Hollow microspheres as a drug carrier: An overview of fabrication and in vivo characterization techniques

Oral controlled release dosage forms encounter several physiological constraints like inability to retain and locate the controlled drug delivery system within the desired region of the gastrointestinal tract (GIT) due to variation in gastric emptying. This leads to non - uniform absorption profile, insufficient drug release and shorter residence time of the dosage form in the stomach. As the fallout of this event, there is incomplete absorption of the drug having absorption window especially, in the upper part of GIT. These considerations have led to the development of oral controlled release dosage forms with gastroretentive properties. Hollow microspheres hold promise as one of the potential approaches for gastric retention. Hollow microspheres are spherical empty particles without core and can remain in the gastric region for prolonged periods. They significantly extend the gastric residence time of drugs, thereby improving bioavailability, reduced the drug waste and improved solubility for drugs that are less soluble at a higher pH environment. This review attempts to bring more insight into recent advances in methods of fabrication techniques and applications of hollow microspheres.