Pharmacokinetic Comparison of a Fixed-Dose Combination of Candesartan Cilexetil/Amlodipine/Atorvastatin Versus Co-administration of Individual Formulations in Healthy Participants

INTRODUCTION

Fixed-dose combinations (FDCs) of angiotensin II receptor blockers, calcium channel blockers, and statins are conventional therapeutic interventions prescribed for cardiovascular diseases. This study aimed at drawing a comparison between the pharmacokinetics and safety of an FDC and the corresponding individual formulations in healthy subjects.

METHODS

A randomized, open-label, single-dose, three-sequence, three-period, partially repeated crossover study was conducted with a cohort of healthy volunteers. A 14-day washout period was maintained between each of the three periods. In this study, candesartan cilexetil, amlodipine, and atorvastatin was administered orally as FDCs of 16/10/40 mg in study 1 and 16/5/20 mg in study 2. The maximum plasma concentration (Cmax) and area under the plasma concentration-time curve from time zero to the time of the last quantifiable concentration (AUClast) of candesartan, amlodipine, and atorvastatin were estimated as the geometric mean ratios (GMRs) and 90% confidence intervals (CIs) of the FDC to individual formulations. If the within-subject coefficient of variation (CVwr) of Cmax was greater than 0.3, the bioequivalence (BE) range calculated using the reference-scaled average bioequivalence was used to assess whether the 90% CI was within the BE range.

RESULTS

The GMRs (90% CIs) for the AUClast for candesartan and amlodipine were 0.9612 (0.9158-1.0089)/0.9965 (0.9550-1.0397) and 1.0033 (0.9800-1.0271)/1.0067 (0.9798-1.0344), and the GMRs (90% CIs) for Cmax were 0.9600 (0.8953-1.0294)/0.9851 (0.9368-1.0359) and 1.0198 (0.9950-1.0453)/1.0003 (0.9694-1.0321) in studies 1 and 2, respectively. The extended BE ranges calculated from the CVwr of the Cmax of atorvastatin were 0.7814-1.2797 and 0.7415-1.3485, respectively. The GMRs (90% CIs) for the AUClast of atorvastatin were 1.0532 (1.0082-1.1003)/1.0252 (0.9841-1.0680), and the GMRs (90% CIs) for Cmax were 1.0630 (0.9418-1.1997)/0.9888 (0.8792-1.1120) in studies 1 and 2, respectively.

CONCLUSION

The Cmax and AUClast values of candesartan cilexetil/amlodipine/atorvastatin 16/10/40 mg and 16/5/20 mg, respectively, were within the BE ranges. There were no clinically significant differences in safety between the two formulations.

TRIAL REGISTRATION

ClinicalTrials.gov identifier, study 1: NCT04478097; study 2: NCT04627207.

Solusomes (novel soluplus® enriched nano-vesicular carriers) for improving the oral bioavailability of Candesartan cilexetil

Candesartan cilexetil (CAN) is administered for treating hypertension and heart failure. CAN suffers poor oral bioavailability, owing to limited aqueous solubility, and first-pass metabolism. Solusomes (novel Soluplus® enriched nano-vesicular carriers) combine the merits of Soluplus®, and the traditional liposomes. They were explored to increase CAN solubility, allow a high drug release rate, and improve the oral drug bioavailability. Solusomes were developed via thin film hydration technique utilizing lipid (phosphatidylcholine; PC) and polymeric solubilizer (Soluplus®; Solu). S6 system comprising PC (0.1% w/v), CAN and Soluplus® (at 1:5 ratio; w/w), following a 5 min sonication period, was the optimum one with respect to drug entrapment efficiency (83.5 ± 2.6%), drug loading (11.9 ± 0.3%), particle size and shape (377.2 ± 12.1 nm, spherical), zeta-potential (-19.6 ± 2.1 mV), saturated drug solubility (32.09 ± 0.71 µg/mL), drug released % after 1 h (68 ± 0.9%), and stability. Significantly higher Cmax (969.12 ± 46.3 ng/mL), shorter median Tmax (1h), and improved relative bioavailability (≈ 6.8 folds) in rabbits could evidence the potential of S6 system in enhancing oral CAN bioavailability. S6 solusomes act as dual platform to improve the oral drug bioavailability and maintain effective drug concentration for a prolonged period.

