Steve Brocchini

University College London | UCL · School of Pharmacy

Extracellular vesicles (EVs) are small membrane vesicles released by cells and one biological function of EVs is they are thought to act as messengers in cell-to-cell communication. EVs are emerging as a promising class of vesicles that could be adapted in formulation due to their lack of immunogenicity and targeting capabilities. EVs have been sho...

This study focuses on the use of methacrylic acid polymers synthesised via the Reversible Addition Fragmentation chain Transfer (RAFT) polymerisation method for the production of amorphous solid dispersions (ASDs) by ball milling, to kinetically solubilize a poorly water-soluble model drug. The solid-state characteristics and the physical stability...

Real-time measurement is important in modern dissolution testing to aid in parallel drug characterisation and quality control (QC). The development of a real-time monitoring platform (microfluidic system, a novel eye movement platform with temperature sensors and accelerometers and a concentration probe setup) in conjunction with an in vitro model...

There are limited treatments currently available for retinal diseases such as age-related macular degeneration (AMD). Cell-based therapy holds great promise in treating these degenerative diseases. Three-dimensional (3D) polymeric scaffolds have gained attention for tissue restoration by mimicking the native extracellular matrix (ECM). The scaffold...

The aggregation of protein therapeutics such as antibodies remains a major challenge in the biopharmaceutical industry. The present study aimed to characterize the impact of the protein concentration on the mechanisms and potential pathways for aggregation, using the antibody Fab fragment A33 as the model protein. Aggregation kinetics were determin...

Since its discovery, small interfering RNA (siRNA) has revolutionised the field of gene silencing therapy because of its great potential in targeting diseases that were considered untreatable. Although several siRNA drugs are already in the market, many challenges remain to be addressed before siRNA therapies can realise their full potential includ...

Knowledge of drug mass transfer from the anterior chamber via the iris-lens barrier has important implications for the development of front of the eye medicines that can also deliver drugs to the vitreous cavity. Here, the design and evaluation of a novel in vitro model that studies anterior clearance kinetics is reported. To mimic some aspects of...

Therapeutic proteins and peptides are clinically important, offering potency while reducing the potential for off-target effects. Research interest in developing therapeutic polypeptides has grown significantly during the last four decades. However, despite the growing research effort, maintaining the stability of polypeptides throughout their life...

Aggregation resulting from the self-association of peptide molecules remains a major challenge during preformulation. Whereas certain organic solvents are known to promote aggregation, ethanol (EtOH) is capable of disrupting interactions between peptide molecules. It is unclear whether it is beneficial or counterproductive to include EtOH in formul...

New in vitro prototypes (PK-EyeTM) were tested with and without eye movement to under- stand diffusion and convection effects on intraocular clearance. Port placement in front ((i) ciliary inflow model) and behind the model lens ((ii) posterior inflow model) was used to study bevacizumab (1.25 mg/50 μL) and dexamethasone (0.1 mg/100 μL) in phosphat...

Designing an antibody with the desired affinity to the antigen is challenging, often achieved by lengthening the hydrophobic CDRs, which can lead to aggregation and cause major hindrance to the development of successful biopharmaceutical products. Aggregation can cause immunogenicity, viscosity and stability issues affecting both the safety and qua...

Dry eye disease is a common ocular disorder that is characterised by tear deficiency or excessive tear evaporation. Current treatment involves the use of eye drops; however, therapeutic efficacy is limited because of poor ocular bioavailability of topically applied formulations. In this study, digital light processing (DLP) 3D printing was employed...

The high target specificity and multifunctionality of proteins has led to great interest in their clinical use. To this end, the development of delivery systems capable of preserving their bioactivity and improving bioavailability is pivotal to achieve high effectiveness and satisfactory therapeutic outcomes. Electrohydrodynamic (EHD) techniques, n...

Surface functionalisation of polymeric electrospun scaffolds with therapeutic biomolecules is often explored in regenerative medicine and tissue engineering. However, the bioconjugation method must be carefully selected to prevent partial or full loss of activity of the biomolecule following chemical manipulation. Perfluorophenyl azide bearing a N‐...

Highlights • Dual acting therapeutic proteins may be a better strategy than drug combinations for treatment of chronic retinal diseases. •Several targets to treat neovascularisation and inflammation have been identified. •A dual acting molecule to increase the duration of action in the vitreous has potential for treatment of chronic retinal diseas...

