Spectrofluorometric determination of cinacalcet hydrochloride: greenness assessment and application to biological fluids andin-vitrodissolution testing.

A facile, simple, green and sensitive spectrofluorometric method was developed for determination of the calcimimetic drug cinacalcet hydrochloride. It is used for the treatment of hyperparathyroidism. The drug showed high native fluorescence intensity at 320 nm after excitation at 280 nm. The method was linear over the range of 5.0-400.0 ng ml-1with excellent correlation (R2= 0.9999). Limit of detection (LOD) and limit of quantitation (LOQ) values were 1.19 and 3.62 ng ml-1, respectively. The percentage recovery was found to be 100.42% ± 1.39 (n=8). The proposed method was successfully applied for determination of cinacalcet in spiked human plasma samples with % recoveries of (87.23 to 109.69%). Two recent greenness metrics (GAPI and Analytical Eco-Scale) were chosen to prove the eco-friendly nature of the method. Furthermore, the proposed method was successfully applied to dissolution study of commercial cinacalcet tablets. The interference likely to be introduced by some commonly co-administrated drugs such as metoprolol and itraconazole was studied; the tolerance limits were calculated.

Variability in Cinacalcet Prescription across US Hemodialysis Facilities.

BACKGROUND AND OBJECTIVES: Calcimimetic drugs used to treat secondary hyperparathyroidism are being considered for inclusion in the Medicare ESRD Prospective Payment System bundle after an evaluation period. Understanding of utilization patterns of calcimimetics across dialysis facilities may help align financial incentives with clinical objectives. Our study's purpose was to describe the distribution of cinacalcet prescription across United States hemodialysis facilities and to explore factors that may influence cinacalcet utilization. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: We used monthly cross-sectional data from the Dialysis Outcomes and Practice Patterns Study in 2014 to characterize the distribution of cinacalcet prescription across 203 United States hemodialysis facilities (10,521 patients). On the basis of associations with parathyroid hormone levels from patient-level analyses, we used linear mixed-effects regressions to estimate the associations between three facility-level exposures (black race, <65 years old, and having ≥3 years on dialysis [vintage]) and the prevalence of cinacalcet prescription, adjusting for facility- and patient-level potential confounders. RESULTS: The mean percentage of patients in each facility with cinacalcet prescription was 23% in June 2014 (median, 22%; interquartile range, 13%-30%). Adjusted for facility-level and nonexposure patient-level variables, the difference in prevalence of cinacalcet prescription between facilities with the highest and lowest quartiles of percentage of black patients was 7.8% (95% confidence interval [95% CI], 0.8% to 14.8%; P for trend =0.03). The adjusted prevalence difference was 7.3% for the percentage of patients aged <65 years (95% CI, -0.1% to 14.7%; P for trend =0.06) and 11.9% for the percentage of patients with ≥3 years of dialysis (95% CI, 2.4% to 21.4%; P for trend =0.02). These associations changed appreciably, becoming much weaker or even reversing, after further adjusting for the patient-level exposure variables. CONCLUSIONS: Facilities treating more patients who are black, under age 65 years, and having dialysis vintage ≥3 years have higher average levels of cinacalcet prescription. However, these differences were strongly attenuated after accounting for the unbalanced distributions of these patient case-mix variables.

Case report: Electron microscopic evaluation of bone from a patient treated with cinacalcet hydrochloride, maxacalcitol, and alfacalcidol for hyperparathyroid bone disease with secondary hyperparathyroidism.

Evaluation of bone is of great importance in chronic kidney disease patients, as these patients are at an increased risk for fractures. We treated a hemodialysis patient suffering from hyperparathyroid bone disease with cinacalcet hydrochloride and concurrent administration of maxacalcitol and alfacalcidol for a year. Hyperparathyroid bone disease is characterized by cortical thinning, increased cortical porosity, reduced trabecular bone volume, and increased hypomineralized matrix volume, and there is little information to date about the effects of treatment with cinacalcet hydrochloride on the bone fragility in patients with hyperparathyroid bone disease. In the present study, histological and backscattered electron microscopic evaluation of this combination treatment revealed an excellent improvement of both bone volume and bone morphology. This treatment improved cortical thinning, cortical porosity, and trabecular thinning. Furthermore, the treatment also reduced hypomineralized matrix volume, indicative of improved mineralization by osteocytes. We speculate that the intermittent maxacalcitol administration may have effectively stimulated the vitamin D receptors expressed on osteocytes and osteoblasts, resulting in increased mineralization. Our approach for evaluating the bone in patients with chronic kidney disease by backscattered electron microscopy is novel.

