Currently, pharmaceutical companies are working on innovative methods, processes and products. Oral mucoadhesive systems, such as tablets, gels, and polymer films, are among these possible products. Oral mucoadhesive systems possess many advantages, including the possibility to be applied in swallowing problems. The present study focused on formulating buccal mucoadhesive polymer films and investigating the physical and physical–chemical properties of films. Sodium alginate (SA) and hydroxypropyl methylcellulose (HPMC) were used as film-forming agents, glycerol (GLY) was added as a plasticizer, and cetirizine dihydrochloride (CTZ) was used as an active pharmaceutical ingredient (API). The polymer films were prepared at room temperature with the solvent casting method by mixed two-level and three-level factorial designs. The thickness, tensile strength (hardness), mucoadhesivity, surface free energy (SFE), FTIR, and Raman spectra, as well as the dissolution of the prepared films, were investigated. The investigations showed that GLY can reduce the mucoadhesivity of films, and CTZ can increase the tensile strength of films. The distribution of CTZ proved to be homogeneous in the films. The API could dissolve completely from all the films. We can conclude that polymer films with 1% and 3% GLY concentrations are appropriate to be formulated for application on the buccal mucosa as a drug delivery system.

Oral mucoadhesive systems, such as polymer films, are among innovative pharmaceutical products. These systems can be applied in swallowing problems and can also be used in geriatrics and paediatrics. In our earlier work, we successfully formulated buccal mucoadhesive polymer films, which contained cetirizine-hydrochloride (CTZ) as the API. The present study focused on investigating the stability and permeability of the prepared films. The stability of the films was studied with an accelerated stability test. During the stability test, thickness, breaking hardness and in vitro mucoadhesivity were analysed. Furthermore, the interactions were studied with FT-IR spectroscopy, and the changes in the amount of the API were also monitored. Cytotoxicity and cell line permeability studies were carried out on TR 146 buccal cells. Compositions that can preserve more than 85% of the API after 6 months were found. Most of the compositions had a high cell viability of more than 50%. Citric acid (CA) decreased the stability and reduced every physical parameter of the films. However, cell line studies showed that the permeability of the films was enhanced. In our work, we successfully formulated CTZ-containing buccal films with adequate stability, high cell viability and appropriate absorption properties.

Hydrophobic ion pairing (HIP) complexation was found to be an efficient approach in modulating the release and enhancing the stability and encapsulation of hydrophilic macromolecules such as proteins in hydrophobic nano/microcarriers. The present work strives to develop and optimize the preparation of the HIP complex of the antimicrobial enzyme lysozyme (LYZ) with the ion-pairing agent (IPA) sodium dodecyl sulphate (SDS) relying on the quality-by-design (QbD) approach. The quality target product profile (QTPP) includes the achievement of maximal lipophilicity in a reversible manner to enable the maintenance of biological activity. The related critical quality attributes (CQAs) were defined as complexation efficacy, complex stability, enzyme recovery and activity. Three risk assessment (RA) tools were used to identify and rank the critical process parameters (CPPs) and critical material attributes (CMAs). From this assessment, the pH of the medium, LYZ:SDS molar ratio and drying conditions were determined as high-risk factors that need to be investigated. To the best of our knowledge, for the first time, electrostatic titration was used as a smart approach to determine the optimum molar ratio at different pH values. Based on the predefined CQAs, pH 8 with an LYZ/SDS molar ratio of 1:8 was found to be the optimal condition for complexation efficiency and recovery (%) of a biologically active enzyme. A cost-effective drying process based on a ventilated oven was developed, which resulted in complex qualities comparable to those obtained by the commonly used freeze-drying method. In a nutshell, the optimum conditions for the preparation of the LYZ/SDS HIP complex were efficiently facilitated by the rational application of QbD principles and the utilization of efficient electrostatic titration and ventilated oven-drying methods.

