Towards a more efficacious treatment for Oropharyngeal Candidiasis (OPC): Hydrogel-forming tablets for the controlled release delivery of Chlorhexidine diacetate

A thesis submitted in partial fulfilment of the requirements of the University of Wolverhampton for the degree of Doctor of Philosophy.Oropharyngeal candidiasis is a localised infection in the oropharynx region caused by Candida species, predominately C. albicans. It is commonly spread among immunocompromised patients and aggravated by hyposalivation or xerostomia. Current treatment is by systemic antifungals, which might be accompanied by gastrointestinal tract disorders, headache, allergic reactions and drug interactions or Candida becoming resistant to them. In the present work, the anti-candida activity of chlorhexidine diacetate (CHD) was tested as the drug of choice, it has no systemic side effects and microorganisms do not develop resistance against it. Thymol and farnesol were also tested individually and in combination with CHD to investigate a synergistic effect against Candida planktonic cells. The effects of CHD and thymol were investigated against C. albicans biofilm after two hours exposure by testing the metabolic stress, vacuolar activity and protein content. The results of the anti-Candida activity of CHD and thymol based on the minimum inhibitory concentration (MIC) and the minimum biocidal concentration (MBC) were 2.5 and 5 μg/ml for the former and 125 and 250 μg/ml for the later. Farnesol did not show an MIC and MBC at the investigated concentrations, however, it increased the MIC and MBC of CHD to 5 and 40 μg/ml and of thymol to 250 and >250 μg/ml, respectively. The antibiofilm activity of CHD and thymol was concentration dependent and CHD was more potent than thymol. A concentration of 20 μg/ml and 2 hours treatment of Candida biofilm grown for 24 hours showed an 85% decrease in oxidative stress, 78% and 60% loss of vacuolar activity and protein content, respectively. The combination of both drugs showed a limited increase in the activity. The cytotoxic effects of CHD and thymol were tested on human embryo kidney epithelial cell line (HEK 293); the metabolic stress, lysosomal activity and protein content were tested. The cytotoxic effects were also concentration dependent and the combination have increased the cytotoxicity. A concentration of 20 μg/ml and 2 hours treatment showed a 40% decrease in oxidative stress and neither the lysosomal activity nor protein content of HEK 293 cells was affected by the treatment Finally, a mucoadhesive hydrogel buccal tablets for the controlled release of CHD were designed and prepared to increase the residence time of an effective concentration of CHD in the oral cavity for two hours. They were prepared using Poloxamer 407 (P407), hydroxypropyl methylcellulose (HPMC) and either sorbitol, mannitol or xylitol at different ratios. The tablets were investigated for their physical properties, ex vivo mucoadhesion, the rate of hydration, gelling efficiency using image analysis, differential scanning calorimetry (DSC), Fourier transforms infrared spectroscopy (FTIR), X-ray diffractometry (XRD) and in vitro dissolution using Apparatus I and a novel method based on controlled flow rate to mimic salivary drug delivery in the oral cavity. Based on the antibiofilm activity and the cytotoxic effect of CHD a concentration of 20 μg/mL was chosen to be released from the tablets to maintain both efficacy and safety. Accordingly, to maintain this concentration the final formulations were prepared with a 2.5 mg dose of CHD. Tablets analysis showed no chemical interaction with the excipient based on DSC, FTIR and XRD. Furthermore, a novel dissolution method was developed based on a constant flow rate of the dissolution media to mimic oral salivary flow. By comparing CHD release using App I and the flow rate method it was shown that hydrogel-forming tablets successfully controlled the release of CHD regardless of the volume of the dissolution media with approximately 90% release and an average release concentration of 19 μg/ml and 1 ml/min flow rate. This making it a potential candidate for future application for treatment of candidiasis in all types of patients

The investigation of thymol formulations containing poloxamer 407 and hydroxypropyl methylcellulose to inhibit candida biofilm formation and demonstrate improved bio-compatibility

© 2022 The Authors. Published by MDPI. This is an open access article available under a Creative Commons licence. The published version can be accessed at the following link on the publisher’s website: https://doi.org/10.3390/ph15010071The aim of this study was to investigate the potential of thymol to inhibit Candida biofilm formation and improve thymol biocompatibility in the presence of hydroxypropyl methylcellulose (HPMC) and poloxamer 407 (P407), as possible drug carriers. Thymol with and without polymers were tested for its ability to inhibit biofilm formation, its effect on the viability of biofilm and biocompatibility studies were performed on HEK 293 (human embryonic kidney) cells. Thymol showed a concentration dependent biofilm inhibition; this effect was slightly improved when it was combined with HPMC. The Thymol-P407 combination completely inhibited the formation of biofilm and the antibiofilm effect of thymol decreased as the maturation of Candida biofilms increased. The effect of thymol on HEK 293 cells was a loss of nearly 100% in their viability at a concentration of 250 mg/L. However, in the presence of P407, the viability was 25% and 85% using neutral red uptake and sulforhodamine B assays, respectively. While, HPMC had less effect on thymol activity the thymol-P407 combination showed a superior inhibitory effect on biofilm formation and better biocompatibility with human cell lines. The combination demonstrates a potential medical use for the prevention of Candida biofilm formation.Published onlin

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

The activity of PHMB and other guanidino containing compounds against acanthamoeba and other ocular pathogens