Gallstones were associated with the gastrointestinal adverse events of cinacalcet in hemodialysis patients with secondary hyperparathyroidism.

This study aimed to investigate the association of gastrointestinal (GI) adverse events of cinacalcet with gallstones in the hemodialysis (HD) patients with secondary hyperparathyroidism (SHPT). A total of 23 HD patients under the treatment with cinacalcet and 101 control patients were enrolled in this cross-sectional study. We investigated the prevalence of gallstones and the association of GI adverse events of cinacalcet with gallstones. The prevalence of gallstones was significantly higher in the HD patients with cinacalcet compared with the controls (47.8% vs. 15.8%). The longer time on HD, hypercalcemia, hyperphosphatemia and elevated parathyroid hormone level were observed in the HD patients with cinacalcet. Besides, GI adverse events of cinacalcet were observed more frequently in the HD patients with gallstones compared with those without gallstones (odds ratio 13.5, 95% CI: 1.80-101). Therefore, screening for gallstones before dosing cinacalcet may reduce the risk of GI adverse events in SHPT patients.

Study on the in vivo-in vitro Correlation of Cinacalcet Hydrochloride Tablets / 中国药房

OBJECTIVE:To investigate the in vitro dissolution behavior and in vivo pharmacokinetics of Cinacalcet hydrochloride tablets, and to evaluate its in vivo-in vitro correlation (IVIVC). METHODS:HPLC method was adopted to determine the accumulative dissolution(Q) of Cinacalcet hydrochloride tablets in 8 kinds of medium [pH 1.2 hydrochloric acid solution,pH 2.0 hydrochloric acid solution,pH 4.5 acetate buffer solution,pH 6.8 phosphate buffer solution,water,artificial gastric fluid(SGF),full belly artificial intestinal fluid(FeSSIF),fasting artificial intestinal fluid(FaSSIF)],and the dissolution curves were drawn. HPLC-MS method was used to determine the blood concentrations of Cinacalcet hydrochloride tablets. A total of 12 healthy male volunteers were selected and given single oral dose of Cinacalcet hydrochloride tablets 75 mg under the state of fasting or satiety(high-fat food). The blood concentration of cinacalcet hydrochlorid was determined before medication(0 h)and 0.5,1,2,3,4,6,8,12,24 h after medication. Average blood concentration-time curves were drawn. The in vivo accumulative absorption percentage (F) of satiety group was calculated by using DAS 3.0 software. Linear regression of F with in vitro Q was carried out to analyze its IVIVC. RESULTS:There was great difference among dissolution curves of Cinacalcet hydrochloride tablets in 8 kinds of dissolution mediums. There were differences of AUC0→t,AUC0→∞ and cmax between fasting group and satiety group,with statistical significance(P＜0.05),showing high-fat food had significant effect on in vivo pharmacokinetics. Correlation coefficient of in vivo F in satiety group with in vitro Q of the tablets in FeSSIF was highest (0.977 9),manifesting good IVIVC (class A). CONCLUSIONS:The in vitro dissolution behavior of Cinacalcet hydrochloride tablets in FeSSIF(paddle method,50 r/min)is well associated with its in vivo pharmacokinetics,which can be used for predicting in vivo dissolution and absorption of the tablets.

Uncertainty Evaluationon of the Content Determination of Cinacalcet Hydrochloride by HPLC / 中国药师

Objective:To establish an HPLC method for the content determination of cinacalcet hydrochloride and evaluate the un-certainty in the measurement. Methods:An Inertsil ODS-SP chromatographic column(250 mm×4.6 mm,5 μm) was used,the mo-bile phase was composed of phosphate buffer solution(pH 6.5) and acetonitrile(60: 40),the flow rate was 1.0 ml·min-1,the de-tection wavelength was 272 nm,the column temperature was 30℃ and the injection volume was 20 μl. The content calculation formula-tion was deduced,the influencing factors were determined,and each component was assessed. Results:The resolution between cina-calcet and the impurity was satisfied,the linear relationship within the range of 10-100 μg?ml-1was excellent(r=0.999 9),the av-erage recovery was 101.09% (RSD=0.54%,n=9),and the LOQ was 0.254 μg?ml-1. The expanded uncertainty was 1.22%, and the result of the content determination was(100.74 ± 1.22)% (k=2). Conclusion:The method is simple,fast,selective,ac-curate and reliable,and can provide reference for the development of quality standards for generic drugs. Based on the influencing fac-tors of uncertainty,the main influencing reasons for the determination results can be found out to improve the reliability of determina-tion.

