Design and evaluation of pharmaceutical availability, stability and quality of modified viscosity eye drops with choline salicylate

In vitro assessment of cytokine modulation by choline salicylate, hyaluronic acid, lidocaine-based six different teething gels in human gingival fibroblast cells

Teething gels are used to treat various oral mucosal conditions and inflammation. The effect of teething gels on cytokines involved in the inflammatory process is unknown. This study aimed to assess the influence of teething gels on the levels of inflammatory cytokines in human gingival fibroblasts using an in vitro assay. In this study, MTT (3-[4,5-methylthiazol-2-yl]-2,5-diphenyl-tetrazolium bromide) test was used to calculate the values that provide 50% survival of the cells with different teething gels applied to human gingival fibroblast cells. Using Enzyme-Linked Immunosorbent Assay kits, Interleukin-1β, Interleukin-6, Interleukin-8, Tumor necrosis factor-α, and Interleukin-10 cytokine levels were measured in the control group and in fibroblast cells treated with each teething gel. The statistical analysis of the data was done with SPSS program. All of the teething gels caused various levels of suppression of the cytokines governing the inflammatory process (p < 0.05). Interleukin-1β levels were significantly lower in the hyaluronic acid group than in the lidocaine group (p < 0.05). Interleukin-8 levels were significantly lower in all teething gel groups compared with the control group (p < 0.0001). In conclusion, all of the teething gels in this study were able to suppress the cytokines that regulate the inflammatory process. Considering the cytotoxic side effects of other teething gels, it is concluded that hyaluronic acid-based teething gels have a safe and tolerable profile in the suppression of cytokines that manage the inflammation process in symptom-directed treatments.

Balsam Poplar Buds: Extraction of Potential Phenolic Compounds with Polyethylene Glycol Aqueous Solution, Thermal Sterilization of Extracts and Challenges to Their Application in Topical Ocular Formulations

Phenolic compounds of natural origin have been valued for their beneficial effects on health since ancient times. During our study, we performed the extraction of phenolic compounds from balsam poplar buds using different concentrations of aqueous polyethylene glycol 400 solvents (10-30% PEG400). The aqueous 30% PEG400 extract showed the best phenolic yield. The stability of the extract during autoclave sterilization was evaluated. The extract remained stable under heat sterilization. Ophthalmic formulations are formed using different concentrations (8-15%) of poloxamer 407 (P407) together with hydroxypropyl methylcellulose (0.3%), sodium carboxymethyl cellulose (0.3%) or hyaluronic acid (0.1%). Physicochemical parameters of the formulations remained significantly unchanged after sterilization. Formulations based on 12% P407 exhibited properties characteristic of in situ gels, the gelation point of the formulations was close to the temperature of the cornea. After evaluating the amount of released compounds, it was found that, as the concentration of polymers increases, the amount of released compounds decreases. Formulations based on 15% P407 released the least biologically active compounds. Sterilized formulations remained stable for 30 days.

Novel Formulation of Eye Drops Containing Choline Salicylate and Hyaluronic Acid: Stability, Permeability, and Cytotoxicity Studies Using Alternative Ex Vivo and In Vitro Models

This work investigated the potential of a novel formulation of eye drops containing a non-steroidal anti-inflammatory drug-choline salicylate (CS)-and hyaluronic acid (HA). Thus, these drops may exert both anti-inflammatory and regenerative activity. The experiment was conducted through the careful characterization of physicochemical properties, stability, and quality of eye drops. Moreover, microbiological analysis, as well as penetration and cytotoxic studies, were performed. The UV, HPLC-UV, and HPLC-MS/MS methods were used to determine the purity and stability of CS. The penetration rate of CS was assessed using a hydrophilic membrane and ex vivo porcine cornea model. Additionally, the cytotoxic effects were evaluated using the SIRC cell line. The interaction between HA and CS was tested using size-exclusion chromatography and IR spectrophotometry. As a result, HA increased the viscosity of the drops, which prolonged their contact with the ocular surface, thus ensuring more effective penetration of CS into the corneal structure. After long-term storage, an interaction in the pharmaceutical phase between CS and HA was observed. However, this interaction did not affect the viability of rabbit corneal cells. Our findings showed that eye drops with CS and HA, stored at 2-8 °C in light-protected conditions, met the criteria of stability and safety.

Role of Choline in Ocular Diseases

Choline is essential for maintaining the structure and function of cells in humans. Choline plays an important role in eye health and disease. It is a precursor of acetylcholine, a neurotransmitter of the parasympathetic nervous system, and it is involved in the production and secretion of tears by the lacrimal glands. It also contributes to the stability of the cells and tears on the ocular surface and is involved in retinal development and differentiation. Choline deficiency is associated with retinal hemorrhage, glaucoma, and dry eye syndrome. Choline supplementation may be effective for treating these diseases.