Ibandronate provides efficacy and safety in the treatment of metastatic bone disease

Design and Biological Evaluation of Delivery Systems Containing Bisphosphonates

Bisphosphonates have found application in the treatment of reoccurrence of bone diseases, breast cancer, etc. They have also been found to exhibit antimicrobial, anticancer and antimalarial activities. However, they suffer from pharmacological deficiencies such as toxicity, poor bioavailability and low intestinal adsorption. These shortcomings have resulted in several researchers developing delivery systems that can enhance their overall therapeutic effectiveness. This review provides a detailed overview of the published studies on delivery systems designed for the delivery of bisphosphonates and the corresponding in vitro/in vivo results.

Synthesis, characterization and in vitro evaluation of new composite bisphosphonate delivery systems

In this study, new composite bisphosphonate delivery systems were obtained from polyurethanes (PUs) and nanocrystalline hydroxyapatite (HA). The biodegradable PUs were first synthesized from poly(ε-caprolactone) diols (PCL diols), poly(ethylene adipate) diol, 1,6-hexamethylene diisocyanate, 1,4-butanediol and HA. Moreover, the PCL diols were synthesized by the ring-opening polymerization catalysed by the lipase from Candida antarctica. Next, composite drug delivery systems for clodronate were prepared. The mechanical properties of the obtained biomaterials were determined. The cytotoxicity of the synthesized polymers was tested. The preliminary results show that the obtained composites are perspective biomaterials and they can be potentially applied in the technology of implantation drug delivery systems.

Efficacy and safety of risedronate 150 mg once a month in the treatment of postmenopausal osteoporosis

INTRODUCTION

Risedronate has been shown to be effective in the treatment of postmenopausal osteoporosis when given orally in daily or weekly doses or on 2 consecutive days per month. This randomized, double-blind, multi-center study was designed to assess the efficacy and safety of a single 150 mg risedronate once-a-month oral dose compared with the 5 mg daily regimen.

METHODS

Women with postmenopausal osteoporosis were randomly assigned to receive risedronate 5 mg daily (n=642) or 150 mg once a month (followed by daily placebo) (n=650) in a double-blind fashion for 2 years. Study drug was taken on an empty stomach at least 30 min before breakfast. Bone mineral density, bone turnover markers, fractures, and adverse events were evaluated. The primary efficacy endpoint was the mean percent change from baseline in lumbar spine bone mineral density after 1 year.

RESULTS

538 patients in the daily group (83.8%) and 556 patients in the once-a-month group (85.5%) completed 1 year. The mean percent change in lumbar spine bone mineral density was 3.4% (95% confidence interval, 3.03% to 3.82%) in the daily group and 3.5% (95% confidence interval, 3.15% to 3.93%) in the once-a-month group. The difference between groups was -0.1% (95% confidence interval, -0.51% to 0.27%). The once-a-month regimen was determined to be non-inferior to the daily regimen based on prospectively defined criteria. The mean percent changes in bone mineral density at sites in the hip (total proximal femur, femoral neck, femoral trochanter) were also similar in both dose groups, as were the changes in biochemical markers of bone turnover. The incidence of adverse events, adverse events leading to withdrawal, and upper gastrointestinal tract adverse events were similar in the 2 treatment groups. Both regimens were well tolerated; the percent of patients who withdrew from treatment as a result of an adverse event was 9.5% in the daily group and 8.6% in the once-a-month group.

CONCLUSIONS

Risedronate 150 mg once a month is similar in efficacy and safety to daily dosing and may provide an alternative for patients who prefer once-a-month oral dosing.