Synthesis and Characterization of Jeffamine Core PAMAM Dendrimer-Silver Nanocomposites (Ag JCPDNCs) and Their Evaluation in The Reduction of 4-Nitrophenol

This paper presents the synthesis, characterization and catalytic evaluation of Jeffamine core PAMAM dendrimer-silver nanocomposites (Ag JCPDNCs). Generation-4 Jeffamine core PAMAM dendrimer (JCPD or P4.NH2) was used as the stabilizing templating agent for the synthesis of Ag-JCPDNCs. Characterization of the synthesized Ag JCPDNC was performed by UV visible (UV-Vis) spectroscopy and high resolution transmission electron microscopy (HRTEM). The catalytic activity of dendrimer nanocomposite (DNC) was assessed on the reduction of 4-nitrophenol (4-NP) to 4 aminophenol (4-AMP) in the presence of sodium borohydride (NaBH4) as reducing agent by monitoring the conversion at λ 400 nm. The prepared Ag JCPDNCs displayed a good catalytic activity (K = 0.12 x 10-2 s-1) for the model reduction reaction of 4-NP with the particle size distribution of 4.72 ± 0.81 nm, which offer a mixed type (interior and exterior) of DNC formation. The Ag JCPDNCs can be a valid complete alternative to their existing candidates in the literature with their different polymeric organics components and be great potential for the future studies as new materials

EDA Çekirdekli Amin, TRIS ve Karboksil Sonlu PAMAM Dendrimerleri Kullanarak Ketoprofenin Çözünürlüğünü Geliştirme

Steroid olmayan antienflamatuar (NSAİ) ilaçlar ağrı kesici, ateş düşürücü ve antiinflamatuar etkilerinden dolayı yaygın bir şekilde kullanılmaktadırlar. Son yıllarda NSAİ ilaçların iyi bilinen klasik etkilerinin yanında birçok farklı terapötik etkilerinin (kanser, Alzheimer ve Parkinson hastalıkları) de bulunduğu keşfedilmiştir. Sonuçlar gösteriyor ki, poli(amidoamin) (PAMAM) dendrimerler varlığında ketoprofen’in (KETO) sudaki çözünürlüğü jenerasyon büyüklüğü (E2-E4) ve dendrimer konsantrasyonun (0-2 mM) artmasıyla önemli ölçüde geliştirilmiştir. KETO’nun (0.22 ± 0.003 mg/mL) çözünürlüğünü arttırmada PAMAM dendrimerlerin rolü E4.TRIS (52.77 ± 2.06 mg/mL)> E4.COOH (36.42 ± 0.54 mg/mL)> E3.TRIS (13.70 ± 0.17 mg/mL)> E3.COOH (11.97 ± 0.14 mg/mL)> E4.NH2 (6.53 ± 0.19 mg/mL)> E2.COOH (5.95 ± 0.10 mg/mL)> E2.TRIS (5.72 ± 0.10 mg/mL)> E3.NH2 (4.21 ± 0.04 mg/mL)> E2.NH2 (2.35 ± 0.04 mg/mL) sırasına göre ve 0.002 M dendrimer varlığında 11 ile 240 kat aralığındadır

Synthesis of surface-modified TREN-cored PAMAM dendrimers and their effects on the solubility of sulfamethoxazole (SMZ) as an analog antibiotic drug

<p>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 (NH₂), Tris(hydroxymethyl)aminomethane (TRIS), and carboxyl (COOH) terminated different generations T2–T4 poly(amidoamine) PAMAM dendrimers. Synthesized PAMAMs were characterized by ¹H NMR, ¹³C 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.NH₂ > T4.COOH > T3.NH₂ > T4.TRIS > T2.NH₂ > 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. <i>In vitro</i> 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%).</p

The effect of PAMAM dendrimer concentration, generation size and surface functional group on the aqueous solubility of candesartan cilexetil

<p>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 (NH₂, 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 (<i>p</i> < 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.NH₂ (91)>G3.NH₂ (50)>G2.NH₂ (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.</p

Synthesis, structural aspects, antimicrobial activity and ion transport investigation of five new [1+1] condensed cycloheterophane peptides

Zaim, Omer/0000-0002-3472-5611; Dulger, Basaran/0000-0002-3184-2652; Dulger, Basaran/0000-0002-3184-2652; Gurbuz, Mustafa Ulvi/0000-0002-8684-5746WOS: 000334496700015Five novel [1+1] condensed cycloheterophane peptides were synthesized via reaction of pyridine-2,6-bis(2-aminothiophenoxymethyl) with several diacid chlorides: glutaryl dichloride, adipoyl dichloride, 2,2'-thiodiacetyl chloride, dithiodiglycoloyl chloride and 3,3'-thiodipropionoyl chloride combinations (L-1-L-5). The compounds were characterized by elemental analyses, mass, FT-IR, H-1, and C-13 NMR spectral data. The antimicrobial activities of the compounds were evaluated using the disk diffusion method in dimethyl sulfoxide as well as the minimal inhibitory concentration dilution method, against several bacteria and yeast cultures. The results were compared with those of commercial antibiotic and antifungal agents. Structure activity relationships were also discussed. Permeability of compound L-5 against Na+ and K+ were also investigated.Fatih University Scientific Research CentreFatih University [P50021004_G1452]; Trakya UniversityTrakya University [TUBAP-2010/174]We would like to extend our gratitude to the Fatih University Scientific Research Centre ( Project-P50021004_G1452) and the Trakya University (Grant # TUBAP-2010/174) for their financial support. Dr. Ahmet Ceyhan Goren and Gokhan Bilsel (TUBITAK-UME), is acknowledged for the Mass analysis