Identification and pharmacokinetics of bioavailable anti-resorptive phytochemicals after oral administration of Psoralea corylifolia L.

Osteoporosis and resulting bone fractures are the major health issues associated with morbidity in the aging population; however, there is no effective treatment that does not cause severe side effects. In East Asia, dried seeds of Psoralea corylifolia L. (PC) have traditionally been used as an herbal medicine to manage urinary tract, cutaneous, and gastrointestinal disorders, as well as bone health. However, the mechanism of action and active biocomponents of PC are unclear. Here, we adopted a pharmacokinetic (PK) study aiming to identify the bioavailable phytochemicals in aqueous and ethanolic extracts of PC (APC) and (EPC), respectively. In addition, we aimed to determine anti-resorptive constituents of PC, which accounted for its beneficial effects on bone health. To this end, we used ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). A rapid, sensitive, and reliable UPLC-MS/MS method was developed and determined the 17 PC ingredients. In the PK study, nine components (two chalcones, two coumarins, one coumestan, two flavonoids, and two isoflavonoids) were observed between 36 and 48 h after oral administration of APC or EPC. Among the bioavailable ingredients, four PC constituents (psoralidin, isobavachin, corylifol A, and neobavaisoflavone) inhibited M-CSF-and RANKL-induced osteoclast differentiation in bone marrow-derived macrophages. In addition, two chalcones and two isoflavonoids markedly inhibited cathepsin K activity, and their binding modes to cathepsin K were determined by molecular docking. In summary, our data suggest that bioavailable multicomponents of PC could contribute to the management of bone health.

Fenugreek steroidal saponins hinder osteoclastogenic bone resorption by targeting CSF-1R which diminishes the RANKL/OPG ratio.

Osteoporosis is skeletal fragility caused by the excessive bone resorption due to osteoclastogenesis. But current drugs are less bioavailable and possess higher toxicity. Our study was conducted to identify safe oral bioavailable drugs from Fenugreek steroidal saponins and to delineate underlying mechanism of them to lower the osteoclastogenic bone resorption. We observed higher molecular docked binding affinities in finally selected eight hit compounds within the range of -11.0 to -10.1 kcal/mol which was greater than currently used drugs. Molecular Dynamics simulation with Root Mean Square Deviation (RMSD), Root Mean Square Fluctuation (RMSF), Solvent Accessible Surface Area (SASA) and Gyration trajectory projection reinforced the stability of the protein-ligand complexes. Pharmacokinetics analysis confirmed bioavailability of seven compounds out of eight, and drug likeliness and bioavailability profile evaluation indicated that they all are eligible to be developed as a potent oral inhibitor of CSF-1R. By literature mining knowledge-driven analysis, RNAseq data and Molecular Dynamics Simulation, we proposed that, the hit derivatives block the CSF-1/CSF-1R induced phosphorylation signaling pathway in both osteoclast and osteoblast resulting in hindrance of RANK expression and formation of Reactive oxygen species (ROS) in osteoclast and osteoblast respectively, thus declines the RANKL/OPG ratio, lowering the osteoclast survival, proliferation and differentiation.

Denosumab biosimilar in postmenopausal osteoporotic women: A randomized, assessor-blind, active-controlled clinical trial.

