scholarly journals Extraction, Characterization, and Molecular Weight Determination ofSenna tora(L.) Seed Polysaccharide

2015 ◽  
Vol 2015 ◽  
pp. 1-6 ◽  
Author(s):  
Harshal A. Pawar ◽  
K. G. Lalitha
Keyword(s):  
Molecular Weight ◽  
Intrinsic Viscosity ◽  
Flow Behavior ◽  
Average Molecular Weight ◽  
Flow Property ◽  
Stability Study ◽  
Angle Of Repose ◽  
Molecular Weight Determination ◽  
Pharmaceutical Excipient ◽  
Accelerated Stability

The objective of the present work was extraction of polysaccharide fromSenna toraL. seed and its characterization as a pharmaceutical excipient. Polysaccharide extraction was based on mechanical separation of the endosperm of seeds ofSenna tora, water dissolution, centrifugation, and precipitation with acetone. Standard procedures were used to study the viscosity, micromeritic properties, and microbial bioburden. Accelerated stability study was carried out on isolated polysaccharide for six months at 40°C/75 RH as per ICH guidelines. The gum obtained fromS. toraseeds was an amorphous free flowing odourless powder with dull brown colour (yield = 35% w/w). The bulk density, tapped density, and angle of repose data reveal thatS. toragum possesses good flow property. The intrinsic viscosity obtained was 1.568 dL/g. The average molecular weight of purifiedS. toragum was found to be 198 kDa by intrinsic viscosity method. The results indicated that viscosity of gum solution increases with increase in temperature. FTIR study revealed the absence of degradation or decomposition of polysaccharide at accelerated stability conditions for six months. It has been concluded that extracted polysaccharide can be used as pharmaceutical excipient in terms of flow behavior, microbial properties, and stability.

Basicity, Water Solubility and Intrinsic Viscosity of Carboxymethyl Chitosan as a Biofunctional Material

2012 ◽  
Vol 531 ◽  
pp. 507-510 ◽  
Author(s):  
Xiang Ping Kong ◽  
Juan Wang ◽  
Chun Jie Wang ◽  
Xia Wu
Keyword(s):  
Molecular Weight ◽  
Acetic Acid ◽  
Intrinsic Viscosity ◽  
Water Solubility ◽  
Average Molecular Weight ◽  
Carboxymethyl Chitosan ◽  
Molecular Weight Determination ◽  
Solution Ph ◽  
Alkaline Conditions

The basicity, water solubility, intrinsic viscosity and molecular weight of carboxymethyl chitosan (CM-chitosan) were investigated. The solution pH remained at about 9.2 at the concentration of higher than 2.0 g/L. The isoelectric point of CM-chitosan was about 4.5 of pH, and the solubility of CM-chitosan at the solution pH of 2.0 to 6.0 was lower than 5 g/L. The acetic acid could be replaced by hydrochloric acid as solvent for the viscosity-average molecular weight determination of chitosan. The intrinsic viscosity values of CM-chitosan have significant differences in acidic and alkaline conditions. The viscosity-average molecular weight of CM-chitosan was (3.8 ± 0.2) × 105, consistent with that of product chitosan of blank test.

Molecular Weights and Intrinsic Viscosities of Polyisobutylenes

1943 ◽  
Vol 16 (3) ◽  
pp. 493-508
Author(s):  
Paul J. Flory
Keyword(s):  
Molecular Weight ◽  
Intrinsic Viscosity ◽  
Average Molecular Weight ◽  
Chain Structure ◽  
Molecular Weight Range ◽  
Molecular Weights ◽  
Satisfactory Precision ◽  
Heterogeneous Polymers ◽  
Definition Of

Abstract Experimental methods for fractionating polyisobutylene and for determining osmotic pressures have been described. The ratio π/c of osmotic pressure to concentration has been found in the case of cyclohexane solutions of polyisobutylene to vary nonlinearly with concentration, contrary to recent theories advanced by Huggins and the writer. The slope of this relationship appears to be independent of molecular weight. Reliable methods for extrapolating π/c to c=0 have been established, enabling the determination of absolute molecular weights with satisfactory precision up to values of about 1,000,000. Molecular weights of polyisobutylenes calculated from Staudinger's equation are too low; the discrepancy is more than ten-fold at high molecular weights. On the basis of data for carefully fractionated samples covering a two-hundred-fold molecular weight range, the intrinsic viscosity is found to be proportional to the 0.64 power of the molecular weight. This decided deviation from Staudinger's “law”cannot in this instance be attributed to nonlinear chain structure, as Staudinger has sought to do in other cases. This dependence of molecular weight on intrinsic viscosity leads to the definition of a “viscosity average”molecular weight which is obtained when the relationship is applied to heterogeneous polymers. The viscosity average is less than the weight average molecular weight, which would be obtained if Staudinger's equation were applicable, and greater than the number average obtained by osmotic or cryoscopic methods.

