Risedronate

Preparation of composite calcium phosphate cement scaffold loaded with Hedysarum polysaccharides and its efficacy in repairing bone defects

It's imperative to create a more ideal biological scaffold for bone defect repair. Calcium phosphate bone cements (CPC) could be used as a scaffold. Some ingredients and osteogenic factors could be added to improve its poor mechanical properties and biological activity. As a macromolecule extracted from traditional Chinese medicine, Hedysarum polysaccharides (HPS) would significantly promote the osteogenic activity of bone biomaterials. Zirconium oxide and starch were added to the solid phase and citric acid was added to the liquid phase to optimize CPC. HPS was loaded onto the scaffold as an osteogenic factor, and the prepared CPS + HPS was characterized. Further, the cytocompatibility of CPS + HPS was assessed according to activity, differentiation, and calcification in neonatal rat calvarial osteoblasts, and the biosafety of CPS + HPS was evaluated according to acute toxicity, pyrogen, sensitization, and hemolysis. The success of CPS + HPS in repairing bone defects was evaluated by using a rabbit femur implantation experiment. After optimization, CPS-20-CA-5 containing 10% starch and 5% citric acid displayed the highest mechanical strength of 28.96 ± 0.03 MPa. HPS-50 was demonstrated to exert the best osteogenic effect. The combination of CPS + HPS achieved HPS-loaded CPC. Material characterization, cytocompatibility, biosafety, and femoral implantation experiments indicated that CPS + HPS possessed better pressure resistance and improved osteogenic ability in bone defect repair.CPS + HPS demonstrated effective pressure resistance and superior osteogenic ability, which may be of great significance for bone defects and bone tissue engineering to promote bone regeneration and repair.

Osteoclast and Sclerostin Expression in Osteocytes in the Femoral Head with Risedronate Therapy in Patients with Hip Fractures: A Retrospective Comparative Study

Background and Objectives: The majority of research on the effects of osteoporosis drugs has measured the bone mineral density (BMD) of the spine and femur through dual-energy X-ray absorptiometry (DEXA) and compared and analyzed the effects of the drugs through changes in the BMD values. This study aims to compare osteoclast and sclerostin expression in osteocytes after risedronate therapy by obtaining femoral heads from patients with hip fractures. Materials and Methods: We obtained the femoral heads of 10 female patients (age: ≥65 years) who received risedronate therapy for at least 1 year through hip arthroplasty during 2019−2021 (risedronate group). Meanwhile, 10 patients who had never received osteoporosis treatment were selected as controls using propensity scores with age, body mass index, and bone density as covariates (control group). While the osteoclast count was evaluated using tartrate-resistant acid phosphatase (TRAP) staining, the sclerostin expression in osteocytes was assessed using immunohistochemistry. Moreover, Western blotting and polymerase chain reaction (PCR) were performed for receptor activation of nuclear factor kappa-Β ligand (RANKL), RANK, osteoprotegerin (OPG), sclerostin, and bone morphogenetic protein-2 (BMP2). Results: TRAP staining revealed significantly more TRAP-positive cells in the control group (131.75 ± 27.16/mm2) than in the risedronate group (28.00 ± 8.12/mm2). Moreover, sclerostin-positive osteocytes were expressed more in the control group (364.12 ± 28.12/mm2) than in the risedronate group (106.93 ± 12.85/mm2). Western blotting revealed that the expressions of RANKL, RANK, sclerostin, and BMP2 were higher in the control group than in the risedronate group (p < 0.05). Furthermore, RANK, sclerostin, and OPG protein levels were higher in the control group than in the risedronate group. Conclusions: In this study, the risedronate group demonstrated lower osteoclast activity and sclerostin expression in osteocytes in the femoral head than the control group.

Current Status of the Diagnosis and Management of Osteoporosis

Osteoporosis has been defined as the silent disease of the 21st century, becoming a public health risk due to its severity, chronicity and progression and affecting mainly postmenopausal women and older adults. Osteoporosis is characterized by an imbalance between bone resorption and bone production. It is diagnosed through different methods such as bone densitometry and dual X-rays. The treatment of this pathology focuses on different aspects. On the one hand, pharmacological treatments are characterized by the use of anti-resorptive drugs, as well as emerging regenerative medicine treatments such as cell therapies and the use of bioactive hydrogels. On the other hand, non-pharmacological treatments are associated with lifestyle habits that should be incorporated, such as physical activity, diet and the cessation of harmful habits such as a high consumption of alcohol or smoking. This review seeks to provide an overview of the theoretical basis in relation to bone biology, the existing methods for diagnosis and the treatments of osteoporosis, including the development of new strategies.

A Mechanistic Study on the Formation of Dronic Acids

Dronic acid derivatives, important drugs against bone diseases, may be synthesized from the corresponding substituted acetic acid either by reaction with phosphorus trichloride in methanesulfonic acid as the solvent or by using also phosphorous acid as the P-reactant if sulfolane is applied as the medium. The energetics of the two protocols were evaluated by high-level quantum chemical calculations on the formation of fenidronic acid and benzidronic acid. The second option, involving (HO)₂P-O-PCl₂ as the nucleophile, was found to be more favorable over the first variation, comprising Cl₂P-O-SO₂Me as the real reagent, especially for the case of benzidronate.

Enantioselective vinylogous aldol reaction of acylphosphonates with 3-alkylidene oxindoles

A simple strategy for yielding chiral tertiary α-hydroxy phosphonates that integrates two highly biologically relevant scaffolds namely 3-alkylidene-2-oxindoles and phosphonates has been described. The hydrogen bonding ability of the bifunctional thiourea catalyst allows simultaneous dual activation of a vinylogous oxindole nucleophile and an acylphosphonate electrophile, affording hydroxyphosphonato-3-alkylidene-2-oxindoles as aldol adducts in high yields (up to 92%) with excellent stereocontrol (up to 99% ee).

