Medronic Acid Research Articles

β,γ-Methylene-ATP and its metabolite medronic acid affect both arterial media calcification and bone mineralization in non-CKD and CKD rats.

Arterial media calcification or pathological deposition of calcium-phosphate crystals in the vessel wall contributes significantly to the high mortality rate observed in patients with CKD. Extracellular nucleotides (ie, ATP or UTP) regulate the arterial calcification process by interacting with (1) purinergic receptors and (2) breakdown via ecto-nucleotidases, such as ectonucleotide pyrophosphatase/phosphodiesterase NPP1 or NPP3, affecting the local levels of calcification inhibitor, pyrophosphate, and stimulator inorganic phosphate (PPi/Pi ratio). Also, it has been shown that ATP analogs (ie, β,γ-methylene-ATP [β,γ-meATP]) inhibit vascular smooth muscle cell calcification in vitro. In the first experiment, daily dosing of β,γ-meATP (2mg/kg) was investigated in rats fed a warfarin diet to trigger the development of non-CKD-related arterial medial calcifications. This study showed that β,γ-meATP significantly lowered the calcium scores in the aorta and peripheral vessels in warfarin-exposed rats. In a second experiment, daily dosing of 4mg/kg β,γ-meATP and its metabolite medronic acid (MDP) was analyzed in rats fed an adenine diet to promote the development of CKD-related arterial medial calcification. Administration of β,γ-meATP and MDP did not significantly decrease aortic calcification scores in this model. Moreover, both compounds induced deleterious effects on physiological bone mineralization, causing an imminent risk for worsening the already compromised bone status in CKD. Due to this, it was not possible to raise the dosage of both compounds to tackle CKD-related arterial calcification. Again, this points out the difficult task of targeting solely ectopic calcifications without negatively affecting physiological bone mineralization. On the other hand, aortic mRNA expression of Enpp1 and Enpp3 was significantly and positively associated with aortic calcification scores, suggesting that normalizing the aortic NPP1/3 activity to control values might be a possible target to treat (CKD-induced) arterial media calcifications.

Ball‐Milling to Access Dinucleoside Polyphosphates and Analogues

AbstractDinucleoside 5’,5’‐polyphosphates (NpnNs) play essential roles in various biological processes. Access to these high value‐added compounds, while avoiding the many drawbacks of solution phase synthesis, is a challenge that has been overcome thanks to mechanochemistry. A straightforward solid‐state synthesis based on activation of phosphate or pyrophosphate sodium salts to their diimidazolides, followed by coupling with commercially available nucleotides, under air conditions, gave symmetrical NpnNs. The scope ranged from Np3Ns to highly challenging Np6Ns. The methodology has also been implemented using medronic acid and imidodiphosphate to obtain NpnNs analogues, some of which are unprecedented.

Structural Diversity in Antiosteolytic Bisphosphonates: Deciphering Structure-Activity Trends in Ultra Long Controlled Release Phenomena.

Bisphosphonate (BP)-based treatments have been extensively prescribed for bone-related conditions, particularly for osteoporosis. Their low bioavailability creates the need for prescribed dosage increase to reach therapeutic levels but generates a plethora of undesirable side effects. A viable approach to alleviating these issues is to design and exploit controlled release strategies. Herein, the controlled release profiles of 15 structurally characterized BPs (actual drugs and structural analogs) were thoroughly studied from tablets containing three (cellulose, lactose, and silica) or two (cellulose, and silica) excipients in human stomach-simulated pH conditions. The BPs were of two types, alkyl-BPs and amino-BPs. Alkyl-BPs included four derivatives of etidronate (acid, disodium, tetra-sodium, and monopotassium forms), medronic acid, and three analogs of etidronate, in which the -CH3 group was replaced by the moieties -H, -CH2CH2CH3, and -CH2CH2CH2CH2CH3. Amino-BPs included the commercial drugs pamidronate, alendronate, neridronate, and ibandronate, as well as three analog compounds. Release curves were constructed based on data taken from 1H NMR peak integration and were expressed as "% BP release" vs time. The controlled release profiles (initial release rate, plateau value, etc.) were correlated with certain structural features (number of hydrogen and metal-oxygen bonds), showing that the molecular and crystal lattice features of each BP profoundly influence its release characteristics. It was concluded that for all BPs, in general, the initial rate became lower as the total number of lattice interactions increased. For the alkyl-BPs elongation of the alkyl side chain seems to decelerate the release. Amino-BPs, in general, show slower release than the alkyl-BPs. No adverse effects of alkyl- and amino-BP drugs on NIH3T3 cell viability were noted.

