Effect of Ticagrelor, a Cytochrome P450 3A4 Inhibitor, on the Pharmacokinetics of Tadalafil in Rats

Concurrent oral delivery of non-oncology drugs through solid self-emulsifying system for repurposing in hepatocellular carcinoma

OBJECTIVE

Present study aimed to identify a safe and effective non-oncology drug cocktail as an alternative to toxic chemotherapeutics for hepatocellular carcinoma treatment. The assessment of cytotoxicity of cocktail (as co-adjuvant) in combination with chemotherapeutic docetaxel (DTX) is also aimed. Further, we aimed to develop an oral solid self-emulsifying drug delivery system (S-SEDDS) for the simultaneous delivery of identified drugs.

SIGNIFICANCE

The identified non-oncology drug cocktail could overcome the shortage of anticancer therapeutics and help to reduce cancer-related mortality. Moreover, the developed S-SEDDS could be an ideal system for concurrent oral delivery of non-oncology drug combinations.

METHODS

The non-oncology drugs (alone and in combinations) were screened in vitro for anticancer effect (against HepG2 cells) using (3-(4, 5-dimethylthiazolyl-2)-2, 5-diphenyltetrazolium bromide; MTT) dye assay, and cell cycle arresting and apoptotic behaviors using the fluorescence-activated cell sorting (FACS) technique. The S-SEDDS is composed of drugs such as Ketoconazole (KCZ), Disulfiram (DSR), Tadalafil (TLF), and excipients like span-80, tween-80, soybean oil, Leciva S-95, Poloxamer F108 (PF-108), and Neusilin® US2 (adsorbent carrier) was developed and characterized.

RESULTS

The cocktail composed of KCZ, DSR, and TLF has showed substantial cytotoxicity (at the lowest concentration of 3.3 picomoles), HepG2 cell arrest at G0/G1 and S phases, and substantial cell death via apoptosis. The Docetaxel (DTX) inclusion into this cocktail has further resulted in increased cytotoxicity, cell arrest at the G2/M phase, and cell necrosis. The optimized blank liquid SEDDS that remains transparent without phase separation for more than 6 months is used for the preparation of drug-loaded liquid SEDDS (DL-SEDDS). The optimized DL-SEDDS with low viscosity, good dispersibility, considerable drug retention upon dilution, and smaller particle size is further converted into drug-loaded solid SEDDS (DS-SEDDS). The final DS-SEDDS demonstrated acceptable flowability and compression characteristics, significant drug retention (more than 93%), particle size in nano range (less than 500 nm) and nearly spherical morphology following dilutions. The DS-SEDDS showed substantially increased cytotoxicity and Caco-2 cell permeability than plain drugs. Furthermore, DS-SEDDS containing only non-oncology drugs caused lower in vivo toxicity (only 6% body weight loss) than DS-SEDDS containing non-oncology drugs with DTX (about 10% weight loss).

CONCLUSION

The current study revealed a non-oncology drug combination effective against hepatocellular carcinoma. Further, it is concluded that the developed S-SEDDS containing non-oncology drug combination alone and in combination with DTX could be a promising alternative to toxic chemotherapeutics for the effective oral treatment of hepatic cancer.

Pharmacokinetic interaction between dronedarone and ticagrelor following oral administration in rats

Dronedarone and ticagrelor have high co-administration potential in patients with both acute coronary syndrome and atrial fibrillation. The objective of the present in vivo study was to investigate the potential interaction between dronedarone (5 and 10 mg/kg) and ticagrelor (5 and 10 mg/kg) when administered orally to rats. Forty Sprague-Dawley rats were randomly distributed into eight groups; consisting of a dronedarone only group, a ticagrelor only group, a dronedarone with ticagrelor-pretreatment group, and a ticagrelor with dronedarone-pretreatment group. Pharmacokinetic exposure (AUC_inf = 1472 ng·h/mL) associated with administration of 10 mg/kg of dronedarone increased significantly, with delayed T _max in the group that received ticagrelor-pretreatment when compared to the dronedarone only group (AUC_inf = 723 ng·h/mL). In addition, pharmacokinetic exposure (AUC_inf = 2391 ng·h/mL) associated with administration of 10 mg/kg of ticagrelor increased significantly, with increased K _el (0.31 h^-1) and decreased V _z/F (14.6 L/kg) in the dronedarone-pretreatment group when compared to the ticagrelor only group (AUC_inf = 1616 ng·h/mL; K _el = 0.21 h^-1; V _z/F  =  31.3 L/kg). Results of our study suggest that further investigation of a potential interaction between dronedarone and ticagrelor in humans is justified and that caution may need to be exercised when dronedarone and ticagrelor pharmacotherapies concomitantly.

Pharmacokinetic/Pharmacodynamic Modeling To Predict the Antiplatelet Effect of the Ticagrelor-Loaded Self-Microemulsifying Drug Delivery System in Rats

Ticagrelor (TCG) has been used as an antiplatelet agent for acute coronary syndrome patients. The aim of this research was to establish a population pharmacokinetic/pharmacodynamic (PK/PD) model of TCG and to apply the model for predicting the PD response of the TCG-loaded self-microemulsifying drug delivery system (TCG-SME) in rats. Pure TCG and TCG-SME (2, 5, and 10 mg/kg of TCG) were orally administered to male Sprague-Dawley rats. Plasma samples were collected at scheduled time-points and then analyzed for TCG plasma concentrations and antiplatelet effects. The inhibition of platelet aggregation of TCG was measured as a PD response. The PK profiles of pure TCG and TCG-SME could be well-explained with a two-compartment PK model. The accuracy of the PK model was assessed with a goodness-of-fit plot and conditional weight residual error (CWRES). Also, the visual predictive check was investigated based on the predictions. A population PK/PD model for pure TCG was established as an indirect response E_max model linked to the two-compartment PK model of pure TCG. The PK/PD model proposed a suitable fitting to link the plasma concentration of TCG simultaneously with platelet aggregation. Based on the PK data of TCG-SME, as well as the established PK/PD model of pure TCG, the PD profiles of TCG-SME were simulated. TCG-SME was more effective in inducing the antiplatelet effect than pure TCG at equivalent doses of TCG. The accuracy of the simulation was verified by comparing the simulated PD profile with the profile observed in rats. The observations were close to the model simulations. In addition, the values of CWRES were almost within ±2. In conclusion, the PK/PD modeling approach can provide a way for predicting mathematically the PD responses from PK profiles of other TCG formulations and a conceptual prediction for future clinical assessment.