OBJECTIVE: The study assessed the efficacy, safety, pharmacokinetic (PK), and immunogenicity profiles of denosumab-biosimilar and denosumab-reference in postmenopausal osteoporotic women from India. MATERIALS AND METHODS: In this randomized, assessor-blind, active-control, multicenter trial, 114 patients were randomly allocated to receive denosumab-biosimilar (n = 58) or denosumab-reference (n = 56) at a subcutaneous dose of 60 mg every 6 months, for a year. Vitamin D and oral calcium were given daily. Lumbar spine bone mineral density (BMD) change was the primary end point. RESULTS: Of 114 randomized patients, 111 (denosumab-biosimilar, n = 56; denosumab-reference, n = 55) completed the study. All 114 patients were part of safety and immunogenicity analyses, 110 (denosumab-biosimilar, n = 56; denosumab-reference, n = 54) were part of efficacy analysis, and 20 (denosumab-biosimilar, n = 10; denosumab-reference, n = 10) were part of PK analysis. The bone mineral density (BMD) (lumbar spine) percent change at 1 year with denosumab-biosimilar and denosumab-reference (7.22 vs. 7.62; difference:-0.40; 95% confidence interval: -5.92, 5.12) showed no statistically relevant difference. Likewise, alkaline phosphatase (bone-specific) and PK parameters also did not show statistically relevant differences. Adverse events were reported in 44.83% of patients on denosumab-biosimilar versus 33.93% of patients on denosumab-reference; most events were mild or moderate and not related to the study drugs. No patients showed anti-denosumab antibody positivity. CONCLUSIONS: Denosumab-biosimilar and denosumab-reference showed biosimilarity in osteoporotic postmenopausal women. Availability of denosumab-biosimilar provides a treatment alternative for patients.

Safety and pharmacokinetics of a biosimilar of denosumab (KN012): Phase 1 and bioequivalence study in healthy Chinese subjects.

BACKGROUND: KN012 is a proposed biosimilar candidate for the reference drug denosumab, with the brand name Prolia®. This study explored the tolerance, variability, and pharmacokinetics (PK) of denosumab and its biosimilar in healthy Chinese subjects. RESEARCH DESIGN AND METHODS: A randomized, double-blind, parallel, two-arm study was performed to analyze the bioequivalence of denosumab biosimilar (60 mg) compared with denosumab. RESULTS: The PK properties of denosumab biosimilar were similar to those of denosumab. When denosumab biosimilar was compared to denosumab, the geometric mean ratios (GMRs) of Cmax, AUC0-t, and AUC0-∞ were 98.74%, 102.54%, and 102.18%, respectively, and the 90% confidence interval was observed to be within 80-125%. The inter-subject variability ranged from 31.4% to 34.6%. Five subjects in the denosumab biosimilar group and one subject in the denosumab group were positive for anti-drug antibodies (ADAs) and negative for neutralizing antibodies (NAbs). Adverse reactions were observed in 100% (52 subjects) and 94.0% (47 subjects) of the subjects in the denosumab biosimilar and denosumab groups, respectively. Reductions in the blood calcium and phosphate levels were the most common adverse reactions. CONCLUSION: The PK characteristics were comparable for the denosumab biosimilar and denosumab groups. Their safety profiles were also similar. TRIAL REGISTRATION: : The trial is registered at the Chinese Clinical Trial website (http://www.chinadrugtrials.org.cn/index.html #CTR20181231).

A phase 1 pooled PK/PD analysis of bone resorption biomarkers for odanacatib, a Cathepsin K inhibitor.

To develop a framework for evaluating the resorption effects of Cathepsin K (CatK) inhibitors and to inform dose regimen selection, a pharmacokinetic/pharmacodynamic (PK/PD) model for odanacatib (ODN) was developed based upon data from Phase 1 studies. Pooled PK/PD data from 11 studies (N = 249) were fit reasonably to a population inhibitory sigmoid Emax model. Body weight on E0 (baseline uNTx/Cr, urinary N-terminal telopeptide normalized by creatinine) and age on Emax (fractional inhibition of the biomarker response) were significant covariates for biomarker response. Simulations of typical osteoporosis patients (by age, sex and weight) indicated minimal differences between sexes in concentration-uNTx/Cr relationship. There was no evidence that regimen (daily vs. weekly dosing) influenced the PK/PD relationship of resorption inhibition for odanacatib. PK/PD models based on data from odanacatib (ODN) Phase 1 studies demonstrated that uNTx/Cr was an appropriate bone resorption biomarker for assessment of the effects of a CatK inhibitor. The models also identified the determinants of response in the PK/PD relationship for ODN (body weight on E0 and age on Emax).

Ultrasound-assisted transdermal delivery of alendronate for the treatment of osteoporosis.

