SARS-CoV-2 is a new member of the coronavirus family and caused the pandemic of coronavirus disease 2019 (COVID-19) in 2020. It is crucial to design and produce an effective vaccine for the prevention of rapid transmission and possible deaths wcaused by the disease. Although intensive work and research are being carried out all over the world to develop a vaccine, an effective and approved formulation that can prevent the infection and limit the outbreak has not been announced yet. Among all types of vaccines, epitope-based peptide vaccines outshine with their low-cost production, easy modification in the structure, and safety. In this review, vaccine studies against COVID-19 have been summarized and detailed information about the epitope-based peptide vaccines against COVID-19 has been provided. We have not only compared the peptide vaccine with other types of vaccines but also presented comprehensive literature information about development steps for an effective and protective formulation to give an insight into on-going peptide vaccine studies against SARS-CoV-2.

This work is based on a natural polymer chitosan used in a nanoparticulate drug delivery system for the controlled release of amiodarone along with β-cyclodextrin. Amiodarone-loaded chitosan nanoparticles were prepared using the ionic gelation method aided by sonication. Amiodarone loading on chitosan nanoparticles was done under optimum conditions. For particle characterization; zeta-sizer, UV/Vis, Fourier-transform infrared spectroscopy, X-ray powder diffraction, differential scanning calorimeter and scanning electron microscope techniques were used. In vitro drug release studies of amiodaroneloaded chitosan nanoparticles were performed using the dialysis diffusion technique. Drug loading and release values were determined using UV/Vis spectroscopy. Amiodarone encapsulated in nanoparticles was completely released at the end of 14 days. About 38 % was released at the end of day 1, 44% released at the end of day 3, 50 % released at the end of day 5 followed slow release. Amiodarone-loaded chitosan nanoparticles could serve as a model for controlled delivery of many antiarrhythmic drugs.

The aim of this study is to improve the solubility, chemical stability, and in vitro biological activity of caffeic acid phenethyl ester (CAPE) by forming inclusion complexes with β-cyclodextrin (β-CD) and hydroxypropyl-β-cyclodextrin (Hβ-CD) using the solvent evaporation method. The CAPE contents of the produced complexes were determined, and the complexes with the highest CAPE contents were selected for further characterization. Detailed characterization of inclusion complexes was performed by using Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and electrospray ionization-mass spectrometry (ESI-MS). pH and thermal stability studies showed that both selected inclusion complexes exhibited better stability compared to free CAPE. Moreover, their antimicrobial activities were evaluated against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) for the first time. According to the broth dilution assay, complexes with the highest CAPE content (10C/β-CD and 10C/Hβ-CD) exhibited considerable growth inhibition effects against both bacteria, 31.25 μg/mL and 62.5 μg/mL, respectively; contrarily, this value for free CAPE was 500 μg/mL. Furthermore, it was determined that the in vitro antioxidant activity of the complexes increased by about two times compared to free CAPE.

The synthesis and applications of the peptides are gaining increasing popularity as a result of the developments in biotechnology and bioengineering areas and for a number of research purposes including cancer diagnosis and treatment, antibiotic drug development, epitope mapping, production of antibodies, and vaccine design. The use of synthetic peptides approved by the health authorities for vaccine, for cancer, and in drug delivery systems is increasing with these developments. The aim of this book chapter is to review the recent developments in the use of peptides in the diagnosis of drug and vaccine systems and to present them to the reader with commercially available illustrations.