Peceosomes for oral delivery of glibenclamide: In vitro in situ correlation

Olive oil and flaxseed oil incorporating niosomes for enhanced in vivo anti-diabetic efficacy of canagliflozin

BACKGROUND

Canagliflozin (CFZ) is broadly implicated for the management of type 2 diabetes mellitus. Unfortunately, it has low oral bioavailability due to poor solubility behavior and restricted membrane permeability.

OBJECTIVE

The current work focuses on development of CFZ encapsulated niosomes for enhanced oral anti-diabetic efficacy.

METHODOLOGY

Niosomes comprising Span 60 and cholesterol were formulated both in absence and presence of olive oil or flaxseed oil. These were evaluated in vitro for average vesicular size, structural morphology, CFZ entrapment efficiency, and drug release. Additionally, the oral hypoglycemic effect of CFZ encapsulated niosomes was explored in diabetic rats.

RESULTS

The fabricated niosomes were negatively charged spherical vesicles with a size range of 103.0-141.7 nm. These entrapped CFZ with efficiency ranging from 92.3% to 96.0%. Drug release investigations reflected that incorporating CFZ into niosomes significantly sustained drug release compared to the aqueous drug dispersion. Oral administration of niosomal formulations significantly enhanced the oral antidiabetic effect of CFZ. Comparing the tested niosomes, similar efficiency was shown eliminating the effect of composition.

CONCLUSION

The enhanced oral bioavailability of niosomes' encapsulated drugs is related to niosomal vesicular structure which allows intact niosomes absorption. The study presented niosomes as promising carriers for improved oral anti-diabetic activity of CFZ.

Surfactant nanovesicles for augmented antibacterial activity against carbapenemase resistant enterobacteriaceae and extended spectrum beta-lactamases producing bacteria: in vitro and in vivo evaluation

The ubiquitous emergence of bacterial resistance is a challenging problem in infectious diseases treatment. Recently, new research lines employed nano-drug delivery systems to enhance antibacterial activity of the existing antibiotics. Accordingly, the objective of this study is to optimize surfactant nanovesicles to improve the antimicrobial effect of meropenem, ertapenem and tigecycline against Carbapenemase Resistant Enterobacteriaceae (CRE) and extended spectrum beta-lactamases producing bacteria (ESBL). Klebsiella pneumoniae and Escherichia coli were used as the test organisms. In vivo and in vitro evaluations were conducted to prove the efficacy of niosome-encapsulated drugs formulations. The results revealed that surfactant vesicles were able to reduce the MIC values of the tested drugs by nine-fold change compared to their free forms. Scanning Electron Microscope (SEM) showed possible adhesion/fusion of the vesicles encapsulated drugs on the bacterial cells compared to its solution. In vivo investigations using animal skin model confirmed the superiority of nanovesicles drug encapsulation regarding both wound size and histopathological examination. Wound surface area was reduced from 24.6mm2 in absence of drug to reach 13.9, and 6.2mm2 in presence of ertapenem solution or niosomes, respectively. Nanovesicular formulations can be considered as effective drug delivery systems that can diminish bacterial resistance against β-lactams antibiotics.

