Next Article in Journal
Development of a Physiologically-Based Pharmacokinetic Model of the Rat Central Nervous System
Next Article in Special Issue
Encapsulation of Alcohol Dehydrogenase in Mannitol by Spray Drying
Previous Article in Journal
Acknowledgement to Reviewers of Pharmaceutics in 2013
Previous Article in Special Issue
Preparation of Microcapsules Containing β-Carotene with Thermo Sensitive Curdlan by Utilizing Reverse Dispersion
Article Menu

Export Article

Open AccessReview
Pharmaceutics 2014, 6(1), 80-96;

Hollow Pollen Shells to Enhance Drug Delivery

Sporomex Ltd., Newland Avenue, Driffield YO25 6TX, UK
Hull York Medical School, University of Hull, Hull HU6 7RX, UK
Department of Chemistry, University of Hull, Hull HU6 7RX, UK
Author to whom correspondence should be addressed.
Received: 24 January 2014 / Revised: 5 March 2014 / Accepted: 6 March 2014 / Published: 14 March 2014
(This article belongs to the Special Issue Microencapsulation Technology Applied to Pharmaceutics 2014)
Full-Text   |   PDF [2069 KB, uploaded 14 March 2014]   |  


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. View Full-Text
Keywords: sporopollenin; exines; pollen; antioxidant; UV protection; porous shells; high loading; controlled release; bioavailability sporopollenin; exines; pollen; antioxidant; UV protection; porous shells; high loading; controlled release; bioavailability

Figure 1

This is an open access article distributed under the Creative Commons Attribution License (CC BY 3.0).

Share & Cite This Article

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.

Show more citation formats Show less citations formats

Related Articles

Article Metrics

Article Access Statistics



[Return to top]
Pharmaceutics EISSN 1999-4923 Published by MDPI AG, Basel, Switzerland RSS E-Mail Table of Contents Alert
Back to Top