A 3-year postmarketing study on the safety and effectiveness of once-monthly risedronate in Japanese patients with osteoporosis

Objectives

This postmarketing study aims to evaluate the safety and effectiveness of oral administration of risedronate at 75 mg once monthly for 36 months in patients with osteoporosis in Japan.

Methods

Participants were ambulatory outpatients with osteoporosis who were ≥ 50 years old and had prevalent vertebral fractures. Outcomes were the incidence rate of adverse drug reaction (ADR), cumulative incidence of vertebral, nonvertebral, and hip fractures, the percent changes of lumbar spinal L_2–4 bone mineral density (BMD), and low back pain. In addition, medication compliance was examined.

Results

Safety, vertebral fractures, and other outcomes were analyzed in 542, 328, and 535 patients, respectively. In the safety analysis set, 88.38% of the patients were women and the mean age was 75.9 years. The monthly medication compliance rate ranged from 83.24% to 95.38%. The incidence rate of ADRs, including 4 severe ADRs, was 10.52% (n = 57). The common ADRs were gastrointestinal disorders, musculoskeletal, and connective tissue disorders. No osteonecrosis of the jaw was reported. The cumulative incidences (95% CI) of vertebral, nonvertebral, and hip fractures at 36 months were 12.58% (8.61–18.18), 6.59% (4.31–10.01), and 1.58% (0.64–3.88), respectively. The L_2–4 BMD increased by 10.59% compared with baseline value (P < 0.01), and the proportion of patients with low back pain decreased to 30.77%, at 36 months.

Conclusions

Administering 75 mg of risedronate once a month remains a favorable compliance rate and may be useful for the treatment of patients, even the elderly, with osteoporosis in daily practice.

Pathogenesis of glucocorticoid-induced osteoporosis and options for treatment

Glucocorticoids are widely used to suppress inflammation or the immune system. High doses and long-term use of glucocorticoids lead to an important and common iatrogenic complication, glucocorticoid-induced osteoporosis, in a substantial proportion of patients. Glucocorticoids mainly increase bone resorption during the initial phase (the first year of treatment) by enhancing the differentiation and maturation of osteoclasts. Glucocorticoids also inhibit osteoblastogenesis and promote apoptosis of osteoblasts and osteocytes, resulting in decreased bone formation during long-term use. Several indirect effects of glucocorticoids on bone metabolism, such as suppression of production of insulin-like growth factor 1 or growth hormone, are involved in the pathogenesis of glucocorticoid-induced osteoporosis. Fracture risk assessment for all patients with long-term use of oral glucocorticoids is required. Non-pharmacological interventions to manage the risk of fracture should be prescribed to all patients, while pharmacological management is reserved for patients who have increased fracture risk. Various treatment options can be used, ranging from bisphosphonates to denosumab, as well as teriparatide. Finally, appropriate monitoring during treatment is also important.

Antiresorptive agents' bone-protective and adjuvant effects in postmenopausal women with early breast cancer

Potent antiresorptive drugs (bisphosphonate and denosumab) are often used to protect bone health in postmenopausal breast cancer patients. In addition, clinical trials have shown that these drugs increase disease-free survival, though the mechanism of adjuvant benefit is largely unknown. Here we review the bone health and adjuvant data for both classes of antiresorptive drugs and highlight differences in their pharmacology. Inhibition of bone resorption is vitally important to protect against osteoporotic fractures, and may also contribute to adjuvant survival benefits by making the bone microenvironment less amenable to breast cancer metastasis. After a course of therapy, stoppage of bisphosphonates yields a persistent antiresorptive effect, whereas discontinuation of denosumab causes a rebound increase in bone resorption markers and a loss of bone mineral density to baseline levels. Whether the potential adjuvant benefits of denosumab are also rapidly lost after drug discontinuation deserves further investigation.

Natural Health Products and Diabetes: A Practical Review

The prevalence of natural health product (NHP) use in Canada is extensive. Patients with chronic diseases, including diabetes, use NHPs at a higher rate than the general population. Many NHPs exert hypoglycemic effects, among other effects relevant to diabetes management. To provide a practical, clinical review of NHPs with such effects targeted to pharmacists, a literature search was performed to collect data on the efficacy and safety profiles of 10 commonly used NHPs that exert antidiabetic properties. The following NHPs are included in this clinical review: alpha-lipoic acid, chromium, magnesium, bitter melon, cinnamon, fenugreek, gymnema, milk thistle, Reishi mushroom and white mulberry. Given the potential of NHPs to additively cause hypoglycemia when used concurrently with conventional medications, pharmacists should be up to date with current evidence around NHPs that may affect diabetes care to prevent adverse reactions and interactions. In addition, effective and respectful communication with patients around NHP use and collaboration with various health-care providers are essential in the patient care process.

