Development and evaluation of an in situ gelling flurbiprofen throat spray for enhanced mucosal drug delivery and throat inflammation treatment

The aim of this study was to develop and assess an in situ gelling-based throat spray formulation. containing flurbiprofen, designed to transform into a gel upon contact with the mucosal surface of the throat. Oral administration of medications during throat inflammation can be challenging, prompting the need for alternative delivery methods such as throat sprays. Conventional throat sprays are limited by rapid drug clearance due to excessive secretions. In. situ gelling systems aim to address this limitation by forming a protective gel layer upon application, thereby enhancing drug residence time and therapeutic efficacy. This research aimed to evaluate the feasibility, efficacy, and potential advantages of an in situ gelling formulation for delivering flurbiprofen to alleviate throat pain and inflammation. Preliminary studies were performed to select formulation components, and drug-excipient compatibility was assessed using the Fourier transform infrared spectrophotometer (FTIR) spectroscopy. Container compatibility studies were also conducted. The formulation was optimized using a 3² full factorial design to study the effects of independent variables (amount of Poloxamer 407 and amount of Carbopol 934) on the dependent variables (gelling temperature, bioadhesion, and t₉₀—time taken for 90% drug release). Formulation batches were evaluated for in situ gelling characteristics, qualitative and quantitative spray properties, and ex vivo drug diffusion. The optimized formulation underwent stability testing. Compatibility studies indicated that flurbiprofen was compatible with selected excipients and containers. Based on these studies, the concentration of Poloxamer 407 and Carbopol 934 was chosen for optimizing the in situ gelling throat spray formulation. The optimized formulation demonstrated prolonged residence time at the application site, potentially enhancing therapeutic efficacy. The developed in situ gelling throat spray formulation of flurbiprofen offers an innovative approach to improving patient compliance and therapeutic outcomes. By extending the duration of drug contact with the throat mucosa, this formulation presents a promising alternative for delivering drugs to treat throat inflammation effectively. However, the present study is limited to in vitro and ex vivo evaluations, and clinical validation is warranted to confirm its therapeutic applicability.