Rapid-onset intranasal delivery of metoclopramide hydrochloride Part II: Safety of various absorption enhancers and pharmacokinetic evaluation

PEGylated Tween 80-functionalized chitosan-lipidic nano-vesicular hybrids for heightening nose-to-brain delivery and bioavailability of metoclopramide

A PEGylated Tween 80-functionalized chitosan-lipidic (PEG-T-Chito-Lip) nano-vesicular hybrid was developed for intranasal administration as an alternative delivery route to help improve the poor oral bioavailability of BCS class-III model/antiemetic (metoclopramide hydrochloride; MTC). The influence of varying levels of chitosan, cholesterol, PEG 600, and Tween 80 on the stability/release parameters of the formulated nanovesicles was optimized using Draper-Lin Design. Two optimized formulations (Opti-Max and Opti-Min) with both maximized and minimized MTC-release goals, were predicted, characterized, and proved their vesicular outline via light/electron microscopy, along with the mutual prompt/extended in-vitro release patterns. The dual-optimized MTC-loaded PEG-T-Chito-Lip nanovesicles were loaded in intranasal in-situ gel (ISG) and further underwent in-vivo pharmacokinetics/nose-to-brain delivery valuation on Sprague-Dawley rats. The absorption profiles in plasma (plasma-AUC_0-∞) of the intranasal dual-optimized MTC-loaded nano-vesicular ISG formulation in pretreated rats were 2.95-fold and 1.64-fold more than rats pretreated with orally administered MTC and intranasally administered raw MTC-loaded ISG formulation, respectively. Interestingly, the brain-AUC_0-∞ of the intranasal dual-optimized MTC-loaded ISG was 10 and 3 times more than brain-AUC_0-∞ of the MTC-oral tablet and the intranasal raw MTC-loaded ISG, respectively. It was also revealed that the intranasal dual-optimized ISG significantly had the lowest liver-AUC_0-∞ (862.19 ng.g^-1.h^-1) versus the MTC-oral tablet (5732.17 ng.g^-1.h^-1) and the intranasal raw MTC-loaded ISG (1799.69 ng.g^-1.h^-1). The brain/blood ratio profile for the intranasal dual-optimized ISG was significantly enhanced over all other MTC formulations (P < 0.05). Moreover, the 198.55% drug targeting efficiency, 75.26% nose-to-brain direct transport percentage, and 4.06 drug targeting index of the dual-optimized formulation were significantly higher than those of the raw MTC-loaded ISG formulation. The performance of the dual-optimized PEG-T-Chito-Lip nano-vesicular hybrids for intranasal administration evidenced MTC-improved bioavailability, circumvented hepatic metabolism, and enhanced brain targetability, with increased potentiality in heightening the convenience and compliance for patients.

Chitosan Hydrogel as Tissue Engineering Scaffolds for Vascular Regeneration Applications

Chitosan hydrogels have a wide range of applications in tissue engineering scaffolds, mainly due to the advantages of their chemical and physical properties. This review focuses on the application of chitosan hydrogels in tissue engineering scaffolds for vascular regeneration. We have mainly introduced these following aspects: advantages and progress of chitosan hydrogels in vascular regeneration hydrogels and the modification of chitosan hydrogels to improve the application in vascular regeneration. Finally, this paper discusses the prospects of chitosan hydrogels for vascular regeneration.

Biomaterials-Enhanced Intranasal Delivery of Drugs as a Direct Route for Brain Targeting

Intranasal (IN) drug delivery is a non-invasive and effective route for the administration of drugs to the brain at pharmacologically relevant concentrations, bypassing the blood-brain barrier (BBB) and minimizing adverse side effects. IN drug delivery can be particularly promising for the treatment of neurodegenerative diseases. The drug delivery mechanism involves the initial drug penetration through the nasal epithelial barrier, followed by drug diffusion in the perivascular or perineural spaces along the olfactory or trigeminal nerves, and final extracellular diffusion throughout the brain. A part of the drug may be lost by drainage through the lymphatic system, while a part may even enter the systemic circulation and reach the brain by crossing the BBB. Alternatively, drugs can be directly transported to the brain by axons of the olfactory nerve. To improve the effectiveness of drug delivery to the brain by the IN route, various types of nanocarriers and hydrogels and their combinations have been proposed. This review paper analyzes the main biomaterials-based strategies to enhance IN drug delivery to the brain, outlining unsolved challenges and proposing ways to address them.

