Clinical Diagnosis and Drug Delivery

Clinical Diagnosis

 

Differential Scanning Calorimetry (DSC) has recently emerged as a promising technique that provides useful information about serum/plasma interactomics (composition in proteins and metabolites, as well as their interactions).

As a result of the illness, serum/plasma composition is altered and it is possible to discriminate between healthy individuals and patients with certain diseases.

A previous study performed in our group (25 healthy subjects and 60 gastric adenocarcinoma patients) showed that there were significant differences in the variables obtained from the calorimetric profiles of healthy and gastric adenocarcinoma patients and also between patients with different disease stages.

The validation and implementation of a methodology (DIGCAL) as a useful tool in diagnosing and monitoring relevant tumor pathologies (pancreatic ductal adenocarcinoma, preneoplasic pancreatic cystic lesions and stomach cancer), as well as in the isolation and identification of potential tumor biomarkers, are proposed in this project.

Calorimetric profiles of serum from healthy subjects and patients with the three types of cancer at different stages will be obtained before and after 6 months of clinical treatment. The multiparametric analysis of the thermal profiles will allow us to establish a clinical protocol for: 1/ screening a certain tumor process; 2/ classifying patients according to their tumour stage; 3/ monitoring the progression or control of the illness; 4/ identifying specific biomarkers for each disease type.

DIGCAL could reach the clinical level not only as a diagnosis tool, but also as a monitoring and tracking system of patients during the therapeutic treatment, adding value in prognostic or pharmacologic decisions. At the same time, identified potential biomarkers could be part of a user-friendly diagnosis kit for primary points of care.

 

Drug Delivery

 

Drug delivery is the method or process of administering a pharmaceutical compound to achieve a therapeutic effect in humans or animals. Drug delivery technologies modify drug release profile, absorption, distribution and elimination for the benefit of improving product efficacy and safety, as well as patient convenience and compliance. Drug release is from: diffusion, degradation, swelling, and affinity-based mechanisms. Most common routes of administration include the preferred non-invasive peroral (through the mouth), topical (skin), transmucosal (nasal, buccal/sublingual, vaginal, ocular and rectal) and inhalation routes. Many medications such as peptide and protein, antibody, vaccine and gene based drugs, in general may not be delivered using these routes because they might be susceptible to enzymatic degradation or cannot be absorbed into the systemic circulation efficiently due to molecular size and charge issues to be therapeutically effective. For this reason many protein and peptide drugs have to be delivered by injection or a nanoneedle array. For example, many immunizations are based on the delivery of protein drugs and are often done by injection.

Current efforts in the area of drug delivery include the development of targeted delivery in which the drug is only active in the target area of the body (for example, in cancerous tissues) and sustained release formulations in which the drug is released over a period of time in a controlled manner from a formulation. In order to achieve efficient targeted delivery, the designed system must avoid the host's defense mechanisms and circulate to its intended site of action. Types of sustained release formulations include liposomes, drug loaded biodegradable microspheres and drug polymer conjugates.

In this sense, Nanoparticles (NP) in Biomedicine represent a promising technology for drug transport and release. There are many possibilities for NP´s surface functionalization and so, many strategies for including drugs in them (allowing NP going mainly to their acting site) can be developed.

This research line represents a new strategy for including some antiviral compounds active against hepatitis C virus (HCV), that were previously developed in this group.

Several materials have been used:

 

1/ Cyclodextrins:

The chemical structure of CDs, cyclic oligosaccharides composed of α-1,4-glycosidic-linked glycosyl residues, pro­vides them structural and physico-chemical properties that allow their use as molecular carriers.

In their hydropho­bic cavity a wide range of compounds ranging from ions to proteins can be trapped. In addition, CDs exhibit low toxic­ity and low immunogenicity, and they have been used in the pharmaceutical field by promoting CD-drug complexes in order to improve the absorption, distribution, metabolism, excretion, and toxicity (ADMET)-related properties of a drug (eg, solubil­ity, stability, delivery and release, membrane permeability and absorption, toxicity). Currently, more than 30 products can be found in the market based on CD complexes.

 

2/ Shell Cross-Linked Polymeric Micelles

Cross-linked polymeric micelles (CLPM), formed by amphiphilic block copolymers, have been successful for biomedical applications.

First, they can fulfill those general requirements for drug delivery systems: water solubility, low toxicity, to increase the stability of the drug inside the living organisms, to facilitate cellular uptake compared to free drug, and to produce its controlled release at a specific location. Second, the amphiphilic nature of the constituent polymer results in a hydrophobic core and a hydrophilic shell that allows encapsulation of both types of drug. Third, these nanoparticles offer further stability under high dilution conditions, below the critical micellar concentration, compared to other polymeric micelles.

Indeed, cross-linking avoids its disintegration in the bloodstream and the release of the drug before reaching the target cell. Particularly, fixation of the micelle structure by light-induced covalent cross-linking, mostly employing acrylate reactive groups, represents a clean and effective procedure to prepare stable polymer micelles that can hold either water-soluble and non-water soluble molecules and transport them through the bloodstream.

 

3/ Block Copolymers Micelles

Polymeric drug carriers are one of the current challenges of nanomedicine. Since the concept of physical drug encapsulation within polymeric aggregates was introduced, a significant number of polymer assemblies have been identified.

In particular, the construction of amphiphilic block copolymer-based drug carriers is a subject of great interest and a stimulating topic of interdisciplinary research in chemistry, biology and materials science. In aqueous media, self-assembly of amphiphilic block copolymers (BCs) to minimize energetically unfavorable hydrophobic water interactions can lead to a variety of polymeric nanostructures including especially appealing spherical micelles and vesicles.