Target-controlled infusion pumps are for patients to control pain or to infuse sedations and anesthesia, typically those who underwent surgery. The pump has a programmable syringe device used to control the injection level of drugs. These pumps are even used in the ICU or operating theaters to manage patient's pain after surgery or sedation. PK-PD Models are used to obtain the drug concentrations levels of the patient. The model depends on the drug flow rates in different parts of the body. There are many parameter sets available to measure the amount of drugs in the patients. This article presents a three compartmental patient model through Simulink to obtain concentrations levels from different parts of the body. The model is checked for a seven parameter set and suggests the set with the best results.