Proteins and peptides have emerged in recent years to treat a wide range of multifaceted diseases such as cancer, diabetes and inflammation. The emergence of polypeptides has yielded advancements in the fields of biopharmaceutical production and formulation. Polypeptides often display poor pharmacokinetics, limited permeability across biological ba...

The processes involved in ocular fibrosis after disease or ocular tissue injury, including surgery play an important part in the development or failure of treatment of most blinding diseases. Ocular fibrosis is one of the biggest areas of unmet need in ophthalmology. Effective anti-scarring therapies could potentially revolutionise the management o...

The majority of blinding conditions arise due to chronic pathologies in the retina. During the last two decades, antibody-based medicines administered by intravitreal injection directly into the back of the eye have revolutionised the treatment of chronic retinal diseases characterised by uncontrolled blood vessel growth, e.g. wet age-related macul...

Transdermal delivery of biological therapeutics is emerging as a potent alternative to intravenous or subcutaneous injections. The latter come with major challenges including patient discomfort, the necessity for trained personnel, specialized sharps disposal, and risk of infection. Microneedle (MN) technology circumvents many of the abovementioned...

Conjugation by bis-alkylation using latently cross-conjugated reagents is a basis for site-specific PEGylation to the two cysteine thiols derived from a native disulfide. Known as disulfide bridging PEGylation, bis-alkylation can also be used to target histidine imidazole residues allowing for His-tag–selective PEGylation at either the N- or C-term...

Aggregation, including the formation of fibrils, poses significant challenges for the development of therapeutic peptides. To develop stable peptide formulations, some understanding of the mechanisms underpinning the fibrillation process is required. A thioflavin T fluorescence assay was first used to determine the fibrillation profile of a GLP-1-l...

Clinical grading systems following glaucoma filtration surgery do not include any effects of the bleb on the intra-ocular pressure and are relatively subjective, therefore carrying the risk of inter and/or intra-observer variability. The main objective of the study is to quantify and model the effect of subconjunctival bleb on flow pressure for ass...

Glaucoma is the leading cause of irreversible blindness with over 70 million people affected worldwide. The surgical management of glaucoma aims to lower intraocular pressure by increasing aqueous outflow facility. The latest manufacturing techniques have allowed for the development of a number of novel implantable devices to improve safety and out...

Intravitreal injections have become the cornerstone of retinal care and one of the most commonly performed procedures across all medical specialties. The impact of hydrodynamic forces of intravitreal solutions when injected into vitreous or vitreous substitutes has not been well described. While computational models do exist, they tend to underesti...

Therapeutic protein medicines have transformed the treatment of blinding diseases (e.g. age-related macular degeneration, AMD) during the last 1–2 decades. Many blinding conditions such as AMD are chronic; and require multiple intravitreal injections over a long period to achieve a high and reproducible dose needed for clinical benefit. Prolonging...

Purpose: Minimally invasive glaucoma surgery (MIGS) devices that drain into the subconjunctival space can be inserted via an ab externo or ab interno approach. Limited experimental data exists as to the impact of either technique on intraocular pressure (IOP) control. We performed microfluidic studies by using ex vivo rabbit eyes to assess the eff...

Purpose: The aim of this study was to present a case of a Baerveldt glaucoma implant lumen being completely occluded with a 3-0 Supramid stent suture. Patient and methods: The patient underwent Baerveldt glaucoma implant surgery with placement of an intraluminal 3-0 Supramid stent suture that acts to restrict flow across the device and reduce th...

Site-selective conjugation generally requires both (i) molecular engineering of the protein of interest to introduce a conjugation site at a defined location and (ii) a site-specific conjugation technology. Three N-terminal...

A circular silicone sheet is clamped at its edge and pressurised by the injection of a liquid beneath creating a pocket. We study experimentally the deformation and pressure increase caused by the compression of a pressurised pocket. Excellent agreement is found between experimental observations and numerical predictions based on an axisymmetric th...

RNA interference induced by double-stranded, small interfering RNA (siRNA) molecules has attracted great attention as a naturally-occurring approach to silence gene expression with high specificity. The Myocardin-Related Transcription Factor/Serum Response Factor (MRTF/SRF) pathway is a master regulator of cytoskeletal gene expression and thus repr...

An antibody mimetic known as Fab-PEG-Fab (FpF) is a stable bivalent molecule that may have some potential therapeutic advantages over IgG antibodies due to differences in their binding kinetics as determined by surface plasmon resonance. Here we describe the thermodynamic binding properties to vascular endothelial growth factor (VEGF) of the FpF an...

