5. Conclusions
In this paper we present a literature review of quantitative models of the pharmaceutical supply chain. We identify three classification categories in terms of strategic, tactical, and operational decisions. The source of uncertainty used in the models is presented in this review, with the finding that the majority of articles use a stochastic form of uncertainty in some of the echelons of the chain. We found in the taxonomy proposed that 52% of the articles correspond to network design, 28% correspond to inventory problems, and 20% correspond to supply chain optimization models.
Several deterministic models are presented, but in the majority of cases the use of techniques is developed under uncertainty. Most of the articles involve stochastic approximations, and only a few uses an alternative approximation of uncertainty, for example, fuzzy logic and robust optimization, among others. In network design 56% of the articles use the demand as deterministic and 22% as stochastic and 22% of the articles used both types of demand while in inventory models 92% of the articles use the demand as stochastic and 8% as deterministic. In supply chain optimization 52% of the articles use the demand as deterministic and 48% as stochastic.