Calcium-Sensing Receptor Genotype and Response to Cinacalcet in Patients Undergoing Hemodialysis.

BACKGROUND AND OBJECTIVES: We tested the hypothesis that single nucleotide polymorphisms (SNPs) in the calcium-sensing receptor (CASR) alter the response to the calcimimetic cinacalcet. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: We analyzed DNA samples in the Evaluation of Cinacalcet HCl Therapy to Lower Cardiovascular Events (EVOLVE) trial, a randomized trial comparing cinacalcet to placebo on a background of usual care. Of the 3883 patients randomized, 1919 (49%) consented to DNA collection, and samples from 1852 participants were genotyped for 18 CASR polymorphisms. The European ancestry (EA; n=1067) and African ancestry (AfAn; n=405) groups were assessed separately. SNPs in CASR were tested for their association with biochemical measures of mineral metabolism at baseline, percent change from baseline to 20 weeks, and risk of clinical fracture as dependent variables. RESULTS: There were modest associations of CASR SNPs with increased baseline serum parathyroid hormone and bone alkaline phosphatase primarily with the minor allele in the EA group (all P≤0.03), but not in the AfAn sample. In contrast, there was a modest association of decreased baseline serum calcium and FGF23 with CASR SNPs (P=0.04) primarily with the minor allele in the AfAn but not in the EA sample. The minor allele of two SNPs was associated with decreased percent reduction in parathyroid hormone from baseline to 20 weeks in the EA population (P<0.04) and this was not altered with cinacalcet. In both EA and AfAn, the same SNP (rs9740) was associated with decreased calcium with cinacalcet treatment (EA and AfAn P≤0.03). Three SNPs in high linkage disequilibrium were associated with a higher risk of clinical fracture that was attenuated by cinacalcet treatment in the EA sample (P<0.04). CONCLUSIONS: These modest associations, if validated, may provide explanations for differences in CKD-mineral bone disorder observed in EA and AfAn populations, and for differential biochemical responses to calcimimetics.

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.

Blood Calcification Propensity, Cardiovascular Events, and Survival in Patients Receiving Hemodialysis in the EVOLVE Trial.

BACKGROUND AND OBJECTIVES: Patients receiving hemodialysis are at risk of cardiovascular events. A novel blood test (T50 test) determines the individual calcification propensity of blood. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: T50 was determined in 2785 baseline serum samples of patients receiving hemodialysis enrolled in the Evaluation of Cinacalcet Therapy to Lower Cardiovascular Events (EVOLVE) trial and the T50 results were related to patient outcomes. RESULTS: Serum albumin, bicarbonate, HDL cholesterol, and creatinine were the main factors positively/directly and phosphate was the main factor negatively/inversely associated with T50. The primary composite end point (all-cause mortality, myocardial infarction [MI], hospitalization for unstable angina, heart failure, or peripheral vascular event [PVE]) was reached in 1350 patients after a median follow-up time of 619 days. After adjustments for confounding, a lower T50 was independently associated with a higher risk of the primary composite end point as a continuous measure (hazard ratio [HR] per 1 SD lower T50, 1.15; 95% confidence interval [95% CI], 1.08 to 1.22; P<0.001). Furthermore, lower T50 was associated with a higher risk in all-cause mortality (HR per 1 SD lower T50, 1.10; 95% CI, 1.02 to 1.17; P=0.001), MI (HR per 1 SD lower T50, 1.38; 95% CI, 1.19 to 1.60; P<0.001), and PVE (HR per 1 SD lower T50, 1.22; 95% CI, 1.05 to 1.42; P=0.01). T50 improved risk prediction (integrated discrimination improvement and net reclassification improvement, P<0.001 and P=0.001) of the primary composite end point. CONCLUSIONS: Blood calcification propensity was independently associated with the primary composite end point, all-cause mortality, MI, and PVE in the EVOLVE study and improved risk prediction. Prospective trials should clarify whether T50-guided therapies improve outcomes.

Evaluation of Parathyroidectomy for Secondary and Tertiary Hyperparathyroidism by the Parathyroid Surgeons' Society of Japan.

