Aniracetam: its novel therapeutic potential in cerebral dysfunctional disorders based on recent pharmacological discoveries

Oxidative Imidation of Benzylic and Cycloalkane C(sp3)-H Bond Donors Using N-Aroyloxyquinuclidinium Salts and Nitriles under Photoredox Catalysis

A series of N-aroyloxyquinuclidinium salts were prepared and used as reagents to perform efficient three-component Ritter-Mumm-type oxidative C-H imidation of donors of 1° and 2° benzylic C-H bonds used as limiting reagents with nitriles as a source of imide nitrogen under photocatalytic conditions; these reagents also exhibit somewhat lower reactivity toward cycloalkanes.

Synthesis of Imidized Cyclobutene Derivatives by Strain Release of [1.1.1]Propellane

Herein, we report the metal-free synthesis of imidized methylene cyclobutane derivatives via a strain-release driven addition reaction of [1.1.1]propellane. Using this strategy, the methylene cyclobutyl cation intermediate generated by protonation of [1.1.1]propellane was found to be trapped by nitriles to form a nitrilium ion intermediate, which subsequently reacted with carboxylic acids to produce imidized methylene cyclobutene derivatives via a Mumm-type rearrangement.

Five Unapproved Drugs Found in Cognitive Enhancement Supplements

Objective

To identify the presence of unapproved pharmaceutical drugs in over-the-counter dietary supplements marketed to improve memory and cognitive function.

Methods

Supplements were identified by searching 2 supplement databases for products labeled as containing omberacetam, aniracetam, phenylpiracetam, or oxiracetam, 4 drugs not approved for human use in the United States. Products were purchased online and analyzed using nontargeted liquid chromatography-quadrupole time-of-flight mass spectrometry methods.

Results

In the 10 products tested, omberacetam and aniracetam were detected along with 3 additional unapproved drugs (i.e., phenibut, vinpocetine and picamilon). By consuming recommended serving sizes, consumers could be exposed to pharmaceutical-level dosages of drugs including a maximum of 40.6 ± 0.4 mg omberacetam (typical pharmacologic dose of 10 mg), 502 ± 0.8 mg of aniracetam (typical pharmacologic dose 200-750 mg), 15.4 ± 0.3 mg of phenibut (typical pharmacologic dose 250-500 mg), 4.3 ± 0.1 mg of vinpocetine (typical pharmacologic dose 5-40 mg), and 90.1 ± 0.7 mg of picamilon (typical pharmacologic dose 50-200 mg). Several detected drugs were not declared on the label, and several declared drugs were not detected in the products. For those products with drug quantities provided on the labels, 75% (9/12) of declared quantities were inaccurate. Consumers could be exposed to up to four-fold greater than pharmaceutical dosages and as many as 4 unapproved drugs when using individual products.

Conclusions

Over-the-counter cognitive enhancement supplements may contain multiple unapproved drugs. The health effects of consuming untested combinations of unapproved drugs at unpredictable dosages without clinician oversight in supplements are unknown.

Synthesis of imides via palladium-catalyzed three-component coupling of aryl halides, isocyanides and carboxylic acids

A palladium-catalyzed three-component synthesis of acyclic imides from feedstock aryl halides, carboxylic acids and isocyanides through the intermediacy of isoimides has been developed. The key to the success of this approach was controlled isocyanide slow addition and organic/aqueous biphasic conditions. This transition-metal-catalyzed approach features readily available starting materials, atom- and step-economy, good functional group compatibility and gram-scale synthetic capability. Utilization of this new method is illustrated in the late-stage functionalization of drugs Carprofen, Loxoprofen and Flurbiprofen. This strategy has also been successfully applied in the synthesis of cyclic imides including phthalimide, homophthalimide, and 2H-2-benzazepine-1,3-dione derivatives.

Designing a Formulation of the Nootropic Drug Aniracetam Using 2-Hydroxypropyl-β-Cyclodextrin Suitable for Parenteral Administration

The nootropic drug aniracetam is greatly limited in its application by low aqueous solubility and a poor oral bioavailability. The primary aim of this study was to design a parenteral formulation of aniracetam that can be administered intravenously. Complexation of aniracetam with 2-hydroxypropyl-β-cyclodextrin (HP-β-CD) was investigated as a strategy to enhance solubility. A phase solubility analysis was performed to quantify the extent of improvement. An 819% increase in the solubility of aniracetam was obtained, reaching 36.44 mg/mL. This marked increase enables aniracetam to exist in an aqueous solvent at levels sufficient for parenteral dosing. A stability test was then devised using a design of experiment approach. The aniracetam-HP-β-CD formulation was subjected to different relative humidity and temperature and cyclodextrin concentrations over a 12-week period. Key changes in FTIR vibrational frequencies suggest the benzene moiety of aniracetam was introduced into the hydrophobic cavity of HP-β-CD. These results are highly supportive of the formation of a predictable 1:1 molar stoichiometric inclusion complex, explaining the improvement seen in physiochemical properties of aniracetam following formulation with HP-β-CD. This novel formulation of aniracetam suitable for parenteral administration will have utility in future studies to further elucidate the pharmacokinetics of this drug.

