Influence of the oral dissolution time on the absorption rate of locally administered solid formulations for oromucosal use: the flurbiprofen lozenges paradigm

Determination of the Permeation and Penetration of Flurbiprofen into Cadaveric Human Pharynx Tissue

Objective

Flurbiprofen 8.75 mg spray and lozenge have a rapid onset of action for sore throat relief, suggesting local action, although tissue penetration and the mechanism of local relief have not been determined. This investigation aimed to quantify the permeation and penetration of flurbiprofen, applied as local pharmaceutical forms, into full-thickness cadaveric human mucosal pharynx tissue, representing the clinical scenario as far as possible.

Methods

A validated high-performance liquid chromatography method quantified the permeation and penetration of flurbiprofen (spray and lozenge formulations) into human cadaveric pharynx tissue using a micro Franz cell model mimicking physiological and anatomical conditions. Full-thickness mucosal pharynx tissue, consisting of oral epithelium, basement membrane, and lamina propria, was utilized to imitate the in vivo setting. Flurbiprofen was analyzed on the surface of the pharynx tissue, within the pharynx tissue and in receiver fluid, over 60 mins.

Results

Flurbiprofen was detected in receiver fluid from 10 mins following spray application and was quantifiable from 20 mins. Flurbiprofen from lozenge was detected from 10 mins and was above the limit of quantitation in receiver fluid from 40 mins. Flurbiprofen recovered from the surface of the pharynx tissue was 24.45% and 8.48% of applied dose for spray and lozenge, respectively. Flurbiprofen recovered within pharynx tissue was 46.50% and 54.65% of applied dose for spray and lozenge, respectively. For flurbiprofen lozenge, recovery within pharynx tissue was 6-fold higher relative to recovery from the pharynx tissue surface.

Conclusion

Flurbiprofen from spray and lozenge formulations penetrated human cadaveric pharynx tissue, indicating that flurbiprofen can reach all layers of the pharynx mucosal tissue, including the underlying lamina propria, which contains blood vessels and nerve fibers that contribute to pain during sore throat. This suggests that flurbiprofen may have a local mechanism of action for sore throat, although this has yet to be determined.

Locally Delivered Flurbiprofen 8.75 mg for Treatment and Prevention of Sore Throat: A Narrative Review of Clinical Studies

BACKGROUND

Antibiotics are inappropriately prescribed to many people with sore throat. As most cases of sore throat are viral and/or self-limiting, guidelines recommend symptomatic management as first-line treatment. This paper reviews the available clinical evidence for the efficacy and safety of low-dose (8.75 mg) flurbiprofen, locally delivered to the throat for the symptomatic management of pharyngitis/sore throat.

METHOD

A literature search was performed on 27 February 2019 using PubMed. Studies that met the following criteria were included in a narrative review: (1) studies evaluating the effectiveness of flurbiprofen for pharyngitis/sore throat; (2) randomized controlled studies; (3) locally administered formulation of study drug/comparator; and (4) flurbiprofen administered at 8.75 mg dose (single- or multiple-dose administration).

RESULTS

A total of 17 papers were included in the review: 15 publications reporting data from nine unique clinical studies of flurbiprofen for acute pharyngitis, and two reporting studies of flurbiprofen for the prevention of postoperative sore throat (POST). Studies in acute pharyngitis demonstrated that single- and multiple-dose flurbiprofen 8.75 mg, locally administered in lozenge, spray or microgranule form, was well tolerated and provided early onset and long-lasting symptomatic relief from throat pain and soreness, sensation of swollen throat, difficulty swallowing, and other associated symptoms. This included patients with more severe symptoms, patients with confirmed Streptococcus A/C sore throat, and patients taking concomitant antibiotics. In addition, a single preoperative dose of flurbiprofen lozenge was shown to be effective for relieving early POST in patients undergoing general anesthesia.

CONCLUSION

Locally administered, low-dose flurbiprofen offers a useful first-line treatment option for symptomatic relief in patients with "uncomplicated" acute pharyngitis/sore throat associated with upper respiratory tract infection, thus potentially helping to reduce unnecessary antibiotic prescribing. It also offers an effective preoperative treatment option for the reduction of early POST severity and incidence.