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.

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.

Tetradecylthioacetic acid inhibits the oxidative modification of low density lipoprotein and 8-hydroxydeoxyguanosine formation in vitro

Oxidative modification of low-density lipoprotein (LDL) is thought to play a key role in the formation of foam cells and in initiation and progression of atherosclerotic plaque. The hypolipidemic 3-thia fatty acids contain a sulfur atom and might therefore possess reducing (antioxidant) properties. Consequently, the effects of 3-thia fatty acids on the susceptibility of LDL particles to undergo oxidative modification in vitro were studied. Tetradecylthioacetic acid (TTA), incorporated into the LDL particle and increased the lag time of copper ion induced LDL oxidation in a dose-dependent manner, 80 mumol/L TTA reduced the generation of lipid peroxides during copper ion induced LDL oxidation (for 2 hours) by 100%, 2,2'-azobis-(2,4-dimethylvaleronitrile) induced LDL oxidation by 64%, and 2,2'-azobis-(2-amidinopropane hydrochloride) induced LDL oxidation (for 6 hours) by 21%. The electrophoretic mobility of the oxidized LDL was reduced by TTA in both copper ion and azo-compounds initiated oxidation. This fatty acid analogue was effectively able to reduce in a dose dependent manner the formation of 8-hydroxydeoxyguanosine from 2-deoxyguanosine with ascorbic acid as the radical producer. TTA bound copper(II) ions and did not reduce copper(II) to copper(I). It failed to scavenge the 1,1-diphenyl-2-picrylhydrazyl radicals. The results suggest that the modification of LDL in the lipid and protein moieties can be significantly reduced by TTA. This acid may exert its antioxidant effect partially through metal ion binding and through free radical scavenging.

Acute rheumatic fever in Kuwait: The declining incidence

The incidence of acute rheumatic fever in children aged 5-14 years in Kuwait was studied prospectively over a period of five years (1984 through 1988). The mean annual incidence in the study period was 2.9/100,000 children. There was a decline in the incidence from 3.7/100,000 in 1984 to 2.5/100,000 in 1988. Twenty-seven percent of children with acute rheumatic fever presented as recurrences in 1985; this also declined to 11% in 1988.