Candesartan cilexetil ameliorates NOSTRIN-NO dependent portal hypertension in cirrhosis and ACLF

In decompensated cirrhosis, the severity of portal hypertension (PHT) is associated with increased hepatic endothelial nitric oxide synthase (eNOS) trafficking inducer (Nostrin), but the mechanism remains unclear. AIM: To investigate: (1) Whether in cirrhosis-PHT models, ± superimposed inflammation to mimic acute-on-chronic liver failure (ACLF) modulates hepatic nitric oxide synthase trafficking inducer (NOSTRIN) expression, nitric oxide (NO) synthesis, and/or endothelial dysfunction (ED); and (2) Whether the "angiotensin II type 1 receptor blocker" candesartan cilexetil (CC) affects this pathway. CD-1 mice received intraperitoneal carbon tetrachloride injections (CCl4 15% v/v in corn oil, 0.5 mL/kg) twice weekly for 12 wk to induce cirrhosis. After 12 wk, mice were randomized to receive 2-wk oral administration of CC (8 mg/kg) ± LPS. At sacrifice, plasma (biochemical indicators, cytokines, and angiotensin II) and liver tissues (histopathology, Sirius-red stains, and molecular studies) were analysed. Moreover, Nostrin gene knockdown was tested in human umbilical vein endothelial cells (HUVECs). When compared to naïve animals, CCl4-treated animals showed markedly elevated hepatic Nostrin expression (P < 0.0001), while hepatic peNOS expression (measure of eNOS activity) was significantly reduced (P < 0.05). LPS challenge further increased Nostrin and reduced peNOS expression (P < 0.05 for both) in cirrhotic animals. Portal pressure and subsequent hepatic vascular resistance were also increased in all cirrhotic animals following LPS challenge. In CCl4 ± LPS-treated animals, CC treatment significantly reduced Nostrin (P < 0.05) and increased hepatic cGMP (P < 0.01). NOSIP, caveolin-1, NFκB, and iNOS protein expression were significantly increased in CCl4-treated animals (P < 0.05 for all). CC treatment non-significantly lowered NOSIP and caveolin-1 expression while iNOS and NFκB expression was significantly reduced in CCl4 + LPS-treated animals (P < 0.05 for both). Furthermore, Nostrin knockdown significantly improved peNOS expression and associated NO synthesis and reduced inflammation in HUVECs. This study is the first to indicate a potential mechanistic role for the Nostrin-eNOS-NO pathway in cirrhosis and ACLF development. Moreover, this pathway provides a potential therapeutic target given the ameliorative response to Candesartan treatment.

Supersaturating drug delivery systems containing fixed-dose combination of two antihypertensive drugs: Formulation, in vitro evaluation and molecular metadynamics simulations

The purpose of this study was to associate the poorly water-soluble antihypertensive drugs candesartan cilexetil (CC) and hydrochlorothiazide (HCTZ) as fixed-dose combination, in the form of ternary Amorphous Solid Dispersions (ASD), using hydroxypropylmethylcellulose acetate succinate (HPMCAS) type M as polymeric carrier. The potential of the system to generate and to maintain supersaturation of both drugs was also evaluated. The ASDs were prepared by ball milling technique and solid-state characterization was performed by differential scanning calorimetry (DSC), Fourier transformed infrared spectroscopy (FTIR) and X-ray powder diffraction (XRPD). Interaction between drugs and polymer in solid-state was evaluated by molecular metadynamics simulations. In vitro supersaturation profiles were determined in biorelevant medium. Physicochemical stability of ASDs was also evaluated under different storage conditions. Amorphization of both drugs was confirmed by solid-state characterization techniques. Molecular metadynamics simulations indicated that CC has stronger interaction with HMPCAS than HCTZ. In vitro supersaturation studies have shown that ternary ASDs could generate and maintain supersaturation of both drugs in biorelevant medium. The polymer reduced the desupersaturation of both drugs. Ternary ASDs also showed physicochemical stability over a period of 90 days, demonstrating the potential of the polymer in reducing the drugs recrystallization over the time. Ternary ASDs of CC, HCTZ and HPMCAS can be considered a promising system to associate the drugs as fixed-dose combinations. Also, these systems generate and maintain supersaturation of both drugs in biorelevant medium, with great storage stability. HPMCAS M was a good carrier for reducing the desupersaturation of associated HCTZ and CC.

