Creation of pacemaker remote monitoring networks between hospital and pharmacies during Covid-19 outbreak.

INTRODUCTION: Remote Monitoring (RM) of Cardiac Implantable Electronic Devices (CIEDs) is proven to be safe and efficient. It has been adopted in our center since years. At the time of the recent Covid-19 outbreak, we introduced and tested a collaborative organizational model, through a new RM device (Totem), creating a network with the surrounding territory and limiting CIED patients' presence in hospital. METHODS: We involved 4 neighbor pharmacies where Totem devices were installed; we called and informed 64 patients with Totem compatible pacemaker (PM) about the possibility to perform their PM follow-up (FU) in-pharmacy; 58 gave their consent and their data were inserted into our RM database. RESULTS: During an 18-month FU period, a total of 70 RM transmissions have been received: one alert of high atrial burden triggering a pharmacological optimization, one alert of high ventricular impedance leading to a new ventricular lead implantation and four alerts of elective replacement indicator. Fulfilled questionnaires revealed complete patient satisfaction. CONCLUSIONS: A collaborative network between our hospital and the surrounding territory to perform RM FUs of CIEDs during Covid-19 pandemic was feasible, leading to patient compliance and satisfaction and revealing important technical and clinical alerts.

Radiosurgery of limited brain metastases from primary solid tumor: results of the randomized phase III trial (NCT02355613) comparing treatments executed with a specialized or a C-arm linac-based platform.

BACKGROUND: Comparative prospective data regarding different radiosurgery (SRS) modalities for treating brain metastases (BMs) from solid tumors are not available. To investigate with a single institute phase III randomized trial whether SRS executed with linac (Arm-B) is superior to a dedicated multi-source gamma-ray stereotactic platform (Arm-A). METHODS: Adults patients with 1-4 BMs from solid tumors up to 30 mm in maximum diameter were randomly assigned to arms A and B. The primary endpoint was cumulative incidence of symptomatic (grade 2-3) radionecrosis (CIRN). Secondary endpoints were local progression cumulative incidence (CILP), distant brain failure, disease-free survival (DFS), and overall survival (OS). RESULTS: A total of 251 patients were randomly assigned to Arm-A (121) or Arm-B (130). The 1-year RN cumulative incidence was 6.7% in whole cohort, 3.8% (95% CI 1.9-7.4%) in Arm-B, and 9.3% (95% CI 6.2-13.8%) in the Arm-A (p = 0.43). CIRN was influenced by target volume irradiated only for the Arm-A (p << 0.001; HR 1.36 [95% CI 1.25-1.48]). Symptomatic RN occurred in 56 cases at a median time of 10.3 months (range 1.15-54.8 months), 27 in the Arm-B at a median time of 15.9 months (range 4.9-54.8 months), and 29 in the Arm-A at a median time of 6.9 months (1.2-32.3 months), without statistically significant differences between the two arms. No statistically significant differences were recorded between the two arms in CILP, BDF, DFS or OS. The mean beam-on time to deliver SRS was 49.0 ± 36.2 min in Arm-A, and 3.1 ± 1.6 min in Arm-B. CONCLUSIONS: Given the technical differences between the treatment platforms investigated in this single-institution study, linac-based SRS (Arm-B) did not lead to significantly lower grade 2-3 RN rates versus the multi-source gamma-ray system (Arm-A) in a population of patients with limited brain metastases of small volume. No significant difference in local control was observed between both arms. For Arm-B, the treatment delivery time was significantly lower than for Arm-A. TRIAL REGISTRATION: ClinicalTrials.gov Identifier NCT02355613.

The 70-year-old newly diagnosed glioblastoma patients are older than the 65-year-old? Outcome evaluation of the two categories in a matched case control study with propensity score balancing.

