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J P Stables

Publications and source records attributed to J P Stables.

47 records · Page 3Linked to original sources
PubMed1996

Synthesis and anticonvulsant activities of N-Benzyl-2-acetamidopropionamide derivatives.

Studies have demonstrated that 2-substituted N-benzyl-2-acetamidoacetamides (2) are potent anticonvulsants. A recent investigation has led to the hypothesis that an important structural feature in 2 for maximal anticonvulsant activity is the placement of a small, substituted heteroatom moiety one atom from the C(2) site. This paper validates this hypothesis. Twelve derivatives of N-benzyl-2-acetamidopropionamide have been prepared in which six different heteroatom substituents (chloro, bromo, iodo, oxygen, nitrogen, and sulfur) were incorporated at the C(3) site. Highly potent activities were observed for the two oxygen-substituted derivatives, N-benzyl-2-acetamido-3-methoxypropionamide (18) and N-benzyl-2-acetamido-3-ethoxypropionamide (19). The ED50 values in mice following intraperitoneal (i.p.) dosing for the maximal electroshock-induced seizure test for 18 and 19 were 8.3 and 17.3 mg/kg, respectively. These values compared favorably to the ED50 value found for phenytoin (ED50 = 6.5 mg/kg). Comparable activities were observed for 18 and 19 upon oral (p.o.) administration to rats (18, ED50 = 3.9 mg/kg; 19, ED50 = 19 mg/kg; phenytoin, ED50 = 23 mg/kg). Evaluation of the individual stereoisomers for 18 demonstrated that the principal anticonvulsant activity resided in the (R)-stereoisomer. The ED50 value for (R)-18 was 4.5 mg/kg, and the ED50 for (S)-18 exceeded 100 mg/kg. This difference in activity for the two stereochemical isomers surpassed comparable values for other members within this class of compounds. The protective indices (PI = TD50/ED50) (where TD50 represents a neurotoxic dose impairing rotorod performance) for (R)-18 in mice (i.p.) and in rats (p.o.) were 6.0 and > 130, respectively.

Acetamides↗
PubMed1996

The anticonvulsant activities of functionalized N-benzyl 2-acetamidoacetamides. The importance of the 2-acetamido substituent.

Recent studies have demonstrated that substituted N-benzyl 2-acetamidoacetamides provide significant protection against maximal electroshock (MES)-induced seizures in mice and rats. In this study, we investigated whether the 2-acetamido moiety was necessary for anticonvulsant activity. Ten derivatives of the known anticonvulsant, N-benzyl 2-acetamido-2-phenyl-acetamide were prepared in which the 2-acetamido group was replaced by hydrogen, methyl, oxygen, and halogen substituents. Evaluation of these compounds in the MES-induced seizure test demonstrated that both the hydroxy and the methexy compounds provided full protection against MES-induced seizures in mice given ip at 100 mg/kg. Moreover, evaluation of the individual stereoisomers for the hydroxy compound showed that the principal activity resided in the (R)-isomer. These findings demonstrated that the 2-acetamido substituent is important but not obligatory for the prevention of MES-induced seizures. Further supporting evidence was provided by comparing the pharmacological activities of N-benzyl 2,3-dimethoxypropionamide with N-benzyl 2-acetamido-3-methoxypropionamide. The ED50 value for the former in the MES test was 30 mg/kg (i.p.), which compared favorably with phenobarbital (ED50 = 22 mg/kg), but the ED50 value for N-benzyl 2-acetamido-3-methoxypropionamide was 8.3 mg/kg.

Acetamides↗
PubMed1996

Synthesis and anticonvulsant activity of some amino acid derivatives. Part 2: Derivatives of Gly, Ala, Leu, Pro, Trp, Phe(4 Cl), Ala(alpha-Me).

Fourteen amides of N-substituted natural and anatural amino acids have been designed and synthesized as potential anticonvulsants. They were evaluated in the maximal electroshock seizure (MES) test, the subcutaneous Metrazol seizure threshold (sc Met) test and the rotorod neurotoxicity (Tox) test. According to the classification of the Anticonvulsant Screening Project (ASP) of the Antiepileptic Drug Development Program (ADDP) eight of synthesized compounds received class I, two class II and four class III. One of the compounds classified in class I (18) was tested quantitatively after i.p. administration in mice. It showed MES ED50 = 67.41 mg/kg and protective index (PI) = 4.5. Conformational models of the synthesized compounds were compared to one another, as well as to models of some standard compounds.

Amino Acids↗
PubMed1996

Structural modifications of the primary amino group of anticonvulsant aryl semicarbazones.

A number of aryl semicarbazones had been shown previously to possess significant anticonvulsant properties. The principal objective of the present investigation was to determine the importance of the primary amino group in this series of compounds by replacing it with other substituents. The results indicate that the amino group was not essential for anticonvulsant activity. However its replacement by an aryl ring generally abolished activity while a terminal phenylamino function was better tolerated. Thus both the size of the group and its hydrogen bonding capabilities appear to influence bioactivity. Alteration of the oxygen atom of the semicarbazones by isosteres did not enhance anticonvulsant properties.

Animals↗
PubMed1996

Synthesis and anticonvulsant activity of some amino acid derivatives. Part 1: alanine derivatives.

Fifteen amides of N-substituted D-Ala, DL-Ala and beta Ala have been designed and synthesized as potential anticonvulsants. All obtained amides as well as one intermediate (8) were evaluated in the maximal electroshock seizure (MES) test, the subcutaneous Metrazol seizure threshold (sc Met) test and the rotorod neurotoxicity (Tox) test in mice. According to the classification of the Anticonvulsant Screening Project (ASP) of the Antiepileptic Drug Development Program (ADDP) eight compounds received class I, three class II and five class III designations. Two of the most active compounds (20, 24) were tested quantitatively. They exhibited, after i.p. administration in mice, a large protective index (PI) 3.2 for 20 and 4.3 for 24 and after oral administration in rat PI > 18 for 20 and > 14 for 24.