Effect of surfactants and hydrophilic polymers on the stability of an antihypertensive drug candesartan cilexetil: Evaluation by HPLC

OBJECTIVES

The objective of this study is to investigate the effect of surfactants (polysorbate 80 and sodium lauryl sulphate) and hydrophilic polymers (polyvinylpyrrolidone and polyethylene glycol 6000) on the stability of candesartan cilexetil under isothermal stress conditions (100°C, 48h).

METHODS

HPLC method was employed to evaluate the drug content and formation of degradation products in stress samples. Drug and degradation products were separated on Hypersil BDS C18 (250×4.6mm, 5μ) column using acetonitrile-water (pH 2.8) in the ratio of 85:15% v/v as a mobile phase.

RESULT

Similar degradation behaviour of drug was observed with polyvinylpyrrolidone, polyethylene glycol 6000 and polysorbate 80; four common degradation peaks were observed at the retention time of 3.7, 4.5, 7.8 and 11minutes. One extra common degradation peak of very low intensity was also observed with polyethylene glycol 6000 and polysorbate 80 at the retention time of 4.2min. The drug was eluting at the retention time of 5.4min. In the case of sodium lauryl sulphate, two prominent degradation peaks were observed at the retention time of 3.7 and 13.25min along with few very low-intensity degradation peaks.

CONCLUSION

The drug showed 41%, 64%, 72% and 98% degradation in presence of polyvinylpyrrolidone, polyethylene glycol 6000, polysorbate 80 and sodium lauryl sulphate, respectively.

Development and in vitro/in vivo performance of self-nanoemulsifying drug delivery systems loaded with candesartan cilexetil

Candesartan cilexetil is widely used in the management of hypertension and heart failure. The drug delivery encounters obstacles of poor aqueous solubility, efflux by intestinal P-glycoprotein and vulnerability to enzymatic degradation in small intestine. Self-nanoemulsifying drug delivery systems (SNEDDS) loaded with candesartan cilexetil were successfully developed to overcome such obstacles. Preliminary screening was carried out to select proper surfactant, co-surfactant and oil combination for successful SNEDDS formulation. All screened excipients were reported for their P-glycoprotein and cytochrome P450 3A4 (CYP3A4) modulation activity. Ternary and pseudo ternary diagrams were constructed to optimize the system. Peppermint oil and clove oil showed a high emulsification ability. The nature of obtained dispersions was identified to be nanoemulsions. Twenty-four formulations were evaluated for stability, robustness to dilution and self-emulsification efficiency. All formulations showed a very short emulsification time of <2min. The emulsification efficiency was significantly superior at pH6.8, at which the largest self-emulsifying region was also observed. Eight formulations were selected for further characterization according to cloud point measurement; mean droplet size, poly dispersity index (PDI) and zeta potential determination in addition to in vitro drug release study. All selected formulations showed very high cloud points (70-90°C), ultrafine mean droplet size (12±1.4 to 24.5±2.13nm), very low PDI values (0.015-0.1305) and almost a complete drug release after 12h. Formulation F15 (Peppermint oil 55% w/w: Cremophor RH40 25% w/w: Labrasol 20% w/w) was selected for further characterization. Its droplet size showed robustness to different dilution folds with different media and its TEM photograph showed spherical particles without any apparent aggregation even after 24h. Formulation F15 successfully controlled the systolic blood pressure of hypertensive rats for 24h with the maximum effect was observed after 2h. These results indicate that, SNEDDS could be promising delivery systems with a rapid onset of action and prolonged therapeutic effect of candesartan cilexetil.

Improved simultaneous quantitation of candesartan and hydrochlorthiazide in human plasma by UPLC-MS/MS and its application in bioequivalence studies

A validated ultra-performance liquid chromatography mass spectrometric method (UPLC–MS/MS) was used for the simultaneous quantitation of candesartan (CN) and hydrochlorothiazide (HCT) in human plasma. The analysis was performed on UPLC–MS/MS system using turbo ion spray interface. Negative ions were measured in multiple reaction monitoring (MRM) mode. The analytes were extracted using a liquid–liquid extraction (LLE) method by using 0.1 mL of plasma volume. The lower limit of quantitation for CN and HCT was 1.00 ng/mL whereas the upper limit of quantitation was 499.15 ng/mL and 601.61 ng/mL for CN and HCT respectively. CN d₄ and HCT-¹³Cd₂ were used as the internal standards for CN and HCT respectively. The chromatography was achieved within 2.0 min run time using a C18 Phenomenex, Gemini NX (100 mm×4.6 mm, 5 µm) column with organic mixture:buffer solution (80:20, v/v) at a flow rate of 0.800 mL/min. The method has been successfully applied to establish the bioequivalence of candesartan cilexetil (CNC) and HCT immediate release tablets with reference product in human subjects.