Determination of aniracetam's main metabolite, N-anisoyl-GABA, in human plasma by LC-MS/MS and its application to a pharmacokinetic study

A simple and rapid high-performance liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS) method has been developed and validated for the determination of 4-p-anisamidobutyric acid (ABA; or N-anysoyl-γ-aminobutiryc acid, N-anisoyl-GABA), a major active metabolite of aniracetam, in human plasma. After protein precipitation of plasma sample with methanol, ABA and the internal standard lisinopril were separated on a Venusil ASB C₁₈ column at 25 °C. The mobile phase consisted of methanol-ammonium acetate (10 mmol/L) (30:70, v/v). The detection was performed on a triple quadrupole tandem mass spectrometer with an ESI source in negative ion mode. Multiple reaction monitoring (MRM) using the precursor→product ion combinations of m/z 235.8→m/z 106.6, and m/z 403.8→m/z 113.6 was used to quantify ABA and lisinopril, respectively. This is the first LC-MS/MS method for ABA with advantages of short analysis time (4.5 min per sample run) and high selectivity attributable to the MRM detection and optimized HPLC conditions. The response was linear in a concentration range of 0.0485-19.4 μg/mL in plasma. The extraction recovery of ABA was between 89.1% and 100.7%. The precision (RSD) and accuracy (RE) of the method were evaluated to be within 7.3% and from 2.5% to 6.9%. The validated method has been applied to the pharmacokinetic study after a single oral administration of aniracetam dispersible tablets to human beings.

Clinical efficacy of aniracetam, either as monotherapy or combined with cholinesterase inhibitors, in patients with cognitive impairment: a comparative open study

INTRODUCTION

Dementia constitutes an increasingly prevalent cognitive disorder with serious socioeconomic implications.

AIMS

In the present study, we aimed to evaluate the efficacy of aniracetam, either as monotherapy or combined with cholinesterase inhibitors (ChEIs), in terms of several neuropsychological parameters, in a considerable number of patients with dementia.

RESULTS

In our prospective, open-label study, we enrolled a total of 276 patients (mean age 71 ± 8 years, 95 males) with cognitive disorders. Our study population comprised four groups: no treatment group (n = 75), aniracetam monotherapy group (n = 58), ChEIs monotherapy group (n = 68), and group of combined treatment (n = 68). Patients were examined with validated neuropsychological tests at baseline, 3, 6, and 12 months of treatment. In patients treated with aniracetam, all studied parameters were adequately maintained at 6 and 12 months, while emotional state was significantly improved at 3 months. In patients treated with ChEIs, we observed a significant cognitive deterioration at 12 months. The comparison between aniracetam and ChEIs in patients with relatively mild dementia (15 ≤ MMSE ≤ 25) revealed a significantly better cognitive performance with aniracetam at 6 months and improved functionality at 3 months. Comparing aniracetam monotherapy with combined treatment in the same population, aniracetam performed better in the cognitive scale at 6 months, and displayed a notable tendency for enhanced mood at 12 months and improved functionality at 6 months.

CONCLUSIONS

Our findings indicate that aniracetam (a nootropic compound with glutamatergic activity and neuroprotective potential) is a promising option for patients with cognitive deficit of mild severity. It preserved all neuropsychological parameters for at least 12 months, and seemed to exert a favorable effect on emotional stability of demented patients.

The intense world theory - a unifying theory of the neurobiology of autism

Autism covers a wide spectrum of disorders for which there are many views, hypotheses and theories. Here we propose a unifying theory of autism, the Intense World Theory. The proposed neuropathology is hyper-functioning of local neural microcircuits, best characterized by hyper-reactivity and hyper-plasticity. Such hyper-functional microcircuits are speculated to become autonomous and memory trapped leading to the core cognitive consequences of hyper-perception, hyper-attention, hyper-memory and hyper-emotionality. The theory is centered on the neocortex and the amygdala, but could potentially be applied to all brain regions. The severity on each axis depends on the severity of the molecular syndrome expressed in different brain regions, which could uniquely shape the repertoire of symptoms of an autistic child. The progression of the disorder is proposed to be driven by overly strong reactions to experiences that drive the brain to a hyper-preference and overly selective state, which becomes more extreme with each new experience and may be particularly accelerated by emotionally charged experiences and trauma. This may lead to obsessively detailed information processing of fragments of the world and an involuntarily and systematic decoupling of the autist from what becomes a painfully intense world. The autistic is proposed to become trapped in a limited, but highly secure internal world with minimal extremes and surprises. We present the key studies that support this theory of autism, show how this theory can better explain past findings, and how it could resolve apparently conflicting data and interpretations. The theory also makes further predictions from the molecular to the behavioral levels, provides a treatment strategy and presents its own falsifying hypothesis.