Mechanism of Action, Pharmacokinetic and Pharmacodynamic Profile, and Clinical Applications of Nitrogen-containing Bisphosphonates

Nitrogen-containing bisphosphonates (nBPs) are bone-specific agents that inhibit farnesyl diphosphate synthase. nBPs’ strong affinity for bone, and not for other tissues, makes them potent inhibitors of bone resorption and bone remodeling activity, with limited potential for side-effects in non-skeletal tissues. Five nBPs are currently approved in the United States. The primary indications are for treatment of osteoporosis (alendronate, ibandronate, and risedronate) and treatment/prevention of skeletal-related events (SREs) in multiple myeloma and breast and prostate cancer patients (ibandronate, pamidronate, and zoledronic acid). nBPs are the most efficacious drugs available for these diseases, reducing osteoporotic fracture risk by 50–60% in persons with low bone mass or prior osteoporotic fracture, and SREs by one-third in cancer patients. The absorbed nBP dose for cancer patients is from seven to ten times that in osteoporosis patients. nBPs are unique in that they first exert profound pharmacodynamic effects long after their blood levels reach zero. Current pharmacokinetic studies indicate that approximately half of any nBP dose reaches the skeleton, with an early half-life of ten days, and a terminal half-life of about ten years. Practical study design limitations and theoretical considerations suggest that both the half-life and the amount of nBP retained in the skeletons of patients on long-term nBP therapy are substantially overestimated by extrapolation directly from current pharmacokinetic data. In fact, the amount of nBP being released from skeletal tissues of long-term-treated patients, particularly in osteoporosis patients, becomes insufficient to maintain full pharmacodynamic efficacy relatively soon after dosing is interrupted.

Gingival Mesenchymal Stem/Progenitor Cells: A Unique Tissue Engineering Gem

The human gingiva, characterized by its outstanding scarless wound healing properties, is a unique tissue and a pivotal component of the periodontal apparatus, investing and surrounding the teeth in their sockets in the alveolar bone. In the last years gingival mesenchymal stem/progenitor cells (G-MSCs), with promising regenerative and immunomodulatory properties, have been isolated and characterized from the gingival lamina propria. These cells, in contrast to other mesenchymal stem/progenitor cell sources, are abundant, readily accessible, and easily obtainable via minimally invasive cell isolation techniques. The present review summarizes the current scientific evidence on G-MSCs' isolation, their characterization, the investigated subpopulations, the generated induced pluripotent stem cells- (iPSC-) like G-MSCs, their regenerative properties, and current approaches for G-MSCs' delivery. The review further demonstrates their immunomodulatory properties, the transplantation preconditioning attempts via multiple biomolecules to enhance their attributes, and the experimental therapeutic applications conducted to treat multiple diseases in experimental animal models in vivo. G-MSCs show remarkable tissue reparative/regenerative potential, noteworthy immunomodulatory properties, and primary experimental therapeutic applications of G-MSCs are very promising, pointing at future biologically based therapeutic techniques, being potentially superior to conventional clinical treatment modalities.

Efficacy and Safety of Bisphosphonate Therapy in Children with Osteogenesis Imperfecta: A Systematic Review

BACKGROUND/AIMS

To systematically assess contemporary knowledge regarding the effectiveness and safety of bisphosphonates (BPs) in children with osteogenesis imperfecta (OI).

METHODS

PubMed/MEDLINE, Embase, and Cochrane were searched for eligible articles up to June 2014. Studies eligible for inclusion were (randomized) controlled trials assessing the effects of BPs in children with OI. Methodological quality was assessed independently by 4 reviewers using the Cochrane Collaboration's tool for risk of bias.

RESULTS

Ten studies (519 children) were included. Four studies (40%) showed a low risk of bias. All studies investigating lumbar spine areal bone mineral density indicated a significant increase as a result of BP treatment. Most studies observed a significant decrease in fracture incidence. The most frequently reported adverse events were gastrointestinal complaints, fever, and muscle soreness. A significant decrease in (bone) pain due to BP treatment was observed in more than half of the studies. Most studies measuring urinary markers of bone resorption reported a significant decrease. The majority of studies with intravenous treatment showed a significant increase in lumbar projection area, whereas studies with oral treatment did not.

CONCLUSIONS

Treatment with oral or intravenous BPs in children with OI results in an increase in bone mineral density and seems to be safe and well tolerated.

Whey Protein Concentrate Hydrolysate Prevents Bone Loss in Ovariectomized Rats

Milk is known as a safe food and contains easily absorbable minerals and proteins, including whey protein, which has demonstrated antiosteoporotic effects on ovariectomized rats. This study evaluated the antiosteoporotic effect of whey protein concentrate hydrolysate (WPCH) digested with fungal protease and whey protein concentrate (WPC). Two experiments were conducted to determine (1) efficacy of WPCH and WPC and (2) dose-dependent impact of WPCH in ovariectomized rats (10 weeks old). In Experiment I, ovariectomized rats (n=45) were allotted into three dietary treatments of 10 g/kg diet of WPC, 10 g/kg diet of WPCH, and a control diet. In Experiment II, ovariectomized rats (n=60) were fed four different diets (0, 10, 20, and 40 g/kg of WPCH). In both experiments, sham-operated rats (n=15) were also fed a control diet containing the same amount of amino acids and minerals as dietary treatments. After 6 weeks, dietary WPCH prevented loss of bone, physical properties, mineral density, and mineral content, and improved breaking strength of femurs, with similar effect to WPC. The bone resorption enzyme activity (tartrate resistance acid phosphatase) in tibia epiphysis decreased in response to WPCH supplementation, while bone formation enzyme activity (alkaline phosphatase) was unaffected by ovariectomy and dietary treatment. Bone properties and strength increased as the dietary WPCH level increased (10 and 20 g/kg), but there was no difference between the 20 and 40 g/kg treatment. WPCH and WPC supplementation ameliorated bone loss induced by ovariectomy in rats.

Effects of risedronate on the morphology and viability of gingiva-derived mesenchymal stem cells

Risedronate has been used for the prevention and treatment of postmenopausal and corticosteroid-induced osteoporosis. The present study was performed to evaluate the effects of risedronate on the morphology and viability of human stem cells derived from the gingiva. Stem cells derived from the gingiva were grown in the presence of risedronate at concentrations that ranged from 1 to 10 µM. The morphology of the cells was viewed under an inverted microscope, and cell proliferation was analyzed with a cell counting kit-8 (CCK-8) on days 2, 4 and 7. The untreated control group showed a spindle-shaped, fibroblast-like morphology. The shapes of the cells treated with 1 and 5 µM risedronate were similar to that of the control group on day 2. However, morphology of the 10 µM group markedly differed from that of the control group. The shapes of the cells in the 1, 5 and 10 µM groups were rounder, and pronounced alterations when compared with the untreated control group were noted in all groups on day 7. The cultures growing in the presence of risedronate showed decreased CCK-8 values on day 7. In conclusion, risedronate produced notable alterations in the morphology of the cells and reduced the viability of gingival mesenchymal stem cells.

