Design, Synthesis, Pharmacodynamic and In Silico Pharmacokinetic Evaluation of Some Novel Biginelli-Derived Pyrimidines and Fused Pyrimidines as Calcium Channel Blockers.

Some new pyrimidine derivatives comprising arylsulfonylhydrazino, ethoxycarbonylhydrazino, thiocarbamoylhydrazino and substituted hydrazone and thiosemicarbazide functionalities were prepared from Biginelli-derived pyrimidine precursors. Heterocyclic ring systems such as pyrazole, pyrazolidinedione, thiazoline and thiazolidinone ring systems were also incorporated into the designed pyrimidine core. Furthermore, fused triazolopyrimidine and pyrimidotriazine ring systems were prepared. The synthesized compounds were evaluated for their calcium channel blocking activity as potential hypotensive agents. Compounds 2, 3a, 3b, 4, 11 and 13 showed the highest ex vivo calcium channel blocking activities compared with the reference drug nifedipine. Compounds 2 and 11 were selected for further biological evaluation. They revealed good hypotensive activities following intravenous administration in dogs. Furthermore, 2 and 11 displayed drug-like in silico ADME parameters. A ligand-based pharmacophore model was developed to provide adequate information about the binding mode of the newly synthesized active compounds 2, 3a, 3b, 4, 11 and 13. This may also serve as a reliable basis for designing new active pyrimidine-based calcium channel blockers.

Fabrication of Nanosuspension Directly Loaded Fast-Dissolving Films for Enhanced Oral Bioavailability of Olmesartan Medoxomil: In Vitro Characterization and Pharmacokinetic Evaluation in Healthy Human Volunteers.

Olmesartan medoxomil (OM) is an antihypertensive drug with poor water solubility and low oral bioavailability (28.6%). Accordingly, this study aimed to formulate and evaluate OM nanosuspension incorporated into oral fast-dissolving films (FDFs) for bioavailability enhancement. OM nanosuspension was prepared by antisolvent-precipitation-ultrasonication method and characterized regarding particle size (122.67 ± 5.03 nm), span value (1.40 ± 0.51), and zeta potential (- 46.56 ± 1.20 mV). Transmission electron microscopy (TEM) of the nanosuspension showed spherical non-aggregating nanoparticles. The nanosuspension was then directly loaded into FDFs by solvent casting technique. A full factorial design (22 × 31) was implemented for optimization of the FDFs using Design-Expert® software. Physical and mechanical characteristics in addition to dissolution profiles of the FDFs were investigated. The optimum formula (FDF1) showed 0.43 ± 0.02 kg/mm2 tensile strength, 20.50 ± 2.12 s disintegration time, and 87.53 ± 2.50 and 95.99 ± 0.25% OM dissolved after 6 and 10 min, respectively. Accelerated and long-term shelf stability studies confirmed the stability of FDF1. More than 75% OM was dissolved within 10 min from FDF1 compared with 9.80 and 47.80% for films prepared using coarse drug powder and market tablet, respectively. Relative bioavailability of FDF1 compared to market tablet was assessed in healthy human volunteers. The Cmax value increased significantly from 66.62 ± 14.95 to 179.28 ± 23.96 ng/mL for market tablet and FDF1, respectively. Similarly, the AUC0-72 value significantly increased from 498.36 ± 217.46 to 1083.67 ± 246.32 ng h/mL for market tablet and FDF1, respectively. Relative bioavailability of FDF1 was 209.28%. The highlighted results verified the effectiveness of OM nanosuspension-loaded FDFs in improving OM bioavailability.

Microemulsion for topical delivery of fenoprofen calcium: in vitro and in vivo evaluation.

The aim of this study was to investigate microemulsion (ME) based topical delivery system for fenoprofen calcium (FPCa) to eliminate its oral gastrointestinal adverse effects. ME was prepared by the water titration method using oleic acid as oil phase, tween 80 as a surfactant and propylene glycol as a cosurfactant. Oleic acid was selected as oil phase due to its good solubilizing capacity. ME existence region was determined using pseudo-ternary phase diagrams for preparing different formulations. Six different formulations were selected with various values of oil (25-68%), water (2-3%), and the mixture of surfactant and cosurfactant (1:1) (24-67%). The selected ME formulae were characterized for optical birefringence, transmission electron microscopy (TEM), pH, % transmittance, electronic conductivity, drug content, droplet size, rheological properties and stability evaluation. In vitro release study of FPCa from ME s through the synthetic membrane and hairless rat skin were evaluated. The optimized formula ME5 consisting of 5% w/w FPCa, 60% w/w oleic acid as oil phase, 3% w/w aqueous phase, and 32% w/w of surfactant phase containing Tween 80 and propylene glycol (1: 1) showed the highest transdermal flux and highest skin permeation rate. Finally, the % inhibition of carrageenan-induced rat paw edema of the optimized formula ME5 was highly significant (p < 0.001) as compared to plain gel of FPCa. In conclusion, ME is a promising technique for topical delivery of FPCa.

