Designing of environmentally ph-responsive antibacterial hydrogels of polyvinyl pyrrolidone for controlled release of tetracycline

Abstract An imminent concern for global public health is the prevention and management of infections caused by microbes because of the poor performance of the existing antimicrobial regime and the developed of emerging resistance against pathogenic microbes. Therefore, new treatment plans have been recognized to effectively address the issues and control bacterial infections. Tetracycline, a broad-spectrum antibiotic, is highly active against gram-positive and gram-negative bacteria. Although tetracycline exhibits excellent antibacterial activities, certain issues, including short half-life, multiple heavy doses in a day, severe adverse effects, and poor patient compliance, limit its application, especially in managing bacterial infections. To attempt this, a pH-responsive hydrogel of polyvinyl pyrrolidone loaded with tetracycline was fabricated. Due to the usage of pH-sensitive monomers, the sensitivity of the polymeric hydrogels was increased, which not only minimizes the absorption of tetracycline in the upper parts of the gastrointestinal tract but also prevents tetracycline degradation in the acidic medium. This unique behavior of the prepared networks protects the gastrointestinal parts from the adverse effects of tetracycline, thus enabling them as the most suitable agents for controlled drug delivery compared to other conventional drug delivery systems. Hence, characterizations, including Fourier transform infrared spectroscopy, thermogravimetric analysis, and differential scanning calorimetry were utilized to determine drug loading and interaction among hydrogel contents. Reduction in polymer, monomer, and drug crystallinity was evaluated by X-ray diffractometry analysis of the developed hydrogel, whereas surface morphology was examined by scanning electron microscopy. Mechanical stability of 55% was perceived with applied stress of 60.30 kPa. Similarly, gel fraction and porosity were found within the 86 ̴ 98% and 75 ̴ 95% ranges. High swelling index and drug release were achieved at a pH of 7.4. In comparison to the commercial product of tetracycline, a prolonged controlled drug release was illustrated by the fabricated hydrogel. Slow degradation of the prepared matrix was perceived with the high composition of hydrogel contents. A cytotoxicity study exhibited the safe and effective use of the prepared hydrogel on two cells: RAW macrophages (RAW 264.7) and mouse fibroblast L929 cells. The formulated hydrogel found antibacterial inhibition zones of 44.60 ± 0.13 mm and 40.21 ± 0.41 mm for Staphylococcus aureus and Escherichia coli. The results affirmed that the developed polymeric hydrogel could be an excellent carrier system for treating a bacterial infection with negligible toxicity.