The talc formulation of Streptomyces antagonist against Mycosphaerella foot rot in pea (Pisum sativum l.) seedlings

Pea is highly susceptible to pre-emergence damping off and foot rot after emergence caused by Mycosphaerella pinodes in western Algerian regions. Rhizosphere Actinomycetes which were antagonistic to the growth of this pathogen were isolated from chellif soils. An isolate of Streptomyces St7c5 provided superior seed protection. An increased in both germination and plant growth were recorded following treatment of seeds with Streptomyces formulated with inert or organic charge when compared to control. Application of the antagonist agent resulted in a significant reduction of Mycosphaerella foot rot to 5% compared with untreated seeds (25%). Hence, the talc formulation of Streptomyces agent can be recommended as one of the crop strategies for the management of foot rotting and blight caused by Mycosphaerella pinodes.     

Effect of Eudragit<Superscript>®</Superscript> RS 30D and Talc Powder on Verapamil Hydrochloride Release from Beads Coated with Drug Layered Matrices

The aim of this study was to investigate the effect of Eudragit RS 30D, talc, and verapamil hydrochloride on dissolution and mechanical properties of beads coated with "drug-layered matrices". This was accomplished with the aid of a three-factor multiple-level factorial design using percent drug release in 1 and 2 h, T(50), tensile strength, brittleness, stiffness and toughness as the responses. Beads were coated in a fluidized-bed coating unit. Surface morphology and mechanical properties were evaluated by surface profilometry and texture analysis, respectively. No cracks, flaws and fissures were observed on the surfaces. The mechanical properties were dependent on the talc/polymer ratio. The release of verapamil from the beads was influenced by matrix components. Increasing the level of both talc and Eudragit decreased the percent drug released from 67% to 4.8% and from 80.7% to 6.7% in 1 and 2 h, respectively, and increased T(50) from 0.8 to 25.7 h. It was concluded that beads could be efficiently coated with "drug-layered matrices". The release of drug, however, depends on a balance between the levels of drug, talc, and polymer, whereby desired dissolution and mechanical properties could be controlled by the talc/polymer ratio and the level of drug loading.     

Agglomeration of ibuprofen with talc by novel crystallo-co-agglomeration technique

The purpose of this research work was to obtain directly compressible agglomerates of ibuprofen with talc by a novel crystallo-co-agglomeration (CCA) technique, which is an extension of spherical crystallization. Ibuprofen-talc agglomerates were prepared using dichloromethane (DCM)-water as the crystallization system. DCM acted as a good solvent for ibuprofen as well as a bridging liquid for agglomeration of crystallized drug with talc. The agglomerates were characterized by differential scanning calorimetry, powder X-ray diffraction, and scanning electron microscopy and were evaluated for tableting properties and for drug release. The process yielded spherical agglomerates containing ∼95% to 96% wt/wt of ibuprofen. Agglomerates containing talc showed uniform distribution of hydroxypropylmethylcellulose and decreased crystallinity, and deformed under pressure. The miniscular form of ibuprofen and the hydrophobicity of talc governed the drug release rate. The batch containing a higher proportion of talc showed zeroorder kinetics and drug release was extended up to 13 hours. The CCA technique developed in this study is suitable for obtaining agglomerates of drug with talc as an excipient.     

Biological control of root-knot nematode,Meloidogyne incognita infesting tomato

Talc based formulations of two antagonistic fungi, Acremonium strictum W. Gams and Aspergillus terreus Thom were tested separately and together for their ability to suppress the development of root-knot disease of tomato caused by the root-knot nematode, Meloidogyne incognita Kofoid & White in two consecutive trials (2007–08). Tomato seedlings were each inoculated with M. incognita at 2 infective second stage juveniles /g of soil. M. incognita caused up to 48% reduction in plant growth parameters compared to un-inoculated control. Control efficacy achieved by combined soil application of both fungi, in terms of galls/root system and soil population/50 ml of soil, was 66 and 69% respectively at 60 days of inoculation compared to control. Soil application by individual fungus did not achieve as much effectiveness as the biocontrol agents applied together. The combined treatment was found to have antagonistic effect on M. incognita development and increased plant vigor. Incorporation of fine powder of chickpea pod waste with talc powder was beneficial in providing additional nutrients to both plant and biocontrol agents and increased the activity of the nematophagous fungi in soil. A. strictum and A. terreus were successfully established in the rhizosphere of tomato plants up to the termination of the experiment.     

Adsorption of Various Enzymes Onto Talcs Scope and Limitations of This New Immobilization System

The adsorption of various enzymes (proteases, lipases and peroxidases) onto the surface of talc (a hydrophobic support) and non- talc materials was investigated. In general, adsorption was favored by the hydrophobicity of the support. We found little evidence for the ionic interactions that characterize adsorption onto mineral supports (clays, porous glasses). Modification of the hydrophobic-hydrophilic balance of the talc support produced new immobilized biocatalysts with high enzyme activity (both lipases and horseradish peroxidase). This represents the first example of this type of talc-protein interaction.