Enteric-coated Alendronate Sodium Nanoliposomes: a Novel Formula to Overcome Barriers for the Treatment of Osteoporosis

Background And Objectives: Alendronate sodium (ALS) is the most common drug used for the treatment of osteoporosis. The challenges facing ALS use include: very poor oral bioavailability (0.6%), esophageal ulcers, and complicated instructions for its use. The objective of this research is to utilize nanotechnology to formulate ALS into enteric-coated nanoliposomes (NLS) to overcome the previously mentioned drawbacks.

Methods: NLS were prepared with lipid components of phosphatidylcholine (PC), cholesterol (CH), and lecithin (Lec) in ratios 4:1:1, 4:2:1, 4:3:1, and 4:4:1, respectively. Formulas that showed the highest entrapment efficiency were prepared either alone or mixed with positive and negative charge-inducing agents and coated with Eudragit L100. Eudragit-coated NLS (EuC-NLS) were evaluated for particle size, zeta potential, morphological examination, and drug release in pH 1.2 and pH 7.4 media. The pharmacokinetic study was carried out in rabbits.

Results: Spherical NLS were successfully developed with a mean size range from 70 to 150 nm. EuC-NLS with PC:CH:Lec:dicetyl phosphate (4:3:1:1) successfully resist the release of ALS in acidic environments and enhanced the bioavailability in rabbits 12-fold compared with the marketed tablets.

Conclusions: EuC-NLS is a promising novel formula for ALS with higher bioavailability and a lower dose, avoiding the side effects of esophageal ulceration.