The aim of the current research work was to develop sonophoresis-assisted transdermal patches for the treatment of osteoporosis. In the present investigation, we formulated alendronate-chitosan nanoparticles by ionotropic external gelation method. The prepared nanoparticles were found to be smooth and free-flowing. The optimized formulation showed 82.7% of drug release over a period of 12 hours with 99.54% EE, the particle size of 250 nm, PDI 0.22 and zeta potential of 28 mV. The solvent casting evaporation method was used for the development of the patches using HPMC as rate-controlling polymer and dibutyl phthalate as the plasticizer. The optimized patch formulation was found acceptable in terms of physical characteristics (appearance, thickness, folding endurance, weight variation, moisture loss and uptake). The drug content was found to be 99.66±0.9 % with 69.44% of drug permeation through the rat skin. The TP3 formulation had drug content of 99.96% which was the highest among all of the formulations and showed relatively controlled skin permeation of 69.44% over the period of 12 hours. Nearly six-time enhancement of bioavailability was observed when alendronate was used in the nanoparticulate form in transdermal patches used with sonophoresis. Over the period of seven days, the plasma calcium concentration in the rat model was decreased from 16 mg/dl to 4 mg/dl (4 times) in rat groups treated with the transdermal patches containing CS-ALN-NP while the concentration dropped only to 12 mg/dl in case of the transdermal patches containing pure Alendronate. These findings (enhanced skin permeation, enhanced bioavailability and suppression of the plasma calcium level) regarding the transdermal delivery system suggest a promising approach for the treatment of osteoporosis.

Population Pharmacokinetic Analysis of the Cathepsin K Inhibitor Odanacatib: Insights Into Intrinsic and Extrinsic Factor Effects on Exposure in Postmenopausal and Elderly Women.

This analysis developed a population pharmacokinetic (PK) model for odanacatib, characterized demographic and concomitant medication covariates effect, and provided odanacatib exposure estimates for subjects in phase 2/3 studies. Data from multiple phase 1 (P005, P025, and P014), phase 2b (P004 and P022), and phase 3 (Long-Term Odanacatib Fracture Trial; P018) studies were pooled to create a data set of 1280 postmenopausal women aged 45 to 91 years (102 from phase 1, 514 from phase 2b, and 664 from phase 3) who received weekly oral odanacatib doses ranging from 3 to 100 mg. A 1-compartment model with first-order absorption, dose-dependent relative bioavailability (F1), and first-order elimination best described odanacatib PK. F1 decreased from the 100% reference bioavailability for a 3-mg oral dose to 24.5% for a 100-mg dose. Eight statistically significant covariates were included in the final PK model: body weight, age, race, and concomitant cytochrome P450 (CYP)3A inhibitors on apparent clearance; body weight on apparent central volume of distribution; and concomitant hydrochlorothiazide, high-fat breakfast, and a study effect on F1. All fixed- and random-effects parameters were estimated with good precision (%standard error of the mean ≤29.5%). This population PK analysis provides insights into intrinsic- and extrinsic-factor effects on odanacatib exposure in postmenopausal and elderly women with osteoporosis. The magnitude of the intrinsic-factor effects was generally modest (odanacatib exposure geometric mean ratios, 0.80-1.21) even in subjects aged >80 years, or in subsets with multiple combinations of factors.

Nanofibrillated cellulose/cyclodextrin based 3D scaffolds loaded with raloxifene hydrochloride for bone regeneration.

This study intended to design novel nanofibrillated cellulose/cyclodextrin-based 3D scaffolds loaded with raloxifene hydrochloride for bone regeneration. The scaffolds were prepared using two different types of cyclodextrins namely; beta-cyclodextrin and methyl-beta-cyclodextrin. The prepared scaffolds were evaluated by characterizing their porosity, compressive strength, in-vitro drug release, FT-IR and XRD as well as their morphological properties using SEM. Results presented that the prepared scaffolds were highly porous, additionally, the scaffold containing drug/beta-cyclodextrin kneaded complex (SC5) showed the most controlled drug release pattern with the least burst effect and reached almost complete release at 480 h. The in-vitro cytocompatibility and regenerative effect of the chosen scaffold (SC5) was assessed using Saos-2 cell line. Results proved that SC5 was biocompatible. Moreover, it enhanced the cell adhesion, alkaline phosphatase enzyme expression and calcium ion deposition which are essential factors for bone mineralization. The obtained observations presented a novel, safe and propitious approach for bone engineering.

