(T0930-10-59) In Vitro and In Vivo Correlations of Danazol-SEDDS Formulations Using MacroFLUX^TM and miniFLUX™

Purpose: Self-emulsifying drug delivery systems (SEDDS) have emerged as a simple and efficient method for delivering medications that face solubility challenges. However, as drug development becomes more complex, traditional dissolution studies are no longer sufficient in predicting the intricate in vivo performance that greatly impacts absorption. This study is investigating the in vitro and in vivo correlation of five different formulations containing a model danazol using Pion's macroFLUX™ and MiniFLUX™.

Methods: Preparation of SEDDS: The concentrations of excipients used for the preparation of the SEDDS preconcentrates are depicted in Figure 1. Glyceryl monolinoleate (Maisine^® CC), Glyceryl monooleate (GMO; Monomuls^® 90-O18 BASF Corp, USA), and polyoxyl 40 hydrogenated castor oil (Kolliphor^® RH 40) were heated to 50 ˚C prior to use. The formulations were prepared by mixing the excipients at room temperature. The final drug load in formulation was adjusted to correspond to 80% of the equilibrium solubility (S_eq) of danazol in the SEDDS. To evaluate the in vivo performance of the Danazol-SEDDS formulations, Sprague-Dawley (SD) rats were orally administered formulations (n=6) and blood plasma levels were monitored over a 24-hour period in the fasted state (12 hours of fasting prior to administration). Liquid chromatography–mass spectrometry (LC-MS) was used for analysis of samples. These in vivo experiments were conducted in collaboration with the University of Copenhagen (Denmark), and a manuscript detailing the findings is currently being prepared. Statistical models were employed to compare the in vitro predictions with the in vivo test results with a goal of establishing the strength of in vitro-in vivo correlations (IVIVCs). In vitro Flux Experiment - SEDDS formulations equivalent to 80 mg of danazol each were tested using MacroFLUX(Pion Inc., Billerica, MA). In this device, the artificial Gastro-intestinal (GIT) mimicking membrane was formed by 50 µL GIT-0 lipid solution on the filter support [hydrophobic polyvinylidenfluoride (PVDF), 0.45 µm pore size, 3.8 cm²]. The acceptor compartment was filled with 8 mL Acceptor sink buffer (ASB; pH 7.4) at stirring speed 500 rpm. Donor compartment of a USP II apparatus (Erweka DT 126 Dissolution Tester, Germany) was filled with 1000 mL fasted state simulated intestinal fluid version 2 (FaSSIF V 2; pH 6.5) at stirring speed 75 rpm. The UV probes (10 mm path length) were set in the donor (λ 300 nm) and acceptor compartments (λ 260 nm) and connected to the Rainbow Dynamic Dissolution Monitor instrument. The flux (J) across the membrane was calculated using the following equation:J (t) = dm/Adt where (m) is the the amount of drug crossing a unit area (A) perpendicular to its flow per unit time (t). The flux values of formulations were calculated from the linear portion of the permeation profile.

Results: Danazol, is a poorly soluble biopharmaceutic classification system (BCS) Class II drug with a LogP of 3.56 and a water solubility of 0.61 μg/mL. Solubility studies revealed that the SEDDS significantly increased the solubility of Danazol (24.4, 14.6, 9.5, 15.5, and 9.0 mg/mL) in F1, F2, F3, F9, and F10 formulations, respectively at room temperature. In vivo study, formulations containing long chain fatty acids and/or high concentrations of polyoxyl 40 hydrogenated castor oil (F1, F2, and F9) exhibited better performance based on drug area under the curve (AUC_0-24). On the other hand, formulations with high concentrations of medium-chain triglycerides (F3 and F10) showed a highly digestible nature indicating lower performance and comparatively lowered AUC_0-24 values in the group (data are not shown). For IVIVC, the formulations were tested using the MacroFlux™ and MiniFLUX™ instruments. It was observed that the formulations consist of two types of lipophilic surfactants: glycerol monocaprylocaprate (HLB 5-6) and glyceryl monooleate, GMO (HLB 3.3-4.1) demonstrated different level of flux with Pion's synthetic lipidic (GIT-O lipids) membrane. Therefore, the formulations were separated into two groups to understand the IVIVC. The in vitro flux data, representing the drug concentration in the receiver chamber after 150 minutes for both groups showed a strong correlation (R²>0.96; “Type C” correlation see Ref 1) with the in vivo drug absorption represented by the AUC_0-24 (Figure 2). In addition, the in vitro studies were conducted using the smaller MiniFLUX™ apparatus to evaluate and compare flux performance with the MacroFlux™ instrument. The strong correlation (R² >0.98) between the two instruments suggests that both could be used during preclinical stage to find the lead formulations. However, MiniFLUX™ apparatus required less amount of drug, media and sink buffer in the test.

Conclusion: SEDDS have shown promising results in enhancing the flux of danazol compared to the drug alone. The in vitro flux and in vivo AUC_0-24 demonstrated a strong IVIVCs. The results provide a pathway for raking performance of formulations containing insoluble drug candidates at an early preclinical stage. Further, the similar rank order was achieved by MiniFLUX™. The in vitro flux showing in vivo correlation beneficial tools in modern drug development process for faster path to the clinics.

References: 1. U.S. Department of Health and Human Services Food and Drug Administration Center for Drug Evaluation and Research (CDER), Extended Release Oral Dosage Forms: Development, Evaluation, and Application of In Vitro/In Vivo Correlations, September 1997.

Acknowledgements: The in vivo experiments were conducted in collaboration with the University of Copenhagen (Denmark), and a manuscript detailing the findings is currently being prepared.

Figure 1. Compositions of F1, F2, F3, F9 and F10 SEDDS

Figure 2 MacroFLUXTM Techniques based IVIVC of Danazol-SEDDS formulations containing 1A) GMO and 1B) Glycerol Monocaprylocaprate and Correlation of Danazol Flux values obtained from MacroFLUXTM and MiniFLUXTM Techniques for 2A) GMO-based SEDDS and 2B) Glycerol Monocaprylocaprate based- SEDDS