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The aim of this study was to develop a freeze-drying protocol facilitating successful processing of plant material containing the small surface antigen of hepatitis B virus (S-HBsAg) while preserving its VLP structure and immunogenicity. Freeze-drying of the antigen in lettuce leaf tissue, without any isolation or purification step, was investigated. Each process step was consecutively evaluated and the best parameters were applied. Several drying profiles and excipients were tested. The profile of 20°C for 20 h for primary and 22°C for 2 h for secondary drying as well as sucrose expressed efficient stabilisation of S-HBsAg during freeze-drying. Freezing rate and postprocess residual moisture were also analysed as important factors affecting S-HBsAg preservation. The process was reproducible and provided a product with VLP content up to 200 µg/g DW. Assays for VLPs and total antigen together with animal immunisation trials confirmed preservation of antigenicity and immunogenicity of S-HBsAg in freeze-dried powder. Long-term stability tests revealed that the stored freeze-dried product was stable at 4°C for one year, but degraded at elevated temperatures. As a result, a basis for an efficient freeze-drying process has been established and a suitable semiproduct for oral plant-derived vaccine against HBV was obtained.

The novel diphenyltin(IV) compound [Ph(2)(HyFoSc)Sn] (2), where H(2)HyFoSc (1) is 3-hydroxy-2-formylpyridine semicarbazone, was prepared and characterized by vibrational and NMR ((1)H, (13)C) spectroscopy. The structure of [Ph(2)(HyFoSc)Sn] was confirmed by single-crystal X-ray crystallography. The doubly deprotonated ligand is coordinated to the tin atom through the enolic-oxygen, the azomethine-nitrogen, and phenolic-oxygen, and so acts as an anionic tridentate ligand with the ONO donors. Two carbon atoms complete the fivefold coordination at the tin(IV) center. Intermolecular hydrogen bonding, C-H --> pi, and pi --> pi interactions combine to stabilize the crystal structure. Compounds 1 and 2 have been evaluated for antiproliferative activity in vitro against the cells of three human tumor cell lines: MCF-7 (human breast cancer cell line), T24 (bladder cancer cell line), A549 (nonsmall cell lung carcinoma), and a mouse fibroblast L-929 cancer cell line.

The lipophilicity of a series of anticancer propargylthioquinoline derivatives has been investigated using chromatographic and computational methods. The parameters of relative lipophilicity (R(MO) and logk0) of the tested compounds were determined experimentally both by reversed-phase thin layer (RP-TLC), and high-performance liquid chromatographic methods (RP-HPLC, LiChrospher RP18 column), with mixtures of acetonitrile and water as mobile phases. Their phospholipophilicity (logk(0IAM)) was determined using immobilized artificial membrane HPLC (IAM. PC DD2 Regis column). Mobile phase acetonitrile concentrations were in the ranges 50-90% (RP-TLC), 55-90% (RP-HPLC) and 35-60% (IAM-HPLC). The R(M), logk and logk(IAM) values of the compounds investigated were linearly dependent on acetonitrile concentration. The analysis led to the calculation of R(MO), logk0 and logk(0IAM) parameter values for each of the tested compounds. Their partition coefficients (logP) were also calculated with the Pallas and CAChe programs. The obtained results indicated that, among experimental methods, both RP-TLC and RP-HPLC gave similar results, and these methods enable the determination of lipophilicity of derivatives of thioquinolines. Using the IAM-HPLC technique a simple method of estimation of phospholipoplilicity was described. The CAChe program might better predict calculated lipophilicity logP values, and therefore is a useful tool for the early stage of design of new propargyl thioquinolines., (Copyright 2006 John Wiley & Sons, Ltd.)