BACKGROUND: The standard of care for elderly, newly-diagnosed glioblastoma patients consists, if feasible, of surgical resection followed by a short course of radiation therapy (RT) with concomitant and adjuvant temozolomide chemotherapy (TMZCHT). To date, the literature lacks of consistence in the definition of elderly, if older than 65 years, or 70 years. Aim of this study was to explore whether differences exist between these two cohorts, comparing outcomes using a propensity score matched analysis (PSM). MATERIALS AND METHODS: Two hundred twenty-one elderly newly diagnosed glioblastoma patients were included. All patients received surgery followed by RT with concurrent and adjuvant TMZCHT. The RT dose prescribed was 60 Gy/30 fractions for patients 65-69-year-old or 40.5 Gy/15 fractions for ≥70-year-old. After 1:1 matching there were 86 patients in each group. Distribution of covariates was adequately balanced in the matched data set. RESULTS: After PSM median PFS time, 1,2,3-year PFS rates were 10 months, 33.3%, 13.1%, and 6.6% for the 65-69-year group, 9 months, 34.7%, 11% and 4.8% for the ≥70-year group (p = 0.530). Median OS time, and 1,2,3-year OS rates were 14 months, 54.1%, 23.4%, 13.9% for the 65-69-year old group, and 12 months, 49.3%, 21.5%, 10% for the ≥70-year group (p = 0.357). No differences were recorded in relation to different groups of age. CONCLUSIONS: The PSM analyses showed a similar outcome in 65-69-year old patients compared to older ones notwithstanding a more burdensome RT schedule. Hypofractionated RT treatment has to be considered also in this group of younger elderly, newly-diagnosed GBM patients.

Development of a new HPLC method using fluorescence detection without derivatization for determining purine nucleoside phosphorylase activity in human plasma.

Purine nucleoside phosphorylase (PNP) activity is involved in cell survival and function, since PNP is a key enzyme in the purine metabolic pathway where it catalyzes the phosphorolysis of the nucleosides to the corresponding nucleobases. Its dysfunction has been found in relevant pathological conditions (such as inflammation and cancer), so the detection of PNP activity in plasma could represent an attractive marker for early diagnosis or assessment of disease progression. Thus the aim of this study was to develop a simple, fast and sensitive HPLC method for the determination of PNP activity in plasma. The separation was achieved on a Phenomenex Kinetex PFP column using 0.1% formic acid in water and methanol as mobile phases in gradient elution mode at a flow rate of 1ml/min and purine compounds were detected using UV absorption and fluorescence. The analysis was fast since the run was achieved within 13min. This method improved the separation of the different purines, allowing the UV-based quantification of the natural PNP substrates (inosine and guanosine) or products (hypoxanthine and guanine) and its subsequent metabolic products (xanthine and uric acid) with a good precision and accuracy. The most interesting innovation is the simultaneous use of a fluorescence detector (excitation/emission wavelength of 260/375nm) that allowed the quantification of guanosine and guanine without derivatization. Compared with UV, the fluorescence detection improved the sensitivity for guanine detection by about 10-fold and abolished almost completely the baseline noise due to the presence of plasma in the enzymatic reaction mixture. Thus, the validated method allowed an excellent evaluation of PNP activity in plasma which could be useful as an indicator of several pathological conditions.

Is hydrokinesitherapy effective on gait and balance in patients with stroke? A clinical and baropodometric investigation.

BACKGROUND: Patients with stroke present an asymmetric posture, severe balance dysfunction with delayed and disrupted equilibrium reactions, exaggerated postural sway and abnormal gait with an increased risk of falling. The aim of this study is to evaluate the efficacy of hydrokinesytherapy on stance, balance and gait in individuals after stroke. METHODS: In this single-blinded randomized controlled trial, patients with stroke were divided into two groups: an experimental one (G1), performing hydrokinesytherapy (3 times/week) in addition to a conventional physical therapy (3 times/week) and a control one (G2), performing only a conventional physical therapy (6 times/week). All of the participants underwent a proper clinical and baropodometric evaluation before and after 8 weeks of treatment. RESULTS: The two groups presented similar clinical and instrumental features at enrolment (mean modified Rankin Scale of 3, and a disease duration of 6.3 ± 1.4 months). After treatment, the patients undergoing hydrokinesytherapy showed a significantly greater improvement than those undergoing traditional training. CONCLUSIONS: Hydrokinesytherapy may be considered a promising treatment in improving gait and balance in individuals following stroke.

