Clinical utility of risedronate in postmenopausal osteoporosis: patient considerations with delayed-release formulation

Icaritin ameliorates RANKL-mediated osteoclastogenesis and ovariectomy-induced osteoporosis

A rapidly aging society and longer life expectancy are causing osteoporosis to become a global epidemic. Over the last five decades, a number of drugs aimed at reducing bone resorption or restoring bone mass have been developed, but their efficacy and safety are limited. Icaritin (ICT) is a natural compound extracted from anti-osteoporosis herb Epimedium spp. and has been shown to inhibit osteoclast differentiation. However, the molecular mechanism by which ICT weaken RANKL-induced osteoclast differentiation has not been completely investigated. Here, we evaluated the anti-osteoclastogenic effect of ICT in vitro and the potential drug candidate for treating osteoporosis in vivo. In vitro study, ICT was found to inhibit osteoclast formation and bone resorption function via downregulating transcription factors activated T cell cytoplasm 1 (NFATc1) and c-fos, which further downregulate osteoclastogenesis-specific gene. In addition, the enhanced mitochondrial mass and function required for osteoclast differentiation was mitigated by ICT. The histomorphological results from an in vivo study showed that ICT attenuated the bone loss associated with ovariectomy (OVX). Based on these results, we propose ICT as a promising new drug strategy for osteoporosis that inhibits osteoclast differentiation.

Adherence to Daily, Weekly, and Monthly Dosing Regimens of Bisphosphonates for Osteoporosis Treatment in Postmenopausal Women in Japan: A Retrospective Study Using Claims Data

Poor medication adherence of osteoporosis patients is a major global medical problem because of its negative impact on health outcomes and quality of life. The aim of this study was to evaluate how differences in dosing regimens influence adherence to oral bisphosphonates using data from a large health insurance provider in Japan. This was a retrospective observational study using claims data obtained between October 2012 and January 2018, from the community-based National Health Insurance program of a large city in Japan. The data included in the analysis were obtained from women 60 to 74 years old whose oral bisphosphonate prescription was detected between April 2013 and February 2017. Treatment adherence was monitored from the initial prescription for one year, i.e., up to January 2018. Primary comparisons among the daily-dosing, weekly-dosing, and monthly-dosing groups were based on the mean medication possession ratio (MPR). Data from a total of 3,958 patients were analyzed. The numbers of patients aged 60-64, 65-69, and 70-74 were 425, 1,400, and 2,133, respectively. The highest mean MPR was 69.4% for the monthly-dosing of bisphosphonates, followed by the weekly-dosing at 63.5%, and daily-dosing at 57.2%. Using the Kruskal-Wallis test with Dunn-Bonferroni correction, there were significant differences in mean MPR for daily versus weekly (p < 0.01), daily versus monthly (p < 0.001), and weekly versus monthly dosing regimens (p < 0.05). These results suggest significantly more patients adhere to a monthly or weekly regimen of bisphosphonates in the treatment of osteoporosis than to a daily regimen.

Optimal Dosing Regimen of Osteoporosis Drugs in Relation to Food Intake as the Key for the Enhancement of the Treatment Effectiveness-A Concise Literature Review

Bisphosphonates and selective estrogen receptor modulators (SERMs) represent the two most important groups of medications taken orally and employed in osteoporosis treatment. Effectiveness of the therapy may be affected by poor patient adherence, in particular, due to the inconvenient dosing regimen of oral bisphosphonates. With this review we aimed to assess the effects that food, beverages, and dietary supplements consumed during treatment, along with the dosing regimens, may have on pharmacokinetics and pharmacodynamics of oral drugs employed in treating osteoporosis; we also aimed to shape the recommendations valuable for professional patients’ counseling and education, to provide appropriate dosing regimens in order to improve adherence to the therapy. Food, beverages such as coffee, juices, and mineral water, as well as dietary supplements containing multivalent cations, e.g., calcium, magnesium, aluminium, iron, showed to have a deleterious effect on the bioavailability of all the investigated oral bisphosphonates, specifically alendronate, risedronate, ibandronate, minodronate, and etidronate. For risedronate, a delayed-release (DR) tablet was designed to solve the malabsorption problem in the presence of food, hence DR risedronate can be ingested following breakfast. For other oral bisphosphonates, the proper interval between drug and food, beverages, and dietary supplements intake should be maintained to minimize the risk of interactions. The effect of food on pharmacokinetic parameters of selective estrogen receptor modulators (SERMs) was found to be clinically irrelevant.

