This article investigates the aqueous solubility of the poorly soluble drug candesartan cilexetil (CC) in the presence of poly(amidoamine) (PAMAM) dendrimers. The effect of variables such as concentration, generation size (G2-G4), and surface groups (NH, COOH and TRIS) of PAMAMs on the aqueous solubility of CC was studied. A two-factor factorial (3 × 3) ANOVA design was used to study the effect of generation size and surface functional group of the PAMAMs. The results showed that the aqueous solubility of CC in the presence of carboxyl and TRIS-terminated PAMAMs was higher than those of amine-terminated PAMAMs, and the effect of surface functional group of the PAMAMs on the aqueous solubility of CC was dependent on the generation size (p < 0.05). The sequence of the observed solubility fold enhancement due to PAMAMs was G4.COOH (8378)>G3.COOH (3456)>G4.TRIS (2362)>G2.COOH (1013)>G3.TRIS (749)>G2.TRIS (293)>G4.NH (91)>G3.NH (50)>G2.NH (37). The CC-PAMAM dendrimer inclusion complexes were characterized by UV-Vis, attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR) and differential thermal analysis (DTA) techniques. Regarding the results of these techniques, improvement in the solubility of CC is expected primarily through the intermolecular hydrogen bonding between the drug and internal tertiary and surface functional groups of the studied PAMAMs.

This study is the first report describing the microwave-assisted synthesis (MAS) of poly(amido amine) (PAMAM) dendrimers with TRIS surface functional groups (PAMAM-TRIS). Six PAMAM-TRIS dendrimers were synthesized using both newly developed conventional and microwave methods. Five of them are novel. Three different cores, one polymeric Jeffamine® T-403 and two monomeric, ethylenediamine and diethylenetriamine, were used in the syntheses. All the reactions were monitored by attenuated total reflectance (ATR). It was observed that microwave reactions proceeded 3.5 to 4.0 times faster than conventional reactions. Therefore, a fast, easy and one-pot MAS of six different water-soluble PAMAM-TRIS dendrimers was accomplished with high (90-96%) yields in short (110-140 min) reaction times and under mild reaction conditions, using methanol as solvent. The other ester terminated half generation precursor PAMAM (PAMAM-OCH 3 ) dendrimers used for the synthesis of the PAMAM-TRIS dendrimers were obtained by utilizing conventional and microwave methods together. For the purification of all the PAMAM dendrimers, a liquid phase polymer-based retention (LPR) technique was used. The PAMAM-TRIS dendrimers were characterized by 1 H NMR, 13 C NMR, ATR (IR), EA, potentiometric and spectroscopic titrations. Furthermore, Cu(II)-PAMAM-TRIS dendrimer complexes were prepared and characterized by UV-Vis spectroscopy. The synthesized PAMAM-TRIS dendrimers can be considered as new drug carrier systems and should find use in widespread application fields, especially in future pharmaceutical and catalytic studies but also in other fields.

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Sulfamethoxazole (SMZ) is a sulfonamide and used widely in the treatment of bacteriostatic and urinary tract infections with trimethoprim as an antibiotic. The problem with SMZ is its poor water solubility, therefore, low bioavailability in clinical applications. In this study, we synthesized new-generation Tris(2-aminoethyl)amine (TREN)-cored amine (NH), Tris(hydroxymethyl)aminomethane (TRIS), and carboxyl (COOH) terminated different generations T2-T4 poly(amidoamine) PAMAM dendrimers. Synthesized PAMAMs were characterized by H NMR,C NMR, ATR-FTIR, spectroscopic titrations, and evaluated as potential solubility enhancers and drug carriers of sulfonamides by taking SMZ as a model drug. The effect of concentration, generation, and surface groups of PAMAMs on the solubility of SMZ was also investigated. Results showed that the solubility of SMZ improved significantly with an increasing generation size (T2-T4) and PAMAM dendrimer concentration (0-2 mM). The role of PAMAMs in the solubility enhancement of SMZ was in the order of T4.NH > T4.COOH > T3.NH > T4.TRIS > T2.NH > T3.COOH > T3.TRIS > T2.COOH > T2.TRIS, and in the ranges of 5- to 45-fold with maximum SMZ loading 7 to 61 mole/mole per PAMAM dendrimer molecule. In vitro release studies demonstrated that SMZ-PAMAM dendrimer complexes at the end of 2-h drug release (16-26%) was considerable slower than pure SMZ (38.8%).

