17β-Estradiol and Tamoxifen Prevent the Over-Glycosylation of Rat Trabecular Bone Collagen Induced by Ovariectomy

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In Vitro–In Vivo Correlation (IVIVC) Population Modeling for the In Silico Bioequivalence of a Long-Acting Release Formulation of Progesterone

Health authorities carefully evaluate any change in the batch manufacturing process of a drug before and after regulatory approval. In the absence of an adequate in vitro–in vivo correlation (Level A IVIVC), an in vivo bioequivalence (BE) study is frequently required, increasing the cost and time of drug development. This study focused on developing a Level A IVIVC for progesterone vaginal rings (PVRs), a dosage form designed for the continuous delivery in vivo. The pharmacokinetics (PK) of four batches of rings charged with 125, 375, 750 and 1500 mg of progesterone and characterized by different in vitro release rates were evaluated in two clinical studies. In vivo serum concentrations and in vitro release profiles were used to develop a population IVIVC progesterone ring (P-ring) model through a direct differential-equation-based method and a nonlinear-mixed-effect approach. The in vivo release, Rvivo(t), was predicted from the in vitro profile through a nonlinear relationship. Rvivo(t) was used as the input of a compartmental PK model describing the in vivo serum concentration dynamics of progesterone. The proposed IVIVC P-ring model was able to correctly predict the in vivo concentration–time profiles of progesterone starting from the in vitro PVR release profiles. Its internal and external predictability was carefully evaluated considering the FDA acceptance criteria for IVIVC assessment of extended-release oral drugs. Obtained results justified the use of the in vitro release testing in lieu of clinical studies for the BE assessment of any new PVRs batches. Finally, the possible use of the developed population IVIVC model as a simulator of virtual BE trials was explored through a case study

The effects of citalopram and fluoxetine on sexual behavior in healthy men: evidence of delayed ejaculation and unaffected sexual desire. A randomized, placebo-controlled, double-blind, double-dummy, parallel group study.

INTRODUCTION: Selective serotonin reuptake inhibitors (SSRIs) are known to induce delayed orgasm and delayed ejaculation, while their effect on other aspects of sexual function, such as sexual motivation, arousal, and erectile function are unclear. AIM: In order to evaluate the effect of chronic administration of two SSRIs, citalopram and fluoxetine, on normal sexual function, we studied the parameters of male sexual behavior, erectile function, and ejaculation on 48 healthy male volunteers, aged 29.5 +/- 4.9, in a randomized, placebo-controlled, double-blind, double-dummy study. Methods. The subjects were randomized to receive placebo (16 subjects), or fluoxetine (20 mg/day) (16 subjects) or citalopram (20 mg/day) for the first week, and 40 mg/day in the following 3 weeks (16 subjects). MAIN OUTCOME MEASURES: Sexual function was investigated at the screening and at the end of the study by means of test of penile erection (TPE) and masturbation ejaculation latency time (MELT) performed during visual erotic stimulation, and at each visit by self-filled questionnaires (International Index Erectile Function [IIEF-15] and Golombock Rust Inventory of Sexual Satisfaction [GRISS]). RESULTS: All the erectile parameters, evaluated by means of RigiScan Plus during TPE, were not significantly different when both fluoxetine and citalopram were compared with placebo. A delay in the ejaculation time was observed both during citalopram and during fluoxetine treatment when compared with placebo, reaching a statistical significance only with citalopram. During the treatment with citalopram and fluoxetine, the IIEF-15 score of all items decreased except for those items related to sexual desire; however, the scores were significantly lower only for the citalopram treatment. CONCLUSIONS: The treatment with citalopram or with fluoxetine was confirmed to delay ejaculation, but was significant only for citalopram. Citalopram and fluoxetine did not affect sexual desire. Citalopram and fluoxetine did not directly affect penile erection as objectively assessed by RigiScan, although an impairment in the subjective assessment of erectile function was observed, but was significant only for citalopram, and it was thought to be a possible consequence of the delayed ejaculation perceived as a trouble

Amygdala-frontal couplings characterizing SSRI and placebo response in social anxiety disorder

UNLABELLED: In patients with social anxiety disorder (SAD) it has been reported that selective serotonin reuptake inhibitors (SSRIs) and placebo induce anxiolytic effects by attenuating neural activity in overlapping amygdala subregions, i.e. left basolateral and right ventrolateral amygdala. However, it is not known whether these treatments inhibit amygdala subregions via similar or distinct brain pathways. As anxiolytic treatments may alter amygdala-frontal couplings we investigated differences and similarities in amygdala-frontal functional co-activation patterns between responders and nonresponders to SSRIs and placebo in patients with SAD. Positron emission tomography (PET) with oxygen-15-labeled water was used to measure anxiety-related regional cerebral blood flow in 72 patients with SAD before and after 6-8 wk of treatment under double-blind conditions. Functional couplings were evaluated with a seed region approach using voxel values from the left basolateral and right ventrolateral amygdala. Responders and nonresponders to SSRIs and placebo showed different treatment-induced co-activations between the left amygdala and the dorsolateral prefrontal cortex (dlPFC) as well as the rostral anterior cingulate cortex (ACC). Conjunction analysis suggested shared anxiolysis-dependent inverse co-activations in SSRI and placebo responders between the left amygdala-dlPFC and left amygdala-rostral ACC, and a shared positive co-activation between left amygdala-dorsal ACC. We demonstrate that amygdala-frontal co-activation patterns differentiate effective from ineffective anxiolytic treatments and that SSRI and placebo responders share overlapping neuromodulatory paths that may underlie improved emotion regulation and reduced expression of anxiety. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT00343707

Comparison of the Clinical Performances of the Immunoenzymometric Assays for N-Terminal and C-Terminal Type I Collagen Telopeptides and the HPLC Assay for Pyridinium Cross-Links

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