Among all the excipients tested, Soluplus dispersion is the most promising candidate for oral formulation development.

In our systematic screening programme for marine actinomycetes, a bioactive Streptomycete was isolated from marine sediment samples of Bay of Bengal, India. The taxonomic studies indicated that the isolate belongs to Streptomyces chibaensis and it was designated as S. chibaensis AUBN1/7. The isolate yielded a cytotoxic compound. It was obtained by solvent extraction followed by the chromatographic purification. Based on the spectral data of the pure compound, it was identified as quinone-related antibiotic, resistoflavine (1). It showed a potent cytotoxic activity against cell lines viz. HMO2 (Gastric adenocarcinoma) and HePG2 (Hepatic carcinoma) in vitro and also exhibited weak antibacterial activities against Gram-positive and Gram-negative bacteria.

Crystal modifications and dissolution rate of piroxicam Piroxicam is a nonsteroidal anti-inflammatory drug with low aqueous solubility which exhibits polymorphism. The present study was carried out to develop polymorphs of piroxicam with enhanced solubility and dissolution rate by the crystal modification technique using different solvent mixtures prepared with PEG 4000 and PVP K30. Physicochemical characteristics of the modified crystal forms of piroxicam were investigated by X-ray powder diffractometry, FT-IR spectrophotometry and differential scanning calorimetry. Dissolution and solubility profiles of each modified crystal form were studied and compared with pure piroxicam. Solvent evaporation method (method I) produced both needle and cubic shaped crystals. Slow crystallization from ethanol with addition of PEG 4000 or PVP K30 at room temperature (method II) produced cubic crystal forms. Needle forms produced by method I improved dissolution but not solubility. Cubic crystals produced by method I had a dissolution profile similar to that of untreated piroxicam but showed better solubility than untreated piroxicam. Cubic shaped crystals produced by method II showed improved dissolution, without a significant change in solubility. Based on the XRPD results, modified piroxicam crystals obtained by method I from acetone/benzene were cube shaped, which correlates well with the FTIR spectrum; modified needle forms obtained from ethanol/methanol and ethanol/acetone showed a slight shift of FTIR peak that may be attributed to differences in the internal structure or conformation.

Aim:The objective of the current study is to increase the dissolution rate of cefuroxime axetil (CA) by formation of binary CA solid dispersion using water soluble carriers such as polyvinylpyrrolidone (PVP K30) and polyethylene glycol (PEG 4000).Methods:Solid dispersions (SDs) between CA and PVP K30/PEG 4000 were formed by dissolving both compounds in a common solvent, methanol, which were rotary evaporated at 40°C for 12 h. Physical mixtures between CA and PVP K30/PEG 4000 were also formulated as to compare the efficiency of SDs. The physicochemical properties of CA and all its formulations were then characterized using differential scanning calorimetric analysis (DSC), powder X-ray diffraction studies (PXRD), and Fourier transform infrared spectroscopy (FTIR).Results:All SD formulations were found to have a higher dissolution rate comparatively to pure CA, while only physical mixtures of PVP K30 were found having a significantly higher dissolution rate. The enhancement of dissolution rate SD by PVP K30 may be caused by increase wettability, solubility, reduction in particle size or the formation of CA β crystalline. Increment of dissolution rate of CA SDs by PEG 4000 similarly may be caused by increase wettability, solubility, and reduction in particle size. This phenomenon may also be caused by amorphization as suggested by DSC and PXRD.Conclusions:The SD of CA with PVP K30 and PEG 4000, lends an ample credence for better therapeutic efficacy.

In our systematic screening programme for marine actinomycetes, a bioactive streptomycete was isolated from marine sediment samples of the Bay of Bengal, India. The isolate yielded a new cytotoxic compound. This was obtained by solvent extraction followed by chromatographic purification. The pure compound was identified from spectroscopic data as a quinone-related antibiotic, 1-hydroxy-1-norresistomycin (1). It showed a potent cytotoxic activity against cell lines viz. HMO2 (gastric adenocarcinoma) and HePG2 (hepatic carcinoma) in vitro. It also exhibited antibacterial activities against Gram-positive and Gram-negative bacteria.Keywords Streptomyces, cytotoxic activity, antibacterial activity, quinone, 1-hydroxy-1-norresistomycin Marine actinomycetes remain an important source in the search for novel bioactive compounds. So far terrestrial substrates have been predominantly exploited as sources of actinomycetes, where as the marine habitat has received much less attention. There are a few reports on bioactive compounds from marine actinomycetes in recent times [1ϳ6]. The marine environment may be an important source of novel anti-cancer, anti-viral, antibacterial and antifungal antibiotics as well as industrially important enzymes.Taxonomic characteristics of the isolate were determined by cultivation on various media as described by Shirling and Gottlieb [7], Waksman [8] and Arai [9]. Cell wall composition was analyzed by the method of Lechevalier and Lechevalier [10], using thin layer chromatography plates as described by Staneck and Roberts [11]. The taxonomic studies indicated that the isolate belongs to Streptomyces chibaensis and it was designated as S. chibaensis AUBN 1 /7.The cytotoxicities of 1 were assessed based on their effects on the growth of tumor cells in vitro according to the NCI guide lines [12]. The cell lines used were HMO2 (gastric adenocarcinoma) and HePG2 (hepatic carcinoma). Cells were grown in 96-well microtitre plates of RPMI 1640 tissue culture medium supplemented with 10% fetal calf serum at 37°C in a humidified atmosphere of 50% CO 2 in air. After 24 hours of incubation 1 (0.1ϳ10.0 mg/ml) was added to the cells. After 48 hours incubation, the cells were fixed by addition of trichloracetic acid and cell protein was assayed with sulforhodamine B [13]. For each concentration tested, the GI 50 (drug concentration causing 50% growth inhibition), TGI values (drug concentration causing 100% growth inhibition) and LC 50 (minimum concentration which reduces the initial cell number to half) were determined (Table 2).A full grown slant culture of the strain AUBN 1 /7 on