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The present paper introduces a plant-mediated green synthesis of highly stable MnFe 2 O 4 @EP@Ag magnetically recyclable nanocomposites (MRNCs) using Epilobium parviflorum (EP) tea extract as a coating material on MnFe 2 O 4 nanoparticles (NPs) for the Ag immobilization. Fourier transform infrared spectroscopy-attenuated total reflectance (ATR-FTIR) studies confirmed the presence of the polyphenolics in EP extract, including tannic, gallic, and other derivatives, which can enhance the complexation properties with silver ions on MnFe 2 O 4 NPs. Thus, the capacity and the surface properties of the resulting nanosorbent (MnFe 2 O 4 @EP) can also improve their ability to form magnetic nanocatalyts without using any additional chemicals, toxic or extra-reducing agents. The transmission electron microscopy (TEM) verified the successful coating of EP extract on MnFe 2 O 4 core as a 5 nm shell. X-ray diffraction (XRD) patterns and scanning electron microscope/energy-dispersive X-ray spectroscopy (SEM-EDX) confirmed the presence of both MnFe 2 O 4 and crystalline silver nanoparticles in the core-shell structure of the MnFe 2 O 4 @EP@Ag MRNCs. The obtained MnFe 2 O 4 @EP@Ag MRNCs displayed high efficiency and catalytic activity for the reduction of various azo dyes like methyl orange (MO), methyl red (MR), congo red (CR), alizarin yellow (AY), nitro aromatic compound, 4-Nitrophenol (4 NP), and a common tracer, rhodamine B (RhB). Results displayed that the MnFe 2 O 4 @EP@Ag MRNCs revealed higher catalytic activity with the normalized rate constant (k nor ) of 350.47 s −1 g −1 for RhB reduction. Furthermore, they were highly efficient in the reduction of other azo dyes and nitro compound in the order of MO (85.51 s −1 g −1 ) > CR (70.09 s −1 g −1 ) > 4 NP (62.15 s −1 g −1 ) > AY (54.67 s −1 g −1 ) > MR (46.73 s −1 g −1 ). In addition, the MnFe 2 O 4 @EP@Ag MRNCs exhibited an excellent unchanged recovery efficiency even after several cycles; therefore, they can be good potential candidates for the treatment of organic pollutants in wastewater and a wide range of applications in heterogeneous catalysis.

Many therapeutically active drugs are poor water soluble and, therefore, bioavailability of these molecules in the living cells is low and a major problem. In this study, new-generation Jeffamine ® D230 core, amine (NH 2 ), Tris(hydroxymethyl) aminomethane (TRIS), and carboxyl (COOH) terminated poly(amidoamine) PAMAM dendrimers (PAMAMs) were synthesized. Synthesized new-generation PAMAMs were characterized by 1 H NMR, 13 C NMR, ATR-FTIR, and investigated as solubility enhancer of a sample non-steroidal anti-inflammatory drug (NSAID) Ibuprofen (IBU). The effect of generation size (D2-D4), concentration (0-2.0 mM), and surface functional group (NH 2 , COOH, TRIS) of the synthesized new-generation PAMAMs on the aqueous solubility of IBU was also investigated. The observed solubility enhancement of IBU was in the order of D4.COOH (18.21 mg/mL)> D3.COOH (13.21 mg/mL)> D4.TRIS (10.30 mg/mL)> D2.COOH (8.55 mg/mL)> D3.TRIS (6.04 mg/mL)> D4.NH 2 (4.56 mg/mL)> D3.NH 2 (3.36 mg/mL)> D2.TRIS (2.42 mg/mL)> D2.NH 2 (1.86 mg/mL). Results showed that synthesized PAMAMs improved the solubility of IBU significantly (30 to 247-fold) with an increasing generation size, and concentration.