A study on solubilization of poorly soluble drugs by cyclodextrins and micelles: complexation and binding characteristics of sulfamethoxazole and trimethoprim.
The present study is focused on the characterization of solubilization of poorly soluble drugs, that is, sulfamethoxazole (SMX) and trimethoprim (TMP) by cyclodextrins (α-, β-, and γ-CDs) and anionic surfactant sodium dodecyl sulfate (SDS). The phase solubility diagrams drawn from UV spectral measurements are of the A(L) type and indicate an enhancement of SMX and TMP solubility in the presence of CDs. Complex formation tendency of TMP with CDs followed the order: γ-CD > β-CD > α-C. However, the complex formation constant values, for SMX-CD system yielded the different affinity and follow the order: β-CD > γ-CD > α-CD. With taking into consideration of solubilization capacity of SDS micelles, it has been found that the solubility enhancement of TMP is much higher than that of SMX in the presence of SDS micelles. The binding constants of SMX and TMP obtained from the Benesi-Hildebrand equation are also confirmed by the estimated surface properties of SDS, employing the surface tension measurements. In order to elucidate the solubilization characteristics the surface tension measurements were also performed for nonionic surfactant Triton X-100. Polarity of the microenvironment and probable location of SMX and TMP were also discussed in the presence of various organic solvents.
General Chemistry Division, Department of Basic Pharmaceutical Sciences, Faculty of Pharmacy, Marmara University, Uskudar, 34668 Istanbul, Turkey. sinemgokturk@gmail.com
Sinem
S
Göktürk
Elif
E
Çalışkan
R Yeşim
RY
Talman
Umran
U
Var
D002626:Chemistry, Pharmaceutical; D003505:Cyclodextrins / Q000737:chemistry*; D008823:Micelles; D004364:Pharmaceutical Preparations / Q000737:chemistry*; D012967:Sodium Dodecyl Sulfate / Q000737:chemistry; D012995:Solubility; D012997:Solvents / Q000737:chemistry; D013420:Sulfamethoxazole / Q000737:chemistry*; D013500:Surface Tension; D013501:Surface-Active Agents / Q000737:chemistry; D014295:Trimethoprim / Q000737:chemistry*; D047392:beta-Cyclodextrins / Q000737:chemistry
D003505:Cyclodextrins; D008823:Micelles; D004364:Pharmaceutical Preparations; D012997:Solvents; D013501:Surface-Active Agents; D047392:beta-Cyclodextrins; D012967:Sodium Dodecyl Sulfate; D014295:Trimethoprim; D013420:Sulfamethoxazole