Enhanced dissolution and oral bioavailbility of cinacalcet hydrochlorde nanocrystals with no food effect.

This study was aimed at improving oral bioavailbility and reducing the food effect of cinacalcet hydrochlorde (CINA), a poorly soluble drug for the treatment of chronic kidney disease, by preparing its nanocrystals (NCs) utilizing the precipitation-ultrasonication method. Based on the single factor method and Box-Behnken design, with the particle size and polydispersity index (PDI) as indexes, the optimal formulation was achieved. It was investigated that the particle size and PDI of the NCs prepared on the basis of optimal formulation were 244 ± 2 nm and 0.168 ± 0.001, respectively. The NCs were solidificated by lyophilization. Scanning electron microscopy, differential scanning calorimetry and x-ray powder diffraction were used to characterize the CINA-NCs, and there was no crystalline change during preparation and lyophilization. The CINA-NCs capsules prepared with 30% (w/v) MCC, 8% (w/v) CCNa and 2% (w/v) talcum powder by orthogonal experimental design presented an enhanced in vitro dissolution rate in four media compared with commercial tablets Sensipar® and raw material. The raw material, blank NCs and CINA-NCs were confirmed to be non-toxic to Caco-2 cells when the drug concentration was below 250 µg ml-1. In the in vivo pharmacokinetic study, the Cmax (the peak concentration of CINA in plasma) and AUC0-t (area under curve by trapezoidal area method) of the CINA-NCs capsules were approximately 1.90-fold and 1.64-fold greater than that of Sensipar® in the fasted state. Overall, this nanotechnology is a promising way to optimize the dosage form of CINA oral administration.

An improved LC-MS/MS method for determination of cinacalcet in human plasma and its application to the evaluation of food intake effect on the pharmacokinetics of cinacalcet in healthy volunteers.

A liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the determination of cinacalcet in human plasma was developed and validated. This assay was based on liquid-liquid extraction and cinacalcet-d4 was used as an internal standard (IS). Separation was achieved on a C18 column by the mobile phase A of water (containing 0.1% formic acid) and the mobile phase B of acetonitrile-water (95:5, v/v) (containing 0.2% formic acid) with gradient elution. Quantification was done using multiple reaction monitoring mode to monitor the precursor-to-product ion transitions of m/z 358.2 → m/z 155.2 for cinacalcet and m/z 362.3 → m/z 155.0 for IS at positive ionization mode. The calibration curve was established over the range 0.05-20.0 ng/mL and the correlation coefficient was >0.99. The intra- and inter-day relative standard deviations were <5.8%. Accuracy determined at four concentrations ranged between 96.0 and 106.0%. This method was successfully applied to a pharmacokinetic description of oral dose of cinacalcet and the significant effect of food intake on the pharmacokinetics of cinacalcet was first demonstrated in Chinese healthy volunteers.

Quality by Design Enabled Development of Oral Self-Nanoemulsifying Drug Delivery System of a Novel Calcimimetic Cinacalcet HCl Using a Porous Carrier: In Vitro and In Vivo Characterisation.

In this present research, work quality by design-enabled development of cinacalcet HCl (CH)-loaded solid self-nanoemulsifying drug delivery system (S-SNEDDS) was conducted using a porous carrier in order to achieve immediate drug release and better oral bioavailability. Capmul MCM (CAP), Tween 20 (TW 20) and Transcutol P (TRP) were selected as excipients. Cumulative % drug release at 30 min (Q30), emulsification times (ET), mean globule size (GS) and polydispersity index (PDI) were identified as critical quality attributes (CQAs). Factor mode effect analysis (FMEA) and Taguchi screening design were applied for screening of factors. The optimised single dose of S-SNEDDS obtained using Box-Behnken design (BBD) consisted of 30 mg of CH, 50 mg of CAP, 149.75 mg of TW 20, 55 mg of TRP and 260.75 mg of Neusilin US2. It showed an average Q30 of 97.6%, ET of 23.3 min, GS of 89.5 nm and PDI of 0.211. DSC, XRD and SEM predict the amorphous form of S-SNEDDS. In vivo pharmacokinetic study revealed better pharmacokinetic parameters of S-SNEDDS. The above study concluded that the optimised S-SNEDDS is effective to achieve the desired objective. Graphical Abstract.

Formulation optimization and pharmacokinetics evaluation of oral self-microemulsifying drug delivery system for poorly water soluble drug cinacalcet and no food effect.

