Procedures for the preparation of acetate buffer and simulated body fluid (SBF)
For acetate buffer:
Acetate buffer was chosen to simulate the human skin pH condition of 5.5. To prepare 1,000 ml of the acetate buffer solution, 150 g of sodium acetate was dissolved in ~250 ml of distilled water. Exactly 15 ml of glacial acetic acid was then added very slowly into the sodium acetate aqueous solution. Finally, distilled water was added into the solution to fill the volume.
For simulated body fluid:
Simulated body fluid (SBF) contains ions normally present in the human blood plasma. It is specifically prepared to have a buffered capacity at the physiological pH of 7.4, using 50 mM of trishydroxylaminomethane and 45 mM hydrochloric acid. The reagents used to prepare SBF used in this work are given in the following table.
TableI. Reagents used to prepare 1 L of SBF.
Order / Reagents / Amount (g)1 / NaCl / 7.996
2 / NaHCO3 / 0.350
3 / KCl / 0.224
4 / K2HPO.3H2O / 0.228
5 / MgCl2.6H2O / 0.305
6 / 1 M HCl / 40 mL
(About 90% of total amount of HCl to be added)
7 / CaCl2 / 0.278
8 / Na2SO4 / 0.071
9 / (CH2OH)3CNH2 / 6.057
Due to the insolubility of GMin an aqueous medium, slight modification of both types of the buffer media was necessary. For this purpose, 0.5% v/v of Tween 80 and 3% v/v of methanol were added in either of the media and the modified acetate and phosphate buffer medium solutions were hereafter called the A/T/M and the S/T/M media, respectively.
Figure I. Cumulative release profiles of GM from (a) 30%GM-loaded and (b) 50%GM-loaded PLLA fiber mats, reported as the percentage of the weights of GM released divided by the actual weights of GM in the samples, by total immersion method in A/T/M medium at the skin temperature of 32 C or S/T/M medium at the physiological temperature of 37 C.