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.

Basic research and clinical applications of bisphosphonates in bone disease: what have we learned over the last 40 years?

It is now 40 years since bisphosphonates (BPs) were first used in the clinic. So, it is timely to provide a brief review of what we have learned about these agents in bone disease. BPs are bone-specific and have been classified into two major groups on the basis of their distinct molecular modes of action: amino-BPs and non-amino-BPs. The amino-BPs are more potent and they inhibit farnesyl pyrophosphate synthase (FPPS), a key enzyme of the mavalonate/cholesterol biosynthetic pathway, while the non-amino-BPs inhibit osteoclast activity, by incorporation into non-hydrolyzable analogs of ATP. Both amino-BPs and non-amino-BPs can protect osteoblasts and osteocytes against apoptosis. The BPs are widely used in the clinic to treat various diseases characterized by excessive bone resorption, including osteoporosis, myeloma, bone metastasis, Legg-Perthes disease, malignant hyperparathyroidism, and other conditions featuring bone fragility. This review provides insights into some of the adverse effects of BPs, such as gastric irritation, osteonecrosis of the jaw, atypical femoral fractures, esophageal cancer, atrial fibrillation, and ocular inflammation. In conclusion, this review covers the biochemical and molecular mechanisms of action of BPs in bone, particularly the discovery that BPs have direct anti-apoptotic effects on osteoblasts and osteocytes, and the current situation of BP use in the clinic.

Ionic complex of risedronate with positively charged deoxycholic acid derivative: evaluation of physicochemical properties and enhancement of intestinal absorption in rats

Risedronate is widely used clinically to treat osteoporosis, Paget's disease, hypercalcemia, bone metastasis, and multiple myeloma. However, its oral efficacy is restricted due to its low bioavailability and severe gastrointestinal adverse effects. This study was designed to evaluate the effect of deoxycholic acid derivatives on the permeability and oral bioavailability of risedronate by increasing its lipophilicity and affinity to bile transporters. We synthesized two bile acid derivatives, N(α)-deoxycholyl-L-lysyl-methylester (DCK) and N(α)-deoxycholyl-L-lysyl-hydroxide (HDCK) as oral absorption enhancers. After ionic complex formation with the bile acid derivatives, the complexes were characterized by powder X-ray diffraction. Their artificial membrane permeabilities and bioavailabilities in rats were investigated in comparison with pure risedronate. Complex formation with DCK or HDCK demonstrated that risedronate existed in an amorphous form in the complex. A physical complex of risedronate with DCK enhanced the apparent membrane permeability of risedronate significantly but pure risedronate was not permeable. An in vivo study revealed that the C max and AUClast of risedronate/DCK (1:2) complex were 1.92- and 2.64-fold higher than those of pure risedronate, respectively. Thus, the risedronate/DCK complex can improve the oral absorption of risedronate and patient compliance by reducing dose frequency and adverse reactions.

Eliminating the need for fasting with oral administration of bisphosphonates

Bisphosphonates are the major treatment of choice for osteoporosis, given that they are attached preferentially by bone and significantly reduce the risk of fractures. Oral bisphosphonates are poorly absorbed (usually less than 1% for nitrogen-containing bisphosphonates) and when taken with food or beverages create complexes that cannot be absorbed. For this reason, they must be taken on an empty stomach, and a period of up to 2 hours must elapse before the consumption of any food or drink other than plain water. This routine is not only inconvenient but can lead to discontinuation of treatment, and when mistakenly taken with food, may result in misdiagnosis of resistance to or failure of treatment. The development of an enteric-coated delayed-release formulation of risedronate with the addition of the calcium chelator, ethylenediaminetetraacetic acid (EDTA), a widely used food stabilizer, eliminates the need for fasting without affecting the bioavailability of risedronate or its efficacy.

Topically administered Risedronate shows powerful anti-osteoporosis effect in ovariectomized mouse model

We investigated the therapeutic effect of topical Risedronate (RIS) on a mouse model of estrogen-deficient osteoporosis. Fourteen-week-old female mice were ovariectomized and assigned to 4 groups: SHAM-operated (SHAM), OVX mice treated with vehicle (OVX-V), OVX mice treated with 0.2% RIS (OVX-0.2% RIS), and OVX-mice treated with 0.02% RIS (OVX-0.02% RIS). Topical samples containing RIS were prepared in 10% (w/w) polyethylene glycol (PEG, MW 400) and 80 μg of sample was spread on the mice's mid-backs every 3 days for 5 weeks. Micro-CT analysis of femora demonstrated that OVX-0.2% RIS exhibited a 29% greater bone mineral density and 24% greater bone volume fraction than that of OVX-V group. Investigation of the trabecular bone in OVX-0.2% RIS revealed a 24% higher bone volume (BV/TV), 51% higher trabecular number (Tb.N), and 40% lower trabecular separation (Tb.Sp) compared to OVX-V mice. Additionally, bone phenotypes of tibiae were further confirmed by histological analysis. OVX-0.2% RIS group exhibited a 494% greater BV/TV, 464% less Tb.Sp, 81% greater active osteoclast surface (Oc.S/BS) and 26% less osteoclast number (N.Oc/BS) than that of OVX-V group. Collectively, these results indicated that topical delivery of RIS has powerful pharmaceutical effects on the prevention of osteoporosis and bone turnover.

