Transdermal and transbuccal delivery of lidocaine and nicotine : combined effects of iontophoresis and chemical enhancers

This study focused on the effects of iontophoresis and chemical enhancers on drug release. The transport of Lidocaine HCl (LHCl) and Nicotine Hydrogen Tartrate (NHT) through the skin and mucosa was evaluated for potential clinical applications. These two potential delivery routes have the advantage of avoiding first-pass effect. Samples were pretreated with enhancer solutions for one hour before the experiments. Passive or 0.3 mA iontophoresis-assisted drug diffusion was conducted for 8 hours to monitor the cumulative amount of drug released. Graphical methods and mathematical optimization techniques were implemented to analyze the data. The effects of chemical enhancers on the delivery rate depend largely on the drug used while iontophoresis mainly increases the steady-state flux. Parametric analyses show that a balance between high flux and fast release should be considered when conducting formulation and optimization studies

Pharma-engineering of multifunctional microneedle array device for application in chronic pain

Chronic pain poses a major concern to modern medicine and is frequently undertreated, causing suffering and disability. Transdermal delivery is the pivot to which analgesic research in drug delivery has centralized especially with the confines of needle phobias and associated pain related to traditional injections, and the existing limitations associated with oral drug delivery. Highlighted within this thesis is the possibility of further developing transdermal drug delivery for chronic pain treatment using an Electro-Modulated Hydrogel- Microneedle array (EMHM) prototype device for the delivery of analgesic medicatio

Kompozitni rezervoari sa umreženim hidrogelom poli(akrilne kiseline) za kontrolisanu dostavu lekova putem nespecifičnih električnih interakcija

Transdermal and subcutaneous drug delivery routes offer many advantages compared to the enteral route of drug administration including improved drug bioavailability, maintenance of optimal drug levels in the systemic circulation, reduction of toxicity, and better patient compliance. The overall aim of this dissertation was to synthesize and characterize composite hydrogels composed of the cross-linked poly(acrylic acid) hydrogel and the hydrophobic polymer base that are suitable for the storage and controlled delivery of cationic drugs mediated by non-specific electrical interactions. We successfully synthesized composite hydrogel membranes and implants by combining the ultraviolet or gamma irradiation-induced polymerization and liquid phase inversion. Physicochemical properties of the materials, such as chemical composition, microstructure, ion-exchange capacity, swelling behavior, and ionic conductivity, were analyzed. In vitro release from composite hydrogel reservoirs was investigated using methylene blue as the model drug. Examined composite hydrogel reservoirs showed mainly diffusion-controlled release kinetics. We developed a modeling approach based on the analytical solution for diffusion and the empirical Weber-Morris model that effectively describes the release kinetics using the concept of apparent diffusion coefficient. Rate-limiting barriers defined by the composite hydrogel microstructure and ion exchange governed the passive release kinetics. Iontophoretic excitation of composite membranes confirmed their electrical responsivity and induced an effective increase in the apparent diffusion coefficient. Obtained composite hydrogels hold promise for drug delivery, but also for applications in nanomaterial synthesis and iontronics.Transdermalni i subkutani načini dostave aktivnih supstanci nude brojne prednosti u poređenju sa enteralnim načinom jer se postiže veća bioraspoloživost leka, njegova optimalna koncentracija u sistemskoj cirkulaciji, smanjena toksičnost i veća komfornost pacijenata. Glavni cilj ove disertacije bila je sinteza i karakterizacija kompozitnih hidrogelova koji sadrže umreženi hidrogel poli(akrilne kiseline) i hidrofobnu polimernu bazu, a pogodni su za skladištenje i kontrolisanu dostavu katjonskih lekova putem nespecifičnih električnih interakcija. Kompozitni hidrogelovi, u formi membrana i implantata, su uspešno sintetisani kombinovanjem metoda polimerizacije indukovane ultraljubičastim ili gama zračenjem i metode mokre fazne inverzije. Analizirana su fizičko-hemijska svojstva materijala kao što su hemijski sastav, mikrostruktura, jonoizmenjivački kapacitet, karakteristike bubrenja i jonska provodljivost. Proces otpuštanja aktivne supstance iz kompozitnih rezervoara sa hidrogelom je ispitivan u in vitro uslovima korišćenjem metilenskog plavog kao model leka. Ispitani kompozitni rezervoari sa hidrogelom su pokazali uglavnom difuziono kontrolisanu kinetiku otpuštanja. Razvijen je pristup modelovanju zasnovan na analitičkom rešenju za difuziju i empirijskom Veber-Moris modelu koji efektivno opisuje kinetiku otpuštanja korišćenjem koncepta prividnog koeficijenta difuzije. Kinetika pasivnog otpuštanja je bila diktirana barijerama definisanim mikrostrukturom kompozitnog hidrogela i jonskom izmenom. Jontoforetska pobuda kompozitnih membrana potvrdila je njihovu elektroresponzivnost i indukovala efektivni porast prividnog koeficijenta difuzije. Očekuje se da dobijeni kompozitni hidrogelovi pronađu primenu u dostavi lekova, kao i u sintezi nanomaterijala i jontronici