Enhanced solubility and intestinal absorption of candesartan cilexetil solid dispersions using everted rat intestinal sacs

OBJECTIVE

Candesartan cilexetil (CAN) is a poor aqueous soluble compound and a P-glycoprotein (P-gp) efflux pump substrate. These key factors are responsible for its incomplete intestinal absorption.

METHODS

In this study, we investigated to enhance the absorption of CAN by improving its solubility and inhibiting intestinal P-gp activity. A phase solubility method was used to evaluate the aqueous solubility of CAN in PVP K30 (0.2-2%). Gibbs free energy [Formula: see text] values were all negative. Solubility was enhanced by the freeze drying technique. The in vitro dissolution was evaluated using the USP paddle method. The interaction between drug and carrier was evaluated by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and Differential scanning calorimetry (DSC) studies. Naringin was selected as P-gp inhibitor. Absorption studies were performed using the everted gut sac model from rat jejunum. The drug analysis was performed by HPLC.

RESULTS

FTIR spectra revealed no interaction between drug and PVP K30. From XRD and DSC data, CAN was in the amorphous form, which explains the cumulative release of drug from its prepared systems. We noticed an enhancement of CAN absorption by improving its solubility and inhibiting the P-gp activity. The significant results (p < 0.05) were obtained for freeze dried solid dispersions in the presence of P-gp inhibitor than without naringin (15 mg/kg) with an absorption enhancement of 8-fold.

CONCLUSION

Naringin, a natural flavonoid, has no undesirable side effects. Therefore, it could be employed as an excipient in the form of solid dispersions to increase CAN intestinal absorption and its oral bioavailability.

Development and characterization of controlled release polar lipid microparticles of candesartan cilexetil by solid dispersion

Candesartan cilexetil (CC) is a newer class of angiotensin II receptor antagonist used for the treatment of hypertension. The solubility of the CC is very poor and its oral bioavailability is only 15%. The controlledrelease polar lipid microparticles of CC (formulations F1, F2, F3 and F4) were prepared using variable erodible lipophilic excipients like hydrogenated castor oil, stearic acid, cetostearyl alcohol and carnauba wax by fusion method. The particle sizes of polar lipid microparticles were less than 50 microns and they were irregular in shape. Drug content ranged between 98.96 ± 2.1 and 101.9 ± 1.6% were present in all the formulations. The formulation F3 showed better drug release throughout the study period in a controlled release manner. Moreover, the in vitro release showed that all the formulations were best fitted to Higuchi model. Accelerated stability studies indicated that there was no significant changes in the chemical and physical characteristics of the formulated drug product during initial and at the end of the study period. The FTIR and DSC studies showed that there was no interaction between the drug and lipophilic excipients and no polymorphic transitions in all formulations. The X-ray diffraction peak of solid dispersion indicated that the crystalline nature of CC disappeared and no new peaks could be observed, suggesting the absence of interaction between drug and excipients.

Development and Validation of a Stability-indicating UV Spectroscopic Method for Candesartan in Bulk and Formulations

A simple, specific, accurate and stability-indicating UV- Spectrophotometric method was developed for the estimation of candesartan cilexitil, using a Shimadzu, model 1700 spectrophotometer and a mobile phase composed of methanol: water in the ratio of 9:1 at wave length (λ(max)) 254 nm. Linearity was established for candesartan in the range of 10-90 μg/ml. The percentage recovery of was found to be in the range of 99.76-100.79%. The drug was subjected to acid, alkali and neutral hydrolysis, oxidation, dry heat, UV light and photolytic degradation. Validation experiments performed to demonstrate system suitability, specificity, precision, linearity, accuracy, interday assay, intraday assay, robustness, ruggedness, LOD, and LOQ. While estimating the commercial formulation there was no interference of excipients and other additives. Hence this method can be used for routine determination of candesartan cilexetil in bulk and their pharmaceutical dosage forms. The proposed method for stability study shows that there was appreciable degradation found in stress condition of candesartan.