L'acceptabilité de la forme orale d'un médicament est fondamentale en pédiatrie dans la mesure où elle conditionne le succès de l'administration et l'adhérence au traitement. Malgré les règlements mis en place pour favoriser le développement de médicaments adaptés à l'usage pédiatrique, le manque de données de haut niveau de preuve portant sur les avantages et les inconvénients des différentes formes orales rend difficile le choix d'une formulation adaptée à l'enfant. L'objectif de ce travail de thèse était (i) d'évaluer les avantages et les inconvénients des différentes formes pharmaceutiques orales chez l'enfant, et (ii) de proposer une méthodologie pour évaluer l'influence de la forme orale sur la balance bénéfice / risque clinique et globale (aspects économiques, pratiques et logistiques) du médicament en pédiatrie. Dans une première partie, après avoir évalué et discuté les avantages et les inconvénients des formes orales utilisées en pédiatrie au moyen d'une revue de la littérature et d'études observationnelles, nous avons proposé un protocole de méta analyse Cochrane. Un état des lieux des formes orales administrées en pédiatrie a permis d'identifier les formes potentiellement non adaptées. Dans une seconde partie, nous avons étudié la faisabilité d'une modélisation pharmacocinétique pharmacodynamique pour évaluer l'influence de la forme orale sur la balance bénéfice / risque appliquée à l'acide valproïque (VPA). Les données de routine (concentrations résiduelles) ne permettant pas de construire un modèle pharmacocinétique afin d'évaluer l'influence des formes orales sur le profil de concentration du VPA, nous avons conçu un protocole d'essai clinique randomisé visant à évaluer l'acceptabilité et l'observance des formes orales du VPA, et à collecter les données pharmacocinétiques et pharmacodynamiques nécessaires à la construction du modèle pour l'évaluation de la balance bénéfice / risque du VPA. L'analyse des difficultés liées à l'évaluation de l'acceptabilité chez l'enfant et des limites à l'utilisation des données de routine tout au long de ce travail de thèse a été déterminante pour la conception de ce protocole / The acceptability of a medicine oral dosage form is fundamental in paediatrics as it determines the success of the administration and treatment adherence. Despite regulations implemented to stimulate the development of appropriate medicine for the paediatric population, the lack of high level proof data concerning advantages and limits of the different oral dosage forms makes difficult the choice of a suitable paediatric dosage form. The objectives of this thesis were (i) to assess advantages and limits of the different available oral dosage forms in children, and (ii) to propose a method to evaluate the influence of the oral dosage form on both clinical and overall (i.e. including economic, practical and logistical aspects) risk/benefit balance in paediatrics. First, we assessed and discussed advantages and limits of oral dosage forms used in children based on a literature review of expert’s opinion and available studies, and conducting observational studies in our paediatric hospital. We finally designed a Cochrane meta-analysis protocol. In addition, the analysis of oral dosage forms currently administered in our paediatric hospital allowed to identify those not suitable for children. Secondly, we studied the feasibility of a pharmacokinetic pharmacodynamic model to assess the influence of the oral dosage form on the valproate (VPA) risk/benefit balance. Routine data (serum trough concentrations) did not allow to simulate the influence of the oral dosage form on the VPA serum level profile. Thus, we designed a protocol of a randomised controlled trial aiming to assess the acceptability and adherence of the different VPA oral dosage forms, and to collect VPA pharmacodynamic and pharmacokinetic data needed for the building of the model to evaluate the influence of the oral dosage form on the risk/benefit balance. The difficulties related to medicine acceptability measurement in children and limits we encountered were decisive for the design of such protocol

Modified-release oral drug delivery dosage forms are widely used in the pharmaceutical field to overcome all the potential issues imposed by the physiological variabilities of the gastrointestinal tract as well as to maintain drug concentrations within the therapeutic window. In the market, they are available only as solid dosage forms such as capsules or tablets. The development of a liquid oral dosage form with modified-release properties has been keenly awaited. This form could increase the compliance of patients with a swallowing impairment (i.e. paediatric, older or critically ill patients) and, consequently, the efficacy of the therapeutic treatment. In this study, a new technology has been developed that consists of multi-layered particles suspended extemporaneously in a syrup. Omeprazole and budesonide have been employed as model drugs. The coating procedure was optimized to obtain a yield of minimum 90% w/w and a median diameter below 500 µm. Once the final suspension is prepared extemporaneously, it presents sufficient stability to guarantee the administration of multiple doses filled into a syrup bottle and kept for a limited storage time at room temperature (e.g. up to 10 doses to be administered within 10 days). / Doctorat en Sciences biomédicales et pharmaceutiques (Pharmacie) / info:eu-repo/semantics/nonPublished

