The solubility of a peptide can be determined based on its amino acid compositions. In general, peptides containing more hydrophobic residues are poorly soluble in water.
Analyzing the amino acid composition of peptide mutants would be a good start.
Using MD trajectories, the solubility of the peptides could be quantitatively characterized by analyzing the formation of aggregates and their sizes. Please follow the attached publication:
Article All-atom molecular dynamics analysis of multi-peptide system...