Applying Different Techniques to Improve the Bioavailability of Candesartan Cilexetil Antihypertensive Drug

In Vitro and in vivo characterization of nasal pH-Responsive in-situ hydrogel of Candesartan-loaded invasomes as a potential stroke treatment

Candesartan (CDN) is a useful anti-stroke medication because it lowers blood pressure, inflammation, oxidative stress, angiogenesis and apoptosis. However, CDN has limited efficacy due to its low solubility and poor bioavailability. This study set out to develop nasal pH-responsive in situ hydrogel of CDN-loaded invasomes a (PRHCLI) for enhancing CDN's release, penetration, bioavailability, and effectiveness as a possible treatment for stroke. Based on the results of the pre-formulation investigation, the optimum CLI formulation for intravasomal delivery of CDN was determined to be 3% of phospholipid, 0.16% of cholesterol, 3% of ethanol, and 1% of cineole. The optimum formulation significantly enhanced CDN permeation and release by 2.06-fold and 59.06%, respectively. The CLI formulation was added to a mixture of chitosan (0.67%w/v) and glyceryl monooleate (0.27%v/v) to develop PRHCLI. The PRHCLI formulation enhanced the release and permeation of CDN relative to free CDN by 2.15 and 2.76 folds, respectively. An experimental rat stroke model was utilized for in vivo studies to evaluate the bioavailability, effectiveness, and toxicity of the PRHCLI formulation. The nasal PRHCLI drops increased the CDN's bioavailability by 3.20-fold compared to oral free CDN. Increased grip strength and decreased flexion, spontaneous motor activity, and Morris Water Maze scores in comparison to oral free CDN showed that nasal PRHCLI drops have better anti-stroke activity. The toxicity evaluation revealed the safety of nasal PRHCLI. Hence, nasal PRHCLI drops may represent a promising avenue as a stroke therapy.

Functional candesartan loaded lipid nanoparticles for the control of diabetes-associated stroke: In vitro and in vivo studies

Diabetes mellitus is a metabolic disease that raises the odds of developing stroke. Candesartan has been used to prevent stroke due to its inhibitory effects on blood pressure, angiogenesis, oxidative damage, and apoptosis. However, oral candesartan has very limited bioavailability and efficacy due to its weak solubility and slow release. The study aimed to develop a nasal formulation of candesartan-loaded liposomes containing ethanol and propylene glycol (CLEP) to improve candesartan's delivery, release, permeation, and efficacy as a potential diabetes-associated stroke treatment. Using design expert software, different CLEP formulations were prepared and evaluated in vitro to identify the optimum formulation, which. The selected optimum formulation composed of 3.3% phospholipid, 10% ethanol, and 15% propylene glycol significantly increased the release and permeation of candesartan relative to free candesartan by a factor of 1.52 and 1.47, respectively. The optimum formulation significantly reduced the infarction after stroke in rats; decreased flexion, spontaneous motor activity, and time spent in the target quadrant by 70%, 64.71%, and 92.31%, respectively, and enhanced grip strength by a ratio of 2.3. Therefore, nasal administration of the CLEP formulation could be a potential diabetes-associated stroke treatment.

Pharmacokinetics and bioequivalence study of candesartan cilexetil tablet in Chinese volunteers under fasting condition: an open-label, randomized-sequence, 2-period crossover study

Candesartan is an antihypertensive agent that acts on an angiotensin II receptor. Candesartan cilexetil is a prodrug that is converted into the active form of candesartan during intestinal absorption. This study aimed to assess the pharmacokinetics and bioequivalence of a reference and a test formulation of candesartan cilexetil tablets in healthy Chinese volunteers. A randomized, open-label, single-dose, crossover study was conducted with two treatment periods. Forty-eight healthy Chinese volunteers participated under fasted conditions. Qualified subjects were randomly divided into two groups (1:1 ratio) to receive either the test or reference formulation first. A washout period of 14 days separated the administration of the two formulations. Blood samples were collected at specific time points and analyzed for candesartan concentration using Ultra High-Performance Liquid Chromatography Tandem Mass Spectrometry (UPLC-MS/MS). The maximum concentration (Cmax), the AUC from time zero to the last measured time point (AUC0-t) and the AUC from time zero to infinity (AUC0-∞) fell within the bioequivalence range of 80% to 125%. These results suggest that the test and reference formulations of candesartan cilexetil tablets are bioequivalent, meaning they have similar rates and extents of absorption in healthy Chinese volunteers. No serious adverse events or side effects were reported throughout the study.