Is generic rifaximin still a poorly absorbed antibiotic? A comparison of branded and generic formulations in healthy volunteers.

Rifaximin is an antibiotic, locally acting in the gastrointestinal tract, which may exist in different crystal as well as amorphous forms. The branded rifaximin formulation contains the polymorph rifaximin-α, whose systemic bioavailability is very limited. This study was performed to compare the pharmacokinetics of this formulation with that of a generic product, whose composition in terms of solid state forms of the active pharmaceutical ingredient was found to be different. Two tablets (2×200mg) of branded and generic formulations were given to 24 healthy volunteers of either sex, according to a single-blind, randomized, two-treatment, single-dose, two-period, cross-over design. Plasma and urinary samples were collected at preset times (for 24h or 48h, respectively) after dosing, and assayed for rifaximin concentrations by high-performance liquid chromatography-mass spectrometry. Rifaximin plasma and urine concentration-time profiles showed relevant differences when generic and branded rifaximin were compared. Most pharmacokinetic parameters were significantly higher after administration of generic rifaximin than after rifaximin-α. In particular, the differences for Cmax, AUC and cumulative urinary excretion between the generic formulation and the branded product ranged from 165% to 345%. The few adverse events recorded were not serious and not related to study medications. The results of the present investigation demonstrate different systemic bioavailability of generic and branded formulations of rifaximin. As a consequence, the therapeutic results obtained with rifaximin-α should not be translated sic et simpliciter to the generic formulations of rifaximin, which do not claim containing only rifaximin-α and will display significantly higher systemic absorption in both health and disease.

Development steps of pharmacokinetics: a perspective on bioanalytical methods and bioequivalence.

This paper describes the main development steps of pharmacokinetics that paralleled the development of analytical bioassay methods. From the first stirrings on 1950s, with very sensitive but not specific radiotracing measurements using 14C or 3H labelled drugs, to further developments with more specific methods like gas chromatography, high pressure liquid chromatography, to the last achievement with tandem mass spectrometry, pharmacokinetics has supported all the development procedures of both NDA (New Drug Application) and ANDA (Abridged New Drug Application). The discovery of new therapeutic active molecules is now concentrated in a few very big companies, and requires pharmacokinetic support from the first screening procedures to the last clinical developments. Medium and small pharmaceutical companies largely use pharmacokinetics for various new applications of existing drugs now out of patent, that require only or mainly pharmacokinetic, bioavailability, bioequivalence investigations in compliance with the ANDA procedure. In spite of guidelines published by US FDA and EU EMA, some open problems on bioequivalence would still require more attention from regulatory authorities, like how to manage the puzzle of endogenous substances, ethical problems against the repeated-dose regimen with some drugs and how to manage Cmax in the presence of the multiple-peak phenomenon.

Critical considerations into the new EMA guideline on bioequivalence.

The market of generic drugs has been greatly developing during the last 15 years in various European Union (EU) member states, mainly in the Mediterranean area, including non-EU countries, i.e., in the Middle East. This has required a more detailed support from EMA (European Medicines Agency) as guidelines are concerned. Previous EU guidelines on bioavailability and bioequivalence neglected some relevant issues often met in bioequivalence trials, defined in the literature as "open questions on bioequivalence". In the absence of EU specific directives these problems were managed by EU investigators in compliance with U.S. FDA (Food and Drug Administration) guidelines that had already considered some of these "open problems". The latest EMA guideline operating from August 1, 2010 focuses on various relevant issues, including directions on orodispersible tablets, how to operate in the case of high variability, or how to manage the carryover effect of plasma concentrations, but, e.g., it is still neglecting the issue of the multiple-peak phenomenon. In addition, comprehensive directions are still needed on how to manage clinical studies in which endogenous substances are involved. The present review focuses on situations now appropriately discussed in the latest EU guideline, as well as other situations that still need to be defined and need further attention by the regulatory agency in order to give additional adequate directions to the investigators.

