In vitro activity: Incubation ofA. fumigatuwith a single dose of caspofungin affected the same proportion of apical and subapical branching cells for up to 72 h.The cells at the active centers for new cell wall synthesis withinA. fumigateshyphae are killed when they are exposed to caspofungin. Caspofungin acetate irreversibly inhibited the enzyme 1,3-β-D-glucan synthase, preventing the formation of glucan polymers and disrupting the integrity of the fungal cell wall. The elimination half-life of caspofungin acetate was 9-10 hours. Caspofungin showed activity againstAspergillusspp. as well as a variety ofCandidaspp. Growth kinetic studies of caspofungin acetate against Candida albicans and Candida tropicalis isolates showed that caspofungin acetate exhibited fungicidal activity (i.e., a 99% reduction in viability) within 3 to 7 h at concentrations ranging from 0.06 to 1 μg/ml (0.25 to 4 times the MIC)[4].The minimal inhibitory concentration for 90% inhibition of Candida species by caspofungin acetate were as follows:C. albicans 0.5 μg/mL (range, 0.25-0.5), C. glabrata 1.0 μg/mL (range, 0.25-2.0), C. tropicalis 1.0 μg/mL (range, 0.25-1.0), C. parapsilosis 0.5 μg/mL (range, 0.25-1.0), and C. krusei 2.0 μg/mL (range, 0.5-2.0).

Kinase Assay: caspofungin Acetate is an antifungal drug that noncompetitively inhibits 1,3-β-d glucan synthase activity.

Cell Assay: Caspofungin suppressed the synthesis of cell wall β-1,3-glucan, which triggered a compensatory stimulation of chitin synthesis. Caspofungin induced morphological changes in Aspergillus fumigates. Moreover, Treatment with caspofungin induced ChsG-dependent upregulation of chitin synthesis and the formation of chitin-rich microcolonies in Aspergillus fumigates.