Sporopollenin is highly cross-linked polymer composed of carbon, hydrogen and oxygen that is extraordinarily stable and has been found chemically intact in sedimentary rocks some 500 million year old. It is the outer shell (exine) of plant spores and pollen and when extracted it is in the form of an empty exine or microcapsule. The exines resemble the spores and pollen from which they are extracted, in size and morphology. Also, from any one plant such characteristics are incredible uniform. The exines can be used is microcapsules or simply as micron-sized particles due to the variety of functional groups on their surfaces. The loading of the exine microcapsules into their cavities is via multi-directional nano-diameter sized channels. The exines can be filled with a variety of polar and non-polar materials. Such as enzymes can be encapsulated within the shells and still remain active. In vivo studies in humans have shown that an encapsulated active substance can have a substantially increased bioavailability than if it is taken alone. The sporopollenin exine surface possesses phenolic, alkane, alkene, ketone, lactone and carboxylic acid groups. Therefore it can be derivatised in a number of ways, which has given rise to its having been used for, such as, solid supported for peptide synthesis, catalysis and ion-exchange chromatography. Also, the presence of the phenolic groups on sporopollenin endows it with antioxidant activity.

Sporopollenin exine capsules (SEC) extracted from Lycopodium clavatum spores were shown to encapsulate ibuprofen as a drug model, with 97 ± 1% efficiency as measured by recovery of the loaded drug and absence of the drug on the SEC surface by scanning electron microscopy (SEM). The encapsulated ibuprofen was shown to be unchanged from its bulk crystalline form by solid state NMR, FTIR and XRD. Essential for drug delivery applications, SEC were shown to be non-toxic to human endothelial cells and free of allergenic protein epitopes by MALDI-TOF-MS and ESI-QqToF-MS. Potential application for targeted release into the intestinal region of the gastrointestinal tract (GIT) was demonstrated by 88 ± 1% of the drug being retained in simulated gastric fluid (SGF) after 45 minutes and 85 ± 2% being released after 5 min in buffer (PBS; pH 7.4). The SEC were shown to provide significant taste masking of encapsulated ibuprofen in a double blind trial with 10 human volunteers.