Browsing by Author "Haj-Ahmad, R."
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Item Open Access Approaches in topical ocular drug delivery and developments in the use of contact lenses as drug-delivery devices(Taylor and Francis, 2017-06-21) Mehta, P.; Haj-Ahmad, R.; Al-Kinani, Ali; Arshad, Muhammad Sohail; Chang, Ming-Wei; Alany, Raid G.; Ahmad, Z.Drug-delivery approaches have diversified over the last two decades with the emergence of nanotechnologies, smart polymeric systems and multimodal functionalities. The intended target for specific treatment of disease is the key defining developing parameter. One such area which has undergone significant advancements relates to ocular delivery. This has been expedited by the development of material advancement, mechanistic concepts and through the deployment of advanced process technologies. This review will focus on the developments within lens-based drug delivery while touching on conventional and current methods of topical ocular drug delivery. A summary table will provide quick reference to note the key findings in this area. In addition, the review also elucidates current theranostic and diagnostic approaches based on ocular lenses.Item Open Access Broad Scale & Structure Fabrication of Healthcare Materials for Drug and Emerging Therapies Via Electrohydrodynamic Techniques(Wiley, 2018-09) Mehta, P.; Zaman, A.; Smith, A.; Rasekh, M.; Haj-Ahmad, R.; Arshad, M. S.; van der Merwe, S.; Chang, M-W.; Ahmad, Z.The engineering of advanced healthcare materials provides a platform to address challenges facing interdisciplinary scientists, clinicians, pharmacists, biomaterial scientists and biomedical engineers. Niche and timely developments arising from the synthesis or extraction of more biocompatible materials, new biologically active components, clearer insights into disease mechanisms and novel therapies or strategies provide several timely opportunities. These include enhanced therapies with greater patient compliance, improved disease targeting, better diagnosis and bespoke medications for individuals. Electrohydrodynamic atomisation (EHDA) engineering comprises several processes making use of electric fields (e.g. through an applied voltage) interplaying with several forces (e.g. gravity and surface tension). Coupled to advanced materials (e.g. formulated media) and specifically configured apparatuses (e.g. nozzles, collectors and downstream processes); effective and controlled fabrication of various structures (fibers, particles, bubbles, grids, droplets) on various scales (macro, micro and nano) possessing various dimensions (2D, 3D and 4D) is readily achieved. The processes have distinct advantages compared to established engineering methods (ambient environment engineering, low shear, scalability, compartmentalisation etc.). This detailed review focuses on key concepts and developments in EHDA engineering pertaining to underlying principles, enabling tools and engineered structures specifically for healthcare remits. From initial experiments involving the behaviour of non-formulated liquids on charged amber to recent developments in complex 3D matrix printing; the EHDA route has progressed significantly, most rapidly in the last two decades, and is capable of providing timely platform opportunities to tackle several global healthcare challengesItem Open Access Electrically atomised formulations of timolol maleate for direct and on-demand ocular lens coatings(Elsevier, 2017-06-15) Mehta, P.; Al-Kinani, Ali A.; Haj-Ahmad, R.; Arshad, Muhammad Sohail; Chang, Ming-Wei; Alany, Raid G.; Ahmad, Z.Item Open Access Electrosprayed mesoporous particles for improved aqueous solubility of a poorly water soluble anticancer agent: in vitro and ex vivo evaluation(Elsevier, 2018-03-30) Ahmad, Z.; Sayed, E.; Karavasili, Chirstina; Ruparelia, K. C.; Haj-Ahmad, R.; Charalambopoulou, G; Giasafaki, D.; Cox, Paul; Singh, Neenu; Giassafaki, Lefki-Pavlina N.; Mpenekou, A.; Steriotis, T.; Markopoulou, C. K.; Vizirianakis, I. S.; Chang, Ming-Wei; Fatoutos, D. G.Encapsulation of poorly water-soluble drugs into mesoporous materials (e.g. silica) has evolved as a favorable strategy