Secondary hyperparathyroidism (SHPT) remains a serious complication in patients with chronic kidney disease, and some patients require parathyroidectomy. The Parathyroid Surgeons' Society of Japan (PSSJ) evaluated parathyroidectomy for SHPT and tertiary hyperparathyroidism (THPT) in Japan. The annual numbers of parathyroidectomies between 2004 and 2013 were evaluated using questionnaires. Since 2010, the PSSJ has registered the patients. In total, 826 patients from 42 institutions were registered. The annual number of parathyroidectomies for SHPT and THPT in Japan increased from 2004 to 2007 and then decreased markedly after 2007, with 296 operations performed in 2013. The number of women and men was almost equal (397/427). Median (interquartile range) age of these patients was 59.0 (24-87) years, the duration of hemodialysis before parathyroidectomy was 10.83 (0.0-38.7) years, and diabetic nephropathy was 87/826 (10.5%). Of these patients 59.6% were treated with cinacalcet at undergoing parathyroidectomy. In 75.3% of patients, a total parathyroidectomy with forearm autograft was performed. In 77.7% of patients, four or more parathyroid glands were removed during the initial operation. The incidences of husky voice and wound hemorrhage were 2.9% and 1.1%, respectively. The number of parathyroidectomies for SHPT in Japan decreased markedly after the introduction of cinacalcet. Based on the evaluation of registered patients, parathyroidectomies have been successfully performed at the institutions participating in the PSSJ.

Influence of preparation methods on amorphous cinacalcet hydrochloride / 中国药科大学学报

@#In the present study, amorphous cinacalcet hydrochloride was prepared by three different approaches including rotary evaporation, quench-cooling and lyophilization. Physicochemical properties of prepared amorphous cinacalcet hydrochloride such as thermal behavior, dissolution and stability were investigated. Results showed that there was no difference in dissolution and chemical stability for amorphous cinacalcet hydrochloride prepared by these three different methods; however, these amorphous materials exhibited significant difference in thermodynamic behavior and physical stability: (1)They had similar Tg but with significant difference in Tc(135. 2, 129. 6 and 153. 9 °C for the amorphous products prepared by rotary evaporation, lyophilization and quench-cooling, respectively); (2)These amorphous products were easy to recrystallize under an environment with high temperature and humidity, especially that prepared by quench-cooling. This study provides an experimental basis for screening preparation methods of amorphous materials.

Studies on related substances in cinacalcet hydrochloride by LC-MS / 中国药科大学学报

@#To develop an LC-MS method for the separation and identification of the related substances in cinacalcet hydrochloride. The separation was carried out on a Thermo BDS Hypersil C18 column(100 mm×4. 6 mm, 2. 4 μm)with mobile phase consisting of 0. 1% ammonium acetate buffer-acetonitrile(93∶7)(A)and acetonitrile(B)by gradient elution. The related substances were identified by electrospray positive ionization high resolution TOF/MS and MS/MS, and verified further through reference substances. Cinacalcet hydrochloride and itsrelated substances were separated under the established LC-MS condition. Ten related substances were detected and identified to be one starting material, one intermediate, four synthetic by-products and five degradation products. It showed that the LC-MS method was useful for separating and identifying the related substances in cinacalcet hydrochloride. And the results obtained are valuable for cinacalcet hydrochloride manufacturing process control and quality assurance.

Development and Validation of a Stability-Indicating RP-UPLC Method for the Estimation of Impurities in Cinacalcet Hydrochloride API and its Formulation.

A sensitive, stability-indicating, gradient reversed-phase ultra-performance liquid chromatography method has been developed for the quantitative estimation of cinacalcet hydrochloride impurities in active pharmaceutical ingredients and pharmaceutical formulations. Efficient chromatographic separation was achieved on an Acquity BEH Shield RP18, 100 × 2.1 mm, 1.7 µm column with the mobile phase containing pH 6.6 phosphate buffer and acetonitrile. The flow rate of the mobile phase was 0.3 mL min(-1) with a column temperature of 35°C and detection wavelength at 223 nm. The relative response factor values of (+)-R-1-(1-Naphthyl)ethylamine, regioisomer, diastereomer isomer-1, and diastereomer isomer-2 were 1.79, 0.99, 0.89, and 0.88, respectively. The cinacalcet hydrochloride formulation sample was subjected to the stress conditions of acid, base, oxidative, hydrolytic, thermal, humidity, and photolytic degradation. Cinacalcet hydrochloride was found to degrade significantly under the peroxide stress conditions. The degradation products were well-resolved from cinacalcet hydrochloride and its impurities. The peak purity test results confirmed that the cinacalcet hydrochloride peak was homogenous in all stress samples and the mass balance was found to be more than 96%, thus proving the stability-indicating power of the method. The developed method was validated according to ICH guidelines.

