Distribution and cost of drugs in a pharmaceutically decentralized health maintenance organization.

A private, free-standing health maintenance organization, Group Health of Arizona, was established with a decentralized pharmacy distribution system. A closed formulary and monthly peer review by pharmacists and physicians influence the number of prescriptions written as well as drug cost. A study was conducted to determine: the 50 most-prescribed items by number and cost; drug cost according to certain therapeutic categories; the average drug cost per prescription; the number of prescriptions dispensed per enrollee; and the cost of drugs dispensed as a percentage of wholesale cost. The objectives of the study were achieved but additional questions requiring future studies were raised.

Bioavailability of 11 sulfisoxazole products in humans.

Single lots of 11 commercially available 500-mg sulfisoxazole tablets were evaluated in vitro and in vivo. All products tested met USP XVIII specifications for weight variation and product assay. However, three products failed to meet the USP XVIII dissolution requirement. The only statistically significant difference observed between the 11 products was a lower peak plasma level exhibited by one product. No useful correlation was observed between the in vivo and in vitro studies for the dosage forms tested.

Bioavailability of 17 ampicillin products.

The bioavailability of single lots of 250-mg ampicillin capsules, available from 17 distributors and/or manufactures, was determined. Each product was evaluated in terms of the serum ampicillin levels achieved at 1, 2, 3, 4, 6, and 8 hr postadministration, the peak serum levels, the time of peak serum level, and the area under the serum level-time curve. There was no statistically significant difference (p is greater than 0.05) between any of the 17 products tested.

Propoxyphene bioavailability: an evaluation of ten products.

Ten commercial products containing 65 mg propoxyphene hydrochloride have been evaluated for their relative bioavailability in human subjects in a complete crossover study. No statistically significant (P greater than 0.05) differences were observed between the products in terms of plasma levels 1, 2, 3, 4, 6, 8, and 12 hours after administration; peak plasma levels; time to achieve peak plasma level; and area under the plasma level-time curve. Individual subjects exhibited considerable differences in the propoxyphene plasma levels, which were similar to the variability observed by others. The average estimated half-life of 3.61 hours was consistent with previously reported values, although it may have underestimated the true value because the low plasma levels remaining after 12 hours were not quantitated.

Rapid, precise, turbidometric assay for low levels of ampicillin in serum after single-dose oral administration.

A turbidometric assay is described for the quantitative measurement of ampicillin in serum. Standard curves prepared with known concentrations of ampicillin in serum exhibited acceptable linearity over a concentration range of approximately 0.2 to 1.8 mug/ml. Data are presented to show the excellent precision of the assay and the application of the assay to clinical studies. The advantages of this method over other procedures are discussed. Because of the questionable stability of ampicillin, samples containing known concentrations of ampicillin in serum were assayed after storage for various lengths of time. Serum samples maintained in the frozen state until the time of assay exhibited approximately 12% degradation after 7 days, whereas those samples which were subjected to repeated thawing and refreezing exhibited approximately 25% degradation after the same time interval.