Pharmacokinetics and pharmacodynamics of ritodrine hydrochloride administered orally and intramuscularly to female healthy volunteers.

Ritodrine hydrochloride ((R,S)-4-hydroxy-alpha-[1-[2-((4-hydroxyphenyl)ethyl]amino)ethyl]benzenemethanol, CAS 26652-09-5) is a direct-acting sympathomimetic agent with a predominant beta-adrenergic activity and a selective action on beta2-receptors. A clinical trial was carried out to investigate the pharmacokinetics, pharmacodynamics and safety of ritodrine hydrochloride administered at the doses of 10, 20 and 30 mg p.o. and 10 mg by i. m. route. A four-way randomised crossover design was adopted on 12 healthy female volunteers with a wash-out of at least 14 days. Concentrations of ritodrine and of the pool of ritodrine in plasma and concentrations of the pool of ritodrine in urine of volunteers were bioassayed with tandem mass spectrometry. The following pharmacokinetic parameters were calculated, using the non-compartmental model: Cmax, AUC0-t, AUC0-INF, t1/2, Vd/f, and Aet after each administration. The distribution volume of ritodrine proved to be about 3 times higher than that of the pool of ritodrine after i. m. injection, confirming the good permeability of ritodrine that massively enters tissue compartments. Statistical analyses of pharmacokinetic parameters ascertained that the p. o. absorption of ritodrine hydrochloride was linearly related with the doses administered in the 10-30 mg range. The pharmacodynamic parameters evaluated complied with the mechanism of action of this drug.

Pharmacokinetics of isoxsuprine hydrochloride administered orally and intramuscularly to female healthy volunteers.

Isoxsuprine (1-(4-hydroxyphenyl)-2-(1-methyl-2-phenoxyethylamino)-1-propanol, CAS 395-28-8) is a peripheral vasodilator that also stimulates beta-adrenergic receptors. It causes a direct relaxation of vascular and uterine smooth muscles and produces positive inotropic and chronotropic effects. It is widely used to arrest premature labour and miscarriage. The aim of this trial was to investigate the pharmacokinetics of isoxsuprine hydrochloride administered orally to healthy young female volunteers as an extended-release formulation at the doses of 30, 60 and 90 mg compared to 10 mg by i.m. route. A randomised, crossover, four-period, multisequence, single-dose design was adopted. Plasma and urine concentrations of free and total isoxsuprine were evaluated by tandem mass spectrometry that reached a low quantification limit of 1 ng/ml. From plasma concentrations Cmax, tmax, AUC(0-t), AUC(0-infinity), t1/2 and Vd and from urine concentration CUE(0-24h) were evaluated by the non-compartmental model. The free drug was present only in plasma after i.m. route, whereas total isoxsuprine, namely the drug after an enzymatic hydrolysis of the conjugate form, was detected in all plasma and urine samples. The distribution volume of the free drug proved to be 2.5 times higher than that of total isoxsuprine, which indicates a good penetration of the free drug into tissue compartments. Oral absorption was evaluated from the p.o./i.m. percentualized ratio of AUC and CUE and proved to be on average around 51%, being linearly correlated with the three doses administered. The oral absorption proved to be sustained as expected from the zero-order kinetics of the drug release from the core of the extended-release formulation. This has justified different values of half-life that was on average 2.2 h after the i.m. route and around 10 h after the three oral doses. After isoxsuprine administration, both oral and i.m. routes, the heart rate increased from baseline during the 9 h monitoring period. This was an expected finding attributable to the stimulating activity of beta-adrenergic receptors. The tolerability of isoxsuprine proved to be very good with all the four administrations performed.