Calcitriol tablets with hybrid lipid-based solid dispersions with enhanced stability and content uniformity.

Calcitriol, as the biologically active form of vitamin D3, is essential for patients with renal osteopathy. The solubilization, stabilization, and content uniformity are key issues in its formulation development. In our previous study, the incomplete release of calcitriol was solved by using the hybrid lipid-based solid dispersion (SD) for calcitriol. However, good stability and content uniformity are still urgently needed. In this study, solid lipid with antioxidant properties and liquid lipid compatible with calcitriol were employed as hybrid lipid carrier (HLC) to establish a solid dispersion. Moreover, the content uniformity of tablets with hybrid lipid carrier based SDs (HLCTs) was further guaranteed due to the multi-dispersion of calcitriol in HLC, solidification, and blank granules. Additionally, the compression of the blank granules was adjusted by the water content. The mixing method of calcitriol-containing and blank granules was also optimized. The obtained HLCTs were evaluated for hardness, disintegration time, in vitro drug dissolution, content uniformity, and stability. Satisfactory HLCTs were developed successfully in this study with superior content uniformity and better stability than the commercial soft capsule (Rocaltrol®). It was proved to be a promising formulation for drugs with poor water-solubility, instability to oxygen and heat, and dose-related toxicity.

A matrix dispersion based on phospholipid complex system: preparation, lymphatic transport, and pharmacokinetics.

Raloxifene hydrochloride (RH) suffers from low oral bioavailability due to its low water-solubility and first-pass metabolism. Therefore, a novel phospholipid complex of RH (RHPC) and a matrix dispersion based on phospholipid complex (RHPC-MD) were successfully prepared and optimized. Several methods were used to validate the formation of RHPC and RHPC-MD, such as differential scanning calorimetry, X-ray diffraction, scanning electron microscopy, transmission electron microscopy, infrared spectroscopy, particle size, and zeta potential, meanwhile, their octanol-water partition coefficient, solubility, and dissolution in vitro were also evaluated. To investigate the absorption mechanism of RHPC in vivo, the RHPC was administered to the chylomicron flow blockage rat model. Interestingly, as we expected, a significant reduction in RHPC absorption (67%) (**p< .01) in presence of cycloheximide (CXI) inhibitor was observed, thus confirming the RHPC could be absorbed by lymphatic transport in vivo. Pharmacokinetic studies revealed that the relative oral bioavailability of RHPC as well as RHPC-MD was 223% and 329%, respectively, when comparing with the commercial RH tablets. These outcomes suggested that the current study provided an attractive formulation to enhance the oral bioavailability of RH and stimulated to further research the absorption mechanism of RHPC in vivo.

Thermosensitive Hydrogel Based on Poly(2-Ethyl-2-Oxazoline)-Poly(D,L-Lactide)-Poly(2-Ethyl-2-Oxazoline) for Sustained Salmon Calcitonin Delivery.

This study developed a thermosensitive hydrogel based on poly(2-ethyl-2-oxazoline)-poly(D,L-lactide)-poly(2-ethyl-2-oxazoline) (PPP) for the delivery of salmon calcitonin to improve the hypocalcemic effect. The tube inversion and rheological tests revealed that the copolymer solution underwent temperature-dependent sol-gel-sol transitions. Observation by scanning electron microscopy (SEM) showed that the hydrogel exhibited a porous three-dimensional network. The swelling test demonstrated that there was a maximum swelling ratio at low temperature (25°C) as compared with the high temperature (37°C). In vitro release revealed that the PPP hydrogel were capable of sustained release of salmon calcitonin (sCT). The in vivo biodegradability study indicated the good degradability of PPP hydrogel. More importantly, the in vivo retention time of the hydrogel in situ was significantly prolonged after subcutaneous injection of the PPP hydrogel compared to the F127 hydrogel. In vivo pharmacodynamics analysis showed that the hypocalcemic effect of both PPP and F127 hydrogel was significantly greater than that of sCT solution, and the mean serum Ca reduction effect could be maintained for 24 h of PPP hydrogel, indicating that PPP hydrogel could achieve a significant enhanced hypocalcemic effect. In conclusion, the PPP hydrogel has been shown to be prospective as a controlled release carrier for injection delivery of protein drugs.

