The effect of the source and the concentration of polymers on the release of chlorhexidine from mucoadhesive buccal tablets.

In the current work, two groups of chlorhexidine mucoadhesive buccal tablets were prepared, using either rod or irregularly-shaped spherical particles of hydroxypropyl methylcellulose and different ratios of poloxamer 407 (P407). The tablets were designed to release the drug over two hours. Their physicochemical properties and drug release profiles were investigated. The impact on dry granulation, the ex-vivo mucoadhesion, the swelling index, the morphology of swollen tablets and the drug release kinetic were investigated. Drug-polymers chemical interaction was studied using Fourier Transforms Infrared Spectroscopy (FTIR) and differential scanning calorimetry (DSC). Due to different particle shapes, the preparation of dry granules required a 40 KN force for rod-shaped particles compared to 10 KN for the irregularly-shaped spherical particles. All formulations showed at least two-hours residence time using ex-vivo mucoadhesion. Statistically, there was no significant difference in the swelling index, drug release nor its kinetic for both groups. However, the microscopical morphology of the swollen tablet and the size of the pores were affected by particle shape. Increasing the ratio of P407 to 62.5% resulted in a pronounced increase in drug release from around 60% to >90% after two hours. Following the FTIR and DSC analyses, no chemical interaction was noted apart from the steric hindrance effect of P407, which was observed even with the physical mixtures.

Exploring the Impact of 1,8-Diioodoctane on the Photostability of Organic Photovoltaics.

Improving the photostability of the light-harvesting blend film in organic photovoltaics is crucial to achieving long-term operational lifetimes that are required for commercialization. However, understanding the degradation factors which drive instabilities is complex, with many variables such as film morphology, residual solvents, and acceptor or donor design all influencing how light and oxygen interact with the blend film. In this work, we show how blend films comprising a donor polymer (PBDB-T) and small molecule acceptor (PC71BM or ITIC) processed with solvent additive (DIO) yield very different film morphologies, device performance, and photostability. We show that DIO is retained approximately 10 times more effectively in ITIC based films compared to PC71BM. Unexpectedly, we see that while high volumes of DIO reduce photostability for encapsulated ITIC devices, when oxygen is introduced DIO can improve the lifetime of PBDB-T:ITIC based cells. Here, the addition of 3% DIO doubles the T 80 compared to ITIC based devices without DIO, suggesting that DIO-induced morphological changes interfere with or reduce photo-oxidative reactions.

Chlorhexidine Mucoadhesive Buccal Tablets: The Impact of Formulation Design on Drug Delivery and Release Kinetics Using Conventional and Novel Dissolution Methods.

Oropharyngeal candidiasis (OPC) is a mucosal infection caused by Candida spp., and it is common among the immunocompromised. This condition is mainly treated using oral antifungals. Chlorhexidine (CHD) is a fungicidal and is available as a mouth wash and oral gel. It is used as an adjuvant in the treatment of OPC due to the low residence time of the current formulations. In this study, its activity was tested against C. albicans biofilm and biocompatibility with the HEK293 human cell line. Then, it was formulated as mucoadhesive hydrogel buccal tablets to extend its activity. Different ratios of hydroxypropyl methylcellulose (HPMC), poloxamer 407 (P407), and three different types of polyols were used to prepare the tablets, which were then investigated for their physicochemical properties, ex vivo mucoadhesion, drug release profiles, and the kinetics of drug release. The release was performed using Apparatus I and a controlled flow rate (CFR) method. The results show that CHD is biocompatible and effective against Candida biofilm at a concentration of 20 µg/mL. No drug excipient interaction was observed through differential scanning calorimetry (DSC) and Fourier-transform infrared spectroscopy (FTIR). The increase in P407 and polyol ratios showed a decrease in the swelling index and an increase in CHD in vitro release. The release of CHD from the selected formulations was 86-92%. The results suggest that chlorhexidine tablets are a possible candidate for the treatment of oropharyngeal candidiasis.