Research in Pharmaceutical Sciences
Volume:18 Issue: 1, Feb 2023

Lysosomal-targeted drug delivery can open a new strategy for drug therapy. However, there is currently no universally accepted simulated or artificial lysosomal fluid utilized in the pharmaceutical industry or recognized by the United States Pharmacopeia (USP).

Experimental approach: 

We prepared a simulated lysosomal fluid (SLYF) and compared its composition to a commercial artificial counterpart. The developed fluid was used to test the dissolution of a commercial product (Robitussin®) of a lysosomotropic drug (dextromethorphan) and to investigate in-vitro lysosomal trapping of two model drugs (dextromethorphan and (+/-) chloroquine). Findings/

The laboratory-prepared fluid or SLYF contained the essential components for the lysosomal function in concentrations reflective of the physiological values, unlike the commercial product. Robitussin® passed the acceptance criteria for the dissolution of dextromethorphan in 0.1 N HCl medium (97.7% in less than 45 min) but not in the SLYF or the phosphate buffer media (72.6% and 32.2% within 45 min, respectively). Racemic chloroquine showed higher lysosomal trapping (51.9%) in the in-vitro model than dextromethorphan (28.3%) in a behavior supporting in-vivo findings and based on the molecular descriptors and the lysosomal sequestration potential of both.

Conclusion and implication: 

A standardized lysosomal fluid was reported and developed for in-vitro investigations of lysosomotropic drugs and formulations.

The lateral habenula (LHb), a key area in the regulation of the reward system, exerts a major influence on midbrain neurons. It has been shown that the gamma-aminobutyric acid (GABA)- ergic system plays the main role in morphine dependency. The role of GABA type B receptors (GABABRs) in the regulation of LHb neural activity in response to morphine, remains unknown. In this study, the effect of GABABRs blockade in response to morphine was assessed on the neuronal activity in the LHb.

Experimental approach: 

The baseline firing rate was recorded for 15 min, then morphine (5 mg/kg; s.c) and phaclofen (0, 0.5, 1, and 2 µg/rat), a GABABRs’ antagonist, were microinjected into the LHb. Their effects on firing LHb neurons were investigated using an extracellular single-unit recording in male rats. Findings/

The results revealed that morphine decreased neuronal activity, and GABABRs blockade alone did not have any effect on the neuronal activity of the LHb. A low dose of the antagonist had no significant effect on neuronal firing rate, while blockade with doses of 1 and 2 µg/rat of the antagonist could significantly prevent the inhibitory effects of morphine on the LHb neuronal activity.

Conclusion and implications:

 This result indicated that GABABRs have a potential modulator effect, in response to morphine in the LHb.

Considering various studies implying anticancer activity of the hydrazone and oxamide derivatives through different mechanisms such as kinases and calpain inhibition, herein, we report the synthesis, characterization, and evaluation of the antiproliferative effect of a series of hydrazones bearing oxamide moiety compounds (7a-7n) against a panel of cancer cell lines to explore a novel and promising anticancer agent (7k).

Experimental approach:

 Chemical structures of the synthesized compounds were confirmed by FTIR, 1HNMR, 13C-NMR, and mass spectra. The antiproliferative activity and cell cycle progression of the target compound were investigated using the MTT assay and flow cytometry.

Compound 7k with 2-hydroxybenzylidene structure was found to have a significant in vitro anti-proliferative influence on MDA-MB-231 (human adenocarcinoma breast cancer) and 4T1 (mouse mammary tumor) cells as the model of triple-negative breast cancer, with the IC50-72 h values of 7.73 ± 1.05 and 1.82 ± 1.14 µM, respectively. Following 72-h incubation with compound 7k, it caused MDA-MB-231 cell death through G1/S cell cycle arrest at high concentrations (12 and 16 µM).

Conclusion and implications:

 Conclusively, this study for the first time reports the anti-proliferative efficacy of compound 7k possessing 2-hydroxyphenyl moiety, which may serve as a potent candidate in triple-negative breast cancer treatment.

The treatment of ventilator-associated pneumonia (VAP) caused by carbapenemresistant Acinetobacter baumannii (CRAB) is still a great challenge. This study evaluated the effectiveness of the colistin/levofloxacin regimen compared to the usual colistin/meropenem regimen in the treatment of patients with VAP caused by CRAB.

Experimental approach: 

The patients with VAP were randomly assigned to experimental (n = 26) and control (n = 29) groups. The first group received IV colistin 4.5 MIU every 12 h + levofloxacin 750 mg IV daily, and the second group received IV colistin with the same dose + meropenem 1 g IV every 8 h for 10 days. The clinical (complete response, partial response, or treatment failure) and microbiological responses at the end of the intervention were recorded and compared between the two groups.