Using an In-Sample Addition of Medronic Acid for the Analysis of Purine- and Pyrimidine-Related Derivatives and Its Application in the Study of Lung Adenocarcinoma A549 Cell Lines by LC–MS/MS

Intracellular purine- and pyrimidine-related derivatives are vital molecules for preserving genetic information and are essential for cellular bioenergetics and signal transduction. This study developed a practical liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for quantifying intracellular purine- and pyrimidine-related derivatives. To solve the distorted peak shape related to di- and triphosphate nucleotides, in-sample addition of medronic acid and ammonium phosphate was performed. Using the BEH-amide column, the results showed that adding 0.5 mM medronic acid to the sample significantly improved the peak shape without causing an obvious ion suppressive effect. Method validation confirmed that the coefficients of determination (R2) values for linearity evaluation were above 0.94 for all analytes. The intraday and interday accuracies ranged from 85.1 to 128.4%, with the precision below 16.6%. The validated method was successfully applied in characterizing the alterations of purine- and pyrimidine-related derivatives in the A549 cell line with perturbed mitochondrial fission or blockade of the electron transport chain. Collectively, this study demonstrates that the strategy of in-sample medronic acid addition is effective in improving the quantification of intracellular purine- and pyrimidine-related derivatives. We believe that our proposed platform can facilitate the development of novel drugs targeting purine and pyrimidine metabolism in the future.

Influence of metals in the column or instrument on performance in hydrophilic interaction liquid chromatography

A method is proposed for measuring the relative contribution of extracolumn and column effects to the detrimental interactions which occur between metal-sensitive solutes and the complete HPLC system. The method involves the substitution of a length of narrow bore silica tubing for the column and measuring the extracolumn contribution, which is subtracted from the total bandspreading measured with a column in place to yield the column contribution. The investigation focussed on HILIC separations, which have been relatively little studied compared with similar effects in RPLC. Metal-solute interactions can lead to tailing peaks and reduced sensitivity or even irreversible adsorption of particularly challenging solutes such as mono-, di- and triphosphorylated nucleotides, which show strong interactions between their phosphate groups and metals. A deactivated HILIC column, treated by a vapour deposition procedure gave generally good results when using high pH (pH 9.0) mobile phases, which suppress the effects of metals. The addition of metal complexing agents such as citrate at low millimolar concentration gave further improvements in peak shape at high pH, and even micromolar concentrations of citrate or medronic acid showed good results. These lower concentrations are more favourable for LC-MS. Addition of the higher concentration of citrate gave acceptable results for the nucleotides even at low pH (pH 3.0). With the standard UHPLC instrument used, loss of efficiency due to metal solute interactions was 25% or less, with most losses due to interactions with the column, although this result will depend on the condition and design of the instrument, which is easily assessed by the proposed procedure.

Double layer coating system to prevent toxic reactions of titanium dioxide from the corrosion of dental implant fixtures

Introduction: Titanium dioxide has been classified by the International Agency for Research on Cancer (IARC) as a Group 2B carcinogen. As indispensable material for dental implant fixture, dental patients are exposed to its toxicological reactions. Objectives: The primary aim of this research is to prevent making nanoparticle titanium dioxide from the corrosion of dental implant fixture. Methods: The authors introduce double layer coating system for controlling corrosional toxicity of TiO2 from the surface of two dental implant fixtures by medronic acid and teriparatide acetate. Results: The first layer coated with medronic acid will generate phosphate bridges, functioning as a corrosionresistant sheath layer, and will be the only connector to Forteo (Teriparatide Acetate). The second layer encloses the essential elements of teriparatide like C, N, O and H with saving the functional radicals like CNO-, C2H3O-, CHO2-, C3H3O-, C2H3O2-,for and it will stimulate the coated implant fixture with PTH receptors, osteoblasts, and osteogenesis. The first layer covers Ti-O-P, acting as a titanium grade 4 antioxidant. Conclusion: The top surface ions in the second layer of the fixture have pharmaceutically functioning parts of the chemical structure of Teriparatide (C181H291N55O51S2) activating osteoblasts more than osteoclast, which leads to an overall increase in bone. Though the recommended duration of use for grade 4 implant fixtures is 3 years, but these new coated fixtures are expected to use the coated fixtures longer than 3 years by containing the stimulating effect of new alveolar bone formation by increasing the mineral density of the alveolar bone around the fixture besides preventing corrosional toxicity of the surface of pre-existing titanium fixtures.