Safety Profiles, Pharmacokinetics, and Changes in Bone Turnover Markers After Twice-Weekly Subcutaneous Administration of Teriparatide in Healthy Japanese Postmenopausal Women: A Single-Blind Randomized Study.

Once-weekly injection of 56.5-µg teriparatide formulation is a potent therapeutic agent for osteoporosis treatment. However, this treatment has an issue of difficulty in continuing the treatment by its adverse side effects including nausea, vomiting, and headaches. To reduce these adverse side effects, we conducted a randomized, single-blind, placebo-controlled study to examine the pharmacokinetics, changes in bone turnover markers, and safety profiles of twice-weekly 28.2-µg teriparatide injections. Different dosing intervals of the twice-weekly 28.2-µg injections were also studied. A total of 100 healthy Japanese postmenopausal women were enrolled in this multiple-dosing study. The systemic exposure of teriparatide acetate in the twice-weekly 28.2-µg injection was half that of the once-weekly 56.5-µg injection. Changes in bone turnover markers in the twice-weekly 28.2-µg injection were comparable to those in the once-weekly 56.5-µg injection. Incidences of adverse events including nausea, vomiting, and headaches were lower in the twice-weekly 28.2-µg injections than those in the once-weekly 56.5-µg injection. Findings were similar in the twice-weekly 28.2-µg injections regardless of the dosing interval. Thus, the new dosing regimen using twice-weekly 28.2-µg injections maintained comparable efficacy to the once-weekly 56.5-µg injections; however, it improved the safety profile and contributed to better continuity of care with teriparatide.

Racial difference in bioavailability of oral ibandronate between Caucasian and Taiwanese postmenopausal women.

Following 150 mg of oral ibandronate, Taiwanese females have greater serum and urine levels of this drug and bone resorption marker suppression than Caucasian women. These inter-ethnic differences seems to be partly explained by a 2.48-fold higher bioavailability of ibandronate in Taiwanese postmenopausal women. INTRODUCTION: Interethnic differences in the pharmacokinetics of oral ibandronate for osteoporosis are unknown. We compared the disposition of oral ibandronate between Caucasian and Taiwanese postmenopausal women. METHODS: Ibandronate 150 mg was administered to 35 Caucasian and 16 Taiwanese postmenopausal women in two separate phase 1 studies. Interethnic comparisons were performed to assess pharmacokinetic properties, including the area under the concentration-time curve (AUC), peak concentration (Cmax), elimination half-life, urinary drug recovery (Ae%), renal clearance (CLr), apparent total clearance (CL/F), and apparent volume of distribution (Vd/F). RESULTS: The mean AUC, Cmax, and Ae% were 2.41-, 1.69-, and 2.95-fold greater in the Taiwanese than in the Caucasian subjects, and the average CL/F and Vd/F were 2.48- and 2.46-fold smaller. There were no significant differences in mean CLr and half-life between both groups. As bisphosphonates are not biotransformed but are mainly excreted in the urine, the total body clearance is close to the CLr. These results suggested a larger bioavailability in the Taiwanese group which resulted in the differences in the CL/F and Vd/F. Multiple linear regression analysis demonstrated ethnicity influences of the pharmacokinetic properties after adjusting for the other variables. CONCLUSIONS: Bioavailability was largely responsible for the interethnic pharmacokinetic differences following oral administration of 150 mg ibandronate and seemed greater in the Taiwanese compared with the Caucasian subjects. Further dose-ranging studies are warranted to determine the optimal dosages of oral ibandronate in patients of Asian or Taiwanese ethnicity.

