Evaluation of different PAMAM dendrimers as molecular vehicle of 1,2,4-triazine N-oxide derivative with potential antitumor activity

Gallic acid-PAMAM and gallic acid-phospholipid conjugates, physicochemical characterization and in vivo evaluation

Gallic acid (GA) is a naturally occurring compound with valuable antioxidant activity. Its oral bioavailability is limited by its high metabolism and rapid clearance. In this paper, GA was conjugated with two different materials, phosphatidylcholine (PC) and polyamidoamine (PAMAM) dendrimer. The prepared conjugates were characterized by FTIR, DSC, and SEM. Also, they were tested for drug content and in vitro drug release. It was found that GA conjugation with both materials have significantly prolonged its release up to 12 h. In vivo hepatoprotective activity of free and conjugated GA was studied in rats after carbon tetrachloride (CCl4)-induced oxidative damage in rat liver through measurement of different liver marker enzymes (aspartate aminotransferase (AST), alanine aminotransferase (ALT)), in addition to the total protein and albumin level in rat serum. Also, histopathological examination of liver cell of all rat groups was done. Results showed that both prepared conjugates have significantly reduced the hepatic marker enzymes accompanied by normalizing total protein and albumin levels in rat serum and with respect to CCl4-induced group (p < .05). Histopathological examination showed that pretreatment of rats with GA-PC or GA-PAMAM before CCL4 could reduce the induced cellular histopathological changes. It appears that conjugation of GA could enhance its bioavailability and increase its hepatoprotective effect.

Formation and characterization of Langmuir and Langmuir-Blodgett films of Newkome-type dendrons in presence and absence of a therapeutic compound, for the development of surface mediated drug delivery systems

Organic macromolecules with dendrimeric architectures are polymeric materials potentially useful as nanocarriers for therapeutic drugs. In this work, we evaluate a series of Newkome-type dendrons in Langmuir and Langmuir-Blodgett films as platforms capable of interacting with a potential antitumoral agent. The nanocomposite is proposed as model for the development of surface mediated drug delivery systems. We were successful in the formation and characterization of pure (dendrons) and composite (drug-dendron) stable and reproducible monolayers, and their transfer to solid substrates. A detailed study of topographic characteristics of the generated surfaces by atomic force microscopy was conducted. Furthermore, we probed dendron monolayer films as anchorage surfaces for mammalian cells. Normal cell attachment and proliferation on the surfaces were observed. No evident cytotoxic effects were detected, demonstrating the adequate biocompatibility of the surfaces.

Synthesis of PAMAM dendrimer-based fast cross-linking hydrogel for biofabrication

Hydrogels possess great potential in biofabrication because they allow cell encapsulation and proliferation in a highly hydrated three-dimensional environment, and they provide biologically relevant chemical and physical signals. However, development of hydrogel systems that mimic the complexity of natural extracellular matrix remains a challenge. In this study, we report the development of a binary hydrogel system containing a synthetic poly(amido amine) (PAMAM) dendrimer and a natural polymer, i.e., hyaluronic acid (HA), to form a fast cross-linking hydrogel. Live cell staining experiment and cell viability assay of bone marrow stem cells demonstrated that cells were viable and proliferating in the in situ formed PAMAM/HA hydrogel system. Furthermore, introduction of a Arginylglycylaspartic acid (RGD) peptide into the hydrogel system significantly improved the cell viability, proliferation, and attachment. Therefore, this PAMAM/HA hydrogel system could be a promising platform for various applications in biofabrication.