Hello, my name is Ana Catarina Silva and
I'm an Assistant Professor of University Fernando Pessoa,
an invited Professor at the Faculty of Pharmacy from Porto, Portugal.
This is the first part of the talk on the "Need for Drug Delivery Systems" and
the second part will be delivered by my colleague Professor Joao Nuno Moreira.
I will start my presentation with an explanation about the general limitations of
the conventional pharmaceutical dosage forms and some of
the strategies used for improved drug bioavailability.
Afterwards, I'll provide an overview about the drug delivery systems and in particular,
the most studied nanosystems.
Finally, I'll end with some concluding remarks.
Among the general limitations of conventional pharmaceutical dosage forms are;
the fast drug elimination from the body which leads to unfavorable pharmacokinetics,
the need to perform repeated administration to achieve
constant drug plasma concentration that can originate problems of patient compliance.
The lack on the drug selectivity for target tissues that is responsible for
adverse and sub-therapeutic effects and the occurrence of
drug degradation and toxicity in the body that can originate in tissue damage.
All these limitations originate bioavailability problems.
Other limitations of the conventional pharmaceutical dosage forms are related to
the frequent synthesis of new drug molecules that belong to the BCS classes II and IV,
presenting lipophilic characteristics and
low solubility which may precipitate in aqueous media
and also to the BCS class III that have
high solubility and poor intestinal permeability.
These drugs present difficulties of formulation and therefore bioavailability problems.