Open questions on bioequivalence: what about the time interval between two consecutive trials?

The interval between two different consecutive pharmacokinetic trials in the same healthy volunteers lasts traditionally 3 months, in compliance with the turnover of blood donations in volunteers. The above trials, in fact, mainly bioequivalence trials, involve pharmacokinetic measurements and relevant blood withdrawals, e.g. 400-500 ml. Operating guidelines do not give any suggestion about the above lapse of time between two consecutive trials. An Italian Ministerial Decree (DM 122/98) requires the above period to last at least 6 months. This appears to be a unique more than a rare request in this field. In fact, it does not add anything to the quality of the trial and invades the field of competence of the ethics committees and virtually needs a national register of the volunteers to allow a check. This appears to be an additional open question on bioequivalence.

Tandem mass spectrometry (LC-MS-MS): a predominant role in bioassays for pharmacokinetic studies.

Plasma concentrations of drugs and drug metabolites in bioavailability studies are routinely bioassayed with high performance liquid chromatography (HPLC), gas chromatography (GC), and liquid chromatography coupled with tandem mass spectrometry (LC-MS-MS) methods. In the 1980s and 1990s, HPLC had achieved a relevant role compared to GC and other techniques in pharmacokinetic bioassays. However, in the last few years the LC-MS-MS technique, known as tandem mass spectrometry, has attained a predominant role over all other techniques. This is because it requires a less amount of matrix, possesses better specificity and sensitivity, and requires a shorter operating time. In the experience of the authors, LC-MS-MS in fact requires on average 3-4 fold shorter time to complete a bioequivalence study when performed by one operator than does HPLC. The higher cost of the apparatus and technical assistance of LC-MS-MS are fully compensated by the shorter operating time. Part or most of the HPLC apparatuses have been or are being replaced by LC-MS-MS systems in laboratories operating in clinical and pre-clinical pharmacokinetics and, to a large extent, in those involved in assessing permeability in screening procedures of new chemical entities. This paper analyses the growing development of the LC-MS-MS technique and compares four couples of methods validated with HPLC or GC versus LC-MS-MS, giving analytical details of the two approaches.

Open questions on bioequivalence: an updated reappraisal.

During the last thirteen years, the author has investigated a relevant number of bioequivalence trials, for the approval of generics, which in the Mediterranean area show an increasing business trend. In his activity the author has faced several problems, most of them not considered in operating guidelines, defined "open questions on bioequivalence". They deal with the most appropriate procedures to adopt in case of studies on drugs with long half-lives, of ethics problems, high data dispersion, endogenous substances, presence of active metabolite(s), prevalent metabolites and reversible metabolism, very low plasma concentrations, multiple peak phenomenon, titre differences, polymorphic metabolism, stereogenic atoms. The relevance of a pilot trial, mainly for modified-release formulations, and the problem of frauds are discussed as well. These open questions are discussed in the present review taking into account EU and US FDA guidelines, current literature and personal experience. In most cases suitable approaches are suggested. Appropriate procedures should be planned and defined in the study protocol and extensively discussed in the final report. An appropriate approach to the "open questions" is a requisite to achieve a clearly defined bioequivalence/bioinequi-valence conclusion.

Bioassay of safinamide in biological fluids of humans and various animal species.

This paper describes three methods to bioassay safinamide (CAS 133865-89-1) in biological fluids of humans and laboratory animals for pharmacokinetic, toxicokinetic and bioavailability studies. Two methods profited from liquid chromatography tandem mass spectrometry (LC-MS-MS) system, one (micro bioassay) working in the low dynamic range 0.5-20 ng/ml, the other in the range 20-6000 ng/ml. A third method used high-performance liquid chromatrography with fluorimetric detection (HPLC-FD), working in the dynamic range 20-1000 ng/ml. All the three methods were validated in compliance with the accreditated views on analytical bioassays. The shorter run time (5.5 min vs 16 min) has led the authors to prefer the two LC-MS-MS methods to the HPLC-FD bioassay, even if all the performances of the three methods were excellent. The methods described in this paper were and are still now extensively used to assay safinamide in more than 10,000 specimens of biological fluids from humans and laboratory animals in the development program of the drug. Main pharmacokinetic results obtained in various Phase I trials on healthy volunteers are briefly reported.