Pharmacology of bisphosphonates

Four decades of preclinical and clinical research of the pharmacology of bisphosphonates have generated data and concepts that have considerably improved their clinical use. However, despite this progress several pharmacological aspects relevant to bisphosphonate action on bone are still incompletely understood. This is mainly due to the complex, unique pharmacological properties of bisphosphonates. We review here the pharmacokinetic and pharmacodynamic data of bisphosphonates that are relevant for their clinical application and for the potential choice of a given compound, focusing on uncertainties that still exist.

Risedronate on two consecutive days per month

Risedronate, an orally administered pyridinal bisphosphonate, is effective in the treatment and prevention of postmenopausal osteoporosis. Efforts to optimize patient adherence and persistence with, and hence the effectiveness of, therapy have led to the development of a 75 mg tablet to be taken on two consecutive days each month (2CDM). After 1 year of treatment, risedronate 75 mg 2CDM was noninferior to risedronate 5 mg once daily in improving lumbar spine bone mineral density (BMD) in an ongoing (2-year) randomized, double-blind, parallel-group, multinational trial in 1229 postmenopausal women with osteoporosis. Mean percentage increases in BMD from baseline at 12 months were 3.4% and 3.6% in the 75 mg 2CDM and 5 mg once-daily groups; the upper limit of the 95% confidence interval for the treatment difference (5 mg once daily - 75 mg 2CDM; -0.19%, 0.62%) did not exceed the predefined noninferiority margin (1.5%). In general, improvements in hip BMD and reductions in bone turnover markers with the 75 mg 2CDM regimen were not significantly different from those with the 5 mg once-daily regimen; there was no significant between-group difference in the incidence of new vertebral fractures at 12 months. The tolerability profile (including the incidence of upper gastrointestinal tract adverse events) of risedronate 75 mg 2CDM in postmenopausal women with osteoporosis was similar to that of risedronate 5 mg once daily.

Synthesis and biological evaluation of indolyl bisphosphonates as anti-bone resorptive and anti-leishmanial agents

A series of indole conjugated bisphosphonate derivatives have been synthesized and evaluated for their in vitro anti-bone resorptive activity using bone marrow osteoclast culture. Two bisphosphonates 23 and 24 significantly inhibited osteoclastogenesis, 23 showed inhibition at 10 and 100 pM which was lower than the concentration of standard drug alendronate, and 24 inhibited osteoclastogenesis at 100 nM which was comparable to alendronate. Two other compounds 13 and 14 also showed inhibition comparable to alendronate, but were cytotoxic in the osteoblast cells. The two active bisphosphonates 23 and 24 induced significant osteoclast apoptosis at concentrations 100 nM for compound 24 and at 10 pM for compound 23 compared to alendronate. In vivo effect of active bisphosphonates 23 and 24 resulted in osteoclastogenesis of bone marrow cells (BMCs) to almost 40-50% (23 showing 8.4% decrease and 24 showing 9.0%) compared to 16.5% of the ovariectomized group. Further, screening of anti-leishmanial activity, four compounds 24-25 and 27-28 showed more than 80% inhibition against both the promastigote and amastigote stages of the Leishmania parasite.

Clinical potential of RANKL inhibition for the management of postmenopausal osteoporosis and other metabolic bone diseases

Osteoporosis affects millions of people worldwide, causing decreases in bone strength and a marked increase in fracture risk. Current therapies increase bone mineral density and reduce the risk of fractures, but dosing requirements are often considered inconvenient, and patient compliance with therapy is poor. This review will discuss recent discoveries in bone biology, which have demonstrated that the interaction of osteoprotegerin (OPG), receptor activator of nuclear factor--kappa B (RANK), and RANK ligand (RANKL) is critical for the regulation of bone remodeling. Collectively, these preclinical studies have shown that endogenous RANKL inhibition by OPG underlies the normal mechanism for maintaining the correct balance between bone resorption and bone formation. Multiple clinical trials are in progress to investigate the therapeutic potential of RANKL inhibition by denosumab, a fully human monoclonal anti-RANKL antibody, in the treatment of postmenopausal osteoporosis and other bone loss diseases. The results of these human trials will also be discussed.

Osteoporosis update: effective prevention and treatment

Osteoporosis is a public health threat to approximately 44 million individuals in the USA, or 55% of men and women over the age of 50 years. The primary goal of osteoporosis management is to prevent fracture, the most devastating consequence. Risk factors and bone mineral density can be assessed to determine appropriate action for prevention and treatment of osteoporosis. Prevention strategies include lifestyle modification, fall prevention, and adequate intake of calcium and vitamin D. Current treatment options include antiresorptive agents and anabolic agents. Adherence and cost issues play major roles in establishing optimal therapy for individual patients. New agents in development are designed to improve osteoporosis treatment and patient adherence. This review focuses on current and future prevention and treatment options for postmenopausal osteoporosis.

How much calcium is in your drinking water? A survey of calcium concentrations in bottled and tap water and their significance for medical treatment and drug administration

INTRODUCTION

Different forms of water vary in calcium content. High divalent ion (i.e., Ca(2+), Mg(2+), etc.) concentration is deleterious to the absorption and efficacy of the bisphosphonate group of drugs in osteoporosis treatment. Water with high calcium concentration may also present an alternate pathway of calcium administration. In either case, knowing the actual concentration is critical.

HYPOTHESIS

The current paper is a surveillance study. We hypothesize that there is considerable variation in the calcium concentrations in the various water sources: tap water from US and Canadian cities of different regions and purified, spring, and mineral bottled waters. In addition, we hypothesize that the water filter removes a significant amount of minerals including calcium from the water.

