## 4 Results and Discussion  
### Characteristics of Pharmacies  
The total registered number of pharmacies in the municipality of Sao Paulo, according to the Regional Pharmaceutical Council of the Sao Paulo state (in 2016) was four hundred and eighty-two, and their distribution in the different regions, were as follows: North (61); South (164); Central (58); East (136); and West (63) [32]. Therefore, the data obtained during this study was derived from 33% of the establishments in Sao Paulo. The results obtained from the ANOVA statistical tests that evaluated the relationship between the RP's responses regarding the RL of expired drugs, the size and location of the pharmacy, and service time of the RP were not statistically significant (\(p>0.05\)). The largest proportion of RP respondents who worked in large-scale pharmacies (n = 72, 44.7%), were located in East-side pharmacies (n = 41, 25.4%) and had a service time of 2-5 years (n = 64, 39.5%). The location, time, and size data for the companies are represented in Figure 3.  
According to the results, the concentration of pharmacies belonging to large networks decreased as distance from the center decreased, and there was a predominance of small and medium-sized pharmacies, in the periphery. One limitation of the study was that there was no survey of all the stores in the same drugstore network, which could have uncovered managerial differences in the subsidiaries of a single company. Figure 2: Questions about the knowledge of the responsible pharmacists (RPs), regarding the RL of expired drugs, post-consumption. The minimum cost of the RL program could be serving as a barrier to the implementation of RL in small pharmacies. As in Brazil, conflicts over role assignments in RL were observed in other countries, due to the implementation of shared responsibility [46]. According to [PERSON] et al. [39], many conflicts still exist due to issues in splitting costs and responsibilities, in areas such as the determination of the value to be paid for transport. The private sector accuses the government of not stipulating well-defined roles in the reverse chain and complains about the lack of incentive policies, for the deployment. On the other hand, the government accuses the private sector of emphasizing challenges with the objective of postponing implementation [39]. There are two categories of costs in relation to RL for Group B waste--collection space and transport. Such costs depend on the return volume of products, modes of transport, and the desired level of service. In an RL system, economic aspects are directly related to decision making. The manager needs to know the costs of different alternatives to inform his decision making [47]. [PERSON] and [PERSON] [48] point out that the performance of an RL system, in terms of the efficiency and effectiveness of its actions, should be viewed from six perspectives--finances, internal and external processes, involved stakeholders, innovation, environment impacts, and social requirements. Measures to recollect unused drugs should be focused on the inevitable occurrence of leftover medicines. The handling of these wastes generates costs, and the final disposal in the form of incineration, even when controlled, results in energy expenditures and generates pollutants, resulting from the burning of the residues [33]. It is noted that one of the major challenges is the dispute over the responsibility for assuming the costs of the appropriate disposal of these wastes (transport and appropriate final disposal in a landfill or an incinerator). Other costs incurred as a result of RL steps, such as collection, segregation, and wrapping, even if irrelevant, lead the stakeholders in small and medium-sized retail establishments to avoid compromise, as these costs are in addition to the costs of collection and incineration, which is carried out by specialized companies.