GABA pharmacology--what prospects for the future?

Following the recognition of GABA as an inhibitory neurotransmitter, the discovery of high affinity GABA uptake, and the characterisation of GABA receptors great progress has been made in developing GABA pharmacology. Tiagabide, the first marketed GABA uptake inhibitor may be followed by new and more selective uptake inhibitors. Knowledge of the molecular pharmacology of GABA-A receptors, both synaptic and non-synaptic, may lead to improved anti-anxiety/anticonvulsant agents devoid of the sedative and dependence liabilities of earlier compounds and new hypnotics. Gaboxadol (THIP) is an example of a novel hypnotic that acts on GABA-A receptors by a non-benzodiazepine mechanism. Exploiting neurosteroid interactions with GABAergic mechanisms also holds much future promise.     

Azithromycin: indications for the future?

The global challenge of optimally treating bacterial infections is continuously evolving. Azithromycin, the first azalide antibiotic, presents pharmacokinetics and pharmacodynamics that allow for a simple dosing regimen with minimal side effects. Current azithromycin uses include a variety of community-acquired respiratory tract, skin and soft tissue, and sexually transmitted disease infections. Azithromycin has also demonstrated substantial activity against atypical organisms such as Mycobacterium avium complex (MAC) and Chlamydia trachomatis. Due to a never-ending need for new antibiotic therapies, several other potential indications for azithromycin are being researched. This article will present various current research associated with azithromycin's potential use for malaria, trachoma, coronary artery disease (CAD), Pseudomonas aeruginosa infections, erythema migrans, short-term therapy for respiratory infections, typhoid, cryptosporidiosis, pelvic inflammatory disease, acne, Mediterranean spotted fever and MAC. As bacterial and parasite resistance patterns fluctuate globally, azithromycin may be an alternative therapy for the previously mentioned indications, which will also enhance patient compliance and therefore effectively eradicate infection worldwide.     

What is the future of PEGylated therapies?

The tremendous potential of biologic drugs is hampered by short half-lives in vivo, resulting in significantly lower potency than activity seen in vitro. These short-acting therapeutic agents require frequent dosing profiles that can reduce applicability to the clinic, particularly for chronic conditions. Therefore, half-life extension technologies are entering the clinic to enable improved or new biologic therapies. PEGylation is the first successful technology to improve pharmacokinetic (PK) profiles of therapeutic agents and has been applied in the clinic for over 25 years. Over 10 PEGylated therapeutics have entered the clinic since the early 1990s, and new PEGylated agents continue to expand clinical pipelines and drug patent life. PEGylation is the most established half-life extension technology in the clinic with proven safety in humans for over two decades. Still, it is one of the most evolving and emerging technologies that will be applied for the next two decades.     

Ketolides: the future of the macrolides?

The prevalence of antibiotic resistance in bacterial pathogens associated with community-acquired respiratory tract infections is increasing. Ketolides, semi-synthetic derivatives of erythromycin, overcome the macrolide resistance mechanisms found in Streptococcus pneumoniae and Streptococcus pyogenes, two key pathogens. They also have improved potency and longer post-antibiotic effects, while maintaining the antibacterial spectrum of the macrolide class. The new ketolides cethromycin (ABT-773) and telithromycin have overall antibacterial properties that suggest they will be clinically useful new antibiotics and are undergoing clinical development and regulatory review.     

Metallo-beta-lactamase inhibitors: promise for the future?

Carbapenem resistance continues to erode the effectiveness of antibiotics such as imipenem and meropenem in the clinic. Resistance mechanisms can include interplay between porin loss (membrane permeability), mutation of penicillin binding proteins necessary for cell division, and expression of class A, B and D beta-lactamases. Bacterial resistance to beta-lactams such as penicillin or amoxicillin has been overcome in the clinic using several strategies, including development of antibiotics not susceptible to hydrolysis by beta-lactamases, or co-administration of the antibiotic with beta-lactamase inhibitors. This overview will focus on progress since 2000 in identifying inhibitors of class B, or metallo-beta-lactamases with the aim of reversing carbapenem resistance.     

Natural products--the future scaffolds for novel antibiotics?

