Recent applications of hydantoin and thiohydantoin in medicinal chemistry.

Hydantoin, imidazolidine-2,4-dione, is a non-aromatic five-membered heterocycle, which is considered a valuable, privileged scaffold in medicinal chemistry. The importance of the hydantoin scaffold in drug discovery has been reinforced by several medicines in clinical use, such as phenytoin, nitrofurantoin, and enzalutamide. Hydantoin has five potential substituent sites, including two hydrogen bond acceptors and two hydrogen bond donors. Two additional attractive features of hydantoin scaffolds are their synthetic feasibility for core scaffolds via established cyclization reactions and their ease of accepting various substituents. Because of these characteristics, many hydantoin derivatives with different substituents have been designed and synthesized and exhibit a broad spectrum of biological and pharmacological activities against, for example, cancers, microbial infections, metabolic diseases, and epilepsy. In this review, recent contributions of hydantoin, thiohydantoin, and selenohydantoin scaffolds to medicinal chemistry are described; some major compounds are presented to emphasize their importance, and their structure-activity relationships (SARs) are briefly addressed. Major discussions are devoted to the structural features or novelty of each scaffold and its SAR. The publications in this review encompass those from 2012 to 2018.

Synthesis and Evaluation of Novel Diazaspiro Hydantoins as Potential Anticonvulsants.

BACKGROUND: Epilepsy, one of the most frequent neurological afflictions in man characterized by excessive temporary neuronal discharges resulting in uncontrolled convulsion, requires special medical attention. Though several new anticonvulsants are introduced, some types of seizures are still not adequately treated with current therapy. Toxicity, intolerance, and lack of efficacy for certain types of seizure are some of the limitations of the current medications. METHODS: Maximal electroshock (MES) seizure model was used in the present study to evaluate the anticonvulsant activity of the drugs. Seizures were induced in ten weeks old male Wistar rats (200-220 g) by delivering electro shock of 150 mA for 0.2 sec by means of a convulsiometer through a pair of ear clip electrodes. The test compounds (1-10, 100 mg/kg) were administered by oral route 30 mins before the maximal electroshock seizure test by suspending in carboxymethylcellulose (1%). The animals were observed closely for 2 mins. The percentage of inhibition of seizure relative to control was recorded and calculated. Phenytoin (100 mg/kg, p.o) was used as a standard drug. The data was analysed by using one way ANOVA followed by dunnett's test. RESULTS: In our present series of compounds the active compounds possess all the requirements essential for anticonvulsant activity as proposed by Dimmock and others. In this study, it reveals that, compounds showing anticonvulsant activity with more lipophilic N-substitution group are more active than hydrophobic substitution in the hydantoin ring. The rapid onset of action is believed to be due to the substitution of more lipophilic propyl group in the N-substitution in the hydantoin moiety. Evidently, this distal hydrophobic centre alters the bioavailability of the molecules. CONCLUSION: The results are encouraging and show that, the hydantoins are more potential molecules for the treatment of anticonvulsant. Anticonvulsants have greatly improved the lives of people with epilepsy. Approximately 70% of patients can achieve complete freedom from seizures with appropriate treatment. Lipophilicity appears to govern the MES activity. If there is lipophilic moiety, then MES activity is favoured. All the compounds have shown promising and significant protective effect on maximal electroshock induced seizures when compared to vehicle treated control rats.

Effect of polyunsaturated fatty acids on diphenyl hydantoin-induced genetic damage in vitro and in vivo.

Phenytoin sodium/diphenyl hydantoin (DPH) is used by a major segment of epileptics and neuro surgery patients with head injury to prevent seizures. DPH is a known mutagen, carcinogen, and teratogen. Essential fatty acids (EFAs) are critical for various tissues and were reported to act as anti-mutagenic agents. In the present study we assessed the effect of five EFAs on DPH-induced genetic damage both in vitro and in vivo. DPH induced significant genetic damage. Of all the EFAs (linoleic acid, alpha-linolenic acid, gamma-linolenic acid, arachidonic acid, dihomo-gamma-linolenic acid, and eicosapentaenoic acid) studied, all except eicosapentaenoic acid showed significant decrease in DPH induced genetic damage as assessed by micronucleus (MN) test. However, gamma-linolenic acid (GLA) was found to be the most effective in reducing the number of MN containing lymphocytes both in vitro and in vivo to control values. EFAs when tested alone produced insignificant increase in the amount of genetic damage but when tested in combination with DPH the number of micronuclei containing lymphocytes was reduced; but the DNA ladder pattern, an indication of DNA damage, was increased. This apparently paradoxical action of EFAs, especially of GLA, suggests that, in all probability, fatty acids induce apoptosis of cells that harbor significant DNA damage. Based on these results we suggest that GLA functions as a unique endogenous molecule that protects cells from accumulating genetic damage.

