Figure 3.

Transfer of a drug molecule (black bullets) upon the collision of two liposomes (here assumed to be two donor liposomes). The drug distribution function changes from initially d ₁ = 1, d ₂ = 0, d ₃ = 0, d ₄ = 0, d ₅ = 1 to d ₁ = 0, d ₂ = 1, d ₃ = 0, d ₄ = 1, d ₅ = 0. This represents an example (for i = 5 and j = 1) of the general scheme d _i → d _i − 1, d _i−1 → d _i−1 + 1, d _j → d _j − 1, and d _j+1 → d _j+1 + 1.