Nasally inhaled therapeutics and vaccination for COVID-19: Developments and challenges

The nose is the initial site of viral infection, replication, and transmission in the human body. Nasally inhaled vaccines may act as a promising alternative for COVID-19 management in addition to intramuscular vaccination. In this review, the latest developments of nasal sprays either as repurposed or antiviral formulations were presented. Nasal vaccines based on traditional medicines, such as grapefruit seed extract, algae-isolated carrageenan, and Yogurt-fermenting Lactobacillus, are promising and under active investigations. Inherent challenges that hinder effective intranasal delivery were discussed in detail, which included nasal device issues and human nose physiological complexities. We examined factors related to nasal spray administration, including the nasal angiotensin I converting enzyme 2 (ACE2) locations as the delivery target, nasal devices, medication translocation after application, delivery methods, safety issues, and other nasal delivery options. The effects of human factors on nasal spray efficacy, such as nasal physiology, disease-induced physiological modifications, intersubject variability, and mucociliary clearance, were also examined. Finally, the potential impact of nasal vaccines on COVID-19 management in the developing world was discussed. It is concluded that effective delivery of nasal sprays to ACE2-rich regions is urgently needed, especially in the context that new variants may become unresponsive to current vaccines and more refractory to existing therapies.

Short Onset and Enhanced Analgesia Following Nasal Administration of Non-Controlled Drugs in Nanovesicular Systems

Nasal nanovesicular delivery systems (NVS) containing the noncontrolled analgesic drugs Ketoprofen, Butorphanol or Tramadol, incorporated in a phospholipid nanovesicular carrier, were designed and investigated. The systems were first characterized for their physicochemical properties. Due to their composition, comprising propylene glycol as a lipid bilayers fluidizer, these systems contain soft vesicles. Pharmacokinetic profiles of Tramadol in plasma and brain and of Ketoprofen in plasma were also assessed. The analgesic effect of each of the three tested drugs was evaluated in the acetic acid mice model for pain. One important result obtained in this work is that the concentration of Tramadol in rats' plasma and brain increased rapidly after administration, reaching a peak value 10 min after administration with a C_max of 2 to 5 folds greater than that for the oral or nasal non-vesicular treatments, respectively. In the case of Ketoprofen, the peak of the drug level in plasma was measured 10 min post nasal administration in NVS. The C_max was three-fold higher relative to oral administration of this drug. In the experiment testing analgesia, a rapid and improved analgesia was observed for the tested drugs when delivered nasally in the nanocarrier. On the other hand, a weaker analgesic effect was observed for oral and nasal control systems. This new approach suggests that nasal delivery of non-controlled drugs in soft nanovesicles may open the way for better and noninvasive treatment of severe pain.

Mechanisms of deformable nanovesicles based on insulin-phospholipid complex for enhancing buccal delivery of insulin

BACKGROUND

Non-injectable delivery of peptides and proteins are not feasible due to its large molecular, high hydrophilic and gastrointestinal degradation. Therefore, proposing a new method to solve this problem is a burning issue.

PURPOSE

The objective of this study was to propose a novel protein delivery strategy to vanquish the poor efficacy of buccal mucosa delivery systems for protein delivery and then investigate the detailed mechanisms of the enhanced buccal delivery of protein, using insulin as a model drug.

MATERIALS AND METHODS

Insulin-phospholipid complex combined with deformable nanovesicles (IPC-DNVs) were prepared, using deformable nanovesicles based on insulin (INS-DNVs) and conventional nanovesicles based on insulin-phospholipid complex (IPC-NVs) as references. Besides, their physicochemical characterization, in vitro transport behavior, in vivo bioactivity and hypoglycemic effect were systematically characterized and compared. Finally, we evaluated the in vivo safety of IPC-DNVs.

RESULTS

First, IPC-DNVs increased insulin permeability through deposition of the IPC and deformability of the DNVs, which was revealed by an in vitro mucosal permeation study. Second, DNVs could act as a drug carrier and penetrate the mucosa to reach the receiver medium as intact nanovesicles, which was supported by the observation of intact nanovesicles in the receiver medium through transmission electron microscopy (TEM). Third, IPC-DNVs exhibited both transcellular and paracellular transport in the form of IPC and DNVs, respectively, which was proved by confocal laser scanning microscopy (CLSM). Unlike the other two formulations, IPC-DNVs exhibited a sustained mild hypoglycemic effect, with a relative bioavailability (Fp) of 15.53% (3.09% and 1.96% for INS-DNVs and IPC-NVs, respectively). Furthermore, buccal administration of IPC-DNVs resulted in no visible mucosal irritation to the buccal mucosa.

