HLB number of vitamins C, E, coenzyme Q10 derivatives and their transportation efficiency into skin

We have been proposing a new delivery system of medicines and supplements. Derivatives of vitamin C, E and coenzyme Q(10) were examined regarding the relationship between the hydrophile-lipophile balance (HLB) number and the transdermal transportation efficiency into the skin. Non-invasive vibrational spectroscopies, infrared attenuated total reflection (IR-ATR) and near-infrared diffusive reflection (NIR-DR) methods were used in order to evaluate transported materials in the skin. Vitamin C derivatives of sodium L-ascorbyl-2-phosphate (hereafter abbreviated as APS) and sodium L-ascorbyl-2-phosphate-6-palmitate (APPS) were examined. APPS contains both a hydrophilic group and a hydrophobic group, since APS has been modified to APPS by deriving palmitic acid ester in the 6-OH position. APPS has the value of HLB around 9.0, while APS has that of 20. The iontophoretic efficiency of APPS is higher than APS. Vitamin E derivatives of DL-alpha-tocopheryl N,N-dimethylglycinate (TDMG) and alpha-tocopheryl acetate (TA) were examined regarding the transdermal transportation effect. Those HLB numbers are 2.3 and 0, respectively. TA is hydrophobic, while TDMG has a hydrophilic terminal group of dimethylglycine HCl materials. Coenzyme Q(10) (CoQ(10)) is hydrophobic and a portion of benzoquinone is also hydrophobic, thus, HLB = 0. CoQ(10) has been modified to a reduced form of CoQ(10) (CoH(2)Q(10)) by NaBH4. CoH(2)Q(10) has a hydroquinone structure of hydrophilic property and HLB = 3.9. Supersonic perforation transported a greater amount of CoH(2)Q(10) into the skin than CoQ(10). The balance of the hydrophilic group and the hydrophobic group in the transported material is an important factor for the effective transportation into the skin. (C) 2006 Elsevier B.V. All rights reserved.