METHODOLOGY

Calcium concentrations in various city tap waters, as well as an assorted number of bottled waters, were determined through the direct inspection of scientific data. The effect of filtering was also determined by mineral analysis of mineral water directly before and after filtration.

RESULT

The calcium concentration of water varies from 1 to 135 mg/L across the USA and Canada. Most spring waters were found to have a relatively low calcium concentration, with an average of 21.8 mg/L. Purified waters contain a negligible calcium concentration. Mineral waters, on the other hand, were generally found to contain higher calcium concentrations, an average of 208 mg/L of calcium. Filtration was found to remove a considerable amount of calcium from the water, removing 89% on average.

CONCLUSION

Calcium concentration in water varied substantially from different sources in the USA and Canada. Bottled waters presented with concentrations of calcium covering a very large range. Certain tap and bottled waters present with concentrations of calcium sufficient to exhibit a deleterious effect on bisphosphonate treatment. Alternatively, certain waters may be used as a source of calcium that may provide over 40% of the recommended daily intake for calcium.

Interleukin-6 and osteoprotegerin systems in Paget's disease of bone: relationship to risedronate treatment

Serum concentrations of interleukin-6 (IL-6), IL-6-soluble receptor (sIL-6R), IL-6 gp130-soluble receptor (sgp130), ligand of receptor activator of nuclear factor (NF)-kappaB (RANKL), and osteoprotegerin (OPG) were determined in 42 patients with polyostotic Paget's disease of bone (PDB) and acquired resistance to clodronate (M/F ratio 23:19; mean age 58.5 +/- 9.4 years) in acute phase of disease and after oral risedronate treatment (30 mg/day for 8 weeks). At baseline, pagetic patients showed higher levels of OPG, sIL-6R, and IL-6 with lower levels of sgp130 compared to 24 age- and sex-matched controls (respectively, 4.69 +/- 1.27 vs. 2.87 +/- 0.54 pmol/L; 40.89 +/- 8.61 vs. 30.98 +/- 4.24 ng/ml; 3.59 +/- 0.97 vs. 1.8 +/- 0.9 pg/ml; 327.34 +/- 43.41 vs. 411.7 +/- 79.5 ng/ml). Response to treatment is related to a significant increase of OPG levels in all patients (from 4.69 +/- 1.27 to 5.48 +/- 1.31 pmol/L). The disease remission, that is, total alkaline phosphatase (tALP) levels within the normal range after therapy, was associated with a simultaneous increase in OPG and sgp130 levels. In patients with tALP higher than the normal range after therapy, the OPG increase was associated with a parallel increase in RANKL levels. Our data suggest that serum levels of components of RANKL/OPG and IL-6 systems, before and after treatment, may be used to better define a therapeutical strategy in pagetic patients.

The Role of Calcium in Osteoporosis Drug Therapy

Great advances have been made in the field of osteoporosis treatment and prevention in recent years that have led to the availability of powerful new drugs. These drugs are viewed by patients and physicians as a major breakthrough in the management of osteoporosis. Unfortunately, this view has led many to ignore the importance of concurrent calcium supplementation to ensure the maximum benefit from these drugs, as evidenced by the recent decline in use of calcium supplements. As the majority of patients fail to consume the minimum recommended dietary intake of calcium, it is critical to recommend calcium supplements to raise total daily calcium intake to the levels needed to ensure maximum efficacy of osteoporosis treatments. Furthermore, osteoporosis drug labeling should be strengthened to encourage proper use of these drugs in combination with calcium supplements.

Risedronate and pamidronate treatment in the clinical management of patients with severe Paget's disease of bone and acquired resistance to bisphosphonates

The aim of this study was to evaluate the efficacy and safety of risedronate and pamidronate in 30 patients (mean age = 57.86 +/- 8.90 years) with severe Paget's disease of bone (PDB), showing acquired resistance to intravenous (IV) clodronate treatment. Fifteen patients were treated with oral risedronate (30 mg/day for 8 weeks). Treatment was repeated in patients without evidence of PDB remission [total alkaline phosphatase (tALP) serum levels in the normal range] at day 120. Fifteen patients were treated with IV pamidronate (30 mg/day for 3 days). Pamidronate treatment (60 mg/day for 3 days) was repeated in patients without evidence of PDB remission at day 120. At day 60, a significant decrease in tALP serum levels was obtained in all pagetic patients. At day 360, 13 (86.6%) patients treated with risedronate achieved PDB remission, 9 patients during the initial treatment and 4 after retreatment. Two patients showed a significant decrease in tALP serum levels without clinical remission after two risedronate treatments. At the same time, 12 (80%) patients treated with pamidronate achieved PDB remission, 6 patients during the first treatment and 6 after retreatment. Three patients showed a significant decrease in tALP serum levels but no clinical remission after two pamidronate courses. Two of these patients showed a relapse during the study. The incidence of minor side effects and transient hyperparathyroidism related to bisphosphonate treatment was significantly lower after risedronate therapy. In patients with resistant PDB, oral risedronate therapy has comparable efficacy to IV pamidronate with a lower incidence of treatment-related side effects.