One of the major challenges faced by the pharmaceutical industry is to accelerate the product innovation process and reduce the time-to-market for new drug developments. This involves billions of dollars of investment due to the large amount of experimentation and validation processes involved. A computational modeling approach, which could explore the design space rapidly, reduce uncertainty and make better, faster and safer decisions, fits into the overall goal and complements the product development process. Our research focuses on the early preclinical stage of the drug development process involving lead selection, optimization and candidate identification steps. Our work helps in screening the most favorable candidates based on the biopharmaceutical and pharmacokinetic properties. This helps in precipitating early development failures in the early drug discovery and candidate selection processes and reduces the rate of late-stage failures, which is more expensive. In our research, we successfully integrated two well-known models, namely the drug release model (dissolution model) with a drug transport model (compartmental absorption and transit (CAT) model) to predict the release, distribution, absorption and elimination of an oral drug through the gastrointestinal (GI) tract of the human body. In the CAT model, the GI tract is envisioned as a series of compartments, where each compartment is assumed to be a continuous stirred tank reactor (CSTR). We coupled the drug release model in the form of partial differential equations (PDE's) with the CAT model in the form of ordinary differential equations (ODE's). The developed model can also be used to design the drug tablet for target pharmacokinetic characteristics. The advantage of the suggested approach is that it includes the mechanism of drug release and also the properties of the polymer carrier into the model. The model is flexible and can be adapted based on the requirements of the clients. Through this model, we were also able to avoid depending on commercially available software which are very expensive. In the drug discovery and development process, the tablet formulation (oral drug delivery) is an important step. The tablet consists of active pharmaceutical ingredient (API), excipients and polymer. A controlled release of drug from this tablet usually involves swelling of the polymer, forming a gel layer and diffusion of drug through the gel layer into the body. The polymer is mainly responsible for controlling the release rate (of the drug from the tablet), which would lead to a desired therapeutic effect on the body. In our research, we also developed a molecular design strategy for generating molecular structures of polymer candidates with desired properties. Structure-property relationships and group contributions are used to estimate the polymer properties based on the polymer molecular structure, along with a computer aided technique to generate molecular structures of polymers having desired properties. In greater detail, we utilized group contribution models to estimate several desired polymer properties such as grass transition temperature (Tg), density (ρ) and linear expansion coefficient (α). We subsequently solved an optimization model, which generated molecular structures of polymers with desired property values. Some examples of new polymer repeat units are - [CONHCH₂ - CH₂NHCO]n -, - [CHOH - COO]n -. These repeat-units could potentially lead to novel polymers with interesting characteristics; a polymer chemist could further investigate these. We recognize the need to develop group contribution models for other polymer properties such as porosity of the polymer and diffusion coefficients of water and drug in the polymer, which are not currently available in literature. The geometric characteristics and the make-up of the drug tablet have a large impact on the drug release profile in the GI tract. We are exploring the concept of tablet customization, namely designing the dosage form of the tablet based on a desired release profile. We proposed tablet configurations which could lead to desired release profiles such as constant or zero-order release, Gaussian release and pulsatile release. We expect our work to aid in the product innovation process. / Ph. D.

Ceramics are distinguished from metals and polymers by their inorganic nature and lack of metallic properties. They can be highly crystalline to amorphous, and their physical and chemical properties can vary widely. Ceramics can, for instance, be made to resemble the mineral phase in bone and are therefore an excellent substitute for damaged hard tissue. They can also be made porous, surface active, chemically inert, mechanically strong, optically transparent or biologically resorbable, and all these properties are of interest in the development of new materials intended for a wide variety of applications. In this thesis, the focus was on the development of different ceramics for use in the controlled release of drugs and ions. These concepts were developed to obtain improved therapeutic effects from orally administered opioid drugs, and to reduce the number of implant-related infections as well as to improve the stabilization of prosthetic implants in bone. Geopolymers were used to produce mechanically strong and chemically inert formulations intended for oral administration of opioids. The carriers were developed to allow controlled release of the drugs over several hours, in order to improve the therapeutic effect of the substances in patients with severe chronic pain. The requirement for a stable carrier is a key feature for these drugs, as the rapid release of the entire dose, due to mechanical or chemical damage to the carrier, could have lethal effects on the patient because of the narrow therapeutic window of opioids. It was found that it was possible to profoundly retard drug release and to achieve almost linear release profiles from mesoporous geopolymers when the aluminum/silicon ratio of the precursor particles and the curing temperature were tuned. Ceramic implant coatings were produced via a biomimetic mineralization process and used as carriers for various drugs or as an ion reservoir for local release at the site of the implant. The formation and characteristics of these coatings were examined before they were evaluated as potential drug carriers. It was demonstrated that these coatings were able to carry antibiotics, bisphosphonates and bone morphogenetic proteins to obtain a sustained local effect, as they were slowly released from the coatings. / <p>Felaktigt tryckt som Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology 710</p>