Formulation and Optimization of Metronidazole and Lactobacillus spp. Layered Suppositories via a Three-Variable, Five-Level Central Composite Design for the Management of Bacterial Vaginosis

Effect of Kangfuxiaomi suppository on pelvic inflammatory disease in rats

Pelvic inflammatory disease (PID) is commonly encountered in gynecological practice. Kangfuxiaomi suppository, made from the compound extract of Periplaneta Americana, is a Traditional Chinese Medicine remedy widely used for the treatment of gynecological disorders. This study aimed to preliminarily explore the therapeutic effect of Kangfuxiaomi suppository in a rat model of PID established by chemical injury and pathogen infection. The key parameters assessed were vulvar inflammation score, vaginal + uterine organ index, and serum levels of interleukin (IL)- 8; tumor necrosis factor (TNF)-α; C-reactive protein (CRP); superoxide dismutase (SOD); and malondialdehyde (MDA). In addition, levels of IL-6, cyclooxygenase (COX)- 2, and IL-2 in cervical tissues as well as that of IL-1β and prostaglandin E-2 (PGE2) in uterine tissues were measured. The expression levels of nuclear factor-kappa B (NF-κB) p65 and Toll-like receptor 4 (TLR4) in uterine tissues were detected by immunohistochemical method. After Kangfuxiaomi suppository treatment, the vulva inflammation score and histopathological score of PID rats showed a tendency to decrease. Serum IL-8, TNF-α, CRP, and MDA levels were reduced, while SOD levels were significantly increased. Levels of IL-6, IL-2, and COX-2 in cervical tissues were somewhat decreased, and PGE2 and IL-1β levels in uterine tissue were significantly decreased. Moreover, the levels of NF-κB p65 and TLR4 protein expression were also decreased. These findings demonstrated the therapeutic effect of Kangfuxiaomi suppository in PID rats. The underlying mechanism may involve enhanced antioxidant capacity and decreased secretion of proinflammatory factors via the NF-κB/TLR4 signaling pathway.

Rectal Bioavailability of Amoxicillin from Hollow-Type Suppositories: Effect of Chemical Form of Amoxicillin

Rectal drug administration could offer advantages in the delivery of medicines for children by avoiding swallowability issues, improving stability and enabling administration by caregivers. This study aimed to evaluate the rectal bioavailability of hollow-type suppositories (HTS) and understand the effect of two chemical forms of amoxicillin: amoxicillin sodium (AS) or amoxicillin trihydrate (AMT). HTS were prepared by incorporating a lipophilic core containing the antibiotic with a polyethylene glycol (PEG) shell. Formulations were characterised in vitro, and the absolute bioavailability was determined in a rabbit model, while drug-base interactions were evaluated using X-ray diffraction crystallography (XRD), differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy. The in vitro amoxicillin release from AMT HTS was delayed, taking 27.3 ± 4.9 h to release 50% drug compared with 1.7 h for the AS HTS, likely due to solubility differences between AMT and AS. The presence of orthorhombic AMT and anhydrous AS crystals in respective HTS was confirmed via XRD and DSC. PEG shells were able to protect the drug chemical stability when stored at 25 °C/60% RH. Despite the difference in their in vitro release rates, a similar rectal bioavailability was found in both forms of amoxicillin (absolute bioavailability 68.2 ± 6.6% vs. 72.8 ± 32.2% for AMT HTS and AS HTS, respectively; p = 0.9682). Both HTS formulations showed little or no irritation to the rectal mucosa following a single dose.

Development of Thermoresponsive Hydrogels with Mucoadhesion Properties Loaded with Metronidazole Gel-Flakes for Improved Bacterial Vaginosis Treatment

Bacterial vaginosis is an infectious disease that has significantly affected women's health. Metronidazole has been widely used as a drug for treating bacterial vaginosis. Nevertheless, the currently available therapies have been found to be inefficient and inconvenient. Here, we developed the combination approach of gel flake and thermoresponsive hydrogel systems. The gel flakes were prepared using gellan gum and chitosan, showing that the incorporation of metronidazole was able to provide a sustained release pattern for 24 h with an entrapment efficiency of >90%. Moreover, the gel flakes were incorporated into Pluronics-based thermoresponsive hydrogel using the combination of Pluronic F127 and F68. The hydrogels were found to exhibit the desired thermoresponsive properties, showing sol-gel transition at vaginal temperature. Following the addition of sodium alginate as a mucoadhesive agent, the hydrogel was retained in the vaginal tissue for more than 8 h, with more than 5 mg of metronidazole retained in the ex vivo evaluation. Finally, using the bacterial vaginosis infection model in rats, this approach could decrease the viability of Escherichia coli and Staphylococcus aureus with reduction percentages of more than 95% after 3 days of treatment, with the healing ability similar to normal vaginal tissue. In conclusion, this study offers an effective approach for the treatment of bacterial vaginosis.