α-Galactosylceramide (GalCer) is a glycolipid widely known as an activator of Natural killer T (NKT) cells, constituting a promising adjuvant against cancer, including melanoma. However, limited clinical outcomes have been obtained so far. This study evaluated the synergy between GalCer and major histocompatibility complex (MHC) class I and MHC cla...

Ilomastat is a matrix metalloproteinase inhibitor (MMPi) that has shown the potential to inhibit scarring (fibrosis) by mediating healing after injury or surgery. A long lasting ocular implantable pharmaceutical formulation of ilomastat is being developed to mediate the healing process to prevent scarring after glaucoma filtration surgery. The ilom...

When this article was first published, the wrong license was listed. This article is available under the Creative Commons Attribution License (CC BY). The correction has been made to the article online.

Many limitations of protein-based medicines have been shown clinically to be alleviated by the covalent conjugation of poly(ethylene glycol) (PEG) in a process known as protein PEGylation. There are at least 15 registered PEGylated products with more in clinical development. Protein PEGylation is generally used to extend the protein circulation tim...

Injectable gels have the potential to encapsulate drugs for sustained release of protein therapeutics for use in the eye. Hyaluronic acid (HA) is a biodegradable clinically used material and poly N-isopropylacrylamide (pNIPAAM) is a stimuli responsive polymer that can display a lower critical solution temperature (LCST) at physiological conditions....

Biotechnology harnesses cellular and biochemical systems to advance knowledge of the molecular cause of disease and to provide new diagnostic tools and more precisely targeted drugs. Within a decade, global investment in medical biotechnology has increased more than ten-fold, resulting in therapies for previously untreatable conditions. But what ex...

Statement of significance: Bevacizumab is a potent protein drug which is highly effective in the treatment of degenerative conditions in the eye. To be effective, frequent injections into the eye are required, which is deeply unpleasant for patients and expensive for healthcare providers. Alternative methods of administration are thus greatly soug...

PCA of PG dendrimers: (A) G0 series (left: NH3-, right: NBD-), (B) G1 series (left: NH3-, right: NBD-), (C) G2 series (left: NH3-, right: NBD-), (D) G3 series (left: NH3-, right: NBD-), (E) G4 series (left: NH3-, right: NBD-), (F) LYS-PG-G4 and TRP-PG-G4 and (G) ORG-PG-G4. Abbreviations: PCA, principal component analysis; NBD, nitrobenzoxadiazole;...

RMSD for the different series of PG dendrimers (heavy atoms). Note: NBD-PG dendrimers (A), NH3-PG dendrimers (blue, G0; gray, G1; red, G2; orange, G3; yellow, G4; B) and (gray, NBD-PG-LYS-G4; red, NBD-PG-TRP-G4; blue, ORG-PG-G4; C). Abbreviations: RMSD, root-mean-square deviation; PG, poly(l-glutamic acid); NBD, nitrobenzoxadiazole; LYS, lysine; TR...

Snapshots of the different conformations observed throughout the trajectory of NBD-PG-G4 dendrimer. Abbreviations: NBD, nitrobenzoxadiazole; PG, poly(l-glutamic acid).

PG dendrimers density distribution for NH3 series (left) and NBD series (right). Note: The density distribution of all atoms of the dendrimer, the atoms from the terminal monomers, water molecules (measured for the oxygen atom) and sodium and chloride atoms was determined individually from the center of mass of the dendrimer. Abbreviations: PG, pol...

2D and 3D representations of GLU dendrimers bearing NBD; NBD is highlighted with vdW representation to allow the visualization of the burying capacity by the dendrimer. Abbreviations: GLU, glutamic acid; NBD, nitrobenzoxadiazole; vdW, van der Waals; PG, poly(l-glutamic acid); LYS, lysine; ORG, Oregon Green 488; TRP, tryptophan.

The eye is a highly specialised organ that is subject to a huge range of pathology. Both local and systemic disease may affect different anatomical regions of the eye. The least invasive routes for ocular drug administration are topical (e.g. eyedrops) and systemic (e.g. tablets) formulations. Barriers that subserve as protection against pathogen e...

Dendrimers and dendrons offer an excellent platform for developing novel drug delivery systems and medicines. The rational design and further development of these repetitively branched systems are restricted by difficulties in scalable synthesis and structural determination, which can be overcome by judicious use of molecular modelling and molecula...

Dendrimers are hyperbranched polymers with a multifunctional architecture that can be tailored for the use in various biomedical applications. Peptide dendrimers are particularly relevant for drug delivery applications due to their versatility and safety profile. The overall lack of knowledge of their three-dimensional structure, conformational beh...