The effect of prophylactic treatment with risedronate on stress fracture incidence among infantry recruits

When subjected to strains or strain rates higher than usual, the bone remodels to repair microdamage and to strengthen itself. During the initial resorption phase of remodeling, the bone is transitorily weakened and microdamage can accumulate leading to stress fracture. To determine whether short-term suppression of bone turnover using bisphosphonates can prevent the initial loss of bone during the remodeling response to high bone strain and strain rates and potentially prevent stress fracture, we conducted a randomized, double-blind, placebo-controlled trial of 324 new infantry recruits known to be at high risk for stress fracture. Recruits were given a loading dose of 30 mg of risedronate or placebo daily for 10 doses during the first 2 weeks of basic training and then a once a week maintenance dose for the following 12 weeks. Recruits were monitored by biweekly orthopedic examinations during 15 weeks of basic training for stress fractures. Bone scans for suspected tibial and femoral stress fractures and radiographs for suspected metatarsal stress fractures were used to verify stress fracture occurrence. By the intention-to-treat analysis and per-protocol analysis, there was no statistically significant difference in the tibial, femoral, metatarsal, or total stress fracture incidence between the treatment group and the placebo. We conclude that prophylactic treatment with risedronate in a training population at high risk for stress fracture using a maintenance dosage for the treatment of osteoporosis does not lower stress fracture risk.

Recognizing and treating glucocorticoid-induced osteoporosis in patients with pulmonary diseases

Glucocorticoids are frequently used to treat patients with pulmonary diseases, but continuous long-term use of glucocorticoids may lead to significant bone loss and an increased risk of fragility fractures. Patients with certain lung diseases, regardless of pharmacotherapy-particularly COPD and cystic fibrosis-and patients waiting for lung transplantation are also at increased risk of osteoporosis. Fragility fractures, especially of the hip, will have substantial effects on the health and well-being of older patients. Vertebral collapse and kyphosis secondary to glucocorticoid-induced osteoporosis (GIO) may affect lung function. Identification of patients with osteopenia, osteoporosis, or fragility fractures related to osteoporosis is strongly recommended and should lead to appropriate treatment. Prevention of GIO in patients receiving continuous oral glucocorticoids is also recommended. In patients receiving either high-dose inhaled glucocorticoids or low- to medium-dose inhaled glucocorticoids with frequent courses of oral glucocorticoids, bone mineral density measurements should be performed to screen for osteopenia and osteoporosis. A bisphosphonate (risedronate or alendronate), calcium and vitamin D supplementation, and lifestyle modifications are recommended for the prevention and treatment of GIO.

Prevention of postmenopausal osteoporosis with pharmacological therapy: practice and possibilities

Postmenopausal osteoporosis (PMO) is a common disease that will become more prevalent in the future, with costly implications for public health. Prevention of the disease and its consequences, namely fractures, is therefore, important for both the individual and society. This review discusses: the goals of PMO prevention; the identification of women at risk, including the use of bone mineral density and bone turnover markers; the relevance in the prevention setting of various current guidelines for PMO management; recent data on therapeutic options for the treatment and prevention of PMO, in particular bisphosphonates, hormone replacement therapy and several other new pharmacological agents. It concludes that it is crucial for PMO prevention to start before disease onset and that, in the light of recent evidence, the existing guidelines need updating if they are to continue to be relevant.

Determinants of induction and duration of remission of Paget's disease of bone after bisphosphonate (olpadronate) therapy

Bisphosphonates are the treatment of choice of Paget's disease of bone. For optimal patient care determinants of the induction and duration of remission of the disease after bisphosphonate therapy must be defined. We addressed these issues in a longitudinal study of 157 patients with biochemically active disease (serum alkaline phosphatase activity >120 U/L) treated with the bisphosphonate olpadronate and followed for a median period of 37 months (range 3-162, mean 46 +/- 30). Two different total doses of olpadronate were used: an effective dose (40 mg intravenously given over 5 or 10 consecutive days) and a high dose consisting of the effective dose followed by oral olpadronate 200 mg/day for 15 days. Treatment induced biochemical remission, defined as normalization of serum alkaline phosphatase activity, in 89.2% of the patients. There were no differences between the two treatment regimens. The only independent determinants of induction of remission were baseline serum alkaline phosphatase activity and number of affected bones. In contrast, duration of remission depended on the dose of olpadronate given (high versus effective dose, RR of relapse 0.49, 95% CI 0.27-0.89). Additional independent determinants of relapse were nadir value of serum alkaline phosphatase activity after treatment, number of previous therapies, and number of affected bones. Pain scores decreased with therapy in 88% of patients with pain complaints. Pain scores were significantly related to the probability of relapse (RR1.54, 95% CI 1.04-2.27). In this long-term study of a large cohort of patients with Paget's disease we confirmed the efficacy of olpadronate therapy. In addition, we identified and quantified determinants of the response to bisphosphonate that can help in improving the management of patients with Paget's disease with bisphosphonates.

Interactions between antiretroviral drugs and drugs used for the therapy of the metabolic complications encountered during HIV infection

Treatment of HIV infection with potent combination antiretroviral therapy has resulted in major improvement in overall survival, immune function and the incidence of opportunistic infections. However, HIV infection and treatment has been associated with the development of metabolic complications, including hyperlipidaemia, diabetes mellitus, hypertension, lipodystrophy and osteopenia. Safe pharmacological treatment of these complications requires an understanding of the drug-drug interactions between antiretroviral drugs and the drugs used in the treatment of metabolic complications. Since formal studies of most of these interactions have not been performed, predictions must be based on our understanding of the metabolism of these agents. All HIV protease inhibitors are metabolised by and inhibit cytochrome P450 (CYP) 3A4. Ritonavir is the most potent inhibitor of CYP3A4. Ritonavir and nelfinavir also induce a host of CYP isoforms as well as some conjugating enzymes. The non-nucleoside reverse transcriptase inhibitor delavirdine potently inhibits CYP3A4, whereas nevirapine and efavirenz are inducers of CYP3A4. Drug interaction studies have been performed with HIV protease inhibitors and HMG-CoA reductase inhibitors. Coadministration of ritonavir plus saquinavir to HIV-seronegative volunteers resulted in increased exposure to simvastatin acid by 3059%. Atorvastatin exposure increased by 347%, but exposure to active atorvastatin increased by only 79%. Conversely, pravastatin exposure decreased by 50%. Similar results have been obtained with combinations of simvastatin and atorvastatin with other HIV protease inhibitors. Thus, the lactone prodrugs simvastatin and lovastatin should not be used with HIV protease inhibitors. Atorvastatin may be used with caution. Although there are no formal studies available, calcium channel antagonists and repaglinide may have significant interactions and toxicity when used with HIV protease inhibitors because of their metabolism by CYP3A4. Sulfonylurea drugs utilise mainly CYP2C9 for metabolism, and this isoenzyme may be induced by ritonavir and nelfinavir with a resulting decrease in efficacy of the sulfonylurea. Losartan may have increased effect when coadministered with ritonavir and nelfinavir because of the induction of CYP2C9 and the expected increase in formation of the active metabolite, E-3174. Overall, well-designed drug-drug interaction studies at steady state are needed to determine whether antiretroviral drugs may be safely coadministered with many of the drugs used in the treatment of the metabolic complications of HIV infection.

