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Biomedical subjects

S Saperstein

Publications and source records attributed to S Saperstein.

10 recordsLinked to original sources
PubMed1989

Pharmacokinetics of norethindrone: effect of particle size.

In 24 healthy women between the ages of 19 and 35 years who had not used oral contraceptive preparations for at least 60 days, it was found that the smaller the particle size of norethindrone (NET) administered, the higher was the plasma NET level obtained. Three different preparations having particle sizes of NET smaller than 250 microns, 44 microns or 10 microns were tested in a crossover pattern. The time required to reach maximum plasma concentration (Tmax) became shorter with decreasing particle size, 1.69 hr, 1.52 hr and 1.06 hr, respectively. As particle size was reduced, the maximum NET plasma concentration (Cmax) increased for the 3 different 1 mg NET preparations, i.e. 8.66 ng/ml, 10.53 ng/ml and 15.73 ng/ml. A trial with a 2 mg NET preparation made with NET utilizing the 44 microns same material displayed a Tmax similar to the 1 mg NET preparation having the same particle size while the Cmax reached a level of 17.56 ng/ml. The area under the plasma concentration versus time curve from 0-24 hrs and the extrapolated total area under the curve, increased with decreasing particle size. The use of a smaller particle size allows for more rapid dissolution or oral contraceptive tablets when measured in vitro; however, there is no evidence that such faster dissolution leads to a significant difference in efficacy. Oral contraceptive tablets have, since their inception, utilized both large and small NET particle size material in various preparations.

Administration, Oral↗
PubMed1989

Bioequivalence of two oral contraceptive drugs containing norethindrone and ethinyl estradiol.

Two oral contraceptive drugs, Formulation A and Formulation B, both of similar hormonal content, were compared with each other to determine if they were bioequivalent. Both drugs contain 1 mg of norethindrone (NET) and 0.035 mg of ethinyl estradiol (EE). Application of an interval test for the ratio of the computed parameter means demonstrated equivalence for the two formulations with respect to the 0-24 hour area under the plasma level versus time curve (AUC24), the total area under the curve (AUCtot) and for the maximum plasma concentration (Cmax) for both ethinyl estradiol and norethindrone. The data support the hypothesis for bioequivalence of the two formulations with respect to total absorption.

Adult↗
PubMed1986

Bioequivalence of norethindrone and ethinyl estradiol for two different weight tablets with the same hormonal content.

Two tablets of differing weights, 100 mg (A) and 50 mg (B), of an oral contraceptive drug (OC) were compared with each other and to a solution (C) of the same components. The composition of the OC consisted of 1 mg of norethindrone (NET) and 0.035 mg of ethinyl estradiol (EE2). Both tablets were shown to differ from the solution, which was more rapidly absorbed, but were not significantly different from each other. Formulation means for NET and EE2, for each of the two products, were similar. Application of an interval test for the ratio of computed parameters demonstrated equivalence of the two formulations with respect to 0-24 hr area under the curve (AUC24) and total area under the curve (AUC+o+) for both NET and EE2 and with respect to concentration maximum (Cmax) for EE2. The data support the hypothesis for bioequivalence of the two formulations with respect to total absorption.

Absorption↗
PubMed1978

Dietary fiber.

Explore the source record for details and available documents.

Adult↗
PubMed1975

Effect on fecal output of various dietary nitrogen sources in pig-tailed monkeys (Macaca nemestrina) fed fiber-free, semisynthetic diets.

Fiber-free liquid diets containing isonitrogenous amounts of various dietary nitrogen sources were fed to five adult male pig-tailed monkeys (Macaca nemestrina) with a mean weight of approximately 10 kg. All liquid diets supplied 3.0 g N/DAY PER MONKEY AND MAINTAINED THE ANIMALS IN A POSTIVE NITROGEN BALANCE. Initial baseline fecal output data were obtained by feeding the animals a commercial solid monkey chow. The dietary nitrogen sources fed were a) egg white protein, b) an enzymatic hydrolysate of fish protein supplemented with L-amino acids to simulate the egg albumin pattern, c) a mixture of pure L-amino acids simulating the egg pattern, d) a casein hydrolysate supplemented with amino acids, and e) an amino acid mixture with Rose's pattern. Total fecal matter, dry fecal matter, percent of moisture, fecal nitrogen, lipids and ash were determined for a 10-day period for each experimental diet. A very significant difference (P smaller than 0.001) was noted between each liquid diet and the solid chow, but no significant differences were found between the various fiber-free liquid diets, pointing to the effect of fiber as a major factor affecting fecal output. Monkeys fed liquid diets excreted fecal matter with a mean of 12.9 g/day, of which 4.7 g/day was dry feces (fecal dry matter 28.5%). Fecal nitrogen was found to be 0.25 g, fecal lipids were 0.19 g, and fecal ash was 0.59 g/day per monkey, respectively.

Amino Acids↗