Synthetic hydroxyapatite: a recruiting platform for biologically active molecules.

Background and purpose - Targeted delivery of drugs is important to achieve efficient local concentrations and reduce systemic side effects. We hypothesized that locally implanted synthetic hydroxyapatite (HA) particles can act as a recruiting moiety for systemically administered drugs, leading to targeted drug accretion.Methods - Synthetic HA particles were implanted ectopically in a muscle pouch in rats, and the binding of systemically circulating drugs such as zoledronic acid (ZA), tetracycline and 18F-fluoride (18F) was studied. The local biological effect was verified in an implant integration model in rats, wherein a hollow implant was filled with synthetic HA particles and the animals were given systemic ZA, 2-weeks post-implantation. The effect of HA particle size on drug binding and the possibility of reloading HA particles were also evaluated in the muscle pouch.Results - The systemically administered biomolecules (ZA, tetracycline and 18F) all sought the HA moiety placed in the muscle pouch. Statistically significant higher peri-implant bone volume and peak force were observed in the implant containing HA particles compared with the empty implant. After a single injection of ZA at 2 weeks, micro HA particles showed a tendency to accumulate more 14C-zoledronic acid (14C-ZA) than nano-HA particles in the muscle pouch. HA particles could be reloaded when ZA was given again at 4 weeks, showing increased 14C-ZA accretion by 73% in microparticles and 77% in nanoparticles.Interpretation - We describe a novel method of systemic drug loading resulting in targeted accretion in locally implanted particulate HA, thereby biologically activating the material.

Long lasting in-situ forming implant loaded with raloxifene HCl: An injectable delivery system for treatment of bone injuries.

Bone injury is very serious in elder people or osteoporotic patients. In-situ forming implants (IFI) for bone rebuilding are usually poly-lactic-co-glycolic acid (PLGA)-based, which have a burst release effect. This study aimed to prepare novel liquid lipid-based PLGA-IFI loaded with raloxifene hydrochloride for prolonged non-surgical treatment of bone injuries by applying solvent-induced phase inversion technique. Labrasol® and Maisine® were added to the selected IFI forming long lasting lipid-based IFI (LLL-IFI). The formulations were characterized by analysing their in-vitro drug release, solidification time, injectability, rheological properties, and DSC in addition to their morphological properties. Results revealed that the LLL-IFI composed of 10%w/v PLGA with a lactide to glycolide ratio of 75:25 with ester terminal and 10% Maisine® possessed the most sustained drug release and lowest burst effect, as well as delayed pore formation compared to its counterpart lacking Maisine®. The selected LLL-IFI and PLGA-IFI formulations were tested for their capability to enhance bone regeneration in bone injuries induced in rats. Both formulations succeeded in healing the bones completely with the superiority of LLL-IFI in the formation of well-organized bone structures lacking fibrous tissues. The results suggest that LLL-IFI and PLGA-IFI are innovative approaches for treating critical and non-critical sized bone injuries.

Hexapeptide-conjugated calcitonin for targeted therapy of osteoporosis.

The high level of bone metabolism associated with osteopenia and multifocal skeletal fracture remains a challenging clinical problem in osteoporosis patients. Salmon calcitonin (sCT), as a peptide medicine, is able to inhibit osteoclast activity and stimulate osteoblast growth. However, calcitonin receptors (CTRs) are widely distributed in vivo, limiting the specificity and therapeutic effects. Here, we report a bone-seeking hexapeptide (Asp6)-conjugated sCT (sCT-Mal-Asp6) for the targeted treatment of osteoporosis. The sCT-Mal-Asp6 was synthesized via a disulfide re-bridge reaction with high specificity and purity. It was demonstrated that the adsorption of sCT-Mal-Asp6 on hydroxyapatite (HA) was about 5.4 times higher than that of sCT. It was demonstrated a prolonged circulation time and 3-fold higher femur tissue accumulation of sCT-Mal-Asp6. In ovariectomized (OVX) models, sCT-Mal-Asp6 significantly increased the ability to attenuate hypercalcemia and reconstruct the trabecula. Our work provides an efficient approach to targeted and effective osteoporosis treatment.