Study of the Characteristics of Scalp Electroencephalography Sensing

Ph.DDOCTOR OF PHILOSOPH

Suportes físicos para imobilização de sistemas de libertação controlada de fármacos bioinspirados pelo processo de polinização

Mestrado em Biotecnologia Industrial e AmbientalNos últimos anos, a administração transdérmica de fármacos foi aponte como uma via de libertação de fármacos de sucesso devido às suas enumeras vantagens. Relativamente aos sistemas convencionais, este é um sistema não doloroso, apresenta menos efeitos secundários e possibilita uma dose menos frequente. Os pensos representam a maior quota do mercado de sistemas de libertação transdérmica de fármaco. No entanto, a sua aplicação tem sido restringida pelos atuais problemas associados à sua administração passiva. Com base no conceito de biomimetismo, um novo e otimizado sistema para administração transdérmica de fármacos é aqui proposto, bioinspirado na capacidade das abelhas aprisionarem e, consequentemente, libertarem o pólen durante o processo de polinização. Assim, foi desenhado um penso hierárico biomimético obtido a partir de polidimetilsiloxano (PDMS) com um micropadrão de pilares (imitando o pêlo presente nas patas das abelhas). A otimização do sistema foi obtida pela conjugação de micropilares espaçados com a mesma distância que o diâmetro das partículas de fármaco. Obteve-se assim uma eficiência de aprisionamento de 24,8 ± 0,4 mg/cm2, estando acima dos valores obtidos para os pensos atualmente disponíveis no mercado, bem como na maioria dos trabalhos até aqui efetuados. A tetraciclina, um antibiótico modelo, foi aqui utilizado para determinar o perfil de libertação de dois sistemas diferentes: pensos com tetraciclina em pó ou com micropartículas de alginato encapsuladas com esse mesmo fármaco. Enquanto o pó de tetraciclina foi rapidamente libertado, o sistema mais complexo permitiu uma libertação controlada do composto ativo durante 5 dias. Os pensos foram caracterizados por microscopia eletrónica de varrimento, microscopia de fluorescência e resistência à tração. Além disso, a atividade antimicrobiana também foi também verificada. Em suma, os resultados obtidos propõem a aplicação deste penso a nível clínico, proporcionando uma elevada concentração de fármaco que poderá resolver os problemas atuais associados aos sistemas de administração passiva de fármacos.In the last years, transdermal drug delivery has been exploited as a successful controlled drug release route due their several advantages (e.g. no painful, less frequent dosage and side effects), being the patches the largest market share of such systems. Nevertheless, current problems associated with passive delivery patches have been limiting their application. Based on the insights behind the biomimetics concept, herein we propose as novel and optimized system for transdermal drug delivery purposes, a bioinspired patch based on the remarkable bee’s ability to catch and release the pollen during pollination. For this purpose, a hierarchical biomimetic polydimethylsiloxane (PDMS) micropatterning patch with micropillars (mimicking the hair of bee’s legs) was engineered. An optimized system was obtained through the combination of patch with micropillars spaced with the same distance as drug microparticles' diameter. In fact, an entrapment efficiency of 24.8 ± 0.4 mg/cm2 was achieved, being above the actual commercially available patches and most of the current research works. The release profile was determinate to two different systems: patches with either tetracycline hydrochloride powder or tetracycline loaded alginate microparticles, a model antibiotic. While tetracycline powder was immediately release, the most complex system allowed for a controlled and sustained release of the active pharmaceutical ingredient (API) for 5 days. The engineered patches were characterized by SEM, fluorescent microscopy, tensile strength and antimicrobial activity was also verified. The results herein obtained suggest that the optimized patch could be further developed for clinical applications, providing high drug concentration that could solve the current problems associated with passive drug delivery patches