The complete response rate was higher (n = 7; 35%) and the failure rate was lower (n = 4; 20%) in the experimental group than in the control group (n = 2; 8%, and n = 11; 44%, respectively), but the differences were not statistically significant. Even though the microbiological response rate was higher in the experimental group (n = 14; 70%) than in the control group (n = 12; 48%), the difference was not statistically significant. The mortality rate was 6 (23.10%) and 4 patients (13.8%) in the experimental and control groups, respectively (P = 0.490).

Conclusion and implication: 

The levofloxacin/colistin combination can be considered an alternative regimen to meropenem/colistin in the treatment of VAP caused by CRAB.

Azithromycin (AZ) is a macrolide antibiotic that is soluble in saliva pH; its bitter taste can be well sensed, decreasing the ability of the patient to get the drug. Thus, handling such a bitter taste is challenging in developing the oral formulation. A wide range of methods has been applied to tackle this problem. Cubosomes are considered nanoparticles forming cubic three-dimensional structures with a tastemasking effect. This research aimed to apply cubosomes to mask AZ's bitter taste.

Experimental approach: 

Cubosomes which contained AZ were obtained by applying the film hydration method. Design expert software (version 11) was then employed for optimizing cubosomes that contained the drug. The encapsulation efficiency, particle size as well as polydispersity index of drug-loaded cubosomes were then subjected to evaluation. Assessment of particle morphology was done through SEM. The antimicrobial qualities of AZ-loaded cubosomes were then assessed by utilizing the disc diffusion method. Then, the taste masking study was carried out by referring to human volunteers. Finding/

AZ-loaded cubosomes were spherical in terms of shape and in the 166-272 nm range, with a polydispersity index of 0.17-0.33 and encapsulation efficiency of 80-92%. The results related to the microbial culture revealed that the antimicrobial qualities related to AZ-loaded cubosomes were like those of AZ. The results obtained by taste evaluation also revealed that the cubosomes could well mask the drug's bitter taste.

Conclusion and implications: 

These findings, thus, revealed that while the antimicrobial impact of AZ is not under the influence of loading in cubosomes, its taste could be well improved.

The purpose of the current study was to investigate the protective effects of acute and chronic administration of different doses of vitamin D3 on pentylenetetrazol (PTZ)-induced epileptiform activities in rats. 

Experimental approach:

Sixty Wistar rats in chronic and acute groups were used in this study. In the chronic groups, animals received vitamin D3 at 50, 100, and 150 μg/kg; vitamin D3 (50 μg/kg, i.p.) + diazepam (0.1 mg/kg, i.p.), and almond oil (i.p.) daily for two weeks whereas, in the acute groups the animal received a single dose of chemicals just 30 min before PTZ administration. The electrophysiological recording was performed by implanting a unilateral bipolar electrode in the pyramidal cell layer of the CA1 region of the hippocampus. Epileptic activities were induced by intraperitoneal injection of PTZ (80 mg/kg, i.p.). The spike count and amplitude were analyzed using the eTrace software.

Chronic administration of all doses of vitamin D3 and its combination with diazepam significantly reduced both spike counts and amplitudes following PTZ administration. While the acute doses were ineffective. 

Conclusion and implication:

The results of the study indicated that chronic but not acute administration of vitamin D3 has a protective effect on PTZ-induced epileptiform activity in rats.

Precise structures of macromolecules are important for structure-based drug design. Due to the limited resolution of some structures obtained from X-ray diffraction crystallography, differentiation between the NH and O atoms can be difficult. Sometimes a number of amino acids are missing from the protein structure. In this research, we intend to introduce a small database that we have prepared for providing the corrected 3D structure files of proteins frequently used in structure-based drug design protocols.

Experimental approach:

 3454 soluble proteins belonging to the cancer signaling pathways were collected from the PDB database from which a dataset of 1001 was obtained. All were subjected to corrections in the protein preparation step. 896 protein structures out of 1001 were corrected successfully and the decision on the remained 105 proposed twelve for homology modeling to correct the missing residues. Three of them were subjected to molecular dynamics simulation for 30 ns.

896 corrected proteins were perfect and homology modeling on 12 proteins with missing residues in the backbone resulted in acceptable models according to Ramachandran, z-score, and DOPE energy plots. RMSD, RMSF, and Rg values verified the stability of the models after 30 ns molecular dynamics simulation. 