Nanotechnology-Based Strategies for Extended-Release Delivery of Angiotensin Receptor Blockers (ARBs): A Comprehensive Review

There has been a significant shift in the perception of hypertension as an important contributor to the global disease burden. Approximately 6 % and 8 % of pregnancies are affected by hypertension, which can adversely affect the mother and the fetus. Furthermore, a hypertensive individual is at increased risk of developing kidney disease, arterial hardening, eye damage, and strokes. Using angiotensin receptor blockers (ARBs) is widespread in treating hypertension, heart failure, coronary artery disease, and diabetic nephropathy. Despite this, some ARBs have limited use due to their poor oral bioavailability and water solubility. To tackle this, a variety of nanoparticle (NP)-based systems, such as polymeric NPs (i. e., dendrimers), polymeric micelles, polymer-drug conjugates, lipid NPs, nanoemulsions, self-emulsifying drug delivery systems (SEDDS), solid lipid NPs (SLNs), nanostructured lipid carriers (NLCs), carbon-based nanocarriers, inorganic NPs, and nanocrystals, have been recently developed for efficient delivery of losartan, Valsartan (Val), Olmesartan (OLM), Telmisartan (TEL), Candesartan, Eprosartan, Irbesartan, and Azilsartan to target cells. This review article provides a literature-based comparison of the various classes of ARBs, their mechanisms of action, and an overview of the nanoformulations developed for ARB delivery and successfully applied to managing hypertension, diabetic complications, and other conditions.

Candesartan exhibits low intrinsic permeation capacity and affects buccal tissue viability and integrity: An ex vivo study in porcine buccal mucosa

Candesartan is a nonpeptide angiotensin II receptor blocker that selectively binds to angiotensin II receptor subtype 1. It is administered orally in its ester form (candesartan cilexetil). However, its poor aqueous solubility results in its low bioavailability; therefore, other routes of administration must be explored. The buccal mucosa has been extensively studied as an alternative route for drug delivery as it improves the bioavailability of drugs administered via the peroral route. Porcine buccal mucosa has been widely used as an ex vivo model to study the permeability of various diffusants; however, studies on candesartan are limited. This study aimed to evaluate the ex vivo permeation profile of candesartan and its effects on the viability and integrity of porcine buccal mucosa. Initially, we evaluated the viability, integrity, and barrier function of the buccal tissue before performing permeability tests using freshly excised tissues or tissues after 12 h of resection. Here, three indicators were used: caffeine, β-estradiol, and FD-20 penetration; mucosal metabolic activity, as determined using MTT reduction assay; and haematoxylin and eosin staining. Our results indicated that the porcine buccal mucosa preserved its viability, integrity, and barrier function before the permeation assay, allowing the passage of molecules with a molecular mass of less than 20 kDa, such as caffeine, but not β-estradiol and FD-20. Furthermore, we analyzed the intrinsic capacity of candesartan to diffuse through the fresh porcine buccal mucosa under two pH conditions. The concentration of candesartan in the receptor chamber of Franz diffusion cell was quantified using ultra-high liquid chromatography. In the permeation assay, candesartan exhibited a low intrinsic permeation capacity that impacted the buccal tissue viability and integrity, suggesting that using the buccal mucosa as an alternative route of administration requires developing a pharmaceutical formulation that reduces the adverse effects on mucosa and increasing the buccal permeability of candesartan.