Skin-targeting platforms based on poly (β-amino ester)s for local immunotherapy

El potencial curatiu de les immunoteràpies per a estimular o suprimir respostes immunes ha revolucionat el paradigma sota el qual malalties como el càncer o trastorns autoimmunes son tractats; no obstant, una implementació extensa d’aquestes no ha sigut possible degut a la seva toxicitat. Donada la capacitat dels nanomaterials de reconduir fàrmacs immunomoduladors cap a teixits diana, les plataformes per alliberar fàrmacs dissenyades a partir de biomaterials podrien solucionar les necessitats més urgents d’aquest camp com l’alliberació específica a cèl·lules diana, l’alliberament local —en comptes de sistèmic— i l’acumulació a teixits diana per tal d’augmentar la seva eficàcia i seguretat. Aquesta tesi proposa l’ús de poly(β-amino ester)s (PBAEs) per al desenvolupant de vehicles d’alliberament dirigits cap a les pell amb l’objectiu de modular el sistema immune a nivell local en els àmbits de la vacunació amb àcids nucleics, la immunoteràpia contra el càncer y la teràpia adoptiva. S’ha presentat una nova llibreria de PBAEs modificats amb oligopèptids i manosa amb especificitat cel·lular cap a les cèl·lules dendrítiques, les principals presentadores d’antigen a la pell. L’efecte sinèrgic entre els oligopèptids i el lligand ha permès millorar substancialment el rendiment d’aquests vector per a vacunació amb mRNA/DNA. Addicionalment, aquest s’han pogut formular sense necessitar de fer servir solvents ni en forma de nanopartícules, a més de poder-los integrar en dispositius mèdics com microagulles, ja sigui en forma de partícules o films, per tal de transferir gens de manera no invasiva. Com a teràpia contra el càncer, una microagulles innovadores fetes a partir d’hidrogels s’han utilitzat per a alliberar un fàrmac immunomodulador mentre recol·lectaven líquid intersticial simultàniament per tal monitoritzar l’eficiència de la teràpia. Les microagulles carregades amb PBAEs foren capaces de reduir la mida de tumors y modular el microambient tumoral, la composició immunològica del qual correlaciona amb la del líquid intersticial mostrejat. Finalment, les microagulles s’han reciclat com a plataforma per a restablir l’equilibri immunològic en transplantaments de pell. Les microagulles reclutaren cèl·lules T reguladores cap als transplantaments gràcies a l’alliberació de citocines mentre vigilaven in situ la migració d’aquestes. En conclusió, aquesta tesi demostra el potencial de les plataformes transdèrmiques derivades de PBAEs per a induir immunomodulació a nivell local. Prioritzant plataformes sense solvents, locals i no-invasives, en aquesta tesi s’han optimitzat nous sistemes basats en PBAEs i integrats en dispositius mèdics com microagulles per a immunoteràpia.El potencial curativo de las inmunoterapias para estimular o suprimir el sistema inmune ha revolucionado el paradigma bajo el que enfermedades como el cáncer o trastornos autoinmunes son tratados; no obstante, la implementación de dichas terapias se ha visto restringida por su toxicidad. Dada la capacidad de los nanomateriales para redirigir fármacos inmunomoduladores a tejidos dianas, las plataformas de liberación basadas en biomateriales podrían solventar las mayores necesidades del ámbito incluyendo, liberación específica a células diana, localizada —en vez de sistémica— y acumulación en tejidos diana para así aumentar su potencia y seguridad. Usando los poly(β-amino ester)s (PBAEs) como piedra angular, esta tesis propone desarrollar vectores dirigidos hacía la piel con el fin de modular el sistema inmune a nivel local en ámbitos tales como vacunación con ácidos nucleicos, inmunoterapia contra cáncer y terapia celular adoptiva. Se ha presentado una nueva librería de PBAEs modificados con oligopéptidos y manosa que poseen especificidad celular hacia células dendríticas, las principales instigadoras en la presentación de antígenos en la piel. El efecto sinérgico entre oligopéptidos y ligando ha permitido mejorar sustancialmente estos vehículos de