Intestinal absorption pathways of lisinopril: Mechanistic investigations

Lisinopril is an antihypertensive drug with poor intestinal permeability. Enhancement of intestinal absorption depends on a clear understanding of the permeation pathways and absorption mechanisms. Unfortunately, these are not fully elucidated for lisinopril. Accordingly, the aim was to determine lisinopril permeation pathways and obstacles limiting membrane transport with subsequent nomination of appropriate permeation enhancers. This employed an in situ rabbit intestinal perfusion technique, which revealed site-dependent absorptive clearance (PeA/L) from a lisinopril simple solution (5 μg/ml), with paracellular absorption playing a role. Regional drug permeability ranked as colon> duodenum> jejunum> ileum opposing intestinal expression rank of P-glycoprotein (P-gp) efflux transporters. Duodenal and jejunal perfusion of a higher lisinopril concentration (50 μg/ml) reflected saturable absorption, suggesting carrier-mediated transport. The effect of piperine and verapamil as P-gp inhibitors on intestinal absorption of lisinopril was investigated. Coperfusion with either piperine or verapamil significantly enhanced lisinopril absorption, with enhancement being dominant in the ileum segment. This supported the contribution of P-gp transporters to poor lisinopril permeability. On the other hand, coperfusion of lisinopril with zinc acetate dihydrate significantly multiplied lisinopril PeA/L by 2.3- and 6.6-fold in duodenum and ileum segments, respectively, through magnifying intestinal water flux. The study explored the barriers limiting lisinopril intestinal absorption. Moreover, the study exposed clinically relevant lisinopril interactions with common coadministered cargos that should be considered for an appropriate lisinopril regimen. However, this requires further in vivo verification.

Permeation enhancers loaded bilosomes for improved intestinal absorption and cytotoxic activity of doxorubicin

The clinical utility of doxorubicin is compromised due to dose related toxic side effects and limited oral bioavailability with no oral formulation being marketed. Enhancement of intestinal absorption and magnification of cytotoxicity can overcome these limitations. Accordingly, the objective was to probe penetration enhancers, bilosomes and their combinations for enhanced intestinal absorption and improved cytotoxicity of doxorubicin. Piperine and dipyridamole were tested as enhancers alone or encapsulated in bilosomes comprising Span60, cholesterol and bile salts. Bilosomes were nanosized spherical vesicles with negative zeta potential and were able to entrap doxorubicin with efficiency ranging from 45.3 % to 53 %. Intestinal absorption studies utilized in-situ rabbit intestinal perfusion which revealed site dependent doxorubicin absorption correlating with regional distribution of efflux transporters. Co-perfusion with the enhancer increased intestinal absorption with further augmentation after bilosomal encapsulation. The latter increased the % fraction absorbed by 4.5-6 and 1.8-2.5-fold from jejuno-ileum and colon, respectively, depending on bilosomes composition. Additionally, doxorubicin cytotoxicity against breast cancer cells (MCF-7) was significantly improved after bilosomal encapsulation and the recorded doxorubicin IC₅₀ value was reduced from 13.3 μM to 0.1 μM for the best formulation. The study introduced bilosomes encapsulating absorption enhancers as promising carriers for enhanced cytotoxicity and oral absorption of doxorubicin.

Menthol augmented niosomes for enhanced intestinal absorption of lopinavir

Lopinavir is effective in treatment of HIV infection but experiences low oral bioavailability due to poor solubility, pre-systemic metabolism, and P-gp intestinal efflux. Co-processing with menthol enhanced its dissolution and intestinal permeability. Niosomes comprising Span 60, cholesterol and poloxamer 407 were formulated in absence and presence of menthol. These were evaluated for size, morphology, entrapment efficiency (EE%), lopinavir release and intestinal absorption. The later employed in situ rabbit intestinal absorption model. Niosomes were spherical with vesicle size of 140.2 ± 23 and 148.2 ± 27nm for standard and menthol containing niosomes, respectively. The EE% values were 94.4% and 96.3% for both formulations, respectively. Niosomes underwent slow release during the time course of absorption with menthol hastening lopinavir release, but the release did not exceed 9%. Niosmoal encapsulation enhanced lopinavir intestinal absorption compared with drug solution. This was reflected from the fraction absorbed from duodenum which was 24.15%, 73.09% and 83.23% for solution, standard niosomes and menthol containing vesicles, respectively. These values were 34.32%, 80.8% and 86.56% for the same formulations in case of jejuno-ileum. Lopinavir absorption from niosomes didn't depend on release supporting intact vesicle absorption. The study introduced menthol containing niosomes as carriers for enhanced lopinavir intestinal absorption.

