TUNING THE MECHANICAL AND ADHESIVE PROPERTIES OF TRANS-DERMAL DRUG DELIVERY SYSTEMS
Tesi di Dottorato
Data di Pubblicazione:
2018
Citazione:
TUNING THE MECHANICAL AND ADHESIVE PROPERTIES OF TRANS-DERMAL DRUG DELIVERY SYSTEMS / G.m.g. Quaroni ; tutor: P. Minghetti ; coordinatore: G. Aldini. DIPARTIMENTO DI SCIENZE FARMACEUTICHE, 2018 Jan 17. 30. ciclo, Anno Accademico 2017. [10.13130/g-m-g-quaroni_phd2018-01-17].
Abstract:
Drugs are usually applied onto the skin either for the treatment of localized diseases or systemic pathologies.
Among the available dosage forms transdermal patches and the newest film-forming systems are considered the most attractive dosage forms.
Firmly adhering to the skin, they assure a prolonged release of the drug predetermining the administered dose and the area of application.
Film-forming systems are composed by a polymeric solution or suspension which contains the active substance(s). Patches in their simplest configuration consist of a flexible backing layer, an adhesive matrix in which the active substance(s) are dissolved or dispersed and a removable release liner.
Both such dosage forms must comply peculiar technological features. Film-forming systems should quickly dry on the skin and the formed film should be almost invisible and non-sticky. Furthermore, their mechanical properties should overcome the stresses caused by body movements. Transdermal patches have to be sticky and exhibit an optimal balance between adhesion and cohesion. Indeed, a patch should strongly adhere to the skin and be easily removed with no or little trauma. Moreover, a certain cohesiveness is necessary so that the patch will not move when applied in vivo and can be peeled away without living any residues.
To satisfy the requirements of flexibility necessary to assure a proper skin/dosage form contact, a material should have an elastic modulus lower than that of the skin and, in the case of a patch, a viscoelastic pattern.
Despite many products are currently available on the market, some critical issues, such as adhesive and mechanical properties, which affect the residence time of the dosage form onto the skin and subsequently its therapeutic efficacy, are still scarcely investigated. Hence, there is the need to study the overall relevant issues involved in designing film-forming systems and transdermal patches and clarify the possible relationships between their features. This kind of relationship could provide useful information to design and optimize both such dosage forms.
This doctoral thesis aimed to evaluate the effect of the formulation compositions on rheological, adhesive and mechanical properties as well as on the in vitro biopharmaceutical performances of different polymeric matrices in order to design film forming systems and transdermal patches. In particular, the experimental work was focused on: (i) the design of film-forming systems based on an ammonium methacrylate copolymer (Eudragit RL) solubilized in a mixture of solvents in different ratios and plasticized by different amounts of plasticizer; the effects of solvent systems as well as the addition of the plasticizer were evaluated on drying time, outward stickiness, mechanical properties and in vitro biopharmaceutical performances; (ii) the design of transdermal patches based on differently plasticized ammonium methacrylate copolymer (Eudragit RL) and the evaluation of their rheological and tack properties, primarily to better understand their debonding mechanisms and adhesive characteristics; moreover, the main technological and in vitro biopharmaceutical properties were tested; (iii) the design of transdermal patches based on a styrenic copolymer (styrene-block-(ethylene-co-butylene)-block-styrene, SEBS); the effects of tackifiers and SEBS molecular weights on the rheological and adhesive properties of the materials were investigated. In particular, the debonding behavior under different operative conditions were evaluated and the technological as well as the in vitro biopharmaceutical performances of the formulated patches were studied.
The overall results allowed to confirm the versatility of the ammonium methacrylate copolymer (Eudragit RL),
Tipologia IRIS:
Tesi di dottorato
Elenco autori:
G.M.G. Quaroni
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