A novel biocompatible polymer derived from D-mannitol used as a vector in the field of genetic engineering of eukaryotic cells.

The design and preparation of new vectors to transport genetic material and increase the transfection efficiency continue being an important research line. Here, a novel biocompatible sugar-based polymer derived from D-mannitol has been synthesized to be used as a gene material nanocarrier in human (gene transfection) and microalga cells (transformation process). Its low toxicity allows its use in processes with both medical and industrial applications. A multidisciplinary study about the formation of polymer/p-DNA polyplexes has been carried out using techniques such as gel electrophoresis, zeta potential, dynamic light scattering, atomic force microscopy, and circular dichroism spectroscopy. The nucleic acids used were the eukaryotic expression plasmid pEGFP-C1 and the microalgal expression plasmid Phyco69, which showed different behaviors. The importance of DNA supercoiling in both transfection and transformation processes was demonstrated. Better results were obtained in microalga cells nuclear transformation than in human cells gene transfection. This was related to the plasmid's conformational changes, in particular to their superhelical structure. It is noteworthy that the same nanocarrier has been used with eukaryotic cells from both human and microalga.

In-Depth Study into Polymeric Materials in Low-Density Gastroretentive Formulations.

The extensive use of oral dosage forms for the treatment of diseases may be linked to deficient pharmacokinetic properties. In some cases the drug is barely soluble; in others, the rapid transit of the formulation through the gastrointestinal tract (GIT) makes it difficult to achieve therapeutic levels in the organism; moreover, some drugs must act locally due to a gastric pathology, but the time they remain in the stomach is short. The use of formulations capable of improving all these parameters, as well as increasing the resident time in the stomach, has been the target of numerous research works, with low-density systems being the most promising and widely explored, however, there is further scope to improve these systems. There are a vast variety of polymeric materials used in low-density gastroretentive systems and a number of methods to improve the bioavailability of the drugs. This works aims to expedite the development of breakthrough approaches by providing an in-depth understanding of the polymeric materials currently used, both natural and synthetic, their properties, advantages, and drawbacks.

Development and characterization of new functionalized polyurethanes for sustained and site-specific drug release in the gastrointestinal tract.

The main objective of the present paper has been the development and study of two new biodegradable polyurethanes, PU(dithiodiethanol-DTDI) and PU[(iPr)Man-DTDI], to be used as sustained matrix forming excipients. Furthermore, their capacity to act as excipient for colon drug delivery systems has been evaluated. Thus, SeDeM diagrams have been obtained to investigate their suitability to be processed through a direct compression process. Matrices containing 10-30% w/w of the polymers and theophylline anhydrous as model drug have been manufactured. Release studies have been carried out using a modified dissolution assay simulating pH and redox conditions for the gastro intestinal tract, including colon. Drug dissolution data have been analyzed according to the main kinetic models and their Excipient Efficiencies for prolonged release have been calculated. The principal parameters of the SeDeM Expert system, such as the parametric profile (mean radius) and the good compression index obtained for the polymers are above the values considered as adequate for direct compression even without addition of flow agents. The obtained values for Excipient Efficiency show good ability of the polymer to control the drug release. Finally, in the case of PU(dithiodiethanol-DTDI), a clear increase in the release rate has been observed when the formulation is subjected to colon simulating conditions.