A microfluidic device for culturing cells, termed a microscale cell culture analog (μCCA), is provided. The microfluidic device allows multiple cell or tissue types to be cultured in a physiologically relevant environment, facilitates high-throughput operation and can be used for drug discovery. The microfluidic device uses gravity-induced fluidic flow, eliminating the need for a pump and preventing formation of air bubbles. Reciprocating motion between a pair of connected reservoirs is used to effect the gravity-induced flow in microfluidic channels. Bacterial contamination is reduced and high throughput enabled by eliminating a pump. The microfluidic device integrates a pharmacokinetic-pharmacodynamic (PK-PD) model to enable PK-PD analyses on-chip. This combined in vitro/in silico system enables prediction of drug toxicity in a more realistic manner than conventional in vitro systems.