Current Drug Metabolism - Volume 21, Issue 9, 2020

Background: Blood-brain barrier (BBB) plays a most hindering role in drug delivery to the brain. Recent research comes out with the nanoparticles approach, is continuously working towards improving the delivery to the brain. Currently, polymeric nanoparticle is extensively involved in many therapies for spatial and temporal targeted areas delivery. Methods: We did a non-systematic review, and the literature was searched in Google, Science Direct and PubMed. An overview is provided for the formulation of polymeric nanoparticles using different methods, effect of surface modification on the nanoparticle properties with types of polymeric nanoparticles and preparation methods. An account of different nanomedicine employed with therapeutic agent to cross the BBB alone with biodistribution of the drugs. Results: We found that various types of polymeric nanoparticle systems are available and they prosper in delivering the therapeutic amount of the drug to the targeted area. The effect of physicochemical properties on nanoformulation includes change in their size, shape, elasticity, surface charge and hydrophobicity. Surface modification of polymers or nanocarriers is also vital in the formulation of nanoparticles to enhance targeting efficiency to the brain. Conclusion: More standardized methods for the preparation of nanoparticles and to assess the relationship of surface modification on drug delivery. While the preparation and its output like drug loading, particle size, and charge, permeation is always conflicted, so it requires more attention for the acceptance of nanoparticles for brain delivery.

Herbal medicines are being used since ancient times and are an important part of the alternative and traditional medicinal system. In recent decades, scientists are embracing herbal medicines based on the fact that a number of drugs that are currently in use are derived directly or indirectly from plant sources. Moreover, herbal drugs have lesser side effects, albeit are potentially strong therapeutic agents. The herbal medicine market is estimated to be around US $62 billion globally. Herbal medicine has gained widespread acceptance due to its low toxicity, low cost, ease of accessibility and efficacy in treating difficult diseases. Safety and efficacy are another important factors in the commercialization process of herbal medicines. Nanotechnology has been shown to be potentially effective in improving the bioactivity and bioavailability of herbal medicines. Development of nano-phytomedicines (or by reducing the size of phytomedicine), attaching polymers with phytomedicines and modifying the surface properties of herbal drugs, have increased the solubility, permeability and eventually the bioavailability of herbal formulations. Novel formulations such as niosomes, liposomes, nanospheres, phytosomes etc., can be exploited in this area. This article reviews herbal medicines, which have prominent activity in the Central Nervous System (CNS) disorders and reported nano-phytomedicines based delivery systems.

Background: Neuropsychiatric diseases primarily characterized by dementia stand third in the global list of diseases causing disability. The poor water solubility, erratic oral absorption, low bioavailability, poor intestinal absorption, and the impeding action of the blood-brain barrier (BBB) are the major factors limiting the therapeutic feasibility of the antipsychotics. Only a small percentage of antipsychotics reaches the therapeutic target site, which warrants administration of high doses, consequently leading to unwanted side-effects. Hence the main struggle for the effective treatment of neuropsychiatric diseases occurs “at the gates” of the brain, which can be mitigated with the use of a nanotechnology-based platform. Methods: The goal of this review is to undertake a comprehensive study about the role of lipid nanoformulations in facilitating the delivery of antipsychotics across BBB along with the available in vitro and in vivo evidence. Results: Lipid nanoformulations have attained great popularity for the delivery of therapeutics into the brain. Their nanosize helps in overcoming the biological barriers, thereby providing easy BBB translocation of the drugs. Besides, they offer numerous advantages like controlled and targeted drug release, minimizing drug efflux, long storage stability, augmented bioavailability, and reduced adverse drug effects to attain an optimal therapeutic drug concentration in the brain. Moreover, employing alternative routes of administration has also shown promising results. Conclusion: Thus, it can be concluded that the lipid nanoformulations bear immense potential in overcoming the challenges associated with the treatment of neuropsychiatric disorders. However, the area warrants further clinical studies to ensure their commercialization, which could revolutionize the treatment of neuropsychiatric diseases in the coming decades.

