(W0930-03-13) Evaluating the Feasibility of Lyophilization for Oral Formulation Development of Monoclonal Antibodies (mAbs)

Purpose: Monoclonal antibodies (mAbs) has generated tremendous excitement as biotherapeutic agents in the treatment of a variety of diseases. They are mainly administered intravenously (IV) however, IV administration poses challenges such as pain, discomfort, and stress. Oral delivery is simple and non-invasive but enzymatic degradation, and the acidic pH of the GIT limits their oral administration. We hereby propose lyophilization as a feasible approach to develop a stable formulation of mAbs (2.5mg/mL) available for oral administration as enteric coated capsules. This study summarizes formulation development and evaluation of a stable lyophilized formulation of two mAbs using suitable process optimization parameters for the lyophilization cycle.

Methods: mAb formulations (2.5mg/mL) were developed in a suitable buffer of pH 5 (mAb₁) and pH 7.4 (mAb₂) respectively. Lyophilization cycle was optimized using placebo formulations containing a suitable bulking agent, stabilizer, and its concentration. EDTA was utilized as a protease inhibitor to mitigate protease induced degradation of mAbs. Lead formulation was achieved using optimized temperature and pressure for freezing, primary drying and secondary drying using FTS Systems LyoStar^TM 3. Modulated differential scanning calorimetry (MDSC) was used to determine the glass transition temperature (T_g) and eutectic temperature (T_eu). Short term stability (T₀, T_15days & T_30days) of the lyophilized formulation was evaluated by determining the cake appearance, reconstitution time, moisture content, % purity and related substances at various conditions.

Results: Trehalose demonstrated the highest cryoprotection as the bulking agent. Increase in the concentration of trehalose from 10% to 20% decreased the T_g of the lead formulation from -36˚C to -34˚C which is desirable for lyophilization process. Lyo cycle was optimized for ~76h at freezing (-50^oC), primary drying (-32^oC) and secondary drying (20^oC) conditions with pressure of 72mTorr (Table 1). Methionine effectively stabilized the mAbs in the lyophilized form suggesting lowest % impurity.  Addition of 0.1% EDTA to lead formulation with 20% trehalose did not influence T_g. Low T_g (-34.6^oC) identified using MDSC assisted in the optimization of the primary drying phase at low temperature thus reducing the primary drying time. Moisture content of all the formulations was < 3%. No significant difference in the mAbs concentration of formulations was observed at T₀ and T_15days at 5^oC, 25^oC and 40^oC. However, Lyo-mAb₁ displayed higher stability compared with Lyo-mAb₂ as evident by the % Purity data (Figure 1&2). Nevertheless, % impurity for both the formulations observed was < 1% suggesting no process related degradation of the mAbs.

Conclusion: This study demonstrated that stable formulations of mAbs can be developed using lyophilization.  Furthermore, this approach can successfully overcome the stability challenges of mAbs caused by enzymatic degradation and hostile acidic pH of the GIT. Lastly, lyophilized formulation in enteric coated capsule dosage form represents a promising approach for oral delivery of mAbs.


Table 1. Process optimization of lyophilization cycle for lead formulations of mAbs (Lyo-mAb1 & Lyo-mAb2) at 2.5mg/mL


Figure 1. Stability (% Purity) of lyophilized mAb formulation (Lyo-mAb1) (2.5mg/mL) at 5oC, 25oC, 40oC and 55oC (T0: 92.7%)


Figure 2. Stability (% Purity) of lyophilized mAb formulation (Lyo-mAb2) (2.5mg/mL) at 5oC, 25oC, 40oC and 55oC (T0: 89.2%)