The present research indicated that a new self-microemulsifying drug delivery systems (SMEDDS) were used to reduce the food effect of poorly water-soluble drug cinacalcet and enhance the bioavailability in beagle dogs by oral gavage. Ethyl oleate, OP-10, and PEG-200 was selected as the oil phase, surfactant and co-surfactant of cinacalcet-SMEDDS by the solubility and phase diagram studies. Central Composite Design-Response Surface Methodology was used to determine the ratio of surfactant and co-surfactant, the amount of oil for optimizing the SMEDDS formation. The prepared formulations were further characterized by the droplet size, self-microemulsifying time, zeta potential, polydispersity index (PDI), and robustness to dilution. The in vitro release profile of cinacalcet-SMEDDS was determined in four different release medium and in fasted state and fed state of simulated gastrointestinal fluid. Cinaclcet-SMEDDS were implemented under fed and fasted state in dogs and product REGPARA® was used as a comparison to the prepared formulation in the pharmacokinetics. The result showed the components of SMEDDS, the amount of oil, the ratio of surfactant, and co-surfactant was optimized using solubility, pseudo-ternary phase diagram studies, and response surface methodology. In vitro drug release studies indicated that the cinacalcet-SMEDDS eliminated the effect of pH variability in release medium and variational gastroenteric environments with improved drug release performance. Pharmacokinetic studies revealed that the profiles of cinacalcet-SMEDDS were similar both in the fasted and fed state compared with commercial product, indicating the formulation significantly promoted the absorption, enhanced bioavailability and had no food effect essentially. It is concluded that poorly water-soluble drug cinacalcet was improved in the solubility and bioavailability by using a successful oral dosage form the SMEDDS, and eliminated food effect as well.

Calcium sensing receptor effects in adipocytes and liver cells: Implications for an adipose-hepatic crosstalk.

The calcium sensing receptor (CaSR) is expressed in human adipose cells, and its activation may associate with adipose tissue (AT) dysfunction. We evaluated whether CaSR stimulation influences adipocyte triglyceride (TG) and fatty acid binding protein 4 (aP2) content, and hepatocyte TGs and proinflammatory cytokine expression. The effect of the calcimimetic cinacalcet on TGs (fluorimetry), lipogenic genes (qPCR) and aP2 (immunoblot) was evaluated in LS14 adipocytes or AT. In the human HepG2 hepatic cell line, we assessed CaSR expression and cinacalcet effect on TGs and lipogenic and proinflammatory genes. CaSR activation decreased adipocyte TG content by 20% and the expression of GPD and LPL by 34% and 20%, respectively. Cinacalcet increased aP2 protein expression by 60%. CaSR expression was shown in HepG2 cells and human liver samples. Cinacalcet-treated HepG2 cells in the presence of oleic acid exhibited a19% increased TG content. No changes were observed in the expression of lipogenic genes in HepG2 cells, however there was a 50%-300% elevation in the expression of proinflammatory cytokines. CaSR activation in adipocytes may associate with decreased TG storage ability and increased aP2. Hepatic CaSR stimulation may elevate steatosis and proinflammatory factors. We propose that CaSR may contribute to obesity-associated hepatic metabolic consequences.

Application of (19) F time-domain NMR to measure content in fluorine-containing drug products.

It is necessary to show that the active content in the dosage form of drugs is within a certain narrow range of the label claim. In case of fluorinated drugs, the active content can be measured by high field solid state NMR because the excipients lack fluorine. To make NMR reachable to any laboratory, simple to use, and at a low cost, measurement of (19) F nucleus using a 23 MHz (for (1) H) low field benchtop time-domain (TD) NMR was investigated. Three fluorinated drug products, cinacalcet, lansoprazole, and ciprofloxacin, were chosen for this study. The doses for these drug products range from 15 to 500 mg. The average drug content measured using (19) F TD-NMR compares well with the reported label claims for the three drugs tested. (19) F TD-NMR is a simple and non-destructive technique to measure drug content in tablets. In addition, the accessibility and simplicity of the technique makes it an excellent process analytical technology tool for development and manufacturing in the pharmaceutical industry. Copyright © 2015 John Wiley & Sons, Ltd.

Glutathione-Based Photoaffinity Probe Identifies Caffeine as a Positive Allosteric Modulator of the Calcium-Sensing Receptor.