CONCLUSION

Our work reveals the mechanisms underlying the enhanced buccal delivery of IPC-DNVs: the DNVs facilitate penetration through the main barrier, and the deposition of IPC enhances buccal absorption. Our results and proposed mechanisms could be an important reference to understand other nanocarriers based on protein (peptide)-phospholipid complexes that penetrate the mucosa and provide a theoretical basis for the future development of buccal delivery systems for insulin.

Metoclopramide nasal spray in vitro evaluation and in vivo pharmacokinetic studies in dogs

Metoclopramide (MCP) can effectively alleviate motion sickness-caused nausea and vomiting. Nasal administration offers the greatest patient compliance. It is suitable for self-administration and offers rapid and complete absorption, no first-pass effects and high bioavailability. In the present study, a MCP nasal spray was prepared and evaluated in vitro and in vivo. Nasal cilia toxicity of Bufo toads was used to screen the preservative types and concentrations. Rabbit nasal mucosa was used to evaluate the mucosa permeability of different MCP nasal sprays with different penetration enhancers and preservative. A three-period crossover trial was then carried out in beagle dogs with three different MCP dosage forms: nasal sprays, oral tablets and intramuscular (IM) solution. Liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) was performed to measure dog plasma MCP, and pharmacokinetic parameters were calculated. The results of ciliatoxicity and permeation study showed that 0.03% methyl paraben lacking penetration enhancers was optimal. Compared to control IM, the bioavailability of oral tablets of MCP was 24.9%, while that of nasal spray was 62.3%. Meanwhile time-to-maximal plasma concentration (T_max) of nasal spray was significantly shorter than that of oral tablets. In conclusion, MCP nasal spray prepared here is safe with minimal ciliatoxicity, rapid onset and high relative bioavailability.

1H NMR studies of binary and ternary dapsone supramolecular complexes with different drug carriers: EPC liposome, SBE-β-CD and β-CD

Binary and ternary systems composed of dapsone, sulfobutylether-β-cyclodextrin (SBE-β-CD), β-CD and egg phosphatidylcholine (EPC) were evaluated using 1D ROESY, saturation transfer difference NMR and diffusion experiments (DOSY) revealing the binary complexes Dap/β-CD (K(a) 1396 l mol(-1)), Dap/SBE-β-CD (K(a) 246 l mol(-1)), Dap/EPC (K(a) 84 l mol(-1)) and the ternary complex Dap/β-CD/EPC (K(a) 18 l mol(-1)) in which dapsone is more soluble.

Enhanced antibacterial effect of ceftriaxone sodium-loaded chitosan nanoparticles against intracellular Salmonella typhimurium

The aim of the present study was to utilize chitosan (CS) nanoparticles for the intracellular delivery of the poorly cell-penetrating antibiotic, ceftriaxone sodium (CTX). In vitro characterization of (CTX-CS) nanoparticles was conducted leading to an optimized formula that was assessed for its biocompatibility to blood (hemolysis test) and cells (MTT assay). Progressively, confocal laser scanning microscopy (CLSM), cellular uptake (microfluorimetry), and antibacterial activity of the nanoparticles were investigated in two cell lines: Caco-2 and macrophages J774.2 pre-infected with Salmonella typhimurium. Results showed that the optimized formula had size 210 nm, positive zeta potential (+30 mV) and appreciable entrapment efficiency for CTX (45%) and included a biphasic release pattern. The nanoparticles were biocompatible and were internalized by cells as verified by CLSM whereas microfluorimetry indicated substantial cellular uptake. Moreover, the CTX-chitosan nanoparticles showed a significant reduction in the count of intracellular S. typhimurium in Caco-2 and macrophages J774.2. This reduction was significantly higher than that obtained in case of placebo nanoparticles, CTX, and CTX-chitosan solutions and might be attributed to enhanced endocytic uptake of the nanoaprticles and antibacterial effect of the chitosan polymer. In conclusion, the results provide evidence for the potential use of chitosan nanoparticles to enhance the intracellular delivery and antibacterial effect of CTX in enterocytes and macrophages.