Schematic Suggestion and Results of Two-Layer Coating System for Controlling Corrosional Toxicity of Titanium Dioxide from Dental Implant Fixture

Introduction: Titanium dioxide has been classified by the International Agency for Research on Cancer (IARC) as a Group 2B carcinogen. As indispensable material for dental implant fixture, dental patients are exposed to its toxicological reactions. Objectives: The primary aim of this research is to prevent making nanoparticle titanium dioxide from the corrosion of dental implant fixture and gain possible osseointegration. Methods: The authors introduce two-layer coating system for controlling corrosional toxicity of TiO2 from the surface of two dental implant fixtures by medronic acid and teriparatide acetate. Results: The first layer coated with medronic acid will generate phosphate bridges, functioning as a corrosion-resistant sheath layer, and will be the only connector to Forteo (Teriparatide Acetate). The second layer encloses the essential elements of teriparatide like C, N, O and H with saving the functional radicals like CNO-, C2H3O-, CHO2-, C3H3O- and C2H3O2-, for and it will stimulate the coated implant fixture with PTH receptors, osteoblasts, and osteogenesis. The first layer covers Ti-O-P, acting as a titanium grade 4 antioxidant. Conclusion: The top surface radicals in the second layer of the fixture have pharmaceutically functioning parts of the chemical structure of Teriparatide (C181H291N55O51S2) activating osteoblasts more than osteoclasts, which leads to an overall increase in bone. Though the recommended duration of use for grade 4 implant fixtures is 3 years, but these new coated fixtures are expected to use longer than 3 years by containing the stimulating effect of new alveolar bone formation by increasing the mineral density of the alveolar bone around the fixture besides preventing corrosional toxicity from the surface of preexisting titanium fixtures. Cheaper producing cost of a coated implant fixture are also suggested.

In silico exploration of binding of selected bisphosphonate derivatives to placental alkaline phosphatase via docking and molecular dynamics

Bisphosphonates constitute a group of pyrophosphate analogues therapeutically active against bone diseases. Numerous studies confirm their anticancer and antimetastatic potential as well as ability to relieve pathological pain. Although this is a known class of compounds, many aspects of their action remain unexplained and their new interaction partners are still being discovered. Due to the structural similarity to pyrophosphate, their interaction with pyrophosphate-recognizing enzymes seems to be feasible. In current work, the placental alkaline phosphatase (PLAP) is considered as a potential target for these class of compounds. PLAP is one of the enzymes responsible for degradation of pyrophosphate with high clinical significance. An elevation of PLAP level are considered as a potential cancer marker. An in silico study of complexes formed between selected phosphate derivatives and PLAP was performed. It indicates that all tested compounds: alendronic acid, clodronic acid, etidronic acid, zoledronic acid, imidodiphosphoric acid, pyrophosphoric acid, medronic acid, chloromethylenediphosphonic acid and hypophosphoric acid form a complexes with PLAP, stabilized by hydrogen bonds, hydrophobic and van der Waals interactions. Zoledronic acid, drug used in prevention of bone complications during cancer treatment was found to have the lowest estimated energy of binding (−6.6 kcal/mol). In silico study yielded very low energy of binding also for hypophosphate, equal −6.4 kcal/mol, despite having no identified hydrogen bonds. Subsequent molecular dynamic simulations, followed by molecular mechanics generalized-born surface area with pairwise decomposition calculations confirmed the stability of protein-ligand complexes. The results indicate that selected phosphate derivatives may potentially interact with the enzyme, changing its function, what should be investigated during in vitro studies.