The calcium-sensing receptor (CaSR), abundantly expressed in the parathyroid gland and kidney, plays a central role in calcium homeostasis. In addition, CaSR exerts multimodal roles, including inflammation, muscle contraction, and bone remodeling, in other organs and tissues. The diverse functions of CaSR are mediated by many endogenous and exogenous ligands, including calcium, amino acids, glutathione, cinacalcet, and etelcalcetide, that have distinct binding sites in CaSR. However, strategies to evaluate ligand interactions with CaSR remain limited. Here, we developed a glutathione-based photoaffinity probe, DAZ-G, that analyzes ligand binding to CaSR. We showed that DAZ-G binds to the amino acid binding site in CaSR and acts as a positive allosteric modulator of CaSR. Oxidized and reduced glutathione and phenylalanine effectively compete with DAZ-G conjugation to CaSR, while calcium, cinacalcet, and etelcalcetide have cooperative effects. An unexpected finding was that caffeine effectively competes with DAZ-G's conjugation to CaSR and acts as a positive allosteric modulator of CaSR. The effective concentration of caffeine for CaSR activation (<10 µM) is easily attainable in plasma by ordinary caffeine consumption. Our report demonstrates the utility of a new chemical probe for CaSR and discovers a new protein target of caffeine, suggesting that caffeine consumption can modulate the diverse functions of CaSR.

Studies on potential interaction between cinacalcet hydrochloride and diclofenac sodium.

Cinacalcet (CT) is an important drug for the treatment hyperparathyroidism. Only few studies havereported thepotential interaction between CT and other potentially coadministered drugs. In this study, the potential of invitro interaction between CT and DF sodium (DF-Na) was investigated. An ion pair salt of CT with DF was obtained by mixing the two compounds in solution; the product was fully characterized by HPLC analysis, UV, FTIR, NMR spectroscopy in addition to DSC. The solubility and partition coefficients were found to significantly decrease and increase, respectively, for the obtained ion pair salt in comparison to the parent compounds. Dissolution studies in phosphate buffer pH 6.8 revealed a significant decrease in the dissolution of an already poorly water soluble drug (decrease to ~20% of the original). Permeation studies, through Caco-2 cells monolayer, revealed a significant decrease in permeation of CT when coexisted with DF (almost to half). Apparent permeability coefficient (Papp) decreased from 3.6 × 10-6 to 1.8 × 10-6 cm/s. Interestingly, a structure for the formed CT-DF salt that could explain the above findings (increase in lipophilicity), could be proposed based on structural modelling, molecular dynamic simulations and NMR proton chemical shifts analysis.

Chiral capillary zone electrophoresis in enantioseparation and analysis of cinacalcet impurities: Use of Quality by Design principles in method development.

A capillary electrophoresis method for the simultaneous determination of the enantiomeric purity and of impurities of the chiral calcimimetic drug cinacalcet hydrochloride has been developed following Quality by Design principles. The scouting phase was aimed to select the separation operative mode and to identify a suitable chiral selector. Among the tested cyclodextrins, (2-carboxyethyl)-ß-cyclodextrin and (2-hydroxypropyl)-γ-cyclodextrin (HPγCyD) showed good chiral resolving capabilities. The selected separation system was solvent-modified capillary zone electrophoresis with the addition of HPγCyD and methanol. Voltage, buffer pH, methanol concentration and HPγCyD concentration were investigated as critical method parameters by a multivariate strategy. Critical method attributes were represented by enantioresolution and analysis time. A Box-Behnken Design allowed the contour plots to be drawn and quadratic and interaction effects to be highlighted. The Method Operable Design Region (MODR) was identified by applying Monte-Carlo simulations and corresponded to the multidimensional zone where both the critical method attributes fulfilled the requirements with a desired probability π≥90%. The working conditions, with the MODR limits, corresponded to the following: capillary length, 48.5cm; temperature, 18°C; voltage, 26kV (26-27kV); background electrolyte, 150mM phosphate buffer pH 2.70 (2.60-2.80), 3.1mM (3.0-3.5mM) HPγCyD; 2.00% (0.00-8.40%) v/v methanol. Robustness testing was carried out by a Plackett-Burman matrix and finally a method control strategy was defined. The complete separation of the analytes was obtained in about 10min. The method was validated following the International Council for Harmonisation guidelines and was applied for the analysis of a real sample of cinacalcet hydrochloride tablets.

Stability of extemporaneously prepared cinacalcet oral suspensions.

