Selma ŞAHİN*,o, Emel Öykü ÇETİN**

*Hacettepe University, Faculty of Pharmacy, Department of Pharmaceutical Technology,
06100 Sıhhiye, Ankara, TURKEY.
**Ege University, Faculty of Pharmacy, Department of Pharmaceutical Technology, 35100 İZMİR.
oCorresponding Author

Summary:
As the equilibration of many drugs between plasma and erythrocytes has been assumed to occur very fast, erythrocytes are not expected to influence the drug distribution and elimination (disposition) within the body. However, disposition of drugs that penetrate slowly to erythrocytes and/or bound to erythrocytes components will be influenced by the erythrocytes, as they cannot leave the capillaries of eliminatory organs. In this review, general characteristics of erythrocytes, blood to plasma concentration ratio, their effects on the drug disposition within the body and their role in drug metabolism were discussed, and their usage was investigated briefly.