Bioactive injectable triple acting thermosensitive hydrogel enriched with nano-hydroxyapatite for bone regeneration: in-vitro characterization, Saos-2 cell line cell viability and osteogenic markers evaluation.

Hydrogels forming in-situ have gained great attention in the area of bone tissue engineering recently, they were also showed to be a good and less invasive alternative to surgically applied ones. The primal focus of this study was to prepare chitosan-glycerol phosphate thermosensitive hydrogel formed in-situ and loaded with risedronate (bone resorption inhibitor) in an easy way with no requirement of complicated processes or large number of equipment. Then we investigated its effectiveness for bone regeneration. In-situ forming hydrogels were prepared using chitosan cross-linked with glycerol phosphate and loaded with risedronate and nano-hydroxyapatite as bone cement. The prepared hydrogels were characterized by analyzing their gelation time at 37 °C, % porosity, swelling index, in-vitro degradation, rheological properties, and in-vitro drug release. Results showed that the in-situ hydrogels prepared using 2.5% (w/v) chitosan cross-linked with 50% (w/v) glycerol phosphate in the ratio (9:1, v/v) reinforced with 20 mg/mL and nano-hydroxyapatite possessed the most sustained drug release profile. This optimized formulation was further evaluated using DSC and FTIR studies, in addition to their morphological properties using scanning electron microscopy. The effect on Saos-2 cell line viability was evaluated also using MTT assay on the optimized hydrogel formulation in addition to their action on cell proliferation using fluorescence microscope. Moreover, calcium deposition on the hydrogel and alkaline phosphatase activity were evaluated. Risedronate-nano-hydroxyapatite loaded hydrogels significantly enhanced the Saos-2 cell proliferation in addition to enhanced alkaline phosphatase activity and calcium deposition. Such results suggest that risedronate-nano-hydroxyapatite loaded hydrogels present great biocompatibility for bone regeneration. Proliferation of cells, as well as deposition of mineral on the hydrogel, was an evidence of the biocompatible nature of the hydrogel. This hydrogel formed in-situ present a good less invasive alternative for bone tissue engineering.

Clinical and translational pharmacology of the cathepsin K inhibitor odanacatib studied for osteoporosis.

Cathepsin K (CatK) is a cysteine protease abundantly expressed by osteoclasts and localized in the lysosomes and resorption lacunae of these cells. CatK is the principal enzyme responsible for the degradation of bone collagen. Odanacatib is a selective, reversible inhibitor of CatK at subnanomolar potency. The pharmacokinetics of odanacatib have been extensively studied and are similar in young healthy men, postmenopausal women and elderly men, and were qualitatively similar throughout Phase 1 development and in-patient studies. Following 3 weeks of 50 mg once weekly dosing the geometric mean area under the curve from 0 to 168 hours was 41.1 µM h, the concentration at 168 hours was 126 nM and the harmonic mean apparent terminal half-life was 84.8 hr. Odanacatib exposure increased in a less than dose proportional manner due to solubility limited absorption. It is estimated that approximately 70% of the absorbed dose of odanacatib is eliminated via metabolism, 20% is excreted as unchanged drug in the bile or faeces, and 10% is excreted as unchanged drug in the urine. The systemic clearance was low (approximately 13 mL/min). Odanacatib decreases the degradation of bone matrix proteins and reduces the efficiency of bone resorption with target engagement confirmed by a robust decrease in serum C-telopeptides of type 1 collagen (approximately 60%), urinary aminoterminal crosslinked telopeptides of type 1 collagen to creatinine ratio (approximately 50%) and total urine deoxypyridinoline/Cr (approximately 30%), with an increase in serum cross-linked carboxy-terminal telopeptide of type 1 collagen (approximately 55%). The 50-mg weekly dosing regimen evaluated in Phase 3 achieved near maximal reduction in bone resorption throughout the treatment period. The extensive clinical programme for odanacatib, together with more limited clinical experience with other CatK inhibitors (balicatib and ONO-5334), provides important insights into the clinical pharmacology of CatK inhibition and the potential role of CatK in bone turnover and mineral homeostasis. Key findings include the ability of this mechanism to: (i) provide sustained reductions in resorption markers, increases in bone mineral density, and demonstrated fracture risk reduction; (ii) be associated with relative formation-sparing effects such that sustained resorption reduction is achieved without accompanying meaningful reductions in bone formation; and (iii) lead to increases in osteoclast number as well as other osteoclast activity (including build-up of CatK enzyme), which may yield transient increases in resorption following treatment discontinuation and the potential for nonmonotonic responses at subtherapeutic doses.

