Insights into the dissolution mechanisms of detergent agglomerates: An approach to assess dissolution heterogeneity

In this work, the dissolution mechanisms of detergent agglomerates with different binders were investigated in aqueous solution. The dissolution processes of detergent agglomerates were online monitored by using in situ UV–VIS spectrophotometer and electric conductivity probe. Dissolution profiles were correlated by Weibull model to evaluate the time-dependent dissolution rate coefficient and to classify the type of dissolution rate function k_t(t). The Kullback-Leibler information distance d_K-L was proposed to assess the degree of dissolution heterogeneity. The results indicate that the sodium linear alkylbenzene sulfonates (NaLAS) and sodium carbonates (Na₂CO₃) in detergent agglomerates have different dissolution behaviors, and their dissolution rates are influenced by the type and content of binders. Moreover, detergent agglomerates using semi-solid NaLAS paste or liquid linear alkylbenzene sulfonic acid (HLAS) as binders in granulation processes follow different dissolution mechanisms in water.