Electrically Triggered Transdermal Drug Delivery Utilizing Poly(Acrylamide)-graft-Guar Gum: Synthesis, Characterization and Formulation Development

Objective: The study aimed to prepare electrically-triggered transdermal drug delivery systems (ETDS) using electrically responsive polyacrylamide-graft-gaur gum (PAAm-g-GaG) copolymer. Methods: The PAAm-g-GaG copolymer was synthesized by adopting free radical polymerization grafting method. This PAAm-g-GaG copolymer hydrogel acts as a drug reservoir and blend films of Guar Gum (GaG) and Polyvinyl Alcohol (PVA) were included as Rate Controlling Membranes (RCM) in the system. The PAAm-g-GaG copolymer was characterized by FTIR, neutralization equivalent values, thermogravimetric analysis and elemental analysis. Results: On the basis of results obtained, it is implicit that the drug permeation decreased with an increase in the concentration of glutaraldehyde and RCM thickness; while drug permeation rate was increased with increasing applied electric current strength from 2 to 8 mA. A two fold increase in flux values was observed with the application of DC electric current. An increase in drug permeation was witnessed under on condition of electric stimulus and permeation was decreased when electric stimulus was "off". The skin histopathology study confirmed the changes in skin structure when electrical stimulus was applied. Conclusion: The electrically-sensitive PAAm-g-GaG copolymer is a useful biomaterial for transdermal drug delivery application.

FURTHER ANALYSIS OF THE REACTION OF PARAMECIUM TO CIGARETTE PAPER ASH SOLUTIONS

The reaction of Paramecium caudatum to solutions containing the ash of cigarette paper was consistent with the response of Paramecium aurelia previously reported. After this confirmation, both these species of Paramecium were used as test organisms during a search for the causative agents for the "Paramecium reaction". A qualitative spectrochemical analysis of cigarette paper ash showed that its chief constituent is calcium (97%) with 12 other detected elements present at levels too low to elicit any response from paramecia. Hydroxyl ions in concentrations equivalent to 0.001 M Ca(OH)2, 0.0008 M KOH, or 0.002 M NaOH simulated but did not duplicate the effect of standard cigarette paper ash solution (as of one cigarette paper in 20 ml water). While neutralization caused the three hydroxide solutions to lose their toxicity, the toxicity of cigarette paper ash solution was not appreciably affected by neutralization. Equivalent solutions of facial tissue, filter paper, and a paper towel, burned the same way as cigarette paper, were used as controls. Each of them affected paramecia differently and none simulated the Paramecium reaction. Further, a comparison between ashes from a paperless cigarette, a whole cigarette, and one with two extra roll-your-own wrappers demonstrated a dependence of the Paramecium reaction on cigarette paper ash as well as a direct correlation between the reaction intensity and the amount of cigarette paper ash present.

PHYSICOCHEMICAL STUDIES OF ALKALI LIGNINS. I. PREPARATION AND PROPERTIES OF FRACTIONS

Alkali lignin was prepared by cooking periodate lignin with sodium hydroxide. Fractionation by gradual decrease of pH was not possible as most of the lignin was precipitated sharply at pH 4.4. Fractionation could be achieved by addition of non-solvents such as acetone, dioxane, or ethanol to an alkaline aqueous solution of the lignin, but the initial fractions when separated could not be redissolved. This difficulty was overcome by using barium chloride as a precipitant when all the fractions remained soluble. X-Ray analysis revealed no difference between the insoluble and soluble fractions.The intrinsic viscosity of the fractions ranged from 0.027 to 0.585 g−1 dl. Reduced viscosities were considerably increased at lower ionic strength indicating that the molecule was a polyelectrolyte. The fractions possessed nearly constant methoxyl content (13%), visible absorption (0.28 cm−1 l g−1 at 5460 Å), U.V. absorption (18 cm−1 l. g−1 at 2800 Å), neutralization equivalent (1.3 meq g−1), and electrophoretic mobility (−12.6 × 10−5 cm2 v−1 sec−1). The partial specific volumes of a high and a low molecular weight fraction were 0.63 and 0.68 g−1 ml respectively.

PHYSICOCHEMICAL STUDIES OF LIGNINSULPHONATES: I. PREPARATION AND PROPERTIES OF FRACTIONATED SAMPLES

High molecular weight ligninsulphonates were separated from other constituents of spent sulphite liquor by a method of dialysis allowing continuous removal of the dialyzates and their replacement by distilled water. The process was controlled by continuous analysis of the residue and dialyzate. The lower molecular weight ligninsulphonates in the dialyzates were separated from the carbohydrates by precipitating their barium salts with ethanol; four fractions corresponding to different times of dialysis were prepared in this manner. The ligninsulphonates in the dialyzed liquor were separated into four additional fractions by ultrafiltration through membranes of different pore sizes. The methoxyl, sulphur, and phenolic hydroxyl contents, neutralization equivalent weights, reducing powers, ultraviolet absorption spectra, diffusion coefficients, and number-average molecular weights of the eight fractions were determined. The molecular weights of the fractions range from 3700 to 58,000 but the integral molecular weight distribution curve indicates the presence of ligninsulphonates with molecular weights as high as 100,000.

BIOCHEMISTRY OF THE USTILAGINALES: II. ISOLATION AND PARTIAL CHARACTERIZATION OF USTILAGIC ACID

The needlelike crystals which form in aerated submerged cultures of the corn smut Ustilago zeae (PRL-119) were found to be a D-glucolipid, m.p. 146-7°C, [Formula: see text] (pyridine), which contained one carboxyl group, two ester groups, at least two terminal methyl groups, and two D-glucose residues per mole. On the basis of elementary analyses, neutralization equivalent, and molecular weight estimations, the molecular formula of the material isolated was approximately C37H62−6O17. The substance was not shown to be chemically homogeneous. Conditions used in culturing the fungus in stirred fermentors to produce the crystalline metabolic product, which was termed "ustilagic acid", are described, and a procedure for the isolation of the material is given.