Phase II/III, randomized, double-blind, parallel-group study of monthly delayed-release versus daily immediate-release risedronate tablets in Japanese patients with involutional osteoporosis

Absorption of oral immediate-release (IR) risedronate tablets is reduced by food intake, thus a delayed-release (DR) tablet has been developed to overcome the necessity of taking IR tablets under fasting conditions. This randomized, double-blind, phase II/III study compared efficacy and safety of risedronate IR once-daily (QD) and DR once-monthly (QM) tablets in Japanese patients with involutional osteoporosis. Patients received 2.5 mg IR on awakening QD, or 25 or 37.5 mg DR on awakening, following breakfast, or 30 min after breakfast, QM for 12 months. Primary endpoint was non-inferiority in mean percent change from baseline to end of study (month 12, last observation carried forward [M12, LOCF]) in mean lumbar spine (L₂-L₄) bone mineral density (BMD) between risedronate IR on awakening and DR following breakfast. Mean percent changes in (L₂-L₄) BMD at M12, LOCF were 5.07% (IR at awakening, n = 190), 3.36% (25 mg DR following breakfast, n = 194), and 4.11% (37.5 mg DR following breakfast, n = 181). Mean percent change in (L₂-L₄) BMD was numerically lower in the DR following breakfast groups versus the respective on awakening and 30 min after breakfast DR groups. Overall incidences of treatment-emergent adverse events (TEAEs) were comparable between groups. In the DR groups, 1.5-4.0% of patients reported TEAEs potentially associated with acute-phase reactions versus 0% in the IR group. In this study, non-inferiority could not be declared for 37.5 or 25 mg DR following breakfast QM (p = 0.1346 or p = 0.6711, respectively) versus 2.5 mg IR on awakening QD.

Osteotropic nanoscale drug delivery systems based on small molecule bone-targeting moieties

Bone-targeted drug delivery is an active research area because successful clinical applications of this technology can significantly advance the treatment of bone injuries and disorders. Molecules with bone-targeting potential have been actively investigated as promising moieties in targeted drug delivery systems. In general, bone-targeting molecules are characterized by their high affinity for bone and their predisposition to persist in bone tissue for prolonged periods, while maintaining low systemic concentrations. Proteins, such as monoclonal antibodies, have shown promise as bone-targeting molecules; however, they suffer from several limitations including large molecular size, high production cost, and undesirable immune responses. A viable alternative associated with significantly less side effects is the use of small molecule-based targeting moieties. This review provides a summary of recent findings regarding small molecule compounds with bone-targeting capacity, as well as nanoscale targeted drug delivery approaches employing these molecules.

Effective mucoadhesive liposomal delivery system for risedronate: preparation and in vitro/in vivo characterization

In this work, we aimed to develop chitosan-coated mucoadhesive liposomes containing risedronate to improve intestinal drug absorption. Liposomes containing risedronate were prepared with 1,2-distearoryl-sn-glycero-3-phosphocholine and distearoryl-sn-glycero-3-[phospho-rac-(1-glycerol)] using the freeze-drying method, with subsequent coating of the anionic surfaces of the liposomes with chitosan. The in vitro characteristics of the chitosan-coated liposomes were investigated, including their stability, mucoadhesiveness, and Caco-2 cell permeability. This formulation was stable in simulated gastric and intestinal fluids, with the percentage of drug remaining in the liposomes being more than 90% after 24 hours of incubation. Chitosan-coated liposomes also showed strong mucoadhesive properties, implying potential electrostatic interaction with the mucous layer in the gastrointestinal tract. Compared with the untreated drug, chitosan-coated liposomes significantly enhanced the cellular uptake of risedronate, resulting in an approximately 2.1–2.6-fold increase in Caco-2 cells. Further, the chitosan-coated liposomes increased the oral exposure of risedronate by three-fold in rats. Taken together, the results of this study suggest that chitosan-coated liposomes containing risedronate should be effective for improving the bioavailability of risedronate.