BACKGROUND
Previous studies have identified significant variability in attention-deficit / hyperactivity disorder (ADHD) prevalence estimates worldwide, largely explained by methodological procedures. However, increasing rates of ADHD diagnosis and treatment throughout the past few decades have fuelled concerns about whether the true prevalence of the disorder has increased over time.


METHODS
We updated the two most comprehensive systematic reviews on ADHD prevalence available in the literature. Meta-regression analyses were conducted to test the effect of year of study in the context of both methodological variables that determined variability in ADHD prevalence (diagnostic criteria, impairment criterion and source of information), and the geographical location of studies.


RESULTS
We identified 154 original studies and included 135 in the multivariate analysis. Methodological procedures investigated were significantly associated with heterogeneity of studies. Geographical location and year of study were not associated with variability in ADHD prevalence estimates.


CONCLUSIONS
Confirming previous findings, variability in ADHD prevalence estimates is mostly explained by methodological characteristics of the studies. In the past three decades, there has been no evidence to suggest an increase in the number of children in the community who meet criteria for ADHD when standardized diagnostic procedures are followed.

ADHD Prevalence Estimates Across Three Decades: An Updated Systematic Review and Meta-Regression Analysis

The Food and Drug Administration (FDA) is a regulatory agency of the United States federal government This article describes the scope of work of each of the FDA's major components, and addresses the role of statisticians at FDA


Keywords:

drug regulation;
clinical trials;
medical devices;
safety;
bioassay

Food and Drug Administration (FDA)

Poly (vinyl alcohol) microneedles: Fabrication, characterization, and application for transdermal drug delivery of doxorubicin.

Recent advances in polymeric transdermal drug delivery systems.

In this study, we used sonophoresis and iontophoresis to enhance the in vitro delivery of methotrexate through human cadaver skin. Iontophoresis was applied for 60 min at a 0.4 mA/sq·cm current density, while low-frequency sonophoresis was applied at a 20 kHz frequency (2 min application, and 6.9 W/sq·cm intensity). The treated skin was characterized by dye binding, transepidermal water loss, skin electrical resistance, and skin temperature measurement. Both sonophoresis and iontophoresis resulted in a significant reduction in skin electrical resistance as well as a marked increase in transepidermal water loss value (p < 0.05). Furthermore, the ultrasonic waves resulted in a significant increase in skin temperature (p < 0.05). In permeation studies, the use of iontophoresis led to a significantly higher drug permeability than the untreated group (n = 4, p < 0.05). The skin became markedly more permeable to methotrexate after the treatment by sonophoresis than by iontophoresis (p < 0.01). A synergistic effect for the combined application of sonophoresis and iontophoresis was also observed. Drug distribution in the skin layers revealed a significantly higher level of methotrexate in the sonicated skin than that in iontophoresis and untreated groups. Iontophoresis and low-frequency sonophoresis were found to enhance the transdermal and intradermal delivery of methotrexate in vitro.

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Electrically and Ultrasonically Enhanced Transdermal Delivery of Methotrexate

Formulation and evaluation of 4-benzylpiperidine drug-in-adhesive matrix type transdermal patch

Development and evaluation of a polyvinyl alcohol based topical gel

Non-Ablative Fractional Laser to Facilitate Transdermal Delivery.

Context: The improper disposal of unused prescription opioids has a potential for abuse as well as environmental contamination. Consequently, there is an imperative need for an environmentally safe...

Sindhu S. Ganti

Papers

Formulation and evaluation of 4-benzylpiperidine drug-in-adhesive matrix type transdermal patch

Development and evaluation of a polyvinyl alcohol based topical gel

Non-Ablative Fractional Laser to Facilitate Transdermal Delivery.

Evaluation of an activated carbon-based deactivation system for the disposal of highly abused opioid medications

Transdermal formulation of 4-benzylpiperidine for cocaine-use disorder