Acidic conditions

Acidic conditions refer to a physiological state characterized by a high concentration of hydrogen ions, resulting in a pH value lower than the standard homeostatic level of approximately 7.4. In clinical and pharmacological contexts, localized acidic conditions are a hallmark of the tumor microenvironment (TME), where extracellular pH typically ranges from 6.5 to 6.9 due to the Warburg effect and poor vascularization [PMID: 24204454, 30584518]. This acidity serves as a driver for cancer progression, promoting tissue remodeling, invasion, and evasion of the immune system [PMID: 23640201]. Therapeutically, this environmental feature is exploited as a trigger for pH-responsive drug delivery systems, such as pH-low insertion peptides (pHLIPs) or acid-labile nanoparticles, which selectively release payloads or insert into cell membranes specifically in low-pH environments [PMID: 28414002]. Additionally, medications like proton pump inhibitors (PPIs) are used to modulate acidity by inhibiting the enzymes responsible for proton secretion, particularly in gastric and oncological settings [PMID: 25435214].

Other names

Extracellular acidityAcidosisTumor microenvironment acidityLow pHHypoxic acidity

Direct neutralization of hydrogen ions, inhibition of proton-exporting enzymes (e.g., H+/K+-ATPase), or utilization of pH-dependent conformational changes for site-specific drug activation.