PURPOSE: The stability of extemporaneously prepared cinacalcet suspensions over 90 days was evaluated. METHODS: Cinacalcet 5-mg/mL suspension was prepared by triturating 30-mg cinacalcet tablets. Twelve 30-mL batches were prepared with a 1:1 mixture of Ora-Plus and either Ora-Sweet or Ora-Sweet SF (sugar free). Three suspensions of each kind were stored at both room temperature and refrigerated conditions. A 1-mL sample was taken from each bottle at 0, 7, 18, 32, 64, and 90 days. Each sample was assayed using high-performance liquid chromatography (HPLC). A new HPLC method for evaluating drug peaks of pure cinacalcet was developed. Stability was defined as retention of at least 90% of the initial drug concentration. RESULTS: The HPLC method established in this study serves as a novel assay for evaluating cinacalcet oral suspensions. For all suspensions tested at individual conditions, the concentration remained above 90% of the initial concentration for 90 days of storage with the exception of Ora-Plus and Ora-Sweet SF suspensions stored under refrigeration, which were stable for 64 days. Usual sedimentation of the suspensions occurred over time but resolved with agitation; there was no other change in visual appearance of the suspensions over the course of the 90-day study. The color and odor of the suspensions throughout the study remained unchanged with respect to the initial time point. CONCLUSION: Extemporaneously compounded cinacalcet 5-mg/mL oral suspensions prepared with a 1:1 mixture of Ora-Plus and either Ora-Sweet or Ora-Sweet SF and stored in 2-oz amber polypropylene plastic bottles were stable for at least 64 days at room temperature and under refrigeration.

Divergent effects of strontium and calcium-sensing receptor positive allosteric modulators (calcimimetics) on human osteoclast activity.

BACKGROUND AND PURPOSE: Strontium ranelate, a drug approved and until recently used for the treatment of osteoporosis, mediates its effects on bone at least in part via the calcium-sensing (CaS) receptor. However, it is not known whether bone-targeted CaS receptor positive allosteric modulators (PAMs; calcimimetics) represent an alternative (or adjunctive) therapy to strontium (Sr2+ o ). EXPERIMENTAL APPROACH: We assessed three structurally distinct calcimimetics [cinacalcet, AC-265347 and a benzothiazole tri-substituted urea (BTU-compound 13)], alone and in combination with extracellular calcium (Ca2+ o ) or Sr2+ o , in G protein-dependent signalling assays and trafficking experiments in HEK293 cells and their effects on cell differentiation, tartrate-resistant acid phosphatase (TRAP) activity and hydroxyapatite resorption assays in human blood-derived osteoclasts. KEY RESULTS: Sr2+ o activated CaS receptor-dependent signalling in HEK293 cells in a similar manner to Ca2+ o , and inhibited the maturation, TRAP expression and hydroxyapatite resorption capacity of human osteoclasts. Calcimimetics potentiated Ca2+ o - and Sr2+ o -mediated CaS receptor signalling in HEK293 cells with distinct biased profiles, and only cinacalcet chaperoned an endoplasmic reticulum-retained CaS mutant receptor to the cell surface in HEK293 cells, indicative of a conformational state different from that engendered by AC-265347 and BTU-compound 13. Intriguingly, only cinacalcet modulated human osteoclast function, reducing TRAP activity and profoundly inhibiting resorption. CONCLUSION AND IMPLICATIONS: Although AC-265347 and BTU-compound 13 potentiated Ca2+ o - and Sr2+ o -induced CaS receptor activation, they neither replicated nor potentiated the ability of Sr2+ o to inhibit human osteoclast function. In contrast, the FDA-approved calcimimetic, cinacalcet, inhibited osteoclast TRAP activity and hydroxyapatite resorption, which may contribute to its clinical effects on bone mineral density LINKED ARTICLES: This article is part of a themed section on Molecular Pharmacology of GPCRs. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v175.21/issuetoc.

Cinacalcet Hydrochloride.

Cinacalcet hydrochloride is a calcimimetic agent that increases the sensitivity to the extracellular calcium of the calcium-sensing receptors of the parathyroid gland which regulates parathyroid hormone secretion. This comprehensive profile on cinacalcet hydrochloride starts with a description: nomenclature, formulae, chemical structure, elemental composition, and appearance. The uses and applications of the drug are included. The methods of preparation of cinacalcet hydrochloride are described and their respective schemes are outlined. The physical characterization of the drug is: ionization constant, solubility, X-ray powder diffraction (XRPD) pattern, crystal polymorphs, melting point, and differential scanning calorimetry. The spectral characteristics of the drug include: ultraviolet spectrum, vibrational spectrum, 1H and 13C nuclear magnetic resonance spectra, and the mass spectrum. The methods of analysis of the drug include: spectrophotometry, electrophoresis, fluorimetry, and high-performance liquid chromatography alone or with mass spectrometry. The stability of the drug in various media and storage conditions are reported. Biological studies on the drug include: the metabolism pharmacokinetics and pharmacodynamics. More than 100 references are listed at the end of the chapter.