Objective(s): Chlorhexidine is a highly effective, broad-spectrum antimicrobial agent available as a mouthwash, gel, spray, root canal rinse, and periodontal chips. Different results of the effectiveness of this substance have been reported in the studies, hence the aim of this survey is a systematic review of the studies conducted on the minimum inhibitory concentration(MIC) of chlorhexidine on Gram-positive and Gram-negative bacteria isolated in health care centers in Iran. Materials and Methods: The data of this systemic review study were searched from international database including EMBASE, Scopus, PubMed/Medline and Cochrane library using appropriate English keywords until October 2022 and after filtering based on inclusion and exclusion criteria, 12 articles entered our study. Results: Out of a total 12 articles, 7 studies were conducted on Gram-positive bacteria,4 studies were conducted on Gram-negative bacteria and 1 study was assessed on both groups. Most studies have been done on Staphylococcus aureus and Pseudomonas aeruginosa. The lowest and admissible MIC was 0.5 µg/mL and on the flip side the highest was 625 µg/mL. Conclusion: Based on our analysis, antibacterial activity of chlorhexidine against Gram-negative and positive bacteria was discouraging. However, further clinical studies are necessitated to provide clinical evidence to support these observations.

Purpose: In this study, a controlled-release drug delivery system loaded with piroxicam and methadone was synthesized and used subcutaneously in rats with experimental tibial defect, and healing were assessed histopathologically. Materials and Methods: For this purpose, 100 adult female rats were randomly divided into five equal groups; control group, chitosan group, piroxicam group, methadone group, and piroxicam-methadone group. The morphological structure of the synthesized drug systems was studied by scanning electron microscope. In addition, the structure of the hydrogels was investigated by Fourier transform infrared spectroscopy and while releasing the hydrogels' gelation time, the release of piroxicam and methadone from the hydrogels was evaluated in vitro. Results: Histological results of the 3rd day of the study showed the lowest extent and severity of inflammation in the chitosan, piroxicam, and piroxicam-methadone groups, while on the 7th day, tissue inflammation and the extent of bleeding were lower in the piroxicam, methadone, and piroxicam-methadone groups than in the other groups. Evaluation of new bone formation on day 21 showed that the chitosan, piroxicam, and methadone groups had better repair than the other groups. Conclusion: It seems that in the control group that did not receive any treatment intervention, following the experimental bone defect, the highest inflammatory response was observed in histological examination and finally the weakest bone repair. On the other hand, the presence of piroxicam, methadone, and chitosan in the piroxicam-methadone group (all of which have anti-inflammatory effects) also seems to have a negative effect on the repair.

Recently, there have been various chemical carriers and routines for treatment of infections. Plant gum nanoparticles are being used greatly for this purpose. They have several advantages over chemical drug carriers including being biodegradable, biocompatible, nontoxic, providing better tolerance to the patient, and having fewer side effects. They also do not cause allergies in humans, do not irritate the skin or eyes, and have low production costs. The use of plant gums as drug carriers is limited due to a series of disadvantages. They may have microbial contamination because of the moisture in their content. Also, in storage, their viscosity decreases due to contact with water. By green nanoparticle synthesis of these plant gums as drug carriers, the disadvantages can be limited. There are several studies showing that plant gum drug carriers can have a great combination with various drugs and nanoparticles, thus they could be extremely effective against multi-resistant bacteria and even systemic illness like cancer. These days, the need for green synthesis of medicine and drug carriers has become quite popular and it will be even more essential in the future because of emerging antibiotic-resistant bacteria and climate change.