Topical Delivery of Fenoprofen Calcium via Elastic Nano-vesicular Spanlastics: Optimization Using Experimental Design and In Vivo Evaluation.

The aim of this study was to investigate the potential of surfactant-based nanovesicular system (spanlastics) for topical delivery of fenoprofen calcium (FPCa) to eliminate its oral gastrointestinal adverse effects. FPCa-loaded spanlastics were prepared by thin film hydration (TFH) technique according to a full factorial design to investigate the influence of formulation variables on the drug entrapment efficiency (%EE), particle size (PS), deformability index (DI), and the % drug released after 24 h through the cellulose membrane (Q24h) using Design-Expert® software. The optimized formula (composed of Span 60 and Tween 60 as an edge activator at weight ratio of 8: 2 in presence of Transcutol P as a cosolvent in the hydration media) exhibited the highest %EE (49.91 ± 2.60%), PS of 536.1 ± 17.14 nm, DI of 5.07 ± 0.06 g, and Q24h of 61.11 ± 2.70%; it was also characterized for morphology and physical stability. In vitro release study of FPCa-loaded spanlastic gel and conventional FPCa gel through a synthetic membrane and hairless rat skin were evaluated. The skin permeation study revealed that spanlastic gel exhibited both consistent and prolonged action. Finally, the % inhibition of carrageenan-induced rat paw edema of spanlastic gel was three times higher than the conventional FPCa gel after 24 h. In conclusion, spanlastic-based gel could be a great approach for improving topical delivery of fenoprofen calcium, providing both prolonged and enhanced anti-inflammatory activity in the treatment of arthritis.

Phospholipid membrane tubulation using ceramide doping "Cerosomes": Characterization and clinical application in psoriasis treatment.

Nanotechnology and material surface modification have provided a functional platform for the advancement of several medical fields such as dermatology. Furthermore, the smart choice of preparation material was proven to confer unique properties to the developed nanosystems. In this context, we focused on the sphingolipid "ceramide", whose deficiency was found to negatively affect psoriasis. Ceramide was doped into surfactant based vesicular phospholipid systems to create tubulated vesicles "cerosomes" loaded with a model anti-psoriatic drug "tazarotene", and their properties were tested as compared to ceramide free vesicles. Cerosomes were characterized for their drug entrapment, viscosity, in vitro drug release, morphology, ex vivo drug skin deposition, thermal behavior, and were clinically tested on psoriatic patients. The factorial design study revealed that the surfactant type, the ceramide: surfactant ratio, and the presence of ethanol in the hydration buffer affected the entrapment efficiency and the viscosity of the vesicles. Ceramide increased the entrapment of tazarotene, decreased its release while enhancing its deposition within the skin, correlating with better clinical therapeutic outcome compared to the topical marketed product. Ceramide was also able to cause significant membrane tubulation in the vesicles, causing them to deviate from the conventional spherical morphology. As a conclusion, cerosomes present a new functional treatment modality for psoriasis which is worthy of future experimentation.

Comparison of the effects of escitalopram and atorvastatin on diet-induced atherosclerosis in rats.

Atherosclerosis is one of the most common disorders among the elderly. Depression may be associated with the development of atherosclerosis. Thus, the aim of this study is to evaluate and compare the effects of escitalopram (a selective serotonin reuptake inhibitor) with atorvastatin (a well known antihyperlipidemic drug) on high fat diet induced atherosclerosis in rats. The results of this study showed that the administration of either escitalopram or atorvastatin for 6 weeks was associated with a significant decrease in serum levels of total cholesterol, triglycerides, low density lipoproteins, very low density lipoproteins, and serum malondialdehyde, and a significant increase in high density lipoproteins when compared with the atherosclerosis model group. Histopathological examination of the aortas from the test rats revealed significant regression of atherosclerotic changes, together with a significant decrease in vascular cell adhesion molecule-1 (VCAM-1) expression in the media of both the escitalopram group and the atorvastatin group when compared with the atherosclerosis model group. This study has shown that escitalopram reduced atherosclerotic changes, thus its use as an antidepressant in elderly patients should be considered.