## 3 Results and Discussion
### In Silico Analysis of Physicochemical Properties, Pharmacokinetics, and Drug-likeness
Solubility data for the benzimidazoles tested (values from \(-\)3.08 to \(-\)3.94, Table 4) indicate that they are sufficiently soluble and can be used as oral drug candidates [30]. An interesting prediction suggested by the SwissADME tool is the ability of compounds (TPSA < 70 A\({}^{2}\), Table 2) except **6a** (TPSA = 81.31 A\({}^{2}\)) to penetrate the blood-brain barrier (BBB) (Table 4). This makes them suitable candidates for the treatment of severe trichinellosis infection, which can involve multiple organs, including the brain. Brain damage in trichinellosis can manifest as either diffuse cerebral damage or focal neurological deficits [31]. Penetration of the BBB is a key factor in central nervous system (CNS) drug delivery, as it blocks the entry of large molecules and over 98% of small drug candidates [32]. Another important prediction of the SwissADME tool concerns the lack of interaction of the compounds in this study with the permeability transition glycoprotein (P-gp) (Table 4). P-glycoprotein plays a crucial role in transporting various substrates across cellular membranes and is key to many physiological processes. In particular, their over-expression is a common response to chemotherapy in tumour cells and to treatment with macrocyclic lactones (including ivermectin) in nematodes. This overexpression can lead to treatment failure by reducing the concentration of therapeutic agents at the target site. It is also well-known that P-gp also contributes to resistance to some anthelmintics [33]. [PERSON] et al. reported that some benzimidazoles interact specifically with P-gp and have been shown to be substrates for P-glycoprotein-mediated drug efflux [34]. However, albendazole and fenbendazole have been shown to have no effect on P-gp activity [35]. None of the compounds tested (**4a-c** and **6a-c**) also interacted with P-gp (Table 4), suggesting a lower risk of efflux-related resistance mechanisms that often compromise drug efficacy. Furthermore, the presence of substructures giving false positive biological output, i.e., showing a potent response in assays irrespective of the protein target, commonly referred to as PAINS (Pan Assay Interference Compounds), was also evaluated. This analysis showed that heterocyclic benzimidazoles **4a-c** and **6a-c** are devoid of this property (PAINS = 0, Table 4). In addition, the properties of methanimines **4a-c** and hydrazones **6a-c** were evaluated using the Brain Or IntestinaL EstimateD (BOILED-Egg) method and the bioavailability radar of the SwissADME tool. The boiled-egg images (Figure 4) were obtained by considering the parameters WLOGP and TPSA reported in Table 3, which are a lipophilic index and a measure of apparent polarity, respectively. These graphs allow an easy understanding and visualization of the two parameters: the passive absorption at the GI tract (white area) and the ability to permeate the BBB (yellow area). As can be seen, all compounds except compound **6a** and albendazole were estimated to be able to cross the BBB, as would be required to reach _Trichinella_ larvae localized in the brain. The red colour of the dotsindicates that all of the benzimidazolzoles tested are theoretically not substrates of P-gp, as previously estimated in Table 4.  
The bioavailability radars presented in the Supplementary Materials offer the drug-likeness depiction of the selected compounds. In the graphs, the pink-coloured area includes the optimal range of each physical-chemical property (lipophilicity, size, polarity, solubility, saturation and flexibility). Based on these results, it can be concluded that the compounds from this study meet all the requirements for drug similarity, with the sole exception of the saturation values (carbon atoms in sp\({}^{3}\) hybridization).