[Role of aldose reductase inhibitors in the development of peripheral neuropathy in experimental diabetes]. / Rol' ingibitorov al'dozoreduktazy v razvitii perifericheskikh neiropatii pri éksperimental'nom diabete.

Streptozotocin-induced diabetes in rats is accompanied by development of diabetic complications such as neuropathies. It was shown that aldose reductase inhibitors (A1-1576, sorbinil and unithiol) administration partially normalized not only polyol pathway. Aldose reductase inhibitors partially restored Na+, K(+)-ATP-ase activity in sciatic nerve of diabetic rats and redox state of nicotinamide adenine dinucleotides. The sorbitol level increases in streptozotocin-diabetic rats as compared to control. Administration of aldose reductase inhibitors to diabetic rats is accompanied by partial reduction of sorbitol level in sciatic nerve. The results obtained confirm the important role of a dose reductase inhibitors, as antidiabetic drugs, in the improvement of diabetic neuropathy.

[The use of general drugs other than antibiotics in periodontitis]. / L'utilisation des médicaments généraux en parodontie à l'exception des antibiotiques.

Outside of the antibiotics, numerous general medications are prescribed in the context of the treatment of periodontal diseases. It appeared to be of interest to study them. The international research on anti-inflammatory drugs will be analysed in the literature. An in-depth study will then be carried out on documents provided by laboratories which market products likely to be active on periodontal diseases in France. All the publications concerning Imudon, Piascledine 300 and Insadol will be more particularly analysed. The operative protocols, conditions and experimentation, as well as the results, will be studied as objectively as possible so as to determine the essential efficacy of one or nother product.

Phase I trial of spiromustine (NSC 172112) and evaluation of toxicity and schedule in a murine model.

Phase I evaluation of spiromustine was performed using an every-3-week schedule and a weekly X 3 schedule. Neurotoxicity was the dose-limiting toxicity presenting as alterations in cortical integrative functions (orientation, language, coordination), leading to a decrease in the level of consciousness. Traditional criteria for grading neurotoxicity poorly characterized these toxicities. The maximum tolerated dose was 6 mg/m2 every 3 weeks and 3 mg/m2 weekly X 3. Concurrent murine studies confirmed spiromustine as a schedule independent drug with toxicity correlating with peak plasma levels. Physostigmine had little effect on decreasing neurotoxicity in the murine model. The solvating agent used was not responsible for the neurotoxicity. Injection of spiromustine on a split-dose schedule decreased the acute neurological toxicity in mice and allowed a larger total dosage to be delivered (compared to single bolus dosage). Based on these results a split-dose schedule is suggested for future clinical trials.

Spiromustine: a new agent entering clinical trials.

Spiromustine is a new alkylating agent, of interest since it was rationally designed as a lipophilic compound capable of penetrating the CNS. This lipophilicity may also enhance alkylating activity against tumors other than brain tumors. Preclinical screening has shown activity against a variety of tumors, including an intracranially implanted ependymoblastoma. Alkylating activity has been demonstrated in an intracerebral glioma in the rat. Spiromustine is a cell cycle non-specific agent. Animal pharmacology studies have shown a biphasic plasma decay curve, with hepatic metabolism and excretion, an enterohepatic circulation of metabolites, and approximately 50% renal excretion of unchanged drug. Toxicology studies in mice, rats and dogs showed that dose-related myelosuppression, and neurotoxicity predominated; other organ toxicities were mild. Spiromustine is currently entering Phase I clinical trials on a variety of schedules.

[Modifications of phosphocalcic metabolism in patients treated with anticonvulsivants (author's transl)]. / Modificaciones del metabolismo fosfocálcico en pacientes tratados con anticonvulsivantes

Differences in the seric values of Ca, P and alk. phosphatase before and after 12 to 18 months of anticonvulsant therapy in 45 patients are reported. They were significant for alk. phosphatase in patients under either barbiturates or barbiturates associated with hydantoin. For calcium they were significant in patients treated with barbiturate plus hydantoins and either one of these plus other drugs. It is assumed that supplementary vitamin D can be necessary in these group of patients.

Evaluation of a muscle relaxant: dantrolene sodium (Dantrium).

Dantrolene sodium (Dantrium) is a skeletal muscle relaxant, unique in that it acts on the muscle itself. It should be considered for use in patients with skeletal muscle spasticity who are in a stable neurological state. After careful adjustment of the dose, a substantial number of such patients will experience one or more of the following benefits: (1) a reduction in pain, (2) an increased ability to make use of residual motor function, (3) a reduction in the level of nursing care required, (4) an increased ability to utilize devices, and (5) an increased ability to participate in rehabilitation. The drug should not be used when reduced spasticity will decrease functional ability. The adverse effects generally are transient; some are the result of central nervous system depression.