Eplerenone nanocrystals engineered by controlled crystallization for enhanced oral bioavailability.

Poor aqueous solubility of eplerenone (EPL) is a major obstacle to achieve sufficient bioavailability after oral administration. In this study, we aimed to develop and evaluate eplerenone nanocrystals (EPL-NCs) for solubility and dissolution enhancement. D-optimal combined mixture process using Design-Expert software was employed to generate different combinations for optimization. EPL-NCs were prepared by a bottom-up, controlled crystallization technique during freeze-drying. The optimized EPL-NCs were evaluated for their size, morphology, thermal behavior, crystalline structure, saturation solubility, dissolution profile, in vivo pharmacokinetics, and acute toxicity. The optimized EPL-NCs showed mean particle size of 46.8 nm. Scanning electron microscopy revealed the formation of elongated parallelepiped shaped NCs. DSC and PXRD analysis confirmed the crystalline structure and the absence of any polymorphic transition in EPL-NCs. Furthermore, EPL-NCs demonstrated a 17-fold prompt increase in the saturation solubility of EPL (8.96 vs. 155.85 µg/mL). The dissolution rate was also significantly higher as indicated by ∼95% dissolution from EPL-NCs in 10 min compared to only 29% from EPL powder. EPL-NCs improved the oral bioavailability as indicated by higher AUC, Cmax, and lower Tmax than EPL powder. Acute oral toxicity study showed that EPL-NCs do not pose any toxicity concern to the blood and vital organs. Consequently, NCs prepared by controlled crystallization technique present a promising strategy to improve solubility profile, dissolution velocity and bioavailability of poorly water-soluble drugs.

Lipid-based nano-formulation platform for eplerenone oral delivery as a potential treatment of chronic central serous chorioretinopathy: in-vitro optimization and ex-vivo assessment.

PURPOSE: Eplerenone (EPL) is a selective mineralocorticoid receptor antagonist used for treatment of chronic central serous chorioretinopathy which characterized by accumulation of subretinal fluid causing a localized area of retinal detachment. unfortunately, EPL suffers from poor oral bioavailability due to poor aqueous solubility in addition to high hepatic first pass metabolism. METHOD: Aiming to improve its oral bioavailability, EPL-loaded nanostructured lipid carriers (NLCs) were prepared by the emulsification solvent evaporation method and in-vitro evaluated for particle size (PS), polydispersity index (PDI), zeta potential (ZP), and entrapment efficiency (EE%). A D-optimal design was used for study the effect of liquid lipid to solid lipid ratio, surfactant type and percentage on PS, PDI, EE%, and for data optimization. The optimized EPL-loaded NLCs system was further evaluated using in-vitro drug release and ex-vivo permeation studies through rabbit intestine in comparison to EPL aqueous suspension. The physicochemical properties of the drug in the optimized system were further examined using FT-IR and X-ray diffraction studies. RESULTS: The resultant NLCs showed small PS (100.85-346.60 nm), homogenous distribution (0.173-0.624), negatively charged particles (ZP -20.20 to -36.75 mV), in addition to EE% (34.31-70.64%). The optimized EPL-loaded NLCs system with a desirability value of 0.905 was suggested through the Design expert® software, containing liquid to solid lipid ratio (2:1) in presence of 0.43%w/v Pluronic® F127 as a surfactant. The optimized EPL-loaded NLCs system showed a PS of 134 nm and PDI of 0.31, in addition to high EE% (76 ± 6.56%w/w), and ZP (-32.37 mV). The ex-vivo permeation study showed two-fold higher drug permeation through rabbit intestine compared to that from the aqueous drug suspension after 24 h, confirming the ability of optimized EPL-loaded NLCs system as successful oral targeting delivery carrier. CONCLUSION: Our results pave the way for a new oral nanotherapeutic approach toward CSCR treatment. In-vivo study is currently under investigation.

Renal function stratified dose comparisons of eplerenone versus placebo in the EMPHASIS-HF trial.

BACKGROUND: Current heart failure guidelines recommend target eplerenone dose of 50 mg/day. We have examined the effect of different eplerenone doses based on pre-specified renal function stratification in the Eplerenone in Mild Patients Hospitalization and Survival Study in Heart Failure (EMPHASIS-HF). METHODS AND RESULTS: In EMPHASIS-HF, the target dose of eplerenone/placebo was stratified at randomization according to estimated glomerular filtration rate (eGFR): 50 mg/day if eGFR ≥ 50 mL/min/1.73 m2 and ≤ 25 mg/day if eGFR 30-49 mL/min/1.73 m2 . Patients remained within these dose ranges during the trial (as per stratification). The primary outcome was a composite of heart failure hospitalization or cardiovascular mortality. Eplerenone was superior to placebo within each respective eGFR stratum [eplerenone vs. placebo in the eGFR ≥ 50 mL/min/1.73 m2 stratum: hazard ratio (HR) 0.58, 95% confidence interval (CI) 0.45-0.74; and eplerenone vs. placebo in the eGFR 30-49 mL/min/1.73 m2 stratum: HR 0.62, 95% CI 0.49-0.78; Pinteraction = 0.89]. Despite receiving lower eplerenone doses, patients in the eGFR 30-49 mL/min/1.73 m2 stratum more often had hyperkalaemia, renal failure events, and drug discontinuation. CONCLUSION: In EMPHASIS-HF the eplerenone dose was stratified according to renal function and the treatment effect was not influenced by renal function: 25 mg/day in patients with eGFR 30-49 mL/min/1.73 m2 was as effective as 50 mg/day in patients with eGFR > =50 mL/min/1.73 m2 . However, patients with impaired renal function experienced more adverse events, despite reveiving lower eplerenone doses. Current guidelines do not recommend tailoring the dose of eplereone according to renal function but the current data suggest they should.

Clinical safety, tolerability, pharmacokinetics and effects on urinary electrolyte excretion of AZD9977, a novel, selective mineralocorticoid receptor modulator.

AIMS: AZD9977 is the first mineralocorticoid receptor modulator in clinical development exerting similar organ protection as eplerenone with minimal urinary electrolyte effects in preclinical studies. The aim was to perform the initial clinical assessment of AZD9977. METHODS: A first-in-human trial explored doses from 5 to 1200 mg. To study effects on urinary electrolyte excretion an additional randomized placebo controlled cross-over four-period clinical trial was performed. Twenty-three healthy volunteers were administered fludrocortisone alone or in combination with AZD9977, eplerenone or both. AZD9977/eplerenone combination was given to assess if AZD9977 can attenuate eplerenone induced natriuresis. RESULTS: AZD9977 at doses from 5 to 1200 mg was safe and well tolerated and pharmacokinetics were compatible with further development. AZD9977 exhibited similar effects on urinary ln [Na+ ]/[K+ ] as eplerenone when using fludrocortisone as mineralocorticoid receptor agonist, and the combination had an additive effect on ln [Na+ K+ ]. CONCLUSIONS: The results in man contradict the results in rodent models driven by aldosterone, in which AZD9977 has minimal electrolyte effects. Future clinical studies with AZD9977 should be performed in presence of endogenous or exogenous aldosterone to assess potential benefit of AZD9977 in patients.