Nasal route: an alternative approach for antiemetic drug delivery

INTRODUCTION

Antiemetic drugs are used in the treatment of nausea and emesis. Development of novel delivery systems for antiemetic drugs, as an alternative to conventional preparations, is important in terms of good patient compliance and improving bioavailability. The nasal route offers unique superiorities, such as fast and high drug absorption, and high patient compliance. Therefore, a considerable amount of research has been carried out on the development of nasal delivery systems for antiemetic drugs.

AREAS COVERED

This review deals with the importance of nasal delivery of antiemetic drugs and the studies performed on this subject. The first part of this review summarizes the properties of the nasal route, its advantages and limitations, parameters affecting drug absorption through nasal mucosa, nasal passage pathways and general approaches to improve nasal transport. The second part reviews the studies conducted on the development of nasal delivery systems.

EXPERT OPINION

Due to its superiorities, the nasal route could be considered as an attractive alternative to oral and parenteral routes. To overcome the barrier properties of the nasal epithelium and to enhance transport of antiemetic drugs, several approaches, including permeation enhancers, in situ gel formulations and micro- and nanoparticulate systems, have been evaluated. The results obtained are promising and indicate that nasal formulations of some antiemetic drugs may enter the market in the near future.

Identification of novel metoclopramide metabolites in humans: in vitro and in vivo studies

Metoclopramide (MCP) is frequently used to treat gastroparesis. Previous studies have documented MCP metabolism, but systematic structural identification of metabolites has not been performed. The aim of this study was to better understand MCP metabolism in humans. For examination of in vivo metabolism, a single oral 20-mg MCP dose was administered to eight healthy male volunteers, followed by complete urine collection over 24 h. In vitro incubations were performed in human liver microsomes (HLM) to characterize metabolism via cytochromes P450 and UDP-glucuronosyltransferases and in human liver cytosol for metabolism via sulfotransferases. Urine and subcellular incubations were analyzed for MCP metabolites on a mass spectrometer with accurate mass measurement capability. Five MCP metabolites were detected in vivo, and five additional metabolites were detected in vitro. The five metabolites of MCP identified both in vitro and in vivo were an N-O-glucuronide (M1), an N-sulfate (M2), a des-ethyl metabolite (M3), a hydroxylated metabolite (M4), and an oxidative deaminated metabolite (M5). To our knowledge, metabolites M1 and M4 have not been reported previously. M2 urinary levels varied 22-fold and M3 levels varied 16-fold among eight subjects. In vitro studies in HLM revealed the following additional metabolites: two ether glucuronides (M6 and M8), possibly on the phenyl ring after oxidation, an N-glucuronide (M7), a carbamic acid (M9), and a nitro metabolite (M10). Metabolites M6 to M10 have not been reported previously. In conclusion, this study describes the identification of MCP metabolites in vivo and in vitro in humans.

Chemotherapy-induced nausea and vomiting: contemporary approaches to optimal management. Proceedings from a symposium at the 2008 Multinational Association of Supportive Care in Cancer (MASCC) Annual Meeting

INTRODUCTION

Chemotherapy-induced nausea and vomiting remains a significant problem for cancer patients.

DISCUSSION

Patient factors such as polypharmacy, medication costs, mucositis, and depression may hinder good antiemetic control, while high workloads, poor communication, and underestimation of the problem on the part of healthcare professionals also play a role. Improving outcomes requires accurate assessment of risk factors, use of guidelines, and better adherence to antiemetic regimens.

CONCLUSION

Extended-release formulations and new delivery systems such as transdermal patches, nasal sprays, and pumps provide a new strategy that may improve patient outcomes.

Nasal administration of metoclopramide from different dosage forms: in vitro, ex vivo, and in vivo evaluation

Nasal drug delivery is an interesting route of administration for metoclopramide hydrochloride (MTC) in preventing different kind of emesis. Currently, the routes of administration of antiemetics are oral or intravenous, although patient compliance is often impaired by the difficulties associated with acute emesis or invasiveness of parenteral administration. In this perspective, nasal dosage forms (solution, gel, and lyophilized powder) of MTC were prepared by using a mucoadhesive polymer sodium carboxymethylcellulose (NaCMC). In vitro and ex vivo drug release studies were performed in a modified horizontal diffusion chamber with cellulose membrane and excised cattle nasal mucosa as diffusion barriers. The tolerance of nasal mucosa to the formulation and its components were investigated using light microscopy. In vivo studies were carried out for the optimized formulations in sheep and the pharmacokinetics parameters were compared with oral solution and IV dosage form. The release of MTC from solution and powder formulations was found to be higher than gel formulation (p < 0.05). Histopathological examination did not detect any severe damage. Hydroxypropyl-beta-cyclodextrin (HPbetaCD) used in powder formulations was found to be effective for enhancing the release and absorption of MTC. In contrast to in vitro and ex vivo experiments nasal bioavailability of gel is higher than those of solution and powder (p < 0.05). In conclusion, the NaCMC gel formulation of MTC with mucoadhesive properties with increased permeation rate is promising for prolonging nasal residence time and thereby nasal absorption.