Conclusion and implication:

A collection of 1001 proteins were modified for some defects such as adjustment of the bond orders and formal charges, and addition of missing side chains of residues. Homology modeling corrected the amino missing backbone residues. This database will be completed for quite a lot of water-soluble proteins to be uploaded to the internet.

Although some proposed mechanisms responsible for tamoxifen resistance have already been present, further study is needed to determine the mechanisms underlying tamoxifen resistance more clearly. The critical role of Notch signaling has been described in promoting resistance in therapeutics, but there is little information about its role in tamoxifen resistance progression.

Experimental approach: 

In the present study, the expression of Notch pathway genes, including Notch4, nicastrin, and the Notch downstream target Hes1 was evaluated using quantitative RT-PCR in 36 tamoxifen-resistant (TAM-R) and 36 tamoxifen-sensitive (TAM-S) patients. Expression data were correlated with the clinical outcome and survival of patients.

mRNA levels of Notch4 (fold change = 2.7), nicastrin (fold change = 6.71), and Hes1 (fold change= 7.07) were significantly higher in TAM-R breast carcinoma patients compared to sensitive cases. We confirmed all these genes were co-expressed. Hence, it seems that Notch signaling is involved in tamoxifen resistance in our TAM-R patients. Obtained results showed that Hes1, nicastrin, and Notch4 mRNA upregulation was correlated with the N stage. The extracapsular nodal extension was associated with nicastrin and Notch4 overexpression. Moreover, nicastrin overexpression was correlated with perineural invasion. Hes1 upregulation was also associated with nipple involvement. Finally, the Cox regression proportional hazard test revealed that overexpression of nicastrin was an independent worse survival factor.

Conclusion and implications: 

Presumably, upregulation of the Notch pathway may be involved in tamoxifen resistance in breast cancer patients.

Irritable bowel syndrome (IBS) is a disease that shows its impacts on many populations worldwide. It is known as a functional disorder of the gastrointestinal tract followed by diarrhea and fecal inconsistency. Due to the lack of treatment in the allopathic medicine system for IBS, people in the western world use different herbs as alternative medicine. In the present study, we evaluated the dried extract of Dracocephalum kotschyi against IBS.

Experimental approach:

 In a randomized, double-blinded, placebo-controlled clinical trial, 76 diarrheapredominant IBS patients were randomly assigned to two equal groups: the control group (given the placebo capsule containing 250 mg of dibasic calcium phosphate) and the treatment groups (given the capsule containing 75 mg of the dry extract of D. kotschyi and 175 mg of dibasic calcium phosphate as filler). The study was conducted based on Rome III criteria. We studied symptoms included in Rome III criteria and divided the study into the duration of drug administration and four weeks after drug administration. These groups were compared with those of the control group.

Significant improvements were found in the quality of life, temperament, and IBS symptoms throughout the treatment duration. Quality of life, temperature, and IBS symptoms were slightly decreased in the treatment group 4 weeks after stopping the treatment. While concluding the study, we found D. kotschyi effective against IBS.

Conclusion and implications: 

Whole extract of D. kotschyi modulated symptoms of IBS patients and improved their quality of life.

Andrographis paniculata (AP) has long been used as an anti-diabetic agent, but the mechanism of action and active substance responsible for the anti-diabetic effect, particularly by inhibiting phosphodiesterase-9 (PDE9), which is one of the targets of anti-diabetic medications, have not been reported. The aim of the present study was to identify a new anti-diabetes candidate from secondary metabolite compounds of AP through PDE9 inhibition.

Experimental approach:

 In order to prepare the chemical structures of the secondary metabolites of AP and PDE9, docking and molecular dynamics simulations were run using Discovery Studio Visualizer, AutoDockTools, AutoDock, and Gromacs, along with a few other supporting software packages.

Molecular docking simulations showed that two of the 46 secondary metabolites of AP had higher free energies of binding, C00003672 (-11.35 kcal/mol) and C00041378 (-9.27 kcal/mol), than native ligand (-9.23 kcal/mol). The results of molecular dynamics showed that compound C00041378 interacted with TRY484 and PHE516, two active side residues of PDE9. ΔGMMGBSA interactions of PDE9 with C00003672, C00041378, and 49E compounds are 51.69, -56.43, and -48.13 kcal/mol, respectively, as well as ΔGMMPBSA interactions of PDE9 with C00003672, C00041378, and 49E compounds, were -12.26, -16.24, and -11.79 kcal/mol kcal/mol, respectively.

Conclusions and implications:

 Based on the evaluations of AP secondary metabolites using docking and molecular dynamics simulation, it is suggested that the C00041378 compound has the potential to be an antidiabetic candidate by inhibiting PDE9.