Portable Near-infrared Spectroscopy for the Non-destructive Quality Control of Polaprezinc (PLZ) Mucoadhesive Films

In a recent study conducted by Kohei Tahara, a professor at Gifu Pharmaceutical University, Tahara and his team explored a new alternative for patients suffering from oral mucositis (1). This new development is a new film formulation of polaprezinc (PLZ), a zinc-based compound with anti-inflammatory and mucosal-protective properties (1). The findings, published in the European Journal of Pharmaceutics and Biopharmaceutics, details the development and quality control innovations of the new PLZ-containing oral film (1).

Oral mucositis is an inflammation of the muscosa, which lines a person’s mouth and gastrointestinal tract (2). The side effects of oral mucositis include a sore and red mouth, as well as mouth sores or white patches of pus in the mouth (2). Cancer patients, including those who receive chemotherapy treatments, are susceptible to contracting this condition (2). As a result, scientists and drug developers have been looking at better ways to treat this condition.

Сhild has stomatitis in mouth. Diseases of oral cavity. Candidiasis in boy. | Image Credit: © Полина Екимова - stock.adobe.com

PLZ has been widely explored for its ability to prevent oral mucositis, which commonly affects cancer patients undergoing intensive treatment (1,3). For example, PLZ has been explored as a medicine to help taste disorders (3). Although previous research has introduced PLZ-containing lozenges, their use is often limited because of the severe pain and discomfort they can cause during administration, particularly in patients with already damaged oral tissues (1).

This is a clinical challenge that Tahara and his team sought to resolve. In their study, they developed and tested a patient-friendly alternative medication, which involved using a thin, mucoadhesive film that can adhere directly to the oral mucosa and deliver the same therapeutic dose—18.75 mg of PLZ—as existing lozenges (1). The researchers created this dosage form to accomplish two goals: 1) to make this medication easier to use, and 2) to minimize pain patients feel using these treatments, especially for pediatric and elderly patients (1).

As part of the experimental procedure, the research team used a solvent casting method to create several film prototypes. This was done to screen for polymers that could effectively incorporate high levels of PLZ (1). After evaluating multiple candidates, hydroxypropyl cellulose (HPC) emerged as the most suitable film-forming polymer because of its favorable handling and adhesive properties (1). However, the high concentration of PLZ posed formulation challenges, resulting in films that were curved and inflexible upon drying (1).

The researchers used glycerin (Gly) as a plasticizer to solve this issue and create the final formulation. The result was that the new formulation exhibited content uniformity, mucosal adhesion, and storage stability, with no significant degradation of PLZ observed over time (1).

Another main part of the study was how the researchers used portable near-infrared (MicroNIR) spectroscopy for the non-destructive quality control of the films. Traditionally, high-performance liquid chromatography (HPLC) has been used to assess drug content in pharmaceutical formulations (1). However, HPLC requires specialized equipment and extensive sample preparation. By contrast, the MicroNIR system used in this study allowed the researchers to use a faster, portable, and more accessible alternative method (1).

Then, the researchers used multivariate analysis to build a calibration model that can predict the PLZ content in the films. Their findings suggested that this process analytical technology (PAT) could improve how pharmacists and clinicians monitor drug content in real time, potentially enabling film preparation and quality assessment within the confined spaces of hospital or community pharmacy dispensing rooms (1).

In their conclusion, the researchers expressed interest in evaluating the mechanical strength of the films when manipulated by hand (1). They also intend to conduct in vivo trials to evaluate the retention time of the films in the oral cavity and their effectiveness in preventing or mitigating mucositis symptoms in animal and human models (1).

References

1. Ito, T.; Yamazoe, E.; Funato, M.; et al. Development of Mucoadhesive Films with High Polaprezinc Content for Oral Mucositis: A Study on Formulation and Near-infrared Spectroscopy-based Quality Control. Eur. J. Pharm. Biopharm. 2025, 211, 114707. DOI: 10.1016/j.ejpb.2025.114707
2. Cleveland Clinic, Mucositis. Cleveland Clinic. Available at: https://my.clevelandclinic.org/health/diseases/24181-mucositis (accessed 2025-04-15).
3. Li, M.; Sun, Z.; Zhang, H.; Liu, Z. Recent Advances on Polaprezinc for Medical Use. Exp. Ther. Med. 2021, 22 (6), 1445. DOI: 10.3892/etm.2021.10880