Publications by authors named "Brayden D"

Biologics have been widely used as injectables in the treatment of inflammatory bowel disease (IBD). Different local treatment attempts have been developed in recent years. However, maintaining systemic levels of biologics is still crucial for achieving colitis remission.

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Labrafac™ MC60 (glycerol monocaprylocaprate) is a lipid-based excipient used in oral formulations as a solubiliser. Due to the high proportions of established permeability enhancers, caprylate (C) and caprate (C), in Labrafac™ MC60, we hypothesised that it might behave as an intestinal permeation enhancer. We therefore evaluated this using two paracellular markers (ex vivo) and insulin (in vivo) as model molecules.

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Osteoarthritis (OA) is the most common form of arthritis, with intra-articular (IA) delivery of therapeutics being the current best option to treat pain and inflammation. However, IA delivery is challenging due to the rapid clearance of therapeutics from the joint and the need for repeated injections. Thus, there is a need for long-acting delivery systems that increase the drug retention time in joints with the capacity to penetrate OA cartilage.

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Surfactants are a diverse group of compounds that share the capacity to adsorb at the boundary between distinct phases of matter. They are used as pharmaceutical excipients, food additives, emulsifiers in cosmetics, and as household/industrial detergents. This review outlines the interaction of surfactant-type excipients present in oral pharmaceutical dosage forms with the intestinal epithelium of the gastrointestinal (GI) tract.

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Selenium methionine (SeMet) is an essential micronutrient required for normal body function and is associated with additional health benefits. However, oral administration of SeMet can be challenging due to its purported narrow therapeutic index, low oral bioavailability, and high susceptibility to oxidation. To address these issues, SeMet was entrapped in zein-coated nanoparticles made from chitosan using an ionic gelation formulation.

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Buccal delivery of small and large molecules is an attractive route of administration that has been studied extensively over the past few decades. This route bypasses first-pass metabolism and can be used to deliver therapeutics directly to systemic circulation. Moreover, buccal films are efficient dosage forms for drug delivery due to their simplicity, portability, and patient comfort.

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Oral administration of macromolecules aimed at systemic delivery has been at the forefront of pharmaceutical research for over 50 years. Yet, in terms of clinical translation for systemic delivery, output is limited to five US Food and Drug Administration (FDA)-approved oral peptide products to date, such are the hurdles. Somewhat neglected by comparison but with potentially lower delivery demands, the goal of local delivery of macromolecules directed mostly to the terminal ileum and colon to treat inflammatory bowel conditions has led to a range of macromolecules including gut-restricted peptides, fusion proteins, enzymes, antibodies, and antisense oligonucleotides that have reached clinical trials.

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Isoleucine-Proline-Proline (IPP) and Leucine-Lysine-Proline (LKP) are food-derived tripeptides whose antihypertensive functions have been demonstrated in hypertensive rat models. However, peptides display low oral bioavailability due to poor intestinal epithelial permeability and instability. IPP and LKP were formulated into nanoparticles (NP) using chitosan (CL113) via ionotropic gelation and then coated with zein.

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A common approach to tackle the poor intestinal membrane permeability of peptides after oral administration is to formulate them with a permeation enhancer (PE). Increased oral bioavailability for oral peptide candidates has been reported from clinical trials when either salcaprozate sodium (SNAC) or sodium caprate (C) is incorporated in the formulation. However, little is known about how they physically interact with peptides in solution.

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Peptide drugs and biologics provide opportunities for treatments of many diseases. However, due to their poor stability and permeability in the gastrointestinal tract, the oral bioavailability of peptide drugs is negligible. Nanoparticle formulations have been proposed to circumvent these hurdles, but systemic exposure of orally administered peptide drugs has remained elusive.

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It is now recognized that a number of excipients previously considered to be "inert" have the capacity to alter drug oral bioavailability through a range of in vivo effects. The various mechanisms through which an excipient can affect in vivo gastrointestinal physiology and drug absorption characteristics were explored in "A Critical Overview of The Biological Effects of Excipients (Part I): Impact on Gastrointestinal Absorption." The next critical issue that needs to be discussed is how these biological effects are evaluated.

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Crosslinked chitosan nanocarriers (140-160 nm) entrapping coumarin-6 ( = 455/508 nm) with or without surface mannosylation were synthesized and assessed for cytotoxicity, adherence and cellular uptake in Caco-2 cells, flux across Caco-2 monolayers, and mucoadhesion to porcine mucin. Mannosylated and non-mannosylated nanocarriers demonstrated biocompatibility with slow release of coumarin-6 at pH 6.8 and 7.

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The absorption of orally administered drug products is a complex, dynamic process, dependant on a range of biopharmaceutical properties; notably the aqueous solubility of a molecule, stability within the gastrointestinal tract (GIT) and permeability. From a regulatory perspective, the concept of high intestinal permeability is intrinsically linked to the fraction of the oral dose absorbed. The relationship between permeability and the extent of absorption means that experimental models of permeability have regularly been used as a surrogate measure to estimate the fraction absorbed.

