Herbal Drugs as Immune Booster Against Viral Infections

Abstract:

The immune system involves both active and passive immunization. The antibodies are developed against the antigens during active immunization and are permanently stored. But, in the case of passive immunization, the antibodies are exposed to the same antigens in every person who is already infected. In order to enhance the immune systems i.e. innate and adaptive immune responses, herbal plants are used as an immune booster. Some of the herbal plants have been proven clinically to enhance immunity that includes Morniga oleifera (Drumstick), Azadirachta indica (Neem), Ocimum sanctum (Tulsi), Withania somnifera (Aswagandha), Zingiber officinale (Ginger), Allium sativum (Garlic), Curcuma longa (Turmeric), Emblica officinalis (Amla) etc. Compared to synthetic drugs, herbal drugs have fewer side effects and stimulate the immune system to defend against various foreign pathogens. Even though herbal medicines are usually considered as safe and effective therapy, it is clinically proven that if a drug is effective, it would have some side effects. But, sometimes, the antioxidant property of herbal medicines is helpful in reducing the toxicities produced by any toxic substances or any drugs. This review aims to encourage the study of various herbal constituents and their role in the treatment of different types of viral infections.

Biomarkers, tools, and test kits for COVID-19

Currently, the COVID-19 pandemic appears to be the biggest challenge to man, claiming over 600,000 lives within 7 months. Various diagnostic kits for COVID-19 have emerged which is important in keeping track of the escalation of the disease. The World Health Organization has implored health agencies time and again to make the test for the novel coronavirus a top priority in their response to the pandemic. Another most challenging task of COVID-19 is to identify asymptomatic cases which silently spread virus to close contacts and become the super spreader. Hence rapid diagnosing, identifying the positive cases, and quarantining are the only ways to prevent the pandemic outbreak. This chapter highlights the different possible diagnostic tests for COVID-19 with their errors in prediction and future directions.

Drug Repurposing Strategy (DRS): Emerging Approach to Identify Potential Therapeutics for Treatment of Novel Coronavirus Infection

Drug repurposing is also termed as drug repositioning or therapeutic switching. This method is applied to identify the novel therapeutic agents from the existing FDA approved clinically used drug molecules. It is considered as an efficient approach to develop drug candidates with new pharmacological activities or therapeutic properties. As the drug discovery is a costly, time-consuming, laborious, and highly risk process, the novel approach of drug repositioning is employed to increases the success rate of drug development. This strategy is more advantageous over traditional drug discovery process in terms of reducing duration of drug development, low-cost, highly efficient and minimum risk of failure. In addition to this, World health organization declared Coronavirus disease (COVID-19) as pandemic globally on February 11, 2020. Currently, there is an urgent need to develop suitable therapeutic agents for the prevention of the outbreak of COVID-19. So, various investigations were carried out to design novel drug molecules by utilizing different approaches of drug repurposing to identify drug substances for treatment of COVID-19, which can act as significant inhibitors against viral proteins. It has been reported that COVID-19 can infect human respiratory system by entering into the alveoli of lung via respiratory tract. So, the infection occurs due to specific interaction or binding of spike protein with angiotensin converting enzyme-2 (ACE-2) receptor. Hence, drug repurposing strategy is utilized to identify suitable drugs by virtual screening of drug libraries. This approach helps to determine the binding interaction of drug candidates with target protein of coronavirus by using computational tools such as molecular similarity and homology modeling etc. For predicting the drug-receptor interactions and binding affinity, molecular docking study and binding free energy calculations are also performed. The methodologies involved in drug repurposing can be categorized into three groups such as drug-oriented, target-oriented and disease or therapy-oriented depending on the information available related to quality and quantity of the physico-chemical, biological, pharmacological, toxicological and pharmacokinetic property of drug molecules. This review focuses on drug repurposing strategy applied for existing drugs including Remdesivir, Favipiravir, Ribavirin, Baraticinib, Tocilizumab, Chloroquine, Hydroxychloroquine, Prulifloxacin, Carfilzomib, Bictegravir, Nelfinavir, Tegobuvir and Glucocorticoids etc to determine their effectiveness toward the treatment of COVID-19.

Improvement in Dissolution Rate of Cefuroxime Axetil by using Poloxamer 188 and Neusilin US2

A combination of fusion and surface adsorption techniques was used to enhance the dissolution rate of cefuroxime axetil. Solid dispersions of cefuroxime axetil were prepared by two methods, namely fusion method using poloxamer 188 alone and combination of poloxamer 188 and Neusilin US2 by fusion and surface adsorption method. Solid dispersions were evaluated for solubility, phase solubility, flowability, compressibility, Kawakita analysis, Fourier transform-infrared spectra, differential scanning calorimetry, powder X-ray diffraction study, in vitro drug release, and stability study. Solubility studies showed 12- and 14-fold increase in solubility for solid dispersions by fusion method, and fusion and surface adsorption method, respectively. Phase solubility studies showed negative ΔG⁰_tr values for poloxamer 188 at various concentrations (0, 0.25, 0.5, 0.75 and 1%) indicating spontaneous nature of solubilisation. Fourier transform-infrared spectra and differential scanning calorimetry spectra showed that drug and excipients are compatible with each other. Powder X-ray diffraction study studies indicated that presence of Neusilin US2 is less likely to promote the reversion of the amorphous cefuroxime axetil to crystalline state. in vitro dissolution studies, T50% and mean dissolution time have shown better dissolution rate for solid dispersions by fusion and surface adsorption method. Cefuroxime axetil release at 15 min (Q15) and DE15 exhibited 23- and 20-fold improvement in dissolution rate. The optimized solid dispersion formulation was stable for 6 months of stability study as per ICH guidelines. The stability was ascertained from drug content, in vitro dissolution, Fourier transform-infrared spectra and differential scanning calorimetry study. Hence, this combined approach of fusion and surface adsorption can be used successfully to improve the dissolution rate of poorly soluble biopharmaceutical classification system class II drug cefuroxime axetil.