Bilosomes as Nanoplatform for Oral Delivery and Modulated In Vivo Antimicrobial Activity of Lycopene

Owing to the disseminating resistance among pathogenic bacteria, especially Klebsiella pneumoniae, there is a high need for alternate compounds with antibacterial activity. Herein, lycopene was isolated from Lycopersicon esculentum L. Molecular docking approach was employed to explore lycopene binding affinity to selected vital proteins of K. pneumoniae with the binding mechanisms being investigated. This proposed a promising antibacterial activity of lycopene. However, the pharmacological use of lycopene is hampered by its poor solubility and limited oral bioavailability. Accordingly, bilosomes were fabricated for oral lycopene delivery. The computed entrapment efficiency, mean vesicular size, and zeta potential values for the optimized formulation were 93.2 ± 0.6%, 485.8 ± 35.3 nm, and −38.3 ± 4, respectively. In vitro drug release studies revealed controlled lycopene release from constructed bilosomes, with the drug liberation being based on the Higuchi kinetics model. Transmission electron microscopic evaluation of bilosomes revealed spherical nanovesicles free from aggregates. Moreover, the in vitro and in vivo antibacterial activity of lycopene and its constructed formulations against multidrug-resistant K. pneumoniae isolates were explored. The optimized bilosomes exhibited the lowest minimum inhibitory concentrations ranging from 8 to 32 µg/mL. In addition, scanning electron microscopy revealed remarkable deformation and lysis of the bilosomes-treated bacterial cells. Regarding in vivo investigation, a lung infection model in mice was employed. The tested bilosomes reduced the inflammation and congestion in the treated mice’s lung tissues, resulting in normal-sized bronchioles and alveoli with very few congested vessels. In addition, it resulted in a significant reduction in pulmonary fibrosis. In conclusion, this study investigated the potential activity of the naturally isolated lycopene in controlling infections triggered by multidrug-resistant K. pneumoniae isolates. Furthermore, it introduced bilosomes as a promising biocompatible nanocarrier for modulation of oral lycopene delivery and in vivo antimicrobial activity.

Cubosomes for Enhancing Intestinal Absorption of Fexofenadine Hydrochloride: In situ and in vivo Investigation

Purpose

The aim of this work was to probe cubosomes for enhanced intestinal absorption and oral bioavailability of poorly absorbable fexofenadine HCl (FEX-HCl).

Materials and Methods

Two cubosomal systems were fabricated utilizing glyceryl mono-oleate, a lyotropic mono lamellar lipid as oil phase and poloxamer407 as stabilizer at weight ratios of 8:2 and 7:3. The morphology of cubosomes was researched using transmission electron microscopy (TEM) and particle size was measured using photon correlation spectroscopy. FEX-HCl release was monitored in vitro. The effect of cubosomal encapsulation on intestinal absorption was assessed using in situ rabbit intestinal perfusion technique. Carrageenan induced rat paw edema model was utilized to monitor in vivo anti-inflammatory effect before and after cubosomal encapsulation.

Results

TEM revealed the existence of spherical and polygonal nanostructures arranged in honeycomb organization. Size measurement reflected nanoparticles with reduced size at higher poloxamer concentration. Release studies revealed liberation of FEX-HCl from cubosomes based on Higuchi kinetics model. The intestinal permeability data indicated incomplete absorption of FEX-HCl from simple aqueous solution with P-glycoprotein efflux contributing to this poor intestinal absorption. Incorporation of FEX-HCl in cubosomes enhanced membrane transport parameters. The intestinal absorption did not correlate with drug release suggesting that drug release is not the rate limiting with possible intact cubosomal transport. Cubosomal encapsulation of FEX-HCl significantly enhanced its in vivo anti-inflammatory efficacy compared to the aqueous FEX-HCl dispersion.

Conclusion

Cubosomes are promising novel carriers for enhancing intestinal absorption of FEX-HCl. Intact FEX-HCl-cubosomal absorption is possible via trans-lymphatic pathway but this requires further investigations.

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.