Thermoresponsive systems composed of poloxamer 407 and HPMC or NaCMC: mechanical, rheological and sol-gel transition analysis

Abstract

Poloxamer 407 (polox407) is widely studied as thermogelling polymer, transitioning to a gel state when warmed. Polox407 has the limitation that it forms weak hydrogels, with rapid dissolution in excess solvent. This study reports the development of new binary polymeric systems composed of polox407 and hydroxypropyl methylcellulose (HPMC) or sodium carboxymethylcellulose (NaCMC) with an aim to improve the rheological and mechanical properties of the hydrogel. The interaction between polox407 and cellulose derivatives was studied, and their interaction with biological surfaces predicted. The carbohydrates affected the mechanical and rheological behavior of polox407 in different ways, dependent on polymer type, concentration, and temperature.Tsol/gel and rheological interaction parameters were useful to select the most suitable formulations for topical or local application, ensuring in situ gelation and the formation of a strong gel. Most of the binary systems exhibited plastic behavior, with thixotropic and viscoelastic properties. Appropriate formulations were identified for local application, such as 17.

Ophthalmic In Situ Gels with Balsam Poplar Buds Extract: Formulation, Rheological Characterization, and Quality Evaluation

“…Storage modulus G′ and loss modulus G″ were measured using a system of parallel plates, the samples were carefully placed on the lower rheometer plate, and the measurements were carried out at a temperature from 20 °C to 50 °C, at an angular frequency omega of 1 rad/s, amplitude gamma of 0.5%, and temperature change rate of 2 °C per min. Flow properties were assessed using a concentric cylinder system, containing 10 g of the experimental formulation substance in a concentric cylinder; measurements were made at 22 °C, 32 °C, and 37 °C, with the shear rate from 1 to 200 1/s [ 36 , 49 ]. Data were processed using RheoPlus software (Anton Paar GmbH, German).…”

“…This leads to the improvement of precorneal residence time and ocular bioavailability. Poloxamer 407 was chosen as a gelling substance [ 36 ], as it is widely used in biomedicine because of its low toxicity and compatibility with many excipients.…”

An Overview on Thermosensitive Oral Gel Based on Poloxamer 407

“…They undergo a sol-gel transition under certain temperature conditions. The gelation temperature indicates the temperature of the phenomenon [ 64 ]. Therefore, the basic prerequisite for developing highly effective viscose preparation is the determination of the sol-gel transition temperature.…”

Interaction between mucoadhesive cellulose derivatives and Pluronic F127: Investigation on the micelle structure and mucoadhesive performance

“…Following sublingual administration, for example, salivation, tongue movement and swallowing can quickly remove the pharmaceutical system from the application site [9,12,13]. To overcome poor retention and weak gel strength, synergistic interactions between F127 and other additives have been explored, including: poloxamer 188 [14,15], carbomers [1,[16][17][18], polycarbophil [18], alginate [19], chitosan [20] and cellulose derivatives [21][22][23][24]. Moreover, mixing polymeric additives with F127 is attractive as the resultant materials would not require the regulatory burden that a chemical modification would impart [6].…”

“…Systems containing F127 combined with HPMC or NaCMC mucoadhesive agents have previously been evaluated for their rheological and mechanical characteristics for use as topical drug delivery systems [21][22][23][24]30]. The addition of cellulose derivatives to F127 hydrogels not only to contribute to the optimization of gel strength [24], but also to improve mucoadhesion [23]. For example, the addition of HPMC and NaCMC to F127 improved the retention of pilocarpine in the pre-corneal area, facilitating its retention and effect on the cornea [31][32][33].…”