Bioequivalence study of fluoxetine hydrochloride in healthy volunteers.

Fluoxetine hydrochloride (CAS 59333-67-4) is a selective serotonin reuptake inhibitor (SSRI) widely used as antidepressant drug. The aim of the present trial was to assess the bioequivalence of a new formulation of the drug (test formulation) as compared to a reference product from the Swiss market. Both drugs were available as 20 mg dispersible tablets. The trial was performed according to a two-period, two-sequence, balanced, randomised, single-dose design with a wash-out phase of at least 56 days. The two formulations were tested in 30 male healthy volunteers. A specific highly sensitive bioassay in tandem mass spectrometry allowed to set the limit of quantification to 100 pg/ml for fluoxetine and norfluoxetine. Average t(max) was 5.4 h for fluoxetine and 71-80 h for norfluoxetine. The peak concentration was on average 14 ng/ml for fluoxetine and 10.5 ng/ml for norfluoxetine. Half-life was on average 48-50 h for fluoxetine and 130-138 h for norfluoxetine. AUC infinity for fluoxetine and norfluoxetine were on average 790 and 2800 ng x ml(-1) x h, respectively. All these figures demonstrate that plasma concentration-time profiles of fluoxetine and norfluoxetine are quite different. Applied statistical tests, suggested by operating guidelines, demonstrated bioequivalence of the test formulation and the reference formulation. The conclusion on bioequivalence was based on both fluoxetine and norfluoxetine results. 90 % confidence Intervals for Cmax, AUCt and AUC infinity (fluoxetine and norfluoxetine) were within the acceptance range (0.80-1.25) and t(max), processed with a non-parametric test, did not show any statistically significant difference between test and reference formulation. Safety and tolerability proved to be similarly good with both test and reference formulation. In conclusion, the present trial has demonstrated bioequivalence of the test and the reference formulation, both consisting of fluoxetine hydrochloride dispersible tablets.

Pharmacokinetics of N-acetylcysteine following repeated intravenous infusion in haemodialysed patients.

OBJECTIVE: N-acetylcysteine (NAC) is a mucolytic agent with anti-oxidant properties. It might have potential positive effects in renal patients and, therefore, its pharmacokinetics and safety in haemodialysis was investigated. METHODS: Twelve dialysis patients received 2 g NAC (10 ml NAC 20% solution i.v.) mixed with 500 ml saline during the first 3 h of the session for six dialysis sessions. A bolus of heparin was injected intravenously as LWH-heparin. In six patients, one session was repeated with NAC mixed with heparin and infused through the heparin pump. RESULTS: Baseline NAC was on average 454 ng ml(-1); its concentration increased to 9,253 ng ml(-1) at the second infusion and attained a steady state between 14,000 ng ml(-1) and 17,000 ng ml(-1) at the fourth dose. We observed a C (max) of 53,458 ng ml(-1) with a t (max) of 3.0 h. Plasma clearance was 1.25 l h(-1) and dialytic clearance 5.52 l h(-1). No side effects were observed. CONCLUSION: In the case of repeated doses, the NAC pre-dose concentration after repeated infusion of 2 g of the drug during the first 3 h of a dialysis session reached the steady state at the fourth infusion, without further accumulation. The dialytic clearance is effective, the total body clearance being reduced to 1.25 l h(-1). In dialysis patients, 2 g NAC given intravenously over 3 h is a safe dosage, with no short-term side effects.

