Développement galénique et analytique d’un collyre à base de tacrolimus 0,06 %

Physicochemical Stability of a Novel Tacrolimus Ophthalmic Formulation for the Treatment of Ophthalmic Inflammatory Diseases

Tacrolimus is an immunosuppressant used to treat a large variety of inflammatory or immunity-mediated ophthalmic diseases. However, there are currently no commercial industrial forms available that can provide relief to patients. Various ophthalmic formulations have been reported in the literature, but their stability has only been tested over short periods. The objective of this study was to evaluate the physicochemical stability of a preservative-free tacrolimus formulation (0.2 and 1 mg/mL) at three storage temperatures (5 °C, 25 °C and 35 °C) for up to nine months in a multidose eyedropper. Analyses performed were the following: visual inspection and chromaticity, turbidity, viscosity, size of micelles, osmolality and pH measurements, tacrolimus quantification by a stability-indicating liquid chromatography method, breakdown product research, and sterility assay. In an in-use study, tacrolimus quantification was also performed on the drops emitted from the eyedroppers. All tested parameters remained stable during the nine month period when the eyedrops were stored at 5 °C. However, during storage at 25 °C and 35 °C, several signs of chemical instability were detected. Furthermore, a leachable compound originating from a silicone part of the eyedropper was detected during the in-use assay. Overall, the 0.2 mg/mL and 1 mg/mL tacrolimus ophthalmic solutions were physicochemically stable for up to nine months when stored at 5 °C.

Stability of tacrolimus ophthalmic solution

PURPOSE

The stability of 0.3-mg/mL tacrolimus ophthalmic solution at different storage temperatures was studied.

METHODS

A sterile ophthalmic solution of 0.3 mg/mL tacrolimus was prepared in triplicate under aseptic conditions by diluting tacrolimus in eye drops. Three aliquots of this solution were transferred into polypropylene bottles and stored at 25, 2-8, or -15 to -25 °C. Samples were collected immediately after preparation and at selected time points and assayed in triplicate using high-performance liquid chromatography (HPLC). Samples were also visually examined for macroscopic changes. The 0.3-mg/mL tacrolimus solution was also exposed to acidic treatment and heat to force its degradation and to evaluate the selectivity of the analytic method. The tacrolimus ophthalmic solution was considered stable if at least 90% of the mean initial concentration remained when analyzed by HPLC.

RESULTS

When stored at 2-8 °C and between -15 and -25 °C, at least 90% of the initial tacrolimus concentration remained throughout the 85-day study period. There were no significant differences in tacrolimus concentrations between the starting and ending points (p > 0.05). However, when tacrolimus solution was stored at 25 °C, the percentage of the initial tacrolimus concentration remaining had decreased to less than 90% on day 28.

CONCLUSION

Tacrolimus diluted to 0.3 mg/mL in eye drop solution was stable for 20 days when stored at 25 °C and for at least 85 days when stored at 2-8 °C or between -15 and -25 °C in polypropylene bottles and protected from light.

Preclinical characterization and clinical evaluation of tacrolimus eye drops

Severe allergic ocular diseases as atopic keratoconjunctivitis can induce corneal damage due to inflammatory substances released from giant papillae. Tacrolimus eye drops are one of the current therapeutic alternatives for its treatment. This work is aimed at developing and characterizing a 0.03% tacrolimus ophthalmic formulation, which was introduced in three types of vehicles (BBS, PVA and Hyaluronic Acid). For this, we have performed in vitro (stability studies) and in vivo assays (corneal permanence time measured directly by Positron Emission Tomography) of three potential formulations. Next, the best formulation was selected, and its toxicological profile and clinical effectiveness have been evaluated. The biopermanence studies (direct measurements and PET/CT) showed that the formulations with PVA and Hyaluronic Acid present more retention time on the ocular surface of rats than PBS. From the stability study, we have determined that tacrolimus with PVA in cold storage is the best option. Tacrolimus with PVA has shown lower cytotoxicity than cyclosporine at early times. On the other hand, the pilot study performed has shown significant improvements in patients, with no noticeable adverse reactions. Based on stability, biopermanence, safety and clinical effectiveness studies, we concluded that tacrolimus-PVA eye drops are a suitable candidate for its clinical application in inflammatory ophthalmology diseases.

Topical Tacrolimus for Corneal Subepithelial Infiltrates Secondary to Adenoviral Keratoconjunctivitis

PURPOSE

The objective of this study was to determine the efficacy and safety of topical tacrolimus compounded in the Pharmacy Service for the treatment of subepithelial corneal infiltrates (SEIs) secondary to adenoviral keratoconjunctivitis.

METHODS

This retrospective study included patients who had been dispensed topical tacrolimus for the treatment of SEIs during the previous year. Patients were treated with tacrolimus 0.03% eye drops twice daily or tacrolimus 0.02% ointment once daily. The following data were recorded: length of treatment, visual acuity before and after treatment, intraocular pressure before, during, and at the end of treatment, previous treatments, and the presence of SEIs after treatment. The subjective symptoms of the patients were also assessed.

RESULTS

Fifty-five patients (85 eyes) were included, 54.5% with bilateral involvement. A total of 31 (36.5%) eyes were treated with tacrolimus ointment and 54 eyes (63.5%) with tacrolimus eye drops. The median length of treatment was 185 days (p25-75: 93.5-426), and the mean follow-up duration was 363 days (p25-75: 148-540). In 62.35% of the eyes, the SEIs were reduced in number and size, and in 31.76%, they were eliminated. The patients had better visual acuity after treatment with highly statistically significant differences. Tolerance was good overall, being better in the eye drops group.

CONCLUSIONS

Topical tacrolimus, compounded in the pharmacy, seems to be an effective and safe alternative for the treatment of SEIs secondary to adenovirus keratoconjunctivitis.