Cationic cycloamylose based nucleic acid nanocarriers

Nucleic acid delivery by viral and non-viral methods has been a cornerstone for the contemporary gene therapy aimed at correcting the defective genes, replacing of the missing genes, or downregulating the expression of anomalous genes is highly desirable for the management of various diseases. Ostensibly, it becomes paramount for the delivery vectors to intersect the biological barriers for accessing their destined site within the cellular environment. However, the lipophilic nature of biological membranes and their potential to limit the entry of large sized, charged, hydrophilic molecules thus presenting a sizeable challenge for the cellular integration of negatively charged nucleic acids. Furthermore, the susceptibility of nucleic acids towards the degrading enzymes (nucleases) in the lysosomes present in cytoplasm is another matter of concern for their cellular and nuclear delivery. Hence, there is a pressing need for the identification and development of cationic delivery systems which encapsulate the cargo nucleic acids where the charge facilitates their cellular entry by evading the membrane barriers, and the encapsulation shields them from the enzymatic attack in cytoplasm. Cycloamylose bearing a closed loop conformation presents a robust candidature in this regard owing to its remarkable encapsulating tendency towards nucleic acids including siRNA, CpG DNA, and siRNA. The presence of numerous hydroxyl groups on the cycloamylose periphery provides sites for its chemical modification for the introduction of cationic groups, including spermine, (3-Chloro-2 hydroxypropyl) trimethylammonium chloride (Q188), and diethyl aminoethane (DEAE). The resulting cationic cycloamylose possesses a remarkable transfection efficiency and provides stability to cargo oligonucleotides against endonucleases, in addition to modulating the undesirable side effects such as unwanted immune stimulation. Cycloamylose is known to interact with the cell membranes where they release certain membrane components such as phospholipids and cholesterol thereby resulting in membrane destabilization and permeabilization. Furthermore, cycloamylose derivatives also serve as formulation excipients for improving the efficiency of other gene delivery systems. This review delves into the various vector and non-vector-based gene delivery systems, their advantages, and limitations, eventually leading to the identification of cycloamylose as an ideal candidate for nucleic acid delivery. The synthesis of cationic cycloamylose is briefly discussed in each section followed by its application for specific delivery/transfection of a particular nucleic acid.

The contemplation of amylose for the delivery of ulcerogenic nonsteroidal anti-inflammatory drugs

This manuscript proposes an innovative approach to mitigate the gastrointestinal adversities linked with nonsteroidal anti-inflammatory drugs (NSAIDs) by exploiting amylose as a novel drug delivery carrier. The intrinsic attributes of V-amylose, such as its structural uniqueness, biocompatibility and biodegradability, as well as its capacity to form inclusion complexes with diverse drug molecules, are meticulously explored. Through a comprehensive physicochemical analysis of V-amylose and ulcerogenic NSAIDs, the plausibility of amylose as a protective carrier for ulcerogenic NSAIDs to gastrointestinal regions is elucidated. This review further discusses the potential therapeutic advantages of amylose-based drug delivery systems in the management of gastric ulcers. By providing controlled release kinetics and enhanced bioavailability, these systems offer promising prospects for the development of more effective ulcer therapies.

Synthesis and evaluation of amylose-mefenamic acid conjugates as colon-targeting prodrugs

Aim: Amide-linked amylose-based prodrugs were developed for colon-targeted release of mefenamic acid. Materials & methods: Activation of prodrug was studied spectrophotometrically, enzyme-linked immunosorbent assay appraised cyclooxygenase-1 (COX-1) and cyclooxygenase-2 (COX-2) inhibition at different concentrations of the prodrug, the behavior of prodrug under physiological conditions was monitored by scanning electron microscopy. Results: Prodrug was poorly activated in the enzyme-free simulated gastric media and simulated intestinal media (SIM) but preincubation in pancreatin followed by treatment in aminopeptidase containing SIM led to a significant activation of prodrug. Conclusion: Amide-linked amylose-mefenamic acid conjugates showed a slow release in simulated gastric media and a controlled release in SIM with pancreatin playing an important role in drug release.

Targeted delivery of fenamates with aminated starch

Aim: To develop controlled-release tablets based on aminated starch. Materials & methods: Aminated starch was characterized with Fourier transform infrared and x-ray diffraction. Thermogravimetric analysis confirmed the preferential oxidation of crystalline region of starch. Results: The tablets achieved an initial fast release of fenamates, which slows down after 12 h. Drug release was not completed in the simulated intestinal media, which may be due to the stability of imine bond in aminated starch at weakly acidic pH. Drug release was completed in simulated acidic media due to the hydrolysis of imine functionality at strongly acidic pH. Conclusion: Aminated starch with an imine functionality may serve as intestine targeted, controlled drug-delivery system. Mucoadhesive potential of tablets further supports this observation.