Evaluation of drug formulations using LD50 testing in mice

The LD50 values were utilized to assess the relative rate of absorption of two very poorly soluble drugs. Formulations of these drugs were studied by micronization; addition of surfactant, alkaline or buffering agents, and/or bile salts; coprecipitation; melt or fusion techniques; or granulation with hydrophilic agents. Differences in toxicities were demonstrated from formulations compared to pure drugs by the LD50 method. This study shows that the LD50 is a practical, rapid method of achieving comparative evaluations of drug formulations.     

A radioimmunoassay for serum calcitonin in the rat

Persisting primitive papilla epithelialis is described in a 22-year-old woman. The papilla has blurred borders, a central papilla eminence and a yellowish colour. In addition pigmentary pseudoretinopathy with perivascular pigment deposits and hypermetropia with aplasia maculae occurred. This picture can be confused classically with pappilloedema.     

Long acting methadone

Tablets were prepared using pan-coating, congealing, plasticization with organic solvents and direct compression methods. The tablets were evaluated using the official dissolution test, and an analysis of the active ingredient was accomplished by employing gas-liquid chromatography. The formulation and dissolution characteristics of sustained release tablets, employing the matrix concept to regulate drug release, were studied. Particle size distribution of plastic material influenced the release rates from porous inert matrices, and it was found that incomplete drug release occurred from these preparations. Three-layer slowly-eroding sustained release tablets, using a swellable gum (carbomer) were formulated; by adjusting the proportion of the gum quantitative release of the drug was attained. Approximation of linearity for drug release-time relationship was achieved from three-layer slowly-eroding tablets containing different concentrations of drug in the middle and outer layers. Administration of the above tablets, containing 30 mg of methadone, produced analgesia in male albino rats for approximately 60 h, without undesirable effects.