Proparacaine complexation with beta-cyclodextrin and p-sulfonic acid calix[6]arene, as evaluated by varied (1)H-NMR approaches

This study focused on the use of NMR techniques as a tool for the investigation of complex formation between proparacaine and cyclodextrins (CDs) or p-sulfonic acid calix[6]arene. The pH dependence of the complexation of proparacaine with beta-CD and p-sulfonic acid calix[6]arene was studied and binding constants were determined by (1)H NMR spectroscopy [diffusion-ordered spectroscopy (DOSY)] for the charged and uncharged forms of the local anesthetic in beta-CD and p-sulfonic acid calix[6]arene. The stoichiometries of the complexes was determined and rotating frame Overhauser enhancement spectroscopy (ROESY) 1D experiments revealed details of the molecular insertion of proparacaine into the beta-CD and p-sulfonic acid calix[6]arene cavities. The results unambiguously demonstrate that pH is an important factor for the development of supramolecular architectures based on beta-CD and p-sulfonic acid calix[6]arene as the host molecules. Such host-guest complexes were investigated in view of their potential use as new therapeutic formulations, designed to increase the bioavailability and/or to decrease the systemic toxicity of proparacaine in anesthesia procedures.

Detection of multiple globin monoadducts and cross-links after in vitro exposure of rat erythrocytes to S-(1,2-dichlorovinyl)-L-cysteine sulfoxide and after in vivo treatment of rats with S-(1,2-dichlorovinyl)-L-cysteine sulfoxide

S-(1,2-dichlorovinyl)- L-cysteine sulfoxide (DCVCS), a Michael acceptor produced by an FMO3-mediated oxidation of the trichloroethylene metabolite S-(1,2-dichlorovinyl)- L-cysteine (DCVC), is a more potent nephrotoxicant than DCVC. Because DCVCS incubations with N-acetyl- L-cysteine at pH 7.4, 37 degrees C resulted in the formation of three diastereomeric monoadducts and one diadduct, globin monoadducts and cross-links formed after in vitro incubations of rat erythrocytes with DCVCS (0.9-450 microM) for 2 h and those present at 30 min after in vivo treatment of rats with DCVCS (23 and 230 micromol/kg) were characterized. ESI/MS of intact globin chains revealed adduction of 1 DCVCS moiety on the beta2 chain at the three lowest DCVCS concentrations and on the beta1 chain after the in vivo treatment with 230 micromol/kg DCVCS. Interestingly, intact globin dimers and trimers were detectable by ESI/MS with all DCVCS concentrations in vitro (also by SDS-PAGE) and in vivo. LC/MS and MALDI/FTICR of trypsin digested peptides from globin samples obtained after in vitro (450 microM DCVCS) or in vivo exposure to DCVCS (230 micromol/kg) suggested the formation of DCVCS monoadducts not only with Cys93 and Cys125 of the beta chains but also with Cys13 of the alpha chains, whereas no monoadducted peptides were detected at lower DCVCS concentrations in vitro or in vivo. However, LC/MS and MALDI-TOF/TOF suggested the presence of several DCVCS-derived peptide cross-links both in vivo and in vitro at all DCVCS exposure levels. Collectively, the results indicate at least 4 out of the 5 cysteine moieties of the rat hemoglobin heterodimer may be alkylated by DCVCS, in reactions that could also lead to the formation of multiple cross-links. DCVCS- and N-acetyl-DCVCS (NA-DCVCS)-derived globin cross-links containing GSH and Cys were also detected by mass spectrometry, providing strong evidence for the reactivity and/or cross-linking ability of DCVCS, NA-DCVCS, and their GSH or Cys conjugates in both the in vitro and the in vivo. Thus, hemoglobin adducts and cross-links may be useful biomarkers to investigate the possible presence of DCVCS in circulation after DCVC or trichloroethylene exposure.