Risedronate Once A Week

Risedronate (risedronic acid), an orally administered pyridinyl bisphosphonate, inhibits osteoclast-mediated resorption of bone and modulates bone metabolism in women with postmenopausal osteoporosis. The long terminal exponential half-life of risedronate (480 hours) has led to the development of a 35mg tablet for once-a-week administration. The beneficial effects of risedronate 35mg once a week on total hip, femoral neck and trochanter bone mineral density (BMD) at 12 months were similar to those of risedronate 5mg once daily. Risedronate 35mg once a week was as effective as risedronate 5mg once daily in improving lumbar spine BMD in a randomized, double-blind, multicenter trial of 1456 women with postmenopausal osteoporosis. Mean percentage increases in BMD from baseline at 12 months were 3.94% and 4.25% in the 35mg and 50mg once-a-week dose groups, compared with 4% in the 5mg once-daily dose group. The differences between the once-a-week doses and the once-daily dose met the predetermined criterion for non-inferiority. An historical analysis suggested that risedronate 35mg once a week reduced the incidence of vertebral fracture significantly more than placebo. The tolerability profile (including the incidence of upper gastrointestinal adverse events) of risedronate 35mg once a week in women with postmenopausal osteoporosis, was similar to that of risedronate 5mg once daily.

Oral bisphosphonates and upper gastrointestinal tract problems: what is the evidence?

OBJECTIVE

To review and evaluate the evidence regarding possible associations of bisphosphonate use with upper gastrointestinal (GI) tract adverse events (AEs).

METHODS

We reviewed and summarized published information and abstracts regarding upper GI tract safety and tolerability of bisphosphonates, including laboratory and animal studies, epidemiological (observational) studies, endoscopy studies, and randomized controlled trials (RCTs). The evidence was summarized by using the principles of evidence-based medicine, giving the greatest credence to high-quality RCTs.

RESULTS

Clinical reports of esophagitis associated with bisphosphonate use appear to have declined in frequency once the importance of proper administration was explained to physicians after early reports of complications. Conflicting results have been reported in endoscopy studies; some reported no significant increase in upper GI tract lesions, whereas others reported a higher incidence of gastric (but not esophageal) lesions among patients taking oral bisphosphonates. Endoscopy studies that reported differences were of short duration (2 weeks) and were not of double-blind design. Results from large RCTs involving thousands of participants detected no increase in upper GI tract AEs among individuals treated with bisphosphonates. Other studies of patients who discontinued taking bisphosphonates and were randomized to blinded re-treatment with either a bisphosphonate or placebo show that most patients (>85%) were able to continue treatment, with no difference in AEs between the bisphosphonate and placebo groups.

CONCLUSIONS

The highest level of evidence, RCTs, suggests little or no increase in risk of upper GI tract problems if bisphosphonates are administered properly. Upper GI tract symptoms are common among patients with osteoporosis. The evidence suggests that many upper GI tract AEs reported during therapy with bisphosphonates may reflect a high background incidence of upper GI tract complaints and an increased sensitivity to detection rather than a causal relationship to therapy.

Review of risedronate in the treatment of osteoporosis

Risedronate (Actonel, Procter & Gamble and Aventis) is a novel, orally administered pyridinyl bisphosphonate. Preclinical studies have shown that risedronate is a potent inhibitor of osteoclasts. Risedronate inhibited bone resorption and increased bone density in the spine and hip. Prospective, randomised, placebo-controlled trials (RCTs) in patients with postmenopausal osteoporosis (PMO) have demonstrated that risedronate decreased the risk of vertebral fractures by up to 49% and of non-vertebral fractures by up to 39% over 3 years in postmenopausal women with one or more prevalent vertebral fractures. This reduction of the risk for vertebral fractures was significant from the first year of treatment (risk reduction up to 65%). Risedronate was the first bisphosphonate to be studied in a large RCT with prevention of hip fracture as the primary end point. In this study, risedronate reduced the risk of hip fracture by 40% in elderly women with low hip bone density and one clinical risk factor for hip fracture and by 60% in women with low bone density and a prevalent vertebral fracture at baseline. Risedronate was also effective in the prevention and treatment of bone loss in glucocorticoid-induced osteoporosis (GIO), with a positive effect on vertebral fractures within the first year. Risedronate was well-tolerated with a safety profile comparable to placebo in all clinical studies. Patients with a previous or current history of upper GI illness or who were taking NSAIDs or aspirin were not excluded from these studies. Importantly, the upper GI safety profile of risedronate was shown to be similar to that of placebo in endoscopic studies. There was no evidence of acute-phase reactions or primary mineralisation defects. The most appropriate dose of risedronate was 5 mg/day.