An Overview on Thermosensitive Oral Gel Based on Poloxamer 407

Abstract

In this review, we describe the application of thermosensitive hydrogels composed of poloxamer in medicine, especially for oral cavities. Thermosensitive hydrogels remain fluid at room temperature; at body temperature, they become more viscous gels. In this manner, the gelling system can remain localized for considerable durations and control and prolong drug release. The chemical structure of the poloxamer triblock copolymer leads to an amphiphilic aqueous solution and an active surface. Moreover, the poloxamer can gel by forming micelles in an aqueous solution, depending on its critical micelle concentration and critical micelle temperature. Owing to its controlled-release effect, a thermosensitive gel based on poloxamer 407 (P407) is used to deliver drugs with different characteristics. As demonstrated in studies on poloxamer formulations, an increase in gelling viscosity decreases the drug release rate and gel dissolution time to the extent that it prolongs the drug's duration of action in disease treatment. This property is used for drug delivery and different therapeutic applications. Its unique route of administration, for many oral diseases, is advantageous over traditional routes of administration, such as direct application and systemic treatment. In conclusion, thermosensitive gels based on poloxamers are suitable and have great potential for oral disease treatment.

Keywords: drug release; oral disease drug; poloxamer; thermoreversible gel; thermosensitive hydrogels.

Figure 1

Poloxamer formula: X and y are the lengths of polyepoxyethane (PEO) and polyepoxypropane (PPO) chains. Adapted with permission [2].

Figure 2

Schematic of the hydrogel formation. Adapted with permission [4].

Figure 3

Schematic of in situ gelation mechanism of thermoresponsive P407 aqueous solution. The temperature rise first causes the micelles of P407 to be rearranged into a cubic structure and subsequently form a hexagonal structure. Adapted with permission [1].

Figure 4

The influence of the concentration of p407 on the temperature of gelation (T_sol→T_Gel) (with standard error bar). Adapted with permission [66].

Figure 5

Thermosensitive gels for the oral cavity.

Figure 6

Representative photograph of CJC thermoreversible gel at (a) room temperature (24 °C) and (b) gelation temperature (32 °C). Adapted with permission. (Copyright 2021) [86].