Background: Scopus is regularly covering Current Drug Metabolism from 2000 onwards. Objective: The major objective is to perform the 1st bibliometric analysis of Current Drug Metabolism (CDM). Methods: The data was retrieved from Scopus in April-May 2020 for detail analysis. Results: The total number of publications was found to be 1551, with 955 reviews (61.57%) and 466 articles (30.05%). From 2000 onwards, we calculated the relative growth rate and doubling time. Based on the number of publications, total 4418 authors, 3235 institutions and 83 countries were directly involved in all publications. M.A. Kamal is the highly productive scientist with fifty-three (53 or 3.73%) publications, King Abdulaziz University is the top university with the highest number of publications (58 or 4.13%) and the USA is the top-ranked country with 365 publications (25.96%). We also provided the h-index, total citations (TC), h-index without self-citations (WSC) and total WSC of the top ten authors, universities and countries. In citations analysis, Prof. Zhou S.F. was the top scientist with the highest (1594) number of citations. In institutional category Department of Drug Metabolism, Merck Research Laboratories, Rahway, United States, is the top ranked institutes with 654 total citations. While, United States is the top-ranked country with 18409 total citations. In co-words analysis, 3387, 30564 and 17333 terms in titles of the manuscripts, abstracts and keywords were recorded, respectively. This indicated that CDM principally focused on understanding drug development ranging from its efficacy to delivery, metabolism, distribution, safety and mechanism of actions. Similarly, various specific drugs were thoroughly discussed in publications. Various enzymatic, genetics, proteins and cancer-related aspects were also described. For data presentations, we used VOSviewer graphical maps. Conclusion: The data confirm that CDM showed continuous growth in the number of publications and citations. However significant measures are needed to make overall progress and improve the rankings in relevant categories.

Background: Chronic respiratory diseases (CRDs) are increasing in prevalence, as reported by the World Health Organization (WHO). Patients with CRDs usually require co-administration of multiple drugs due to the complex pathogenic mechanisms of CRDs and the existence of concomitant diseases. Polypharmacy (co-administration of more than four medications) is the main risk factor of the occurrence of drug-drug interactions (DDIs) that may lead to reducing treatment efficacy and/or increasing adverse effects. Methods: This literature-based review focuses on metabolism-based DDIs, the most prevalent DDIs responsible for difficulties in therapeutic management in patients with CRDs. Results: Clinically relevant metabolism-based DDIs occur between drugs used for the treatment of respiratory diseases (corticosteroids, orally inhaled bronchodilators, methylxanthines, anti-leukotrienes, antimicrobials, endothelin receptor antagonists, phosphodiesterase inhibitors, antitussives, and antineoplastic agents) and drugs affecting cytochrome P450 (CYP) (inducers and inhibitors). Considering alternative therapies, adjusting medication doses, or monitoring patients during treatment are recommended to prevent the harmful consequences of these interactions. Conclusion: Providing information on clinically relevant interactions of drugs more likely prescribed in daily practices of physicians is essential to improve patient safety. A list of known metabolism-based interactions of drugs affecting the respiratory systems should be available for physicians engaged in the treatment of CRDs.

Background: Tuberculosis (TB) is an infectious disease caused by Mycobacterium tuberculosis, which still has high prevalence worldwide. In addition, cases of drug resistance are frequently observed. In the search for new anti-TB drugs, compounds with antimycobacterial activity have been developed, such as derivatives of pyrazinoic acid, which is the main pyrazinamide metabolite. In a previous study, the compounds were evaluated and showed moderate antimycobacterial activity and no important cytotoxic profile; however, information about their pharmacokinetic profile is lacking. Objective: The aim of this work was to perform physicochemical, permeability, and metabolic properties of four pyrazinoic acid esters. Method: The compounds were analyzed for their chemical stability, n-octanol:water partition coefficient (logP) and apparent permeability (Papp) in monolayer of Caco-2 cells. The stability of the compounds in rat and human microsomes and in rat plasma was also evaluated. Results: The compounds I, II and IV were found to be hydrophilic, while compound III was the most lipophilic (logP 1.59) compound. All compounds showed stability at the three evaluated pHs (1.2, 7.4 and 8.8). The apparent permeability measured suggests good intestinal absorption of the compounds. Additionally, the compounds showed metabolic stability under action of human and rat microsomal enzymes and stability in rat plasma for at least 6 hours. Conclusion: The results bring favorable perspectives for the future development of the evaluated compounds and other pyrazinoic acid derivatives.

Pregnant women are often excluded from routine clinical trials. Consequently, appropriate dosing regimens for majority of drugs are unknown in this population, which may lead to unexpected safety issue or insufficient efficacy in this un-studied population. Establishing evidence through the conduct of clinical studies in pregnancy is still a challenge. In recent decades, physiologically-based pharmacokinetic (PBPK) modeling has proven to be useful to support dose selection under various clinical scenarios, such as renal and/or liver impairment, drug-drug interactions, and extrapolation from adult to children. By integrating gestational-dependent physiological characteristics and drug-specific information, PBPK models can be used to predict PK during pregnancy. Population pharmacokinetic (PopPK) modeling approach also could complement pregnancy clinical studies by its ability to analyze sparse sampling data. In the past five years, PBPK and PopPK approaches for pregnancy have made significant progress. We reviewed recent progress, challenges and potential solutions for the application of PBPK, PopPK, and exposure-response analysis in clinical drug development for pregnancy.