Liquid antisolvent crystallization of pharmaceutical compounds: current status and future perspectives

The present work reviews the liquid antisolvent crystallization (LASC) to prepare the nanoparticle of pharmaceutical compounds to enhance their solubility, dissolution rate, and bioavailability. The application of ultrasound and additives is discussed to prepare the particles with narrow size distribution. The use of ionic liquid as an alternative to conventional organic solvent is presented. Herbal compounds, also known for low aqueous solubility and limited clinical application, have been crystalized by LASC and discussed here. The particle characteristics such as particle size and particle size distribution are interpreted in terms of supersaturation, nucleation, and growth phenomena. To overcome the disadvantage of batch crystallization, the scientific literature on continuous flow reactors is also reviewed. LASC in a microfluidic device is emerging as a promising technique. The different design of the microfluidic device and their application in LASC are discussed. The combination of the LASC technique with traditional techniques such as high-pressure homogenization and spray drying is presented. A comparison of product characteristics prepared by LASC and the supercritical CO₂ antisolvent method is discussed to show that LASC is an attractive and inexpensive alternative for nanoparticle preparation. One of the major strengths of this paper is a discussion on less-explored applications of LASC in pharmaceutical research to attract the attention of future researchers.

A developed composite hard-gelatin capsules: delayed-release enteric properties

Present study focused on improvement of the formulation of conventional hard gelatin capsules using gastric acid-resistant polymers. We have utilized the same approach of making conventional drug capsules to develop novel capsules with delayed release properties. For this purpose, delayed-release capsules were produced by improving the formulation of hard gelatin capsules. In addition, the effect of adding intestinal polymers such as Hydroxy propyl methyl cellulose phthalate, Glucomannan, and Polyvinyl alcohol to hard gelatin capsules were investigated. The capsules' release rate was determined. The degradation tests in an acidic environment were performed and the results were recorded. In fact, the delayed-release hard gelatin capsules pass through the stomach with small amount of the drug release; but their shell remains intact and dissolves as it enters the intestine environment. This article shows that enteric polymers with out interactions, only by changing the formulations will have delayed release properties. this makes sensitive drugs pass through stomach environment and have higher absorption.

Effect of Soluplus® on γ-cyclodextrin solubilization of irbesartan and candesartan and their nanoaggregates formation

The poor aqueous solubility of irbesartan (IRB) and candesartan cilexetil (CAC) may hamper their bioavailability when orally or topically administered. Among several attempts, the promising nanoaggregate formation by γ-cyclodextrin (γCD) complexation of drugs in aqueous solution with or without water-soluble polymers was investigated. According to phase solubility studies, Soluplus® showed the highest complexation efficiency (CE) of drug/γCD complexes among the polymers tested. The aqueous solubility of IRB and CAC was markedly increased as a function of Soluplus^® concentrations. The binary drug/γCD and ternary drug/γCD/Soluplus^® complex formations were supported and confirmed by solid-state characterizations, including differential scanning calorimetry (DSC), powder X-ray diffraction (PXRD), and Fourier transform infrared (FT-IR) spectroscopy. The true inclusion mode was also proved by proton nuclear magnetic resonance (¹H-NMR) spectroscopy. The nanoaggregate size and morphology of binary and ternary systems were observed using dynamic light scattering (DLS), and transmission electron microscopy (TEM) techniques. The size of these nanocarriers depends on the concentration of Soluplus^®. The use of Soluplus^® could significantly enhance drug solubility and stabilize complex nanoaggregates, which could be a prospective platform for drug delivery systems.