Pharmacokinetics and pharmacodynamics of safinamide, a neuroprotectant with antiparkinsonian and anticonvulsant activity.

OBJECTIVE: This paper describes the pharmacokinetics and the pharmacodynamics, in terms of monoamino oxidase type B (MAO-B) inhibition, in male healthy volunteers of orally administered safinamide, a new neuroprotectant that in experimental models has demonstrated strong anticonvulsant and antiparkinson activities. METHODS: Four clinical trials covering the dose range of 25-10,000 microg/kg were carried out to describe pharmacokinetics, pharmacodynamics and tolerability of safinamide, administered in single or repeated dose regimen to steady state, including a food interaction trial. All the above trials were carried out after the Ethics Committee's approval and signature of the consent form by the volunteers. In single dose trials blood sampling covered a 24 h-period in pharmacodynamic trials, 48 h-period in pharmacokinetic trials. In the case of repeated dose regimen to steady state a pre-dose sample was drawn on the first six study days, whereas the curve was explored on the 7th study day, prolonging blood sampling over a 48 h-period after the last dosing. Safinamide level was determined in plasma by a very sensitive and specific LC-MS-MS method, with a low limit of quantification of 0.5 ng/ml of plasma. Pharmacokinetic analysis was carried out with non-compartmental method and, in one case, also with the two-compartmental method. Monoamine oxidase activity of both types A and B (MAO-A and MAO-B) was determined in plasma at different times (MAO-B) and correlated to safinamide levels, or in urine (MAO-A). RESULTS: Pharmacokinetics of safinamide proved to be linearly and proportionally related to the administered doses. The absorption of safinamide was rapid with peak plasma concentrations ranging from 2 to 4 h. Food prolonged the rate and did not affect the extent of absorption of safinamide. In repeat dose regimen once daily, the steady state was reached on the 5th study day with a marginal accumulation factor of 1.5-1.7. The drug was cleared with a t(1/2) of about 22 h. Safinamide reversibly inhibited MAO-B enzyme. Full inhibition was observed with single doses >/= 600 microg/kg, and a relevant, dose dependent, progressive inhibition was encountered with doses starting from 25 microg/kg. Even at the highest single dose of 10 mg/kg no evidence of MAO-A inhibition was observed. CONCLUSION: Enteral absorption of the drug is linear and proportional to the doses administered. The drug is cleared from the body with a t(1/2) of approximately equal to 22 h, without producing any clinically relevant accumulation at steady state. The MAO-B inhibitory activity, without affecting MAO-A, is useful to prevent a dopamine bioinactivation in patients suffering from Parkinson's disease. Safinamide tolerability in the four clinical trials proved to be good.

The degree of predictivity in pilot studies on six subjects in bioequivalence trials.

This study, based on computer simulations, analysed the degree of predictivity of pilot trials on six subjects, with the idea of a further pivotal trial on 18 or more volunteers aimed at assessing bioequivalence. Volunteers enrolled in 10 pivotal bioequivalence trials were considered. For every trial, a thousand bootstrap samples were generated to simulate trials with six subjects, while keeping a balanced design for sequence, period and formulation. Then a standard ANOVA for crossover trials, with 90% confidence intervals for the ratios, was done on C(max) and AUC for each simulated trial. The number of subjects needed to achieve bioequivalence was based on the residual error of the ANOVA. When this number was smaller or equal in the case of bioequivalence, or larger in the case of insufficient evidence to conclude on bioequivalence, to the number of the subjects enrolled in the original trial, the subgroup was considered predictive. Otherwise it was considered non-predictive.The average predictivity index, calculated by dividing the number of predictive findings by the total number of subgroups, in our case 1000, and multiplying the result by 100, was 71.1% for C(max) and 82.9% for AUC. Results of the simulations suggest that pilot trials on six volunteers can be useful for predicting the pool size of volunteers in bioequivalence trials, and for in vivo-in vitro correlation studies in pharmaceutical development strategy.