Localized Drug Delivery through Mammary Papilla

The goal of this study is to investigate the feasibility of drug delivery to the breast through mammary papilla (nipple). To this end, feasibility studies were performed with excised porcine mammary papilla. 5-fluorouracil (5FU; MW= 130 Da; Log P= -0.89), estradiol (EST; MW= 273 Da; Log P= 3.6) and bovine serum albumin (BSA; MW= 67 kDa) were used as model hydrophilic, hydrophobic and macromolecular compounds respectively. Microscopic studies were performed after treatment with hydrophilic dye sulforhodamine B (SRB) and lipophilic dye nile red (NR). The retention of 5FU and EST in the mammary papilla was similar but higher amount of 5FU was found to be transported across the tissue. In case of BSA, it was mainly retained in the mammary papilla and was not found to travel across it. Microscopic studies showed that both the dyes are taken up into the ducts of mammary papilla. Overall the findings from this study show that mammary papilla is a potentilal route of drug delivery and the transport into and across it is dependent on the physicochemical properties of the drug. This is a promising delivery strategy for prevention and treatment of breast cancer.