Formulation and Bioavailability of Novel Mucoadhesive Buccal Films for Candesartan Cilexetil in Rats

Candesartan cilexetil (CC) is an antihypertensive drug. It has low solubility and faces hepatic first-pass metabolism after oral ingestion. We formulated bioadhesive buccal films and studied the respective drug pharmacokinetics. Different bioadhesive films were prepared (40, 80, 120, 160, 200, and 240 mg CC per film) by using the solvent casting method. The drug concentrations used affect the drug entrapment mechanism, which was reflected in the film physicochemical properties like thickness, weight, drug content, bioadhesion, and drug release. Low drug concentration (F2, 40 mg per film) led to minute drug crystal dispersion while increasing the drug concentration (F7, 240 mg per film) showed drug crystal encapsulation, which affects the drug release. The drug pharmacokinetic from the prepared films was studied compared to the oral form by serial blood sampling via an inserted catheter in the carotid of rats. High-Performance Liquid Chromatography assay was used to measure the plasma concentration of CC in different forms. Compared to other films, the F2 showed the highest maximal concentration (Cmax) and the lowest elimination half-life (t_1/2). Bioadhesion buccal film of CC has better bioavailability, especially at low concentrations. The ease, robustness, and ruggedness of the preparation suggests the same procedure for drugs like CC.

New Peceol™/Span™ 60 Niosomes Coated with Chitosan for Candesartan Cilexetil: Perspective Increase in Absolute Bioavailability in Rats

PURPOSE

Candesartan cilexetil (CC), a prodrug of candesartan (CDT), is a class II BCS drug that suffers from poor oral bioavailability because of low aqueous solubility, P-gp efflux and first-pass metabolism. The absolute bioavailability reported for CC was only 15% and the methods to increase it remain elusive, thus the aim of our work was to prepare new CC-loaded niosomes encompassing, for the first time, glycerol monooleate GMO (Peceol™), as P-gp efflux inhibitor and promoter of lymphatic transport with Span™ 60 as bioenhancer. The prepared niosomes were further coated with chitosan for augmenting the CC oral absorption.

METHODS

The niosomes were prepared by thin film hydration method through quality by design approach, using two levels of each of three critical process parameters (CPPs), namely, XA (the molar ratio of surfactant mixture to cholesterol) at a ratio of 1:1 or 2:1; XB (the molar ratio of Span™ 60 to Peceol™) at a ratio of 1:1 or 2:1; and XC (the drug amount) at 15 mg or 30 mg. The investigated critical quality attributes (CQAs) were entrapment efficiency percent, particle size, and polydispersity index. The optimized uncoated and chitosan coated formulations were subjected to DSC and stability study. In vitro drug release, biocompatibility with Caco-2 cells and lastly the absolute bioavailability evaluation in rats were assessed.

RESULTS

The physical properties of the optimized and stable niosomes were satisfactory. The ingredients were compatible with each other and biocompatible with Caco-2 cells. The synergistic combination of Peceol™ and Span™ 60 probably surmounted the P-gp efflux with an increase in oral absolute bioavailability of niosomes to five times that of CC suspension.

CONCLUSION

The new niosomal formulations of CC containing Peceol™ with Span™ 60 and cholesterol either uncoated or coated with chitosan were a successful paradigm in achieving high oral absolute bioavailability and increased Caco-2 cells biocompatibility.

Solid Dispersion: A Mechanistic and Realistic Approach on Antihypertensive Drug as a Drug Carrier System

A major percentage of the new chemical entities are reported to have poor aqueous solubility. Several antihypertensive drugs used clinically have either low solubility or high hepatic metabolism, thereby presenting low bioavailability (BA) and high pharmacokinetic variability. Improving the aqueous solubility of drug molecules would assist in overcoming the variability, and several approaches for improving solubility have been reported. Solid dispersion (SD) is known as a potential technique to conquer the problem of poor aqueous solubility and low BA. Drug solubility is improved by increasing the wetting property of drugs. This review is focused on discussing various approaches to improve solubility, classification, and different approaches used for formulation of SDs, along with special emphasis on the application of the SD approach for improving solubility and eventually enhancing dissolution and increasing the BA of antihypertensive drugs. The review leads to the conclusion that the use of more than one polymeric carrier for formulating SDs might help in overcoming storage and stability issues and in increasing the commercial viability and success of SDs.