Fabricating pentaazatetraethylene modified sulfonated polyacrylamide for dye adsorption from aqueous media: isotherms and kinetics models.

In this study, pentaazatetraethylene-modified sulfonated polyacrylamide (PAm-SO3-N5) was synthesized and used as a novel efficient adsorbent to remove calmagite from aqueous media. To this end, a central composite design (CCD) was applied to reduce the number of reaction variables (i.e., adsorbent concentration, temperature, initial concentration, and pH) on calmagite removal. The results showed that calmagite was entirely adsorbed by the PAm-SO3-N5 within 30 min. In addition, a pseudo-second-order (PSO) model was prepared as the optimum formula to fit the kinetics information. The modeling results revealed that film diffusion and adsorption are rate-limiting stages to remove the dyes. Using a Langmuir isotherm to fit the equilibrium data, the highest equilibrium adsorption was calculated to be 1732.5 mg/g. In the present study, the ΔH value indicates that the adsorption is of chemical type. Also, the negative sign of ΔS° shows that PAm-SO3-N5 removes calmagite during a relatively stable process with randomness in the system. The increase in ΔG° values with increasing temperature indicates a descending trend in the feasibility degree of calmagite adsorption. Eventually, recycling the adsorbent for 7 cycles to adsorb calmagite dye showed no remarkable activity loss.

Comparison of different doses of subconjunctival sunitinib with bevacizumab in the treatment of corneal neovascularization in experimental rats.

BACKGROUND: To compare the efficacy of subconjunctival administration of bevacizumab and different doses of sunitinib malate in reducing corneal neovascularization (CNV). MATERIALS AND METHODS: In this experimental study, central corneal cauterization was created in the right eye of fifty male Sprague-Dawley rats. On day 1 (1 week after cauterization), rats were randomly assigned into five treatment groups. Group control (n = 10) received subconjunctival injection of 0.02 ml of base saline solution. Group 1 (n = 10) received 0.02 ml of bevacizumab (25 mg/ml). Group 2, 3, and 4 (n = 10 for each group) were treated with 0.02 ml of sunitinib malate (10, 20, and 50 µg/ml, respectively). On days 1, 7, and 14, digital photographs of the cornea were taken, and the area of CNV was measured. RESULTS: During the 2-week follow-up, CNV area in treatment groups was less than in control group (P < 0.05). On day 7, corneal avascular area was highest in Group 3 at 63%. On day 14, the area of CNV in Groups 2 and 3 was less than in Group 1 (P = 0.031 and 0.011, respectively), but the difference between Groups 2 and 3 was not statistically significant (P = 0.552). The decreased CNV area on day 14 in Group 4 was significant in comparison to bevacizumab, but it was not significant on day 7 (P = 0.25 on day 7 and 0.002 on day 14). CONCLUSION: Subconjunctival sunitinib malate is more effective than bevacizumab in regressing CNV. This effect is more prominent on day 14.