Design, development, in silico and in vitro characterization of Docetaxel-loaded TPGS/ Pluronic F 108 mixed micelles for improved cancer treatment

Abstract

BackgroundDocetaxel (DTX) has been used to treat numerous types of cancers. It's poor solubility, serious side effects, and multi-drug resistance (MDR) limits its use in cancer treatment. As mixed micelles (MMs) can be developed easily to improve the pharmacokinetics and dynamics of DTX, the current study was aimed to develop DTX-loaded MMs and investigate their anticancer effects alone and in combination with Verapamil (VPM) to repurpose in ovarian cancer. MethodsThe DTX interaction with the lipophilic core of TPGS with Pluronic® F108 (PF108) MMs (DTP MMs) was studied using in silico study. The critical micelle concentration (CMC) of TPGS, PF108, and their molar ratios were determined using Iodine spectroscopic method. A solvent evaporation method was used to prepare the DTP MMs, and were optimized using 32 full factorial design. The inhibitory effect of drug and co-polymers on p-glycoprotein (P-gp) and β-tubulin were investigated with help of in silico studies. DTP MMs were characterized for % entrapment efficiency (%EE), mean particle size (MPS), zeta potential, surface morphology using TEM, in vitro drug release, % haemolysis against human blood, and cytotoxicity against SKOV-3 cells using MTT assay. ResultThe in silico studies confirmed the good DTX interaction with lipophilic cavity of MMs. The CMC value of TPGS, PF108 and their molar ratios (MMs) were found to 0.01 mM, 0.032 mM, and 0.025 mM respectively. Out of 9 formulations, formulation K3 was optimized based on %EE (73.93 ± 2.4%), % drug loading capacity (%DLC) (2.06 ± 0.08%) and MPS (233 ± 3 nm, PDI with 0.439 ± 0.26). The developed DTP MMs showed a sustained release behaviour, reduced hemolytic behaviour, and lower in vitro cytotoxicity when compared to plain DTX. TEM images showed that the self-assembled MMs are well distributed as spherical-shaped particles. The IR, DSC, and PXRD studies indicate no chemical interaction between drug and excipients. The molecular docking study reveals the P-gp inhibitory effect of VPM and TPGS; whereas, DTX and TPGS have shown potential binding affinity towards β-tubulin. The presence of VPM at lowest concentration showed significantly improved SKOV-3 cell growth inhibition; whereas, the higher VPM concentration does not result in increased cell death as compared to plain DTX and K3 MMs. ConclusionThe developed DTP MM is a promising approach for improved ovarian cancer treatment. Further, VPM could be repurposed along with DTP MMs against ovarian cancer. As VPM improves the anticancer effect of DTX at lowest concentration, it can be successfully being used in clinical cancer treatment with its minimum inherent pharmacological activities. However, further studies are needed to optimize VPM clinical dose for cancer treatment with DTX or other drugs. The P-gp inhibitory effect of VPM and TPGS, and tubulin inhibitory effect of TPGS are further needs to be proved quantitatively using other techniques in order to use them against resistant and non-resistant cancer types.