Solid oral modified-release dosage forms provide numerous advantages for drug delivery compared to
dosage forms where the drugs are released and absorbed rapidly following ingestion. Natural polymers are of particular
interest as drug carriers due to their good safety profile, biocompatibility, biodegradability, and rich sources.
This review described the current applications of important natural polymers, such as chitosan, alginate, pectin,
guar gum, and xanthan gum, in solid oral modified-release dosage forms. It was shown that natural polymers have
been widely used to fabricate solid oral modified-release dosage forms such as matrix tablets, pellets and beads,
and especially oral drug delivery systems such as gastroretentive and colon drug delivery systems. Moreover,
chemical modifications could overcome the shortcomings associated with the use of natural polymers, and the
combination of two or more polymers presented further advantages compared with that of single polymer. In conclusion,
natural polymers and modified natural polymers have promising applications in solid oral modified-release
dosage forms. However, commercial products based on them are still limited. To accelerate the application of natural
polymers in commercial products, in vivo behavior of natural polymers-based solid oral modified-release dosage forms should be
deeply investigated, and meanwhile quality of the natural polymers should be controlled strictly, and the influence of formulation and
process parameters need to be understood intensively.