Acetylation↗
PubMed1995

Synthesis and anticonvulsant activity of enaminones. 3. Investigations on 4'-, 3'-, and 2'-substituted and polysubstituted anilino compounds, sodium channel binding studies, and toxicity evaluations.

In a continuing evaluation of the aniline-substituted enaminones, the synthesis of additional para-substituted analogs has been made in an attempt to further quantify the electronic (sigma) and lipophilic (pi) requirements for anticonvulsant activity in this series. In addition, meta- and ortho-substituted and polysubstituted compounds have been synthesized and evaluated for anticonvulsant activity. In the para-substituted series, 4-cyano analogs (32 and 33) (+ sigma, - pi), which were highly active via intraperitoneal (ip) injection in mice, were inactive on oral (po) administration in rats. The para-substituted trifluoromethoxy (+ sigma, + pi) analog (8) had significant potency by both routes. Meta substitution limited the activity due to steric factors. Bromo and iodo substituents produced active para-substituted analogs (5 and 17) but were inactive when substituted in the meta position (37 and 41, respectively). Ortho substitution provided no clear relationship due to nonparametric deviations. Neither 1, the prototype enaminone, nor 2, the putative metabolite, produced significant nephrotoxicity or hepatotoxicity. Sodium channel binding of 1 and 8 indicated that 8 displayed relatively potent sodium channel binding but 1 showed weaker effects with IC50 values of 489 and 170 microM respectively against [3H]batrachotoxinin A 20 alpha-benzoate ([3H]BTX-B).

Animals↗
PubMed1995

Progress report on new antiepileptic drugs. A summary of the Second Eilat Conference.

The Second Eilat Conference on New Antiepileptic Drugs was held at the King Solomon's Palace Hotel from October 31 to November 3, 1994. Epileptologists and scientists from 20 countries attended the conference, which was held to discuss new trial designs, drug approval, early use of new antiepileptic drugs, and new drugs in development. Over the last six years, several novel antiepileptic drugs have been introduced worldwide, and new information on their safety and efficacy has become available. These include felbamate, gabapentin, lamotrigine, oxcarbazepine, and vigabatrin. Drugs in development include those at an advanced stage, such as topiramate and tiagabine, as well as those just entering clinical trials, such as remacemide and levetiracetam. The following is a summary of the presentations for drugs in development and newly marketed drugs. The meeting concluded with a presentation, 'Still Searching for the Magic Bullet'.

Anticonvulsants↗
PubMed1995

Comparative anticonvulsant activity and neurotoxicity of 4-amino-N-(2,6-dimethylphenyl)phthalimide and prototype antiepileptic drugs in mice and rats.

We compared the anticonvulsant activity and neurotoxicity of 4-amino-N-(2,6-dimethylphenyl)phthalimide (ADD 213063) with those of phenytoin (PHT), carbamazepine (CBZ), phenobarbital (PB), ethosuximide (ESM), valproate (VPA), and felbamate (FBM). Evaluation of anticonvulsant properties performed according to well-established procedures in rats and mice showed that ADD 213063 is most effective in protecting animals against maximal electroshock seizures (MES). This anti-MES activity is achieved with nontoxic doses, with the optimal effect recorded in rats dosed orally with anti-MES ED50 and protective index (PI) values of 25.2 mumol/kg and > 75, respectively. ADD 213063 protects to a lesser extent against seizures induced by subcutaneous (s.c.) picrotoxin and subcutaneous pentylenetetrazol (PTZ) in mice dosed intraperitoneally and orally, respectively. The profile of anticonvulsant action of ADD 213063 closely parallels that of CBZ.

Animals↗
PubMedDate not supplied

Anticonvulsant activity of p-chlorophenyl substituted arylsemicarbazones--the role of primary terminal amino group.

A series of p-chlorophenyl substituted arylsemicarbazones were synthesized and evaluated for anticonvulsant activity. Most of the compounds provided significant protection against maximal electroshock-induced seizures (MES) at 100 mg/kg after 0.5 h and at 300 mg/kg after 4 h in both MES and pentetrazole-induced (PTZ) seizures. In the strychnine-induced seizures (scSTY), the majority of the compounds showed protection at 30 mg/kg. The compound 2 was active in both MES and PTZ tests. The study has shown that the terminal primary amino group is not necessary for anticonvulsant activity.

Animals↗
PubMedDate not supplied

[Rational conception, synthesis and evaluation of phenytoinergic potential anticonvulsants. A series ofretrobenzamides: N-(nitrophenyl) benzamides and N-(aminophenyl) benzamides].

Retrobenzamides [N-(nitrophenyl) benzamides and N-(aminophenyl)benzamides] were developed in the perpective of a design for phenytoinergic agents. Anticonvulsant and neurotoxic properties of these compounds were evaluated in mice and rats in two seizure models (maximal electroshock-induced seizures [MES] and seizures induced by subcutaneous administration of pentylenetetrazole [scPtz]) and in the rotorod test. Data obtained were compared with those recorded on carbamazepine and phenytoin (antiepileptic drugs widely utilized in human clinics), ameltolide (anticonvulsant compound recently developed by Eli Lilly in human clinical trials) and other compounds previously reported by our research group. Studies on retrobenzamides in mice administered by intraperitoneal route point out a good anticonvulsant potential in the MES test for the amino derivatives (N-(aminophenyl)benzamides) and moderate activity in the case of the corresponding "nitro" derivatives. In rats dosed orally, aminoretrobenzamides were less active in the MES test than in mice dosed intraperitoneally.

Animals↗