to improve drug solubility and bioavailability. Several techniques (e.g. spray drying, solvent evaporation, microwave irradiation) have been utilized for the encapsulation of active pharmaceutical ingredients (APIs) into inorganic porous matrices. In the present work, a novel chalcone (KAZ3) with anticancer properties was successfully synthesized by Claisen-Schmidt condensation. KAZ3 was loaded into mesoporous (SBA-15 and MCM-41) and non-porous (fumed silica, FS) materials via two techniques; electrohydrodynamic atomization (EHDA) and solvent impregnation. The effect of both loading methods on the physicochemical properties of the particles (e.g. size, charge, entrapment efficiency, crystallinity, dissolution and permeability) was investigated. Results indicated that EHDA technique can load the active in a complete amorphous form within the pores of the silica particles. In contrast, reduced crystallinity (~79%) was obtained for the solvent impregnated formulations. EHDA engineered formulations significantly improved drug dissolution up to 30-fold, compared to the crystalline drug. Ex vivo studies showed EHDA formulations to exhibit higher permeability across rat intestine than their solvent impregnated counterparts. Cytocompatibility studies on Caco-2 cells demonstrated moderate toxicity at high concentrations of the anticancer agent. The findings of the present study clearly show the immense potential of EHDA as a loading technique for mesoporous materials to produce poorly water-soluble API carriers of high payload at ambient conditions. Furthermore, the scale up potential in EHDA technologies indicate a viable route to enhance drug encapsulation and dissolution rate of loaded porous inorganic materials.Item Open Access Fibrous polymeric buccal film formulation, engineering and bio-interface assessment(Elsevier, 2017-10-03) Nazari, K.; Kontogiannidou, Eleni; Haj-Ahmad, R.; Andreadis, Dimitrios; Rasekh, M.; Bouropoulos, Nikolaos; van der Merwe, Susanna M.; Chang, Ming-Wei; Fatouros, Dimitrios; Ahmad, Z.Polymer based dosages form the mainstay of drug delivery systems either as simple matrix carrier materials or active release behavior modulating agents. In addition, several techniques have been developed further to deliver novel polymeric structures. One such method is electrospinning (ES); a maturing process which is operational at the ambient environment and enables drug loading (in molecularly dispersed form) directly into a fibrous polymer matrix system. Since there is an impending need to address healthcare challenges arising from an increase in the aging population (requiring enhanced treatments), the ES method was used to develop fibrous polymer composite-indomethacin (INDO) films for potential use in the buccal region. Films were assessed for their inter-facial behavior at bio-interfaces (in-vitro and ex-vivo). Polymeric excipients possessing an established profile for commercial dosage form development were selected. Fibrous films (all fibre components <400 nm) were characterised using DSC, TGA, FTIR, Raman and XRD. DSC and XRD demonstrated INDO change from crystalline to amorphous state. FTIR and Raman data suggest INDO, PVP and co-polymers (Methocel™ E5, Methocel™ E15 and Tween® 80) were integrated in stable fashion into filamentous structures via ES. Variable INDO release behavior from several matrices was observed suggesting a potential route to tailor drug release based on polymeric excipient use and ratio. Furthermore, permeation studies using a porcine buccal model demonstrated sustained permeation once dosages are attached to the buccal mucosa. The insoluble nature of cellulose excipients were used to promote sustained release while the use of Tween® 80 surfactant was used to enhance permeation of INDO through polymer interaction with excised tissue. Finally, histology studies indicate polymer excipient selection impacts the bio-interface. In summary, a facile approach to formulate, encapsulate and engineer fibrous polymeric buccal films (on demand) is shown. The method enables drug dispersion directly within the composite polymeric system, which has a clear impact on drug release, in-vitro and ex-vivo bio-interaction.Item Open Access Microneedle Coating Techniques for Transdermal Drug Delivery.