Increasingly complex proteins can be made by a recombinant chemical approach where proteins that can be made easily can be combined by site-specific chemical conjugation to form multifunctional or more active protein therapeutics. Protein dimers may display increased avidity for cell surface receptors. The increased size of protein dimers may also...

There is a need to prolong drug residence time using a biocompatible formulation in the subconjunctival space after surgery to treat glaucoma. Drug releasing discs were prepared with 2-(hydroxyethyl)methacrylate (HEMA) and 2-methacryloyl- oxyethyl phosphorylcholine (MPC). The ratio of bound water (Wb) to free water (Wf) ratio increased from 1:0.3 t...

Purpose: The purpose of this study was to develop a topical matrix metalloproteinase inhibitor preparation for antiscarring therapy. Methods: The broad spectrum matrix metalloproteinase inhibitor ilomastat was formulated using 2-hydroxypropyl-β-cyclodextrin in aqueous solution. In vitro activity of ilomastat-cyclodextrin (ilomastat-CD) was exami...

Corticosteroids have long been used to treat intraocular inflammation by intravitreal injection. We describe dexamethasone loaded poly-DL-lactide-co-glycolide (PLGA) microparticles that were fabricated by thermally induced phase separation (TIPS). The dexamethasone loaded microparticles were evaluated using a two-compartment, in vitro aqueous outfl...

This chapter outlines the developing applications for polymeric materials in nanopharmacy and pharmaceutical science, and some of the opportunities for, and also barriers against, the use of macromolecules and conjugates as therapeutics. It is also important to consider some recent routes by which polymers can be made to controlled chain lengths an...

Infliximab is an antibody that neutralizes TNF-α and is used principally by systemic administration to treat many inflammatory disorders. We prepared the antibody mimetic Fab-PEG-Fab (FpFinfliximab) for direct intravitreal injection to assess whether such formulations have biological activity and potential utility for ocular use. FpFinfliximab was...

This paper discusses the development of a multivariate-based regression model for estimating the critical attributes to establish a design-space for poly(lactic-co-glycolic acid) (PLGA) nanoparticles formulated by a double emulsion-solvent evaporation method. A three-level, full factorial experimental design is used to assess the impact of three di...

Purpose: Intraocular pressure and aqueous humor flow direction determined by the scleral flap immediately after trabeculectomy are critical determinants of the surgical outcome. We used a large-scale model to objectively measure the influence of flap thickness and shape, and suture number and position on pressure difference across the flap and flo...

Protein formulation development relies on the selection of excipients that inhibit protein-protein interactions preventing aggregation. Empirical strategies involve screening many excipient and buffer combinations using force degradation studies. Such methods do not readily provide information on intermolecular interactions responsible for the prot...

Proteins that are modified by chemical conjugation require at least two separate purification processes. First the bulk protein is purified, and then after chemical conjugation, a second purification process is required to obtain the modified protein. In an effort to develop new enabling technologies to integrate bioprocessing and protein modificat...

The Fc-fusion mimetic RpR was prepared by disulfide bridging conjugation using PEG in the place of the Fc. RpR displayed higher affinity for VEGF than aflibercept. This is caused primarily by a slower dissociation rate, which can prolong a drug at its site of action. RpRs have considerable potential for development as stable, organ specific therape...

An ageing population, together with a greater understanding of ocular disease, are driving the development of new generations of protein therapeutics for ocular use. Currently, antibodies to treat age related macular degeneration (AMD) are administered about every 4-6 weeks by intravitreal (IVT) injections. Although IVT injections are generally saf...

Two series of fibers containing the active ingredients acyclovir, ciprofloxacin and cyanocobalamin, and combinations of these drugs, were prepared by electrospinning. One set used the hydrophilic poly(vinylpyrrolidone) (PVP) as the filament-forming polymer, while the other used the slow-dissolving poly(ε-caprolactone) (PCL). The fibers were found t...

ExPress devices are available as P50 and P200 models, the numbers related to their luminal diameters in μm. We compared their Poiseuille's Law-based theoretical resistance values with experimental values and correlated these with their luminal dimensions derived from electron microscopy. Scanning electron microscopy was performed on P50 and P200 de...

Dendritic cell (DC)-based cancer vaccines are expected to elicit a specific immune response against tumor cells. It is thus important to design an efficient platform to target DCs and modulate the intracellular trafficking of antigens. The goal is to develop PLA-PEG-bis-sulfone polymeric nanoparticles (NPs) that can be functionalized site-specifica...