Abstract. The amalgamation of polymer and pharmaceutical sciences led to the introduction of polymer in the design and development of drug delivery systems. Polymeric delivery systems are mainly intended to achieve controlled or sustained drug delivery. Polysaccharides fabricated into hydrophilic matrices remain popular biomaterials for controlled-release dosage forms and the most abundant naturally occurring biopolymer is cellulose; so hdroxypropylmethyl cellulose, hydroxypropyl cellulose, microcrystalline cellulose and hydroxyethyl cellulose can be used for production of time controlled delivery systems. Additionally microcrystalline cellulose, sodium carboxymethyl cellulose, hydroxypropylmethyl cellulose, hydroxyethyl cellulose as well as hydroxypropyl cellulose are used to coat tablets. Cellulose acetate phthalate and hydroxymethyl cellulose phthalate are also used for enteric coating of tablets. Targeting of drugs to the colon following oral administration has also been accomplished by using polysaccharides such as hdroxypropylmethyl cellulose and hydroxypropyl cellulose in hydrated form; also they act as binders that swell when hydrated by gastric media and delay absorption. This paper assembles the current knowledge on the structure and chemistry of cellulose, and in the development of innovative cellulose esters and ethers for pharmaceuticals.
A comparative study of the influence of ethanol, benzene, acetone, isopropanol, and mixtures of ethanol-acetone, ethanol-benzene, and ethanol-isopropanol as slurry media on the degree of substitution and viscosity of carboxymethyl starch during carboxymethylation is presented. It is shown that the degree of substitution increases with increasing acetone, isopropanol, or benzene content in the mixed solvent. After the same carboxymethylation steps the degree of substitution with ethanol=benzene mixture is higher than that with ethanol=isopropanol mixture.
Tobacco caterpillar, Spodoptera litura is destructive pest causes severe losses to various crops worldwide. The potential of different entomopathogenic fungi (EPFs) against S. litura was conducted at Institute of Plant Protection, MNS-University of Agriculture, Multan by using leaf dip method. Larvae and eggs were the most susceptible while pupae were less susceptible to the tested entomopathogenic fungal isolates. The early instar larvae were highly susceptible to EPFs as compared to the later instar larvae. The median lethal concentration (LC50) values for third instar larvae were 1.13×107 conidia ml-1 and 2.16×107 conidia ml-1 for B. bassiana 25 and I. fumosorosea 32, respectively. The entomopathogenic fungi pathogenicity was increased with increase in conidial concentration and mortality rate also increased. Median lethal time (LT50) of S. litura was increased with decreased in fungus conidial concentrations. The median lethal concentration (LC50) values for eggs were 1.22×106, 2.33×107 and 4.91×106 in Metarhizium anisopliae L6, Beauveria bassiana 25 and Isaria fumosorosea 32, respectively. During the study, no significant effect was recorded on adult emergence while the virulence potential of I. fumosorosea had significant impact on pupal formation. Key words: Armyworm, Entomopathogens, Pathogenicity, Biological Control
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