Pharmacoperones and the calcium sensing receptor: exogenous and endogenous regulators.

Calcium sensing receptor (CaSR) mutations or altered expression cause disorders of calcium handling. Recent studies suggest that reduced targeting to the plasma membrane is a feature common to many CaSR loss-of-function mutations. Allosteric agonists (calcimimetics) can rescue signaling of a subset of CaSR mutants. This review evaluates our current understanding of the subcellular site(s) for allosteric modulator rescue of CaSR mutants. Studies to date make a strong case for calcimimetic potentiation of signaling not only at plasma membrane-localized CaSR, but at the endoplasmic reticulum, acting as pharmacoperones to assist in navigation of multiple quality control checkpoints. The possible role of endogenous pharmacoperones, calcium and glutathione, in folding and stabilization of the CaSR extracellular and transmembrane domains are considered. Finally, the possibility that dihydropyridines act as unintended pharmacoperones of CaSR is proposed. While our understanding of pharmacoperone rescue of CaSR requires refinement, promising results to date argue that this may be a fruitful avenue for drug discovery.

Long-term effect of cinacalcet hydrochloride on abdominal aortic calcification in patients on hemodialysis with secondary hyperparathyroidism.

BACKGROUND: Secondary hyperparathyroidism (SHPT) is one of the common complications in dialysis patients, and is associated with increased risk of vascular calcification. The effects of cinacalcet hydrochloride treatment on bone and mineral metabolism have been previously reported, but the benefit of cinacalcet on vascular calcification remains uncertain. The aim of this study was to evaluate the impact of cinacalcet on abdominal aortic calcification in dialysis patients. SUBJECTS AND METHODS: Patients were on maintenance hemodialysis with insufficiently controlled SHPT (intact parathyroid hormone [PTH] >180 pg/mL) by conventional therapies. All subjects were initially administered 25 mg cinacalcet daily, with concomitant use of calcitriol analogs. Abdominal aortic calcification was annually evaluated by calculating aortic calcification area index (ACAI) using multidetector computed tomography (MDCT), from 12 months before to 36 months after the initiation of cinacalcet therapy. RESULTS: Twenty-three patients were analyzed in this study. The mean age was 59.0±8.7 years, 34.8% were women, and the mean dialysis duration was 163.0±76.0 months. After administration of cinacalcet, serum levels of intact PTH, phosphorus, and calcium significantly decreased, and mean Ca × P values significantly decreased from 67.4±7.9 mg(2)/dL(2) to 52±7.7 mg(2)/dL(2). Although the ACAI value did not decrease during the observation period, the increase in ACAI between 24 months and 36 months after cinacalcet administration was significantly suppressed. CONCLUSION: Long-term administration of cinacalcet was associated with reduced progression of abdominal aortic calcification, and achieving appropriate calcium and phosphorus levels may reduce the rates of cardiovascular events and mortality in patients on hemodialysis.

A novel asymmetric synthesis of cinacalcet hydrochloride.

A novel route to asymmetric synthesis of cinacalcet hydrochloride by the application of (R)-tert-butanesulfinamide and regioselective N-alkylation of the naphthyl ethyl sulfinamide intermediate is described.

Marked increase in bone formation markers after cinacalcet treatment by mechanisms distinct from hungry bone syndrome in a haemodialysis patient.

A 59-year-old female who was on dialysis due to diabetic nephropathy was referred to our hospital for severe hyperparathyroidism refractory to intravenous vitamin D receptor activator treatment. With subsequent cinacalcet hydrochloride treatment, parathyroid hormone (PTH) levels were only slightly suppressed. However, progressive increases were observed in serum alkaline phosphatase (ALP) and bone-specific alkaline phosphatase (BAP) levels with mild hypocalcaemia. A bone biopsy, obtained immediately before surgical parathyroidectomy after 3 months of cinacalcet treatment, revealed no disappearance of osteoclasts. These data suggest that cinacalcet hydrochloride treatment may induce a marked promotion of bone formation by mechanisms distinct from hungry bone syndrome that usually develops after parathyroidectomy.