Ultralong floating hydrogel raft for prolonged gastric retention

Abstract

The optimal therapeutic efficiency of any treatment depends on patient adherence to the medication regimen. Medication adherence is the cornerstone of treatment outcomes that may consequently impact economic and healthcare costs. With the oral route being the preferred route of drug administration, slow or extended-release oral formulations can therefore be utilized. Here, a biocompatible oral delivery system that can be retained in the stomach for a week, while providing continuous release of the encased drug, is proposed. The fabrication of the delivery system was achieved using a simple mould casting technique. The hydrogel-based raft was able to float under simulated gastric conditions for seven days with pH switches to mimic the fasted and fed states of the stomach. The functionality of such a delivery system has been exemplified using two different model drugs -Risperidone and Metoprolol tartrate of varied solubilities and has been shown to effectively sustain the release of drugs under the tested conditions. IMPACT STATEMENTAn oral delivery system is proposed to tackle the soaring problem of medication non-adherence predominantly for conditions that require long-term medication. The proposed delivery system is designed to float in the stomach, thereby prolonging gastric retention and sustaining drug release for over a week. Subsequently, once drug release is completed it can be dissolved away using an extrinsic trigger. Any chronic disease condition that requires multiple dosing per day or to be taken over a prolonged period would benefit from such a sustained-releasing drug delivery system. This reduces dosing frequency and consequently improves patient medication compliance. The proposed design allows for easy adaptation to different drugs making it customisable to the patient's needs. The application of the delivery system may also be extended to the delivery and retention of miniature devices, like glucose sensors that are to be retained for an extended period in the body, for the purpose of health monitoring or probing. In addition, this technology could have an impact beyond biomedical/pharmaceutical applications, where the need for extended-release is a requirement. For instance, as a floating device for environmental purposes, i.e., slow release of pesticides into water bodies against mosquito breeding, may be a possibility.

Hydrogels for Mucosal Drug Delivery

“…Emulsion gelation is another technique used to make floating hydrogels. Here, oil droplets are encapsulated within hydrogels during cross-linking to decrease the hydrogel density in aqueous solution to form floating hydrogels. , Other reported floating hydrogel designs include hydrophobic hydrogels, superporous hydrogels, and hydrogel rafts. ,,− …”

“…Gastroretentive systems that prolong gastric residence time are used to allow drug absorption in the upper GI tract and to prolong drug release in a controlled manner. Examples of gastroretentive systems include floating devices, − expandable dosage forms, − and mucus or tissue adhesive systems. − Mucoadhesive systems are limited by the mucus turnover time of 1–2 days and epithelial turnover time of 4–5 days across the entire GI tract.…”

Biocompatible floatable device for controlled release applications

“…After the solution has been stirred homogeneously overnight, it is then heated up in a water bath at 80⁰C for 5mins, while Reproduced with permission from Springer Nature'. [150] Experimental…”