Average molecular weight determination of a polyester by NIR spectroscopy

1994 ◽  
Vol 33 (4) ◽  
pp. 377-380 ◽  
Author(s):  
S. James Robbins ◽  
Wayne D. Mockel ◽  
Connie J. Lyons
Keyword(s):  
Molecular Weight ◽  
Average Molecular Weight ◽  
Nir Spectroscopy ◽  
Molecular Weight Determination

End-Group Method for Molecular Weight Determination of PET Depolymerization under Microwave Irradiation

2012 ◽  
Vol 554-556 ◽  
pp. 1933-1937 ◽  
Author(s):  
Qing Hua Feng ◽  
Qing Hua Tang ◽  
Wei Lu Zhang ◽  
Yan Hua Jia ◽  
Dong Zhang
Keyword(s):  
Molecular Weight ◽  
Microwave Irradiation ◽  
Average Molecular Weight ◽  
Relative Number ◽  
Group Method ◽  
Molecular Weight Determination ◽  
Stannous Oxide ◽  
Hydrolytic Depolymerization ◽  
End Group

A series of catalysis hydrolytic depolymerization of PET catalyzed by zinc acetate, zinc sulfate, stannous oxide respectively under microwave irradiation at different temperature with time was studied, in which the microwave power was 260W, the ratio of water to PET was 10:1 and the dosage of the catalysts was 0.5% of PET. The relative number average molecular weight of the undepolymerized PET was determined by end-group method. The results show that the molecular weight of the undepolymerized PET decreases with the reaction time increasing, and tends to be stable at the end of the depolymerization reaction. Under the same time, the temperature is higher, the molecular weight is smaller. The molecular weight of the undepolymerized PET reduces most quickly with stannous oxide among the three catalysts.

scholarly journals Physicochemical Characterization of Grewia ferruginea Hochst. ex A. Rich Mucilage for Potential Use as a Pharmaceutical Excipient

2020 ◽  
Vol 2020 ◽  
pp. 1-10 ◽  
Author(s):  
Tsadkan Gebremeskel Haile ◽  
Gereziher Gebremedhin Sibhat ◽  
Fantahun Molla
Keyword(s):  
Flow Behavior ◽  
Sorption Property ◽  
Physicochemical Characterization ◽  
Moisture Sorption ◽  
Pharmaceutical Formulations ◽  
Flow Property ◽  
Microbial Load ◽  
Oral Toxicity ◽  
Pharmaceutical Excipient ◽  
Potential Use

Gum and mucilages from natural sources are in recent times increasingly investigated for pharmaceutical applications. Different studies have shown that the gum and mucilage fraction of various species of the genus Grewia were found to be effective viscosity enhancers, stabilizers, disintegrants, suspending agents, gelling agents, bioadhesives, film coating agents, and binders. However, no study has been conducted on the potential use of Grewia ferruginea mucilage (GFM) as a pharmaceutical excipient. Therefore, this study was aimed at characterizing the Grewia ferruginea bark mucilage for its potential use as a pharmaceutical excipient. The mucilage was extracted from the Grewia ferruginea inner stem bark through aqueous extraction, precipitated with 96% ethanol, dried, and powdered. The powdered mucilage was characterized for different physicochemical properties such as powder property, loss on drying, solubility and swelling index, ash value, pH, viscosity, moisture sorption property, microbial load, and acute oral toxicity. According to the results, the percentage yield of the final dried and powdered GFM was found to be 11.96% (w/w). The density and density-related properties of the mucilage showed good powder flow property. The GFM exhibited pseudoplastic flow behavior. Moisture sorption property of GFM revealed its hygroscopic nature, and its solubility and swelling property was increased with temperature. The pH of GFM was near neutral. Microbial load of the mucilage was within the pharmacopoeial limit, and the oral acute toxicity test revealed that the mucilage is safe up to 2000 mg/kg. From the investigations of this study, it can be concluded that Grewia ferruginea bark mucilage has the potential to be utilized as an excipient in pharmaceutical formulations.

Physical Properties of Fractions of GR-S and Their Vulcanizates

1949 ◽  
Vol 22 (2) ◽  
pp. 494-517 ◽  
Author(s):  
John A. Yanko
Keyword(s):  
Molecular Weight ◽  
Intrinsic Viscosity ◽  
Large Scale ◽  
Average Molecular Weight ◽  
Three Dimensional ◽  
Reduced Pressure ◽  
Molecular Weights ◽  
Styrene Copolymers ◽  
Straight Line ◽  
The Relationship

Abstract A large-scale precise fractionation of GR-S (X-55) was carried out at 25° C, using a fractional precipitation technique. Nine fractions, each weighing approximately 150 grams and comprising about 11 per cent by weight of the original unfractionated sample, were obtained, with number-average molecular weights varying from 4000 to 1,650,000. High molecular fractions undergo gelation rapidly, even when dried in the absence of light at reduced pressure, and the higher the molecular weight of the fraction, the greater the amount of gel formed. Compared to unfractionated butadiene-styrene copolymers of similar gel contents, the gel portions of the higher molecular fractions had unusually high swelling indices, indicating qualitatively that the average molecular weights between points of effective cross-linking in the three-dimensional gel structure were higher than those found in the past in unfractionated samples of similar gel contents. Through the concentration range studied, the intrinsic viscosity values varied as a straight-line function of the concentration terms for all the fractions. However, the negative slopes of these lines increased as the molecular weight of the fraction increased, demonstrating the greater dependence of the intrinsic viscosity values of the higher molecular fractions on the concentration variable. The relationship between number-average molecular weight, as determined by osmometric measurements, and limiting intrinsic viscosity of the GR-S fractions is given by the equation: [η]0=5.4×10−4 M0.66, which is similar to that obtained by French and Ewart. The μi values calculated from the equation of Huggins were essentially the same (0.35) through the molecular range 12,400 to 723,000.

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