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Giovanni Di Perri

Publications and source records attributed to Giovanni Di Perri.

44 records · Page 3Linked to original sources
PubMed2002

The unbound percentage of saquinavir and indinavir remains constant throughout the dosing interval in HIV positive subjects.

AIMS: To measure the unbound plasma concentrations of saquinavir (SQV) and indinavir (IDV) and to relate them to the total plasma concentrations in order to establish the unbound percentage of protease inhibitors in vivo during a full dosage interval profile. METHODS: HIV-infected subjects (n = 35; median CD4 cell count = 340 x 10(6) cells l-1, range: 120-825; viral load < 50 copies ml-1 in 22/35) treated with SQV or IDV containing regimens were studied. Plasma drug samples were collected at 0, 2, 4, 8 and 12 h postdose for the twice daily regimens and 0, 1, 2, 4 and 8 h for the three times daily regimens. Ultra-filtration was used to separate unbound IDV and SQV in plasma and their respective concentrations were measured by a fully validated method using high performance liquid chromatography-mass spectometry (h.p.l.c.-MS/MS). RESULTS: Based on the ratio AUCunbound/AUCtotal, the median unbound percentage (95% CI for differences) of SQV and IDV from all the samples studied was 1.19% (0.99, 1.58%) and 36.3% (35.1, 44.2%), respectively. No significant difference was seen in the percentage binding of SQV between patients receiving SQV alone (median = 1.49%) or with ritonavir (median = 1.09%; P = 0.141; 95% CI for difference between medians = -0.145, 0.937) over the pharmacokinetic profile. Similarly, no significant difference was seen in the percentage binding of IDV in patients receiving IDV alone (median 35.2%) or with ritonavir (median = 41.3%; P = 0.069; 95% CI for difference between medians = -0.09, 15.4). The unbound concentrations of SQV (P < 0.0001; 95% CI for r(2) = 0.634, 0.815) and IDV (P < 0.0001; 95% CI for r(2) = 0.830, 0.925) remained constant as a proportion of total concentration over the full dosing profile. CONCLUSIONS: These in vivo data confirm previously published in vitro measurements of SQV and IDV protein binding. The unbound percentage of both protease inhibitors remained constant over the dosing interval.

Adult↗
PubMed2002

Pharmacokinetics of saquinavir co-administered with cimetidine.

The present study evaluated the effect of cimetidine, a histamine H(2) receptor antagonist able to inhibit cytochrome P450 metabolism, on the steady-state pharmacokinetics of saquinavir soft gel. Twelve healthy volunteers (eight males and four females) participated in an open-label, double-phase pharmacokinetic study. Volunteers took saquinavir soft gel 1200 mg three times a day for 13 days and then saquinavir soft gel 1200 mg twice a day with cimetidine 400 mg twice a day from day 14 to 26. The pharmacokinetics of saquinavir on days 13 and 26 were compared. All 12 volunteers completed the study. The association of cimetidine with saquinavir soft gel 1200 mg twice a day resulted in a significant increase in saquinavir AUC(0-24) (120%; P = 0.023) and C(max) (179%; P = 0.019), whereas C(trough) did not differ significantly (32% increase; P = 0.272). Increased exposure to saquinavir was observed in healthy volunteers after co-administration with cimetidine. The most significant increase involved C(max). Further pharmacokinetic studies in HIV-infected subjects are warranted to confirm the boosting effect of cimetidine and to investigate any impact that the increase in saquinavir C(max) may have on intracellular accumulation of the drug.

Adult↗
PubMed2002

Simultaneous determination of rifampicin and efavirenz in plasma.

Complex drug interactions involving antiretroviral agents and drugs for the management of opportunistic infections demand the monitoring of plasma drug concentrations to prevent treatment failure. The high occurrence of tuberculosis in HIV-infected subjects makes the management of HIV treatment complex. Rifampicin, a potent inducer of the cytochrome P 450 metabolic pathway, is a very active antituberculosis drug that accelerates the metabolism of protease inhibitors. Regimens containing efavirenz, a non-nucleoside reverse transcription inhibitor, could be an alternative, but efavirenz plasma concentrations may be altered after the coadministration of rifampicin. Efavirenz is also a cytochrome P 450 inducer and may alter rifampicin plasma levels. Due to the increasing need to monitor plasma concentrations in HIV patients with tuberculosis, a high-performance liquid chromatographic (HPLC) method has been developed to measure rifampicin and efavirenz at the same time in a small amount of sample. This HPLC method is highly sensitive and precise, suitable for pharmacokinetic studies or routine clinical monitoring of rifampicin and efavirenz simultaneously in HIV patients with tuberculosis.

Adult↗
PubMedDate not supplied

Pharmacodynamic analysis of antimalarials used in Plasmodium falciparum imported malaria in northern Italy.

BACKGROUND: Conventional treatment of imported malaria in Italy consists of quinine or mefloquine. Since beta-arthemeter is now available, an open-label pharmacodynamic analysis was performed in 73 adults with uncomplicated Plasmodium falciparum malaria. In vitro susceptibility to mefloquine and quinine was evaluated at admission. METHODS: According to clinical status, baseline parasitemia (P(0)), and premunition, the patients received intravenous quinine, oral mefloquine, or beta-arthemeter. The following parameters were measured: parasitemia at 0, 6, 12, and 24 hours and then every 24 hours until negative; time to 50%, 90%, and 100% reduction in parasite density (PC(50), PC(90), and PCT); parasite reduction ratio at 24 and 48 hours (PRR(24) and PRR(48)); percentage of patients with undetectable parasitemia at 48 hours (PPUP(48)); time required to eradication; in vitro susceptibility to mefloquine and quinine by World Health Organization Microtest Mark III. RESULTS: Of the study patients, 54.8% were immigrants from malaria-endemic countries. All the infections were acquired in Africa. All the patients were treated successfully. According to the pharmacodynamic parameters measured, no significant differences were recorded among patients with or without prior exposure to malaria. Pharmacodynamic comparison was performed between quinine and beta-arthemeter. Significantly higher clearance times were recorded for beta-arthemeter vs quinine (PC(50), PC(90), and PCT: 16.8, 42.6, and 72 h for quinine vs 7.9, 12.2, and 48 h for beta-arthemeter; p values: .02, < .0001, and .008, respectively). The number of patients who obtained a PPUP(48) with beta-arthemeter was higher than with quinine (66.7 vs 9.1%, p < .003), and PRR(24) was significantly higher in beta-arthemeter-treated patients (617 vs 3.15, p = .0001). PRR(48) and time to eradication were not measurable in the beta-arthemeter group (negative P at 48 h in most cases). Two recrudescences occurred after 5 and 7 days of beta-arthemeter monotherapy. All strains were fully susceptible to quinine and mefloquine. CONCLUSIONS: Pharmacodynamic properties of mefloquine and quinine are in the range reported in literature. The better PCT and pharmacodynamics of beta-arthemeter suggest that it could be used as a first-line agent, coadministered with mefloquine.

Administration, Oral↗