Aniracetam restores the effects of amyloid-beta protein or ageing on membrane fluidity and intracellular calcium concentration in mice synaptosomes

In the present study, we observed the in vitro effect of aniracetam on membrane fluidity and free calcium concentrations ([Ca(2+)]i) of frontal cortical (FC) and hippocampal (HP) synaptosomes of aged mice and young mice treated with amyloid-beta protein (Abeta) Membrane fluidity was measured by using fluorescence anisotropy of the lipophilic probe, 1,6-diphenyl-1,3,5-hexatriene (DPH). [Ca(2+)]i was measured by using Fura 2-AM fluorescent spectrophotometry. We found that membrane fluidity of the FC and HP synaptosomes was decreased in 14 months old mice compared with that in 3 months old mice. Similarly, Abeta25-35 (1 microM) decreased the membrane fluidity in 3 months old mice. These effects of ageing and Abeta25-35 on membrane fluidity were restored by aniracetam in a concentration-dependent manner. Furthermore, Abeta25-35 (1 microM) largely increased [Ca(2+)]i in FC and HP synaptosomes in 3 months old mice, but this effect on HP synaptosomes was effectively reversed by aniracetam (1-4 mM). The present findings suggest that aniracetam restores age- and Abeta-induced alterations in membrane fluidity or Abeta-induced increase in [Ca(2+)]i, demonstrating a possible beneficial role of aniracetam in the clinic treatment for senile dementia or Alzheimer's disease.

Therapeutic potential of positive AMPA modulators and their relationship to AMPA receptor subunits. A review of preclinical data

BACKGROUND

Positive alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) modulators enhance glutamate transmission via the AMPA receptor by altering the rate of desensitization; alone they have no intrinsic activity. They are the only class of compounds known that may pharmacologically separate AMPA subtypes.

OBJECTIVE

This manuscript will review preclinical work on positive AMPA modulators, with clinical examples where relevant.

RESULTS

The activity of these compounds appears to be determined by the AMPA receptor subunit composition. Studies have shown that splice variant and/or subunit combinations change the desensitization rate of this receptor. Also, these subunits are heterogeneously expressed across the central nervous system. Therefore, the functional outcome of different positive AMPA modulators could indeed be different. The origins of this pharmacological class come from hippocampal long-term potentiation studies, so quite naturally they were first studied in models of short- and long-term memory (e.g., delayed match to sample, maze performance). In general, these agents were procognitive. However, more recent work with different chemical classes has suggested additional therapeutic effects in models of schizophrenia (e.g., amphetamine locomotor activity), depression (e.g., forced swim test), neuroprotection (e.g., NMDA agonist lesions) and Parkinson's disease (e.g., 6-hydroxydopamine lesion).

CONCLUSIONS

In conclusion, positive modulation of AMPA may offer numerous therapeutic avenues for central nervous system drug discovery.

Facilitation of alpha-amino-3-hydroxy-5-methylisoxazole-4-propionate receptor transmission in the suprachiasmatic nucleus by aniracetam enhances photic responses of the biological clock in rodents

This study was designed to test whether the alpha-amino-3-hydroxy-5-methylisoxazole-4-propionate (AMPA) receptor-facilitating drug, aniracetam, could potentiate photic responses of the biological clock in the suprachiasmatic nucleus (SCN) of rodents. Using the whole-cell patch technique, we first demonstrated that AMPA currents elicited by either local AMPA application or optic chiasm stimulation were augmented by aniracetam in the neurons of the SCN. The AMPA application-elicited increase of intracellular Ca2+ concentration in SCN slices was also enhanced by aniracetam treatment. The systemic injection of aniracetam dose-dependently (10-100 mg/kg) potentiated the phase delay in behavioral rhythm induced by brief light exposure of low intensity (3 lux) but not high intensity (10 or 60 lux) during early subjective night. Under the blockade of NMDA receptors by (+) MK801, aniracetam failed to potentiate a light (3 lux)-induced phase delay in behavioral rhythm. Aniracetam increased the photic induction of c-Fos protein in the SCN that was elicited by low intensity light exposure (3 lux). These results suggest that AMPA receptor-mediated responses facilitated by aniracetam can explain enhanced photic responses of the biological clock in the SCN of rodents.