Characterization of freeze-dried gallic acid/xyloglucan.

Drug development and industrial pharmacy (2013-11-16)
Namon Hirun, Tanatchaporn Sangfai, Vimon Tantishaiyakul
ABSTRACT

Tamarind seed xyloglucan (TSX) is generally used for drug delivery systems. Gallic acid (GA) possesses various pharmacological activities. It has a good solubility and bioavailability but short half-life. To prepare a sustained-release of GA to overcome its relatively short half-life. GA was blended with TSX and freeze-dried. The physicochemical properties of freeze-dried GA and freeze-dried GA/TSX were characterized, and the release profiles of GA from these freeze-dried samples were investigated. All freeze-dried samples were characterized by PXRD, spectroscopic and thermal analyses. The dissolution studies were performed according to the United States Pharmacopeia (USP) XXX. According to FTIR, FT-Raman and (13)C CP/MAS NMR, the spectra of freeze-dried GA were similar to that of the anhydrous form. Nevertheless, DRIFTS and DSC were able to differentiate these two forms. The crystallinity of GA in the freeze-dried GA/TSX was the same as that of the freeze-dried GA. DSC indicates that there were interactions between GA and TSX. It was of interest that a freeze-dried sample with low amount of GA, 0.2% GA/1% TSX was mostly in an amorphous form. Moreover, all freeze-dried GA/TSX preparations demonstrated a sustained-release of GA compared to GA alone. The freeze-dried 1% GA/1% TSX provided the best sustained-release of GA of up to 240 min. TSX could change a crystal form of a small molecule to a mostly amorphous form. It was of importance that the freeze-dried GA/TSX could effectively retard the release of GA. These samples may be able to overcome the limitation for the therapeutic use of GA due to its short biological half-life.

MATERIALS
Product Number
Brand
Product Description

Sucrose, European Pharmacopoeia (EP) Reference Standard
Supelco
Sucrose, Pharmaceutical Secondary Standard; Certified Reference Material
USP
Sucrose, United States Pharmacopeia (USP) Reference Standard
Sigma-Aldrich
Sucrose, ACS reagent
Sigma-Aldrich
Sucrose, meets USP testing specifications
Sigma-Aldrich
Sucrose, Grade I, suitable for plant cell culture
Supelco
Sucrose, analytical standard, for enzymatic assay kit SCA20
Sigma-Aldrich
Sucrose, ≥99.5% (GC)
Sigma-Aldrich
Sucrose, BioXtra, ≥99.5% (GC)
Sigma-Aldrich
Sucrose, ≥99.5%
Sigma-Aldrich
Sucrose, BioReagent, suitable for cell culture, suitable for insect cell culture, ≥99.5% (GC)
Sigma-Aldrich
Sucrose, Grade II, suitable for plant cell culture
Sigma-Aldrich
Sucrose, for molecular biology, ≥99.5% (GC)
Supelco
Sucrose, analytical standard
Sigma-Aldrich
D-(+)-Xylose, ≥99%
Sigma-Aldrich
D-(+)-Xylose, BioXtra, ≥99%
Sigma-Aldrich
D-(+)-Xylose, ≥99%
Sigma-Aldrich
Sucrose, puriss., meets analytical specification of Ph. Eur., BP, NF
Sigma-Aldrich
Sucrose, BioUltra, for molecular biology, ≥99.5% (HPLC)
Millipore
Sucrose, suitable for microbiology, ACS reagent, ≥99.0%
Sigma-Aldrich
D-(+)-Xylose, BioUltra, ≥99.0% (sum of enantiomers, HPLC)
Galactose, European Pharmacopoeia (EP) Reference Standard
SAFC
Galactose, plant-derived
Xylose, European Pharmacopoeia (EP) Reference Standard
USP
Galactose, United States Pharmacopeia (USP) Reference Standard
Supelco
Galactose, Pharmaceutical Secondary Standard; Certified Reference Material
Sigma-Aldrich
Allyl methyl sulfone, 96%
Sigma-Aldrich
D-(+)-Galactose, powder, anhydrous, BioReagent, suitable for cell culture, suitable for insect cell culture
Sigma-Aldrich
D-(+)-Galactose, ≥98%
Sigma-Aldrich
D-(+)-Galactose, BioXtra, pH 5.0-7.0 (20 °C, 1 M in H2O), ≥99%