Anti-acne preparations containing tetracycline, azelaic acid and azeloglycine: Optimization of stability and physicochemical properties.

Background: Acne vulgaris is a common inflammatory skin condition affecting almost 85% of the adolescent and young adult population. The etiopathogenesis of this dermatosis involves an imbalance in the skin microbiome, leading to inflammation of both the skin and hair follicles.

Objectives: The aim of this study was to develop topical anti-acne formulations with increased therapeutic efficacy and reduced risk of developing antibiotic resistance. Six hydrogel formulations containing azelaic acid or its derivative, azeloglycine, in combination with tetracycline hydrochloride were prepared as part of the study.

Material and methods: The investigated formulations were prepared using an Eprus U500 pharmaceutical mixer and the pH was determined using an ERH-11S electrode designed for dense substances and a CPC-505 Elmetron pH-meter. The formulations were analyzed for tetracycline stability in the presence of additional active ingredients and varying pH over a period of 35 days using high-performance liquid chromatography (HPLC). In addition, the effects of azeloglycine and azelaic acid on the viscosity of the prepared formulations were evaluated using a Brookfield DV2T rotational viscometer.

Results: Chromatographic analysis showed significant stability of tetracycline in most formulations, with azeloglycine-containing formulations showing less degradation of the antibiotic than azelaic acid-containing preparations. In addition, azeloglycine-containing gels exhibited more favorable rheological properties, which may facilitate better application and be more beneficial to patients.

Conclusion: The results suggest that formulations containing azeloglycine and tetracycline may be a promising strategy for acne therapy, offering increased tetracycline stability and an optimal rheological profile, which may result in prolonged therapeutic effect and more effective drug delivery to the skin.