Natural products have played a pivotal role in antibiotic drug discovery with most antibacterial drugs being derived from a natural product or natural product lead. However, the rapid onset of resistance to most antibacterial drugs diminishes their effectiveness considerably and necessitates a constant supply of new antibiotics for effective treatment of infections. The natural product templates of actinonin, pleuromutilin, ramoplanin and tiacumicin B, which are compounds undergoing clinical evaluation, represent templates not found in currently marketed antibacterial drugs. In addition, the new templates present in the recently discovered lead antibacterials arylomycin, GE23077, mannopeptimycin, muraymycin/caprazamycin, nocathiacin and ECO-0501, are discussed. Despite extensive efforts to identify antibiotic leads from molecular targets, only the peptide deformylase inhibitor LBM-415 is currently in clinical trials. It is proposed that new antibacterial assays which combine cell-based screening with molecular targets could offer better prospects for lead discovery.     

Therapeutics for alcoholism: what's the future?

As with other addictions, human alcoholism is characterised as a chronically relapsing condition. Consequently, the therapeutic goal is the development of clinically effective, safe drugs that promote high adherence rates and prevent relapse. These products can then be used in conjunction with psychosocial approaches. In this review, preclinical studies are highlighted that indicate the mechanism of action of currently used anti-craving medications or demonstrate the potential of novel pharmacological agents for the treatment of alcohol use disorders. While current pharmacological strategies are far from ideal, there are a number of candidate molecules that may ultimately be developed into therapeutic agents. In addition, prescribing clinicians should also consider strategies such as combinations of various drugs to aid in the regulation of aberrant alcohol consumption.     

Is there any future for felbamate treatment?

Felbamate (2-phenyl-1,3-propanediol dicarbamate), a representative of novel antiepileptic drugs (AESs), proved to have broad-spectrum anticonvulsive activity. Particularly beneficial efficacy was found against partial seizures and Lennox-Gastaut syndrome. Therefore, felbamate started to be indicated not only as an adjunctive antiepileptic drug but also in monotherapy. Unfortunately, it was also evidenced that the drug may induce aplastic anemia or hepatic failure. The former complication was frequently described in patients with previously diagnosed hematopoetic disturbances. Thirty-four cases of well-documented bone marrow suppression, occurred fatal in thirteen cases. Subsequently, felbamate's usage was essentially restricted and at present felbamate is not a first-line AED. However, excluding anemia-prone individuals, new possibilities may open for felbamate position in add-on therapy of drug-resistant epilepsy. Experimental studies provide a good theoretical basis for this kind of treatment.     

Is there a future for renin inhibitors?

Pharmacological interruption of the renin-angiotensin system is possible at three major sites, the angiotensin-converting enzyme (ACE), the AT1 receptor and at the interaction of renin with its substrate, angiotensinogen. Skeggs and his associates in 1957 argued logically but without prognostic accuracy that 'since renin is the initial and rate-limiting substance in the renin-angiotensin system, it would seem that the renin inhibition approach would be the most likely to succeed'. In fact, the development of agents that act at all three levels has enjoyed substantial success, yet renin inhibition, which showed early progress in studies in humans, has languished. Our task in this essay is to review the reasons for the slow evolution of renin inhibition and to discuss the potential of such agents in modern pharmacotherapy. All of the structure-action relationships have involved variation on the original peptide structure. The possibility that alternative approaches based on x-ray crystallography and reconstruction of the structure of the active site would lead to novel agents, appears not to have been explored systematically. This opportunity is all the more attractive because renin is one of the few targets that is actually soluble and amenable to x-ray crystallographic studies. At the moment, it appears that all renin inhibitor development programs have been closed, although hints periodically reappear to indicate that one company or another is pursuing a novel agent. The decision to close programs seems to have reflected not the therapeutic potential of renin inhibitors, but rather the cost of their synthesis, continuing problems with bioavailability and the remarkable success of the competitor class--the AngII antagonists. We believe that the potential of renin inhibition in human therapy has been under estimated and still shows substantial promise.     

Squalamine: a polyvalent drug of the future?

The purpose of this mini-review is to summarize and highlight the different advances in our understanding of the antimicrobial and antiangiogenic activity of squalamine, a cationic steroid isolated in 1993 from the dogfish shark Squalus Acanthias. Indeed, squalamine has shown to be useful for the treatment of important diseases such as cancers (lung, ovarian, brain and others), age-related macular degeneration (AMD) and the control of body weight in man. All these results led to a question: could we consider squalamine as a polyvalent drug of the future?     

Systems biology: personalized medicine for the future?

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Highlights? Recent achievements in genomic research. ? Pioneering efforts in personalized health monitoring with omics profiling. ? The benefits and concerns for personalized medicine.