A new theranostic system for bone disorders: Functionalized folate-MDP hydroxyapatite nanoparticles with radiolabeled copper-64

Hydroxyapatite nanoparticles have been investigated as biological agents for the treatment and diagnosis of bone diseases due to their properties, providing high affinity to bone tissues and also due to the possibility to chemically modify the surfaces of these nanoparticles to provide active targeting to bone tumors or other bone disorders. In this work, synthetic hydroxyapatite nanoparticles and their surface modifications with folic and medronic acid were studied. Copper-64 was produced by neutron irradiation in a TRIGA MARK I nuclear reactor, and the functionalized nanoparticles radiolabeled with this radioisotope. The multi-technique characterization includes FTIR, PXRD, TGA, DSC, CHN, Zeta potential, XPS, SEM, TEM, and Gamma spectroscopy. Furthermore, the evaluation of the chemical interaction stability was through leaching tested for efficiency. The results indicate that folic and medronic acids can be covalently bonded to HA surface, producing a new material not yet described in the literature, been stably attached to hydroxyapatite nanoparticle surfaces, able to provide active targeting for bone disorders. The complexation of copper-64 provides high radiochemistry purity, although the specific activity must be improved.

Application of Stable Isotope Tracing to Elucidate Metabolic Dynamics During Yarrowia lipolytica α-Ionone Fermentation.

SummaryTargeted metabolite analysis in combination with 13C-tracing is a convenient strategy to determine pathway activity in biological systems; however, metabolite analysis is limited by challenges in separating and detecting pathway intermediates with current chromatographic methods. Here, a hydrophilic interaction chromatography tandem mass spectrometry approach was developed for improved metabolite separation, isotopologue analysis, and quantification. The physiological responses of a Yarrowia lipolytica strain engineered to produce ∼400 mg/L α-ionone and temporal changes in metabolism were quantified (e.g., mevalonate secretion, then uptake) indicating bottleneck shifts in the engineered pathway over the course of fermentation. Dynamic labeling results indicated limited tricarboxylic acid cycle label incorporation and, combined with a measurable ATP shortage during the high ionone production phase, suggested that electron transport and oxidative phosphorylation may limit energy supply and strain performance. The results provide insights into terpenoid pathway metabolic dynamics of non-model yeasts and offer guidelines for sensor development and modular engineering.

Application of mobile phase additives to reduce metal-ion mediated adsorption of non-phosphorylated peptides in RPLC/MS-based assays

Metal-ion mediated adsorption in liquid chromatography has been identified as a contributing factor in poor peak shape, tailing, and diminished recovery of compounds prone to cation exchange-like interaction with metal-based activity sites. Peptides that exhibit negative charge-bearing amino acids such as aspartic acid and glutamic acid are particularly sensitive to metal-ion mediated adsorption in RPLC/MS-based separations when using weak acids (e.g. formic acid) as mobile phase additives. Citric acid and medronic acid as metal complexing mobile phase additives were evaluated for their ability to mitigate metal-ion mediated adsorption in RPLC/MS-based peptide mapping assays. In this study, chromatographic performance was stabilized with peak tailing for peptides of interest reduced by as much as 40% in the presence of a chelator at a mobile phase concentration of 1 ppm. Performance gains were observed to be stable over a 67-hour time study with an average USP tailing factor of 1.00, % RSD = 0.64. The stabilizing effect of the chelator improved peptide mapping assay robustness with relative peak areas for target impurities calculated at 2.28% (% R.S.D. = 2.36) and 2.40% (% R.S.D. = 2.37). Collectively this study demonstrates that chelators as mobile phase additives offers a means to improve chromatographic performance for biomolecules sensitive to metal-ion mediated adsorption under formic acid-based RPLC conditions.

Improved LC/MS Methods for the Analysis of Metal-Sensitive Analytes Using Medronic Acid as a Mobile Phase Additive.

Phosphorylated compounds and organic acids with multiple carboxylate groups are commonly observed to have poor peak shapes and signal in LC/MS experiments. The poor peak shape is caused by the presence of trace metals, particularly iron, contributed from a variety of sources within the chromatographic system. To ameliorate this problem, different solvent additives were investigated to reduce the amount of metal in the flow path to achieve better analytical performance for these metal-sensitive compounds. Here, we introduce the use of a solvent additive that can significantly improve the peak shapes and signal of metal-sensitive metabolites for LC/MS analysis. Moreover, the additive is shown to be amenable for other metal-sensitive applications, such as the analysis of phosphopeptides and polar phosphorylated pesticides, where the instruments could be used in either positive or negative analysis mode.

Synthesis of medronic acid monoesters and their purification by high-performance countercurrent chromatography or by hydroxyapatite.

