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Pre-Clinical Efficacy Studies
Published in Harry Yang, Steven J. Novick, Bayesian Analysis with R for Drug Development, 2019
The above relationship between doses and is commonly referred to as Loewe additivity. Let . When , it means that the same treatment effect can be achieved at a lower combination dose level (synergism); when , it implies that high-dose levels have to be given to achieve the same treatment effect (antagonism); and when , it indicates that the treatment effects are additive and there is no advantage or disadvantage in combining them (additivity). One advantage of the Loewe additivity model is that serves as the basis for the isobologram, a graphical tool for synergism or antagonism analysis.
Inhibitory effect of proteinase K against dermatophyte biofilms: an alternative for increasing the antifungal effects of terbinafine and griseofulvin
Published in Biofouling, 2022
Raimunda Sâmia Nogueira Brilhante, Raissa Geovanna Pereira Lopes, Lara de Aguiar, Jonathas Sales de Oliveira, Géssica dos Santos Araújo, Germana Costa Paixão, Waldemiro de Aquino Pereira-Neto, Rosemayre Souza Freire, João Victor Serra Nunes, Renan Pereira de Lima, Flávia Almeida Santos, José Júlio Costa Sidrim, Marcos Fábio Gadelha Rocha
The analysis of biofilm susceptibility compared the absorbance data with equal variances and normal distribution, the Student's t-test (two groups of data) and ANOVA followed by Tukey's post hoc test were applied to the analysis of paired data (three or more groups were used). For the groups of absorbance data where asymmetry and/or high dispersion were verified, the Mann–Whitney nonparametric test (two groups of unpaired data) and Friedman (three or more groups of paired data) were used. Statistical analyses of interaction tests were performed using Combenefit software (Cancer Research UK Cambridge Institute, Cambridge, UK) with an analysis of drug interactions based on the Loewe additivity model.
Inhibiting effect of p-Coumaric acid on U87MG human glioblastoma cell growth
Published in Journal of Chemotherapy, 2022
Maria Antonietta Oliva, Salvatore Castaldo, Rossella Rotondo, Sabrina Staffieri, Massimo Sanchez, Antonietta Arcella
To evaluate drug interactions, the Loewe additivity model was applied. The IC50-values of pCA and TMZ at 48 h were used to define the diagonal line of additivity at 50% inhibition level in isobologram analysis. The value of isobole combination was estimated by using Loewe additivity CI = 18, 19]. Therefore, according to the isobole combination, the value that falls below the line of additivity indicates synergistic effects. U87Mg cells were plated in 96-well plates at a density of 5000 cells/well and treated with TMZ 10 µM and pCA 0.5 mM, as single drugs and in combination for 48 h. The synergistic cytotoxicity was determined by MTT assay.
Assessment of complex genomic alterations induced by AZT, 3TC, and the combination AZT +3TC
Published in Drug and Chemical Toxicology, 2020
Allyne Cristina Grando, Nilza Nascimento Guimarães, Ana Paula de Souza, Mauricio Lehmann, Kênya Silva Cunha, Rafael Rodrigues Dihl
The combination indexes (CIs) of drugs, defined based on the Loewe additivity principle (1957), were calculated according to Ramakrishnan and Jusko (1986) using the mean values of each experimental group calculated for each slide using the formula CI = [(mA/mAB) + (mB/mAB)], where “m” is mean of MNi, NPB, or NBUD frequencies induced by drugs alone (A or B) and in combination (AB). Antagonism, synergism, and additivity were indicated by CI >1, CI <1, CI =1, respectively.