Concentrations of N-descyclopropylmethylprazepam in whole-blood, plasma, and milk after administration of prazepam to humans

Cyclopropyl Scaffold: A Generalist for Marketed Drugs

In recent decades, much attention has been given to cyclopropyl scaffolds, which commonly exist in natural products and synthetic organic molecules. Clinical drug molecules with cyclopropyl rings are an area of focus in therapeutic research due to their interesting chemical properties and unique pharmacology activity. These molecular drugs against different targets are applicable in some therapeutic treatment fields including cancer, infection, respiratory disorder, cardiovascular and cerebrovascular diseases, dysphrenia, nervous system disorders, endocrine and metabolic disorders, skin disease, digestive disorders, urogenital diseases, otolaryngological and dental diseases, and eye diseases. This review is a guide for pharmacologists who are in search of valid preclinical/clinical drug compounds where the progress, from 1961 to the present day, of approved marketed drugs containing cyclopropyl scaffold is examined.

Transfer of drugs and other chemicals into human milk

The American Academy of Pediatrics places emphasis on increasing breastfeeding in the United States. A common reason for the cessation of breastfeeding is the use of medication by the nursing mother and advice by her physician to stop nursing. Such advice may not be warranted. This statement is intended to supply the pediatrician, obstetrician, and family physician with data, if known, concerning the excretion of drugs into human milk. Most drugs likely to be prescribed to the nursing mother should have no effect on milk supply or on infant well-being. This information is important not only to protect nursing infants from untoward effects of maternal medication but also to allow effective pharmacologic treatment of breastfeeding mothers. Nicotine, psychotropic drugs, and silicone implants are 3 important topics reviewed in this statement.

Pharmacokinetics of flutoprazepam, a novel benzodiazepine drug, in normal subjects

The single dose pharmacokinetics of flutoprazepam and its active N-desalkyl metabolite were determined in 8 normal subjects by using newly developed, highly sensitive, GC-MS and HPLC techniques. Following a 2 mg dose of the drug, the concentrations of unchanged flutoprazepam in serum were extremely low (below 5 ng/ml at 2 h) and declined rapidly to undetectable levels within 6-9 h after dosing. At all sampling times, the serum concentration of the N-dealkylated metabolite (N-desalkylflurazepam) was much greater than that of the parent compound. This metabolite appeared in serum rapidly (within 2 h), reached a peak between 2 and 12 h and declined slowly, with an elimination half-life of about 90 h on average. The serum concentration of two additional putative metabolites (3-hydroxy-flutoprazepam and N-desalkyl-3-hydroxy-flutoprazepam) was below the limit of detection (2 ng/ml) in all samples. Mild CNS effects (documented by prolonged choice reaction time) were present at 2 and 4 h but were no longer detectable at 9 h. It is suggested that unchanged flutoprazepam is unlikely to contribute significantly to clinical effects and that the drug exerts its therapeutic activity through conversion to the slowly eliminated N-desalkyl metabolite.

Radioimmunoassay for determination of prazepam and its metabolites

The development of a radioimmunoassay for the analysis of prazepam and its metabolites is described. It includes the preparation of the immunogen, immunization and measurement of specificity and sensitivity.

[Benzodiazepines: significance of kinetics for therapy]

The onset and duration of action of benzodiazepines after single oral doses depend largely on absorption rate and the rate and extent of distribution. The rate and extent of accumulation during multiple dosage depend on elimination half-life and clearance. A framework is proposed for classification of benzodiazepines according to elimination half-life. Long acting benzodiazepines have half-life values usually exceeding 24 h. Drugs in this category have long-acting pharmacologically active metabolites, often desmethyldiazepam, accumulate extensively during multiple dosage, and may have impaired clearance in the elderly and those with liver disease. Intermediate and short-acting benzodiazepines have half-life values from 5-24 h and active metabolites are uncommon. Accumulation during multiple dosage is less extensive than with the long-acting group and diminishes as the half-life becomes shorter. Age and liver disease have a small influence on metabolic clearance. The half-life of ultrashort-acting benzodiazepines is less than 5 h. These drugs are essentially nonaccumulating. Pharmacokinetic classification may assist in understanding differences among benzodiazepines, but does not explain all of their clinical actions.