(Pharmaceutics, 2015-11-05) Haj-Ahmad, R.; Khan, H.; Arshad, M. S.; Rasekh, M.; Hussain, A.; Walsh, Susannah E.; Li, X.; Chang, M-W.; Ahmad, Z.Item Metadata only Pharmaceutical and biomaterial engineering via electrohydrodynamic atomization technologies(Elsevier, 2016-09-28) Mehta, P.; Haj-Ahmad, R.; Rasekh, M.; Arshad, Muhammad Sohail; Smith, Ashleigh; van der Merwe, Susanna M.; Li, Xiang; Chang, M-W.; Ahmad, Z.Item Open Access Porous Inorganic Drug Delivery Systems—a Review(Springer, 2017-02-28) Sayed, E.; Haj-Ahmad, R.; Ruparelia, K. C.; Arshad, M. S.; Chang, M-W.; Ahmad, Z.Innovative methods and materials have been developed to overcome limitations associated with current drug delivery systems. Significant developments have led to the use of a variety of materials (as excipients) such as inorganic and metallic structures, marking a transition from conventional polymers. Inorganic materials, especially those possessing significant porosity, are emerging as good candidates for the delivery of a range of drugs (antibiotics, anticancer and anti-inflammatories), providing several advantages in formulation and engineering (encapsulation of drug in amorphous form, controlled delivery and improved targeting). This review focuses on key selected developments in porous drug delivery systems. The review provides a short broad overview of porous polymeric materials for drug delivery before focusing on porous inorganic materials (e.g. Santa Barbara Amorphous (SBA) and Mobil Composition of Matter (MCM)) and their utilisation in drug dosage form development. Methods for their preparation and drug loading thereafter are detailed. Several examples of porous inorganic materials, drugs used and outcomes are discussed providing the reader with an understanding of advances in the field and realistic opportunities.Item Open Access Stable Increased Formulation Atomisation Using a Multi-Tip Nozzle Device(Springer, 2018-06-05) Ahmad, Z.; Haj-Ahmad, R.; Rasekh, M.; Nazari, K.; Onaiwu, E.V.; Yousef, B.; Morgan, S.; Evans, D.; Chang, Ming-Wei; Hall, John; Samwell, C.Electrohydrodynamic atomisation (EHDA) is an emerging technique for the production of micron and nano-scaled particles. The process often involves Taylor cone enablement, which results in a fine spray yielding formulated droplets, which then undergo drying during deposition. In this work novel multi-tip emiiter (MTE) devices were designed, engineered and utilised for potential up-scaled EHDA, by comparison with a conventional single needle system. To demonstrate this, the active ketoprofen (KETO) was formulated using polyvinylpyrrolidone (PVP) polymer as the matrix material. Here, PVP polymer (5% w/v) solution was prepared using ethanol and distilled water (80:20) as the vehicle. KETO was incorporated as 5% w/w of PVP. Physical properties of resulting solutions (viscosity, electrical conductivity, density and surface tension) were obtained. Formulations were electrosprayed through both single and novel MTEs under EHDA conditions at various flow rates (5-300 μl/min) and applied voltages (0-30 kV). The atomization process using MTEs and single nozzle was monitored at using various process parameters via a digital optical camera. Resulting particles were collected 200mm below processing heads and were analyzed using differential scanning calorimetry (DSC), thermal gravimetric analysis (TGA), X-ray diffraction (XRD) and scanning electron microscopy (SEM). Digital recordings confirmed stable MTE jetting at higher flow rates. Electron micrographs confirmed particle size variation arising due to nozzle head design and evidenced stable jetting derived greater near uniform particles. DSC, XRD and TGA confirm KETO molecules were encapsulated and dispersed into PVP polymer particles. In conclusion, novel MTE devices enabled stable atomisation even at higher flow rates when compared to the conventional single needle device. This indicates an exciting approach for scaling-up (EHDA) in contrast to current efforts focusing on multiple nozzle and pore based processing outlets.