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Article Synopsis
  • Nanoparticle-based oral drug delivery systems can target inflamed areas in the gastrointestinal tract but face challenges due to harsh conditions and mucus barriers.
  • The study focuses on developing mucus-penetrating nanoparticles made from PLGA polymers with varying PEG chain lengths to effectively deliver monoclonal antibodies against TNF-α for treating inflammatory bowel disease.
  • Results showed that while both types of nanoparticles successfully carried the antibody, only the PLGA-PEG2k nanoparticles effectively reduced inflammation in mice, highlighting the importance of PEG chain length on drug delivery effectiveness.
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Background: Food proteins are a source of hydrolysates with potentially useful biological attributes. Bioactive peptides from food-derived proteins are released from hydrolysates using exogenous industrial processes or endogenous intestinal enzymes. Current in vitro permeability assays have limitations in predicting the oral bioavailability (BA) of bioactive peptides in humans.

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Article Synopsis
  • The use of chemical permeation enhancers (PEs) is a common method tested to improve the oral absorption of peptides, but only a few have made it to clinical trials, showing minimal increases in bioavailability.
  • Despite low bioavailability rates (~1%), recent FDA approvals for oral formulations of semaglutide and octreotide have occurred, highlighting that even small improvements can lead to success.
  • The key challenge lies in maintaining the necessary concentration of PEs and active agents at the intestinal epithelium, and addressing physiological factors like intestinal transit time and dilution to enhance oral absorption of these drugs.
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The oral route of administration is by far the most convenient route, especially in the treatment of chronic conditions. However, many therapeutics present formulation difficulties which make them unsuitable for oral delivery. Recently, we synthesized a denatured whey protein isolate (dWPI) bead entrapped with insulin.

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Article Synopsis
  • The FDA has approved oral formulations of peptides like semaglutide for diabetes and octreotide for acromegaly, showing that specific formulations can enable oral delivery.
  • An assessment of MYCAPSSA®, the oral octreotide formulation, highlights its competitive advantages over traditional depot injections and discusses the innovative Transient Permeation Enhancer (TPE®) technology used to improve intestinal absorption.
  • Despite oral octreotide having a much lower bioavailability compared to subcutaneous injections, its twice-daily convenience may appeal to acromegaly patients over less frequent injection methods.
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For many diabetics, daily, lifelong insulin injections are required to effectively manage blood glucose levels and the complications associated with the disease. This can be a burden and reduces patient quality of life. Our goal was to develop a more convenient oral delivery system that may be suitable for insulin and other peptides.

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Laurate (C)-sucrose esters are established intestinal epithelial permeation enhancers (PEs) with potential for use in oral delivery. Most studies have examined blends of ester rather than specific monoesters, with little variation on the sugar moiety. To investigate the influence of varying the sugar moiety on monoester performance, we compared three monoesters: C-sucrose, C-lactose, and C-trehalose.

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Adenosine is a purine nucleoside pivotal for homeostasis in cells and tissues. Stimulation of the adenosine receptors (AR) has been shown to regulate the nuclear orphan receptor 4A (NR4A1-3) family, resulting in attenuation of hyper-inflammatory responses in myeloid cells. The NR4A1-3 orphan receptors are early immediate response genes and transcriptional regulators of cell and tissue homeostasis.

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Bile salts were first tested as epithelial permeation enhancers (PEs) for the intestine and buccal routes over 20 years ago. They are not as popular as other PEs due to their non-specific mechanism of action and perceived toxicity potential. We revisited two of them by comparing efficacy and toxicity of sodium glycodeoxycholate (SGC) and sodium deoxycholate (DC) for both routes using in vitro and ex vivo methods.

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SNAC and C are intestinal permeation enhancers (PEs) used in formulations of peptides for oral delivery in clinical trials. Our aims were to compare their: (i) mechanism of action in isolated rat intestinal mucosae mounted in Ussing chambers and in non-everted gut sacs, (ii) effects on mucosa integrity in those models and also in in situ intra-jejunal instillations and (iii) interactions with intestinal mucus. SNAC increased the apparent permeability coefficient (P) of the paracellular marker, FITC-dextran 4000 (FD4), across isolated rat gastric mucosae in concentration-dependent fashion, whereas C did not, while both reduced the transepithelial electrical resistance (TEER).

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Article Synopsis
  • Nanotechnology is growing in drug delivery and medical imaging by utilizing unique nanomaterials that can encapsulate therapeutics and improve targeting, addressing issues like solubility and crossing the blood-brain-barrier (BBB).
  • Challenges exist in translating nanomedicine from lab to clinic; physiological barriers like the BBB and gut mucus often hinder drug delivery, and some formulations have performed poorly in trials despite potential benefits.
  • While nanomedicines have shown improved effectiveness in terms of pharmacokinetics and reduced toxicity, there are ongoing concerns about their ability to navigate the body’s natural defenses, prompting calls for further research and development.
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