transporte para vacunación. Además, los PBAEs se han podido formular como vectores alternativos a las nanopartículas y que no precisan solventes, así como integrarlos en dispositivos médicos como microagujas, ya sea en forma de partículas o de films, para transferir genes de manera no invasiva. Como terapia contra el cáncer, se han diseñado microagujas de hidrogel que permiten la liberación de un fármaco inmunoestimulante además de colectar líquido intersticial para monitorear la respuesta a la terapia in situ. Las microagujas cargadas con PBAEs pudieron reducir el tamaño de los tumores y modular el microambiente tumoral, la composición del cual correlaciona con la del líquido intersticial colectado con dicha plataforma. Finalmente, las microagujas fueron usadas para restablecer el equilibrio inmunológico en trasplantes de piel. Las microagujas pudieron reclutar células T reguladoras hacia el trasplante mediante la liberación de citoquinas quimioatrayentes además de informar sobre su proceso de migración hacia el trasplante. En conclusión, esta tesis demuestra el potencial de las plataformas transdérmicas basadas en PBAEs para inducir inmunomodulación local. Priorizando plataformas sin solventes, locales, y poco invasivas, se han desarrollado sistemas basados en PBAEs e integrados con microagujas para inmunoterapia.The curative potential of immunotherapies to augment or suppress immune responses has shifted the paradigm for managing various diseases including cancer and autoimmune disorders, yet broad implementation has been curtailed by detrimental off-target toxicities. Given the ability of nanomaterials to direct immunomodulators to target tissues, nanomedicine-based delivery platforms formulated in carrier biomaterials could surmount the most pressing needs in the field being cell-specific targeting, local —rather than systemic— administration, and tissue accumulation to ultimately enhance the safety and potency of these therapeutic products. Using poly(β-amino ester)s (PBAEs) as foundational nanocarriers, this thesis proposes to engineer PBAE-based delivery platforms to target the immunologically rich milieu of the skin for local immunomodulation in the contexts of nucleic acid vaccination, cancer immunotherapy and adoptive T cell therapy. First, a novel library of oligopeptide- and mannose-modified PBAEs is presented for refined targeting of dendritic cells (DCs) as primary orchestrators of antigen presentation in the skin. The synergistic potential of oligopeptide and ligand decoration to target dermal DC subsets has been demonstrated as a powerful tool to upgrade delivery vectors for gene vaccination. Nanoparticle- and solvent-free delivery of nucleic acids using PBAEs formulated as polyelectrolyte films (PEMs) has also been confirmed. PBAEs can be successfully integrated in transdermal devices such as microneedles, either as PEMs or as polyplexes, to mediate minimally-invasive gene transfer. Moving to cancer immunotherapy, a hydrogel-based MN platform is presented for delivery of an immunostimulatory drug and retrieval of interstitial skin fluid (ISF) for in situ immune surveillance of the response to therapy. It has been proven that PBAE-loaded MNs suppress tumor growth and modulate the immune signature of the tumor microenvironment, which appears to correlate with that from MN-sampled ISF. Finally, hydrogel MNs are proposed for restoring immune homeostasis in transplanted skin allografts. Recruitment of adoptively-transferred regulatory T cells into the allografts has been achieved by delivering chemoattractant chemokines with the MNs while also monitoring the Treg homing process via ISF sampling, confirming the potential of MNs as a mode of tissue surveillance. In conclusion, this thesis demonstrates the potential of transdermal platforms derived from PBAEs for local immunomodulation. Shifting from hypodermic administration to solvent-free, local, and minimally-invasive approaches, PBAE-based systems have been engineered with microneedles for immunotherapy delivery