Abstract:

Volume-based procurement refers to the group-buying model in which the required quantity of procurement is announced in the bidding， and the price and corresponding production capacity are considered in the bidding. The drug volume-based procurement can promote the reform of the drug sector， enhance the attractiveness of bidding， effectively solve the problem of falsely high drug prices in China， give full play to the advantage of “quantity for price”， and play a positive role in improving patient welfare. At present， China’s centralized use of procurement prices for similar drugs has been carried out and has achieved remarkable results. However， in addition to prices， the improvement of the overall efficiency of the pharmaceutical supply chain is also a key issue in management practice and research. Therefore， when considering downstream asymmetric retailers competing， what kind of effective mechanism should the government design to achieve the optimization of the pharmaceutical supply chain system？ In view of this， it aims to design a more effective coordination mechanism to thoroughly solve the problem of profit distribution in asymmetric retailer group buying in this paper. From the perspective of horizontal competition in the supply chain， a competitive supply chain model between a single drug manufacturer and two asymmetrically competing drug retailers is constructed， in which drug manufacturers dominate the supply chain. Since drug retailers in asymmetric competition jointly purchase drugs in a group-buying model， drug manufacturers provide drugs to retailers with different purchase volumes at wholesale prices， that is， the drug purchase prices of competitive asymmetric drug retailers are the same. The Stackelberg game sequence of the three is as follows. Firstly， a single drug manufacturer sets a wholesale price based on the principle of profit maximization. Secondly， two competing asymmetric drug retailers with different market sizes set their own retail prices.The results of the research show that　（1） The price sensitivity of drugs and the degree of competition among drug retailers are the reference indicators for drug retailers’ group buying， that is， the selection of drug types in the “volume-based procurement” mode of purchase and sale. At the same time， drug manufacturers can formulate appropriate wholesale price and quantity discount rates are used to reduce the price of medicines and increase the benefits of medical medicines for patients. （2） Considering quantity discount contracts in the drug group-buying supply chain cannot achieve the coordination of asymmetric retailer group-buying， and pharmaceutical companies and smaller hospitals or pharmacies may be reluctant to participate. （3） In the supply chain of drug group purchases， pharmaceutical companies and hospitals （pharmacies） use a combination of quantity discounts and two pricing contracts， and drug manufacturers can adjust fixed costs to realize transfer payments of profits. Further the Pareto improvement of the profit of each member in the supply chain is realized， and a long-term effective drug group purchase mechanism is formed. The research results of this article supplement the theoretical research of group buying， and enrich the management enlightenment of group buying on drug procurement in the pharmaceutical supply chain.

Key words: volume-based procurement, group-buying, competitive supply chain, quantity discount contract