title: The absorption of (99m)Tc-alendronate given by rectal route in rabbits.
abstract: Alendronate sodium (ALD) is a bisphosphonate medication used in the treatment and prevention of osteoporosis. Absorption of ALD as oral formulation is very poor (0.5%-1%). Its bioavailability can decrease with food effect. It has some gastrointestinal adverse effects such as gastritis, gastric ulcer, and esophagitis. The aim of this study was to develop a rectal formulation of ALD as an alternative to oral route and to investigate the absorption of it by using gamma scintigraphy. For this reason, ALD was labeled with Technetium-99m ((99m)Tc) by direct method. The radiochemical characterization of the (99m)Tc-ALD was carried out by paper chromatography, thin layer chromatography, and electrophoresis methods. The labeling efficiency of (99m)Tc-ALD was found 99% without significant changes until 6 h postlabeling at room temperature. The rectal suppositories containing (99m)Tc-ALD were prepared by fusion method using polyethylene glycol (PEG) 1500. The (99m)Tc-labeled ALD suppositories were administrated to rabbits by rectal route. Serial scintigrams over all bodies of the rabbits were obtained at different time intervals using a gamma camera. We found that the rectal absorption of (99m)Tc-ALD from suppository formulation was possible. According to our results, this formulation of ALD can be suggested for the therapy of osteoporosis as an alternative route.
authors.affiliation: Department of Radiopharmacy, Faculty of Pharmacy, Ege University, Bornova, Izmir, Turkey. makbule.asikoglu@ege.edu.tr
authors.forename: Makbule
authors.initials: M
authors.lastname: Asikoğlu
authors.forename: Isik
authors.initials: I
authors.lastname: Ozguney
authors.forename: Ipek
authors.initials: I
authors.lastname: Ozcan
authors.forename: Oya
authors.initials: O
authors.lastname: Orumlu
authors.forename: Tamer
authors.initials: T
authors.lastname: Guneri
authors.forename: Kamil
authors.initials: K
authors.lastname: Koseoğlu
authors.forename: Hayal
authors.initials: H
authors.lastname: Ozkilic
mesh_terms: D000284:Administration, Oral; D000285:Administration, Rectal; D019386:Alendronate / Q000008:administration & dosage / Q000737:chemistry / Q000493:pharmacokinetics*; D000818:Animals; D001682:Biological Availability; D050071:Bone Density Conservation Agents / Q000008:administration & dosage / Q000737:chemistry / Q000493:pharmacokinetics*; D055598:Chemical Phenomena; D002626:Chemistry, Pharmaceutical; D002627:Chemistry, Physical; D004058:Diffusion; D018565:Food-Drug Interactions; D007408:Intestinal Absorption / Q000502:physiology*; D007553:Isotope Labeling; D008297:Male; D011817:Rabbits; D012995:Solubility; D013667:Technetium / Q000737:chemistry
chemical_list: D050071:Bone Density Conservation Agents; D013667:Technetium; D019386:Alendronate