Pollen: a Novel Encapsulation Vehicle for Drug Delivery

is discharged from the anther as a dusty material and carried by either wind or insects to a plant ovary which is fertilised to generate a seed. Spores are the equivalent element in non-flowering plants such as mosses, ferns or fungi. Both spores and pollen grains are encased within a robust double-layered wall (a section of which is shown in Figure 1) which protects the fragile genetic material needed for reproduction. The inner layer (intine) is made of cellulose, while the outer skeleton (exine) consists of a unique polymer in nature known as sporopollenin. For the purpose of this review, the term ‘pollen’ will be used to include plant spores. From a health point of view, contradictory effects have been observed for spores and pollen. Some, such as ragweed pollen (Ambrosia trifida) and Aspergillus niger, are allergenic and may cause diseases such as farmer’s