Colon targeted dosage form of Capecitabine using folic acid anchored modified carbon nanotube: in vitro cytotoxicity, apoptosis and in vivo roentgenographic study.

OBJECTIVE: Development of dosage form comprising of Capecitabine loaded carbon nanotubes for its targeted delivery to the colon. METHOD: Single walled carbon nanotubes (SWCNT) were functionalized by -COOH and Chitosan along with Folic acid. Capecitabine was loaded in these SWCNT's, and the system was analyzed by FTIR, SEM and Raman spectroscopy. Percent drug loading was assessed and the cytotoxicity (COLO320DM and HT29) was verified by using MTT and SRB assay. The apoptosis study was carried out by flowcytometry. The system was enclosed in an enteric coated capsule with pH sensitive polymers and characterized for invitro disintegration, dissolution and invivo roentgenographic studies. RESULTS: FTIR, Raman and XRD studies indicated the confirmation of attachments, whereas SEM exhibited size range of 200-500 nm. Drug loading capacity was observed to be 94.63 ± 1.07%. Cytotoxicity studies of Capecitabine and FA-CHI-F-SWCNT-Capecitabine against COLO320DM by using MTT assay showed that FA-CHI-F-SWCNT- Capecitabine exhibited 86.45 ± 0.5788% inhibition whereas pure Capecitabine showed 50.52 ± 0.3106% inhibition. Against HT29, the % inhibition was observed to be 82.76 ± 0.4668% and 56.41 ± 0.2316% respectively for FA-CHI-F-SWCNT-Capecitabine and pure Capecitabine. In case of SRB assay of COLO320DM, the FA-CHI-F-SWCNT-Capecitabine exhibited 89.62 ± 0.4095% inhibition and Capecitabine showed 84.36 ± 0.2559% inhibition, whereas against HT29, FA-CHI-F-SWCNT-Capecitabine showed 81.36 ± 0.2958% inhibition and Capecitabine exhibited 90.62 ± 0.4196% inhibition. CONCLUSION: FA-CHI-F-SWCNT loaded system revealed better cytotoxicity as compared with pure Capecitabine against two different cell lines. Invivo studies revealed that the prepared capsule formulation remained intact in the stomach thereby preventing drug release in the gastric milieu.

Understanding the Specific Implications of Amino Acids in the Antibody Development.

As the demand for immunotherapy to treat and manage cancers, infectious diseases and other disorders grows, a comprehensive understanding of amino acids and their intricate role in antibody engineering has become a prime requirement. Naturally produced antibodies may not have the most suitable amino acids at the complementarity determining regions (CDR) and framework regions, for therapeutic purposes. Therefore, to enhance the binding affinity and therapeutic properties of an antibody, the specific impact of certain amino acids on the antibody's architecture must be thoroughly studied. In antibody engineering, it is crucial to identify the key amino acid residues that significantly contribute to improving antibody properties. Therapeutic antibodies with higher binding affinity and improved functionality can be achieved through modifications or substitutions with highly suitable amino acid residues. Here, we have indicated the frequency of amino acids and their association with the binding free energy in CDRs. The review also analyzes the experimental outcome of two studies that reveal the frequency of amino acids in CDRs and provides their significant correlation between the outcomes. Additionally, it discusses the various bond interactions within the antibody structure and antigen binding. A detailed understanding of these amino acid properties should assist in the analysis of antibody sequences and structures needed for designing and enhancing the overall performance of therapeutic antibodies.

Significance of antibody numbering systems in the development of antibody engineering.

Immunotherapy has become increasingly popular in recent years for treating a variety of diseases including inflammatory, neurological, oncological, and auto-immune disorders. The significant interest in antibody development is due to the high binding affinity and specificity of an antibody against a specific antigen. Recent advances in antibody engineering have provided a different view on how to engineer antibodies in silico for therapeutic and diagnostic applications. In order to improve the clinical utility of therapeutic antibodies, it is of paramount importance to understand the various molecular properties which impact antigen targeting and its potency. In antibody engineering, antibody numbering (AbN) systems play an important role to identify the complementarity determining regions (CDRs) and the framework regions (FR). Hence, it is crucial to accurately define and understand the CDR, FR and the crucial residues of heavy and light chains that aid in the binding of the antibody to the antigenic site. Detailed understanding of amino acids positions are useful for modifying the binding affinity, specificity, physicochemical features, and half-life of an antibody. In this review, we have summarized the different antibody numbering systems that are widely used in antibody engineering and highlighted their significance. Here, we have systematically explored and mentioned the various tools and servers that harness different AbN systems.