© 2022 The Authors. Published by MDPI. This is an open access article available under a Creative Commons licence. The published version can be accessed at the following link on the publisher’s website: https://doi.org/10.3390/microorganisms10071375In recent years, a rise in the number of contact lens users in the UK and worldwide coincided with an increased incidence of microbial keratitis. The aim of this study was to investigate the antimicrobial activities of polyhexamethylene guanidine (PHMG), polyaminopropyl biguanide (PAPB), and guazatine in comparison to the common contact lens disinfectant constituent, polyhexamethylene biguanide (PHMB). The study investigated these compounds against a broad range of organisms, including Acanthamoeba castellanii, Acanthamoeba polyphaga, Staphylococcus aureus, Pseudomonas aeruginosa, and Candida albicans. This study demonstrated that PHMG, PAPB, and guazatine are equal in activity to PHMB against Acanthamoeba trophozoites and cysts. PHMG and PAPB are also equal in activity to PHMB against S. aureus and P. aeruginosa, whereas PHMG shows significantly better activity than PHMB against C. albicans (p < 0.001). To our knowledge, this is the first study to demonstrate the effectiveness of PHMB, PHMG, PAPB, and guazatine against Acanthamoeba and other ocular pathogens. As alternatives to PHMB, these compounds warrant further investigation for inclusion in contact lens solutions and for the treatment of keratitis

The effects of progesterone administration in mice during pregnancy on ovarian development and anogenital distance of the offspring

Background: Progesterone is highly used in pregnant women as therapeutic agent to maintain and support pregnancy. Objective: To explore the effects of progesterone usage allover gestation till 7days postnatally on mice offspring ovaries development and anogenital distance. Material and methods: Ten pregnant mice were equally divide into control group that was injected with sesame oil which is used as a solvent for progesterone and treated group that is daily intraperitoneally injected with progesterone (dissolved in sesame oil 1:10) at dose 10.2mg/kg (the equivalent human dose) all through gestation till7day postnatal then sacrificed and measuring the anogenital distance (the distance between anus and genital papilla). Histological slides were prepared and Diameters of the ovary, primary oocyte and primordial follicles were measured and histopathological changes analysis was done. Result: Progesterone administration cause significant increment (p>0-05) in anogenital distance, significant decrement in primary oocyte diameter and primordial follicle diameter, with no significant difference in the ovary diameter. Histopathological changes were seen as hemorrhage, detachment of follicular cells from basement membrane with irregular arrangement and thickening or death of follicular cells, pyknosis of primary oocytes and vacculation. Stromal cells degeneration. Conclusion: The current study revealed that progesterone injection of mice with equivalent human dose during pregnancy is embryotoxic and teratogenic, may alter the female reproductive performance with virilizing the female genitalia. The benefit of progesterone as a therapies need to be proven before recommended as supportive treatment during pregnancy

The Investigation of Thymol Formulations Containing Poloxamer 407 and Hydroxypropyl Methylcellulose to Inhibit Candida Biofilm Formation and Demonstrate Improved Bio-Compatibility

The aim of this study was to investigate the potential of thymol to inhibit Candida biofilm formation and improve thymol biocompatibility in the presence of hydroxypropyl methylcellulose (HPMC) and poloxamer 407 (P407), as possible drug carriers. Thymol with and without polymers were tested for its ability to inhibit biofilm formation, its effect on the viability of biofilm and biocompatibility studies were performed on HEK 293 (human embryonic kidney) cells. Thymol showed a concentration dependent biofilm inhibition; this effect was slightly improved when it was combined with HPMC. The Thymol-P407 combination completely inhibited the formation of biofilm and the antibiofilm effect of thymol decreased as the maturation of Candida biofilms increased. The effect of thymol on HEK 293 cells was a loss of nearly 100% in their viability at a concentration of 250 mg/L. However, in the presence of P407, the viability was 25% and 85% using neutral red uptake and sulforhodamine B assays, respectively. While, HPMC had less effect on thymol activity the thymol-P407 combination showed a superior inhibitory effect on biofilm formation and better biocompatibility with human cell lines. The combination demonstrates a potential medical use for the prevention of Candida biofilm formation.</p

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

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.</p

The Activity of PHMB and Other Guanidino Containing Compounds against Acanthamoeba and Other Ocular Pathogens

In recent years, a rise in the number of contact lens users in the UK and worldwide coincided with an increased incidence of microbial keratitis. The aim of this study was to in-vestigate the antimicrobial activities of polyhexamethylene guanidine (PHMG), polyaminopropyl biguanide (PAPB), and guazatine in comparison to the common contact lens disinfectant constituent, polyhexamethylene biguanide (PHMB). The study investigated these compounds against a broad range of organisms, including Acanthamoeba castellanii, Acanthamoeba polyphaga, Staphylococcus aureus, Pseudomonas aeruginosa, and Candida albicans. This study demonstrated that PHMG, PAPB, and guaza-tine are equal in activity to PHMB against Acanthamoeba trophozoites and cysts. PHMG and PAPB are also equal in activity to PHMB against S. aureus and P. aeruginosa, whereas PHMG shows significantly better activity than PHMB against C. albicans (p &lt; 0.001). To our knowledge, this is the first study to demonstrate the effectiveness of PHMB, PHMG, PAPB, and guazatine against Acanthamoeba and other ocular pathogens. As alternatives to PHMB, these compounds warrant further investigation for inclusion in contact lens solutions and for the treatment of keratitis.</p

Nano particles as new disinfectan In Moringa oleifera

ABSTRACT. Contamination is a big problem in in vitro cultures, especially in woody plants. In this paper, different sterilization material been used to compare their efficiency in sterilization with Nanoparticles. Silver and copper Nanoparticles had been widely used in many fields. Plants in vitro rarely get used with nanoparticles. Silver &amp;Cupper nanoparticles had used in many concentrations. It was clear that using these particles have a good benefit to get clean cultures, even with high concentrations. This paper gives us clear idea to use silver Nanoparticles as alternative cleaning solution