Predicting the Effects of Different Triazole Antifungal Agents on the Pharmacokinetics of Tamoxifen.

Tamoxifen is an antiestrogen drug that is widely used in the adjuvant chemotherapy of estrogen receptor-α (ERα)-positive breast cancer. Chemotherapy could suppress immune function in breast cancer patients, which may cause invasive fungal infections (IFIs). Triazoles (voriconazole, fluconazole, and itraconazole) were commonly used for IFI. The physiologically based pharmacokinetic (PBPK) models were developed to investigate the influence of different triazoles on tamoxifen pharmacokinetics in this paper. To investigate the influence of different triazoles (voriconazole, fluconazole, itraconazole) on tamoxifen pharmacokinetics. Adjusted physicochemical data and pharmacokinetic parameters of voriconazole, fluconazole, itraconazole, and tamoxifen were obtained from published literatures. PBPK models were built and verified in healthy subjects using GastroPlus™. Voriconazole, itraconazole, and tamoxifen were administered orally. Fluconazole was administered intravenously. Simulated plasma concentration-time curves of the voriconazole, fluconazole, itraconazole, and tamoxifen showed good agreement with the observed profiles, respectively. The DDI simulations showed that the pharmacokinetic parameters of tamoxifen were increased by various degrees when coadministered with different triazoles. In healthy subjects, the area under the plasma concentration-time curve from 0 to t h (AUC0-t) of tamoxifen was increased by 41%, 5%, and1% when coadministrated with voriconazole, fluconazole, and itraconazole, respectively. The PBPK models adequately characterized the pharmacokinetics of tamoxifen and triazoles. Among the three triazoles, voriconazole exhibited the greatest effect on tamoxifen pharmacokinetics. In clinical practice, an effective dosage adjustment of tamoxifen may need to be considered and TDM for tamoxifen is advisable to guide dosing and optimize therapy when coadministered with voriconazole.

Pharmacology of bisphosphonates.

The biological effects of the bisphosphonates (BPs) as inhibitors of calcification and bone resorption were first described in the late 1960s. In the 50 years that have elapsed since then, the BPs have become the leading drugs for the treatment of skeletal disorders characterized by increased bone resorption, including Paget's disease of bone, bone metastases, multiple myeloma, osteoporosis and several childhood inherited disorders. The discovery and development of the BPs as a major class of drugs for the treatment of bone diseases is a paradigm for the successful journey from "bench to bedside and back again". Several of the leading BPs achieved "blockbuster" status as branded drugs. However, these BPs have now come to the end of their patent life, making them highly affordable. The opportunity for new clinical applications for BPs also exists in other areas of medicine such as ageing, cardiovascular disease and radiation protection. Their use as inexpensive generic medicines is therefore likely to continue for many years to come. Fifty years of research into the pharmacology of bisphosphonates have led to a fairly good understanding about how these drugs work and how they can be used safely in patients with metabolic bone diseases. However, while we seemingly know much about these drugs, a number of key aspects related to BP distribution and action remain incompletely understood. This review summarizes the existing knowledge of the (pre)clinical and translational pharmacology of BPs, and highlights areas in which understanding is lacking.