Rapamycin has been used topically to treat facial angiofibromas associated with tuberous sclerosis for more than a decade. In the absence of a commercial form, a large number of formulations have been clinically tested. However, given the great heterogeneity of these studies, particularly with regard to the response criteria, it was difficult to know the impact and thus to compare the relevance of the formulations used. The objective of this work was therefore to evaluate the link between the diffusion of rapamycin and the physico-chemical characteristics of these different formulations on Strat-M^® membranes as well as on human skin using Franz cells. Our results underline the importance of the type of vehicle used (hydrogel > cream > lipophilic ointment), the soluble state of rapamycin and its concentration close to saturation to ensure maximum thermodynamic activity. Thus, this is the first time that a comparative study of the different rapamycin formulations identified in the literature for the management of facial angiofibromas has been carried out using a pharmaceutical and biopharmaceutical approach. It highlights the important parameters to be considered in the development and optimization of topical rapamycin formulations with regard to cutaneous absorption for clinical efficacy.

Objectives In recent years, various formulations containing rapamycin, mainly petrolatum-based, have been tested on facial angiofibromas in tuberous sclerosis. They are often poorly tolerated due to irritation and bleeding. In addition, their effectiveness was insufficient in young adults. The objective of this study was to develop and characterise a hydro-alcoholic gel containing solubilised rapamycin. The stability of the product stored at 4°C was evaluated over 1 year. Methods Two different 0.1% rapamycin gels were formulated with or without α-tocopherol and urea. Different methods were used to characterise the gels: HPLC, gas chromatography, pH, visual observation and optical microscopy. A physico-chemical and microbiological stability study was also conducted for 1 year at 4°C. Results Gels were physically and microbiologically stable after 1 year at 4°C: organoleptic characteristics and pH unchanged, no significant decrease in rapamycin was observed, tocopherol droplet size was constant and rheological behaviour was not altered. Conclusions This study describes a new gel formulation to improve skin penetration using various excipients to promote skin tolerance. This study provides, for the first time, detailed stability data for a hydro-alcoholic rapamycin gel.

Introduction: This study aimed to determine the stability of cetuximab: (1) under “in-use” conditions after dilution to 1 mg/mL in 0.9% sodium chloride in polyolefin bags and (2) as an undiluted solution (5 mg/mL) repackaged in polypropylene bags or kept in the vial after opening. Methods: Ready-to-use 500 mg/100 mL vials of cetuximab solution were diluted to 1 mg/mL in 100 mL bags of 0.9% sodium chloride or repackaged as a 5 mg/mL solution into empty 100 mL bags. Bags and vials were stored at 4°C for 90 days and 25°C for 3 days. A syringe sample of 7 mL was taken from each bag for the initial determinations. The sampled bags were weighed to determine their initial weight and placed under the planned storage conditions. The physicochemical stability of cetuximab was estimated using validated methods. Results: No changes in turbidity, no protein loss, and no changes in cetuximab tertiary structure were observed after 30 days of storage or when subjected to a temperature excursion of 3 days at 25°C and when stored at 4°C for up to 90 days, regardless of the concentrations and batches. The colligative parameters did not change under any of the tested conditions. No evidence of microbial growth was found in bags after 90 days of storage at 4°C. Conclusion: These results support the extended in-use shelf-life of cetuximab vials and bags, which can be cost-effective for healthcare providers.

Introduction: The extended stability of the trastuzumab biosimilar Ogivri™ (MYL-1401O; trastuzumab-dkst) was studied under different storage conditions, including following reconstitution of the lyophilized powder (21 mg/mL) but undiluted and stored in vials at 4°C; after dilution at two concentrations (0.8 and 2.4 mg/mL) in polyolefin bags and stored at 4°C; and following a three-day thermal excursion to 25°C. Methods: Several methods were utilized to assess the physical and chemical stability of the drug under different storage conditions. Results: At all storage conditions tested, there was no change in the tertiary structure of MYL-1401O as assessed by second-derivative ultraviolet and fluorescence-derived spectral analysis, and no evidence of oligomer formation or fragmentation was observed as assessed by gel exclusion chromatography and dynamic light scattering, confirmed by assessment of quinary structures using size-exclusion chromatography. Ion-exchange chromatography showed no significant changes in the distribution of ionic variants, particularly deamidations. Thermal denaturation curves indicated no destabilization of the three-dimensional structure after 90 days at 4°C or after thermal excursion for 72 h at 25°C. Conclusion: The trastuzumab biosimilar MYL-1401O maintained its physical and chemical stability for at least 90 days at 4°C or after thermal excursion to 25°C, supporting the safe use of MYL-1401O in several real-world settings, including advanced preparation for administration or when a break in the cold cycle occurs.