory drug widely used in painful and inflammatory diseases. In standard conditions, by exposure to relative humidity even below 60% at 25 degrees C, the anhydrous form DS gives rise to a hydrate species DSH, a tetrahydrate form different from that obtained by crystallisation from water and previously described. The method of preparation and the physico-chemical properties of the hydrate form were investigated. Data from FTIR spectroscopy, X-ray powder diffraction and thermal analysis were used for the identification and the characterisation of DSH. DS and DSH were easily differentiated by their IR spectra, X-ray patterns and thermal behaviour. DSH stability was followed at room temperature over a period of 1 year and under different conditions of temperature to verify the tendency to solid-solid transition and to study its existence range. Solubility and intrinsic dissolution studies were performed to compare the physico-chemical properties of DS and DSH. Differences in solubility and intrinsic dissolution rates were pointed out: these studies showed that DS dissolved faster than DSH. Storage under uncontrolled environmental conditions or contact with water vapour during manufacturing process could thus influence the performance of the final dosage form.

Calibration↗

PubMed2004

Diclofenac sodium multisource prolonged release tablets--a comparative study on the dissolution profiles.

The aim of this work was to compare the dissolution behaviour of six diclofenac sodium prolonged release tablets of different brands obtained from the national market. The formulations contain the same amount of drug substance but different types and/or amount of excipients. The influence of these differences in formulation on the release characteristics of the dosage forms was evaluated on the European Pharmacopoeia apparatus 2 (paddle) employing eight different dissolution media in the pH range 1.2-8. Friability and hardness were tested too according to the European Pharmacopoeia. Dissolution profiles obtained from the studied formulations showed that the release characteristics vary considerably among different manufacturers and that even identical formulations show rather dissimilar release profiles in all the studied media. Use of both SIF without pancreatin and SIF without pancreatin containing 1% (w/v) Tween 20 resulted in strong discrimination among products. A correlation between friability and hardness and in vitro dissolution was evidenced for two formulations having identical excipient composition.

Anti-Inflammatory Agents, Non-Steroidal↗

PubMed2003

Effects induced by hydroxyl radicals on salmon calcitonin: a RP-HPLC, CD and TEM study.

The effects of hydroxyl radical attack on a peptidic drug were studied in vitro. Different chemico-physical techniques were used to investigate structural damage induced by oxidative stress conditions in salmon calcitonin (sCT), a peptide hormone used in treating osteoporosis. Reversed-phase liquid chromatography (RP-HPLC), circular dichroism (CD) and transmission electron microscopy (TEM) were applied to measure formation of oxidation/degradation products and to reveal the conformational and ultrastructural modifications in the presence of OH. free radicals. Hydroxyl radicals were obtained from ferrous sulfate and ascorbic acid mixtures. The RP-HPLC results revealed the formation of new chromatographic peaks indicating a number of degradation/oxidation products formed in the presence of OH. free radicals. CD spectra showed slight protein conformational modifications as well as aggregation. TEM confirmed sCT aggregation and suggested the formation of fibrillar aggregates.

Calcitonin↗