Background: Captopril (CAP), an angiotensin-converting enzyme inhibitor (ACEI), is widely prescribed for managing hypertension, heart failure, and related conditions. When administered orally, CAP undergoes hepatic metabolism, resulting in a bioavailability of 60–75%. However, to bypass the first-pass metabolism and other limitations of the oral route, mucoadhesive buccal films have gained attention as a promising alternative with several advantages. The aim of this work was the formulation and optimization of chitosan-ascorbate mucoadhesive films for buccal delivery of CAP for the management of a hypertension crisis (10 mg and 20 mg) by employing quality by design (QbD) principles and the design of experiment (DoE) approach. Materials and methods: In the present work, chitosan (CHI) was selected as a film-forming agent due to its permeability-enhancing properties, which could be further improved through salification with ascorbic acid (AA). The polymer films were prepared by the solvent casting method. Results: The optimized CAP-loaded formula showed appropriate in vitro mucoadhesion force (>15 N) and breaking hardness (>14 N). The different CAP-containing films had a high drug content (>95%) with homogeneous drug distribution, thus complying with the requirements of Pharmacopeia. FT-IR and RAMAN spectroscopy analyses demonstrated successful incorporation of the drug, and interaction was observed between the excipients of the films, especially in the form of hydrogen bonds. The dissolution test showed immediate release of the API with a similar release pattern from both concentrations of CAP-loaded films. Conclusions: The properties of the prepared films met the predetermined critical quality attribute requirements. The optimized formula of CHI 1.4%, AA 2.5%, and glycerol 0.3% appears to be a promising buccal drug delivery system for CAP.

Background/Objectives: Films in the mouth offer a promising alternative drug delivery system for oral administration, with several advantages over traditional oral formulations. Furthermore, their non-invasive nature and easy administration make them conducive to increasing patient compliance. The use of active agents in these films can further improve their drug delivery properties, making them an even more useful drug delivery system. Methods: In this research, carrageenan was used as a polymer, while glycerine was added as a plasticizer, furthermore, lidocaine hydrochloride and diclofenac sodium were used as the active agents. The prepared films were characterized by analytical techniques. Results: The results showed that glycerine reduced the mucoadhesivity and breaking hardness of the films and increasing the temperature made the films brittle. These results are also confirmed by the statistical analysis. Based on the FTIR results, glycerine can be used in films without structural changes. Conclusions: Based on the findings, films prepared from a solution with a concentration of 1.5% carrageenan and 1.5% glycerine at 70 °C are suitable as a drug delivery system for use on the buccal mucosa when combined with active agents. Carrageenan was successfully used as a carrier for two different types of active agents.

Background: Buccal films have attracted continued interest due to their several advantages. However, developing effective buccal films for hydrophilic drugs remains challenging due to limited buccal permeability. Captopril, a water-soluble ACEI, represents a suitable model for evaluating buccal films. Chitosan–ascorbate has previously been studied in solution for its cytotoxicity and permeation-enhancing properties. However, its performance as a buccal-film dosage form requires further investigation. The present study extends earlier formulation work by evaluating the in vitro cytotoxicity, permeability, and stability of captopril-loaded chitosan–ascorbate buccal films. Methods: Blank and captopril-loaded films were assessed. Cytotoxicity and permeability were evaluated using TR146 cells and compared with chitosan–acetate films as a reference. Accelerated stability test (40 °C/75% RH, three months) was performed to monitor moisture content, mechanical properties, and drug content. FT-IR spectroscopy was used to investigate potential chemical interactions. Results: All films maintained cell viability above 80%. Chitosan–ascorbate films significantly increased captopril permeation compared with chitosan–acetate films, achieving up to a 12–16-fold increase in cumulative drug permeation. The stability test did not reveal any new chemical reactions or interactions based on FT-IR analysis, indicating that the polymer system remained structurally stable; however, it showed continuous moisture uptake, slight deterioration of mechanical properties and a decrease in drug content. Conclusions: This study provides an in vitro, dosage-form–level evaluation of captopril-loaded chitosan–ascorbate buccal films, demonstrating acceptable cytocompatibility and moderate enhancement of permeability. However, significant moisture sensitivity under accelerated conditions can represent limitations, highlighting the importance of protective packaging or further formulation optimization to overcome this.