We achieved the synthesis of important medronic acid monoalkyl esters via the dealkylation of mixed trimethyl monoalkyl esters of medronic acid. Two methods were developed for the purification of medronic acid monoesters: 1) small scale (10–20 mg) purification by using hydroxyapatite and 2) large scale (tested up to 140 mg) purification by high-performance countercurrent chromatography (HPCCC).

Functional investigation of bone implant viability using radiotracers in a new model of osteonecrosis

OBJECTIVES:Conventional imaging methods are excellent for the morphological characterization of the consequences of osteonecrosis; however, only specialized techniques have been considered useful for obtaining functional information. To explore the affinity of radiotracers for severely devascularized bone, a new mouse model of isolated femur implanted in a subcutaneous abdominal pocket was devised. To maintain animal mobility and longevity, the femur was harvested from syngeneic donors. Two technetium-99m-labeled tracers targeting angiogenesis and bone matrix were selected.METHODS:Medronic acid and a homodimer peptide conjugated with RGDfK were radiolabeled with technetium-99m, and biodistribution was evaluated in Swiss mice. The grafted and control femurs were evaluated after 15, 30 and 60 days, including computed tomography (CT) and histological analysis.RESULTS:Radiolabeling achieved high (>95%) radiochemical purity. The biodistribution confirmed good blood clearance 1 hour after administration. For 99mTc-hydrazinonicotinic acid (HYNIC)-E-[c(RGDfK)2, remarkable renal excretion was observed compared to 99mTc-methylene diphosphonate (MDP), but the latter, as expected, revealed higher bone uptake. The results obtained in the control femur were equal at all time points. In the implanted femur, 99mTc-HYNIC-E-[c(RGDfK)2 uptake was highest after 15 days, consistent with early angiogenesis. Regarding 99mTc-MDP in the implant, similar uptake was documented at all time points, consistent with sustained bone viability; however, the uptake was lower than that detected in the control femur, as confirmed by histology.CONCLUSIONS:1) Graft viability was successfully diagnosed using radiotracers in severely ischemic bone at all time points. 2) Analogously, indirect information about angiogenesis could be gathered using 999mTc-HYNIC-E-[c(RGDfK)2. 3) These techniques appear promising and warrant further studies to determine their potential clinical applications.

Polarographic determination of Sn(II) in samples containing Sn(IV) such as in 99m-Technetium radiopharmaceutical kits

A sensitive, alternative method to titrimetry or spectrophotometry for the evaluation of tin(II) ions (0–5 μg ml −1) in matrices containing tin(IV) ions was investigated. Differential pulse polarography was chosen. The supporting electrolyte was a buffer solution 0.7M NaF/0.1 M NaNO 3/0.1 M HEPES at pH 8. The potential was swept from −500 to −800 mV vs. Ag/AgCl/ saturated KCl, using a dropping mercury electrode with a drop time of 1 s, a sweep rate of 4 mVs −1, a differential modulation with a pulse time of 40ms, a delay time of 20ms, a measurement time of 20ms and a pulse amplitude of −50 mV. In technetium labelling kits, containing medronic acid (methylenediphosphonic acid), 10 −3 M ZnCl 2 was added to the supporting electrolyte in order to eliminate the interference of medronic acid. This polarographic method is suitable for the determination of Sn(II) in samples containing Sn(IV) with or without medronic and ascorbic acid.

The natural course of radionuclide bone scanning in the evaluation of total knee replacement — A 2 year prospective study

In order to establish the natural course of radionuclide bone scanning images after total knee replacement 41 consecutive patients were scheduled for examination 3, 7, 12 and 24 months after surgery. The mean age was 69 years (range 50-80 years); the female:male ratio was 4:1. Thirty-two patients completed the entire program. A total of 143 99Tcm medronic acid complex scintigrams was performed. No significant difference between the grades of total scintigraphic uptake at any of the four examinations nor any difference between the first and the last examinations could be demonstrated (P = 0.58, Friedman test and P = 0.20, Wilcoxon test, respectively). Twelve months after surgery one fifth of the knees still demonstrated definitely increased scintigraphic uptake and 24 months after surgery 12.5% of the knees had definitely increased uptake. We believe that the increased uptake seen for a variable length of time after surgery limits the usefulness of radionuclide bone scanning in the evaluation of total knee replacement.