Development of a Novel Transdermal Delivery System of Alendronate, a Nitrogen Containing Bisphosphonate, Using a New Type of Hydrophilic Patch and Dissolving Microneedle Arrays

Alendronate is a nitrogen-containing bisphosphonate that is widely used for the treatment of osteoporosis in postmenopausal women. However, the oral bioavailability (BA) of alendronate is approximately 0.9 to 1.8%. In addition, the oral administration of alendronate has been associated with mucosal damage including gastritis, gastric ulcer, and erosive esophagitis. To prevent these adverse effects of alendronate, patients with osteoporosis should sit up or walk for more than 30 min after oral administration, leading to poor compliance and QOL in these patients. To improve the compliance and QOL of these patients, we developed a new transdermal delivery system for alendronate using a new type of hydrophilic patch and dissolving microneedle arrays. The skin permeation of alendronate observed using our transdermal delivery system was sufficient for the treatment of osteoporosis in rat models. These findings indicate that our transdermal delivery system of alendronate is a promising approach that may result in improved therapeutic effects and better compliance and QOL in patients undergoing treatment for osteoporosis.