Pharmaceutics 2014, 6(1), 80-96; doi:10.3390/pharmaceutics6010080
Review

Hollow Pollen Shells to Enhance Drug Delivery

Received: 24 January 2014; in revised form: 5 March 2014 / Accepted: 6 March 2014 / Published: 14 March 2014
(This article belongs to the Special Issue Microencapsulation Technology Applied to Pharmaceutics 2014)
This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Abstract: Pollen grain and spore shells are natural microcapsules designed to protect the genetic material of the plant from external damage. The shell is made up of two layers, the inner layer (intine), made largely of cellulose, and the outer layer (exine), composed mainly of sporopollenin. The relative proportion of each varies according to the plant species. The structure of sporopollenin has not been fully characterised but different studies suggest the presence of conjugated phenols, which provide antioxidant properties to the microcapsule and UV (ultraviolet) protection to the material inside it. These microcapsule shells have many advantageous properties, such as homogeneity in size, resilience to both alkalis and acids, and the ability to withstand temperatures up to 250 °C. These hollow microcapsules have the ability to encapsulate and release actives in a controlled manner. Their mucoadhesion to intestinal tissues may contribute to the extended contact of the sporopollenin with the intestinal mucosa leading to an increased efficiency of delivery of nutraceuticals and drugs. The hollow microcapsules can be filled with a solution of the active or active in a liquid form by simply mixing both together, and in some cases operating a vacuum. The active payload can be released in the human body depending on pressure on the microcapsule, solubility and/or pH factors. Active release can be controlled by adding a coating on the shell, or co-encapsulation with the active inside the shell.
Keywords: sporopollenin; exines; pollen; antioxidant; UV protection; porous shells; high loading; controlled release; bioavailability
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MDPI and ACS Style

Diego-Taboada, A.; Beckett, S.T.; Atkin, S.L.; Mackenzie, G. Hollow Pollen Shells to Enhance Drug Delivery. Pharmaceutics 2014, 6, 80-96.

AMA Style

Diego-Taboada A, Beckett ST, Atkin SL, Mackenzie G. Hollow Pollen Shells to Enhance Drug Delivery. Pharmaceutics. 2014; 6(1):80-96.

Chicago/Turabian Style

Diego-Taboada, Alberto; Beckett, Stephen T.; Atkin, Stephen L.; Mackenzie, Grahame. 2014. "Hollow Pollen Shells to Enhance Drug Delivery." Pharmaceutics 6, no. 1: 80-96.

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