Showing papers on "Liquid paraffin published in 2007"

Formulation and in vitro Evaluation of Eudragit ® Microspheres of Stavudine

Abstract: Purpose: The aim of this study was to formulate and evaluate microencapsulated controlled release preparations of a highly water-soluble drug, stavudine, using Copolymers synthesized from acrylic and methacrylic acid esters (Eudragit RS 100 and RL 100) as the retardant material. . Methods: Microspheres were prepared by solvent evaporation method using an acetone / liquid paraffin system. Magnesium stearate was used as the droplet stabilizer and n-hexane was added to harden the microspheres. The prepared microspheres were characterized for their micromeritic properties and drug loading, as well by fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry, x-ray powder diffractometry and scanning electron microscopy. The in vitro release studies were performed in pH 6.8, phosphate buffer. Results: The prepared microspheres were white, free flowing and spherical in shape. The drug-loaded microspheres showed 67-91% of entrapment and release was extended upto 6 to 8 h. The infrared spectra and differential scanning calorimetry thermographs showed stable character of stavudine in the drug-loaded microspheres and revealed the absence of drugpolymer interactions. X-ray diffraction patterns showed that there was decrease in crystallinity of the drug. Scanning electron microscopy study revealed that the microspheres were spherical and porous in nature. Conclusion: The best-fit release kinetics was achieved with Higuchi plot followed by zero order and First order. The release of stavudine was influenced by the drug to polymer ratio and particle size & was found to be diffusion controlled.

Agarose–gelatin conjugate for adherent cell-enclosing capsules

Abstract: Spherical capsules were prepared by extruding aqueous agarose-gelation conjugate solution into co-flowing liquid paraffin at 38 degrees C and cooling the resultant emulsion. Capsule diameter was controlled between 40 and 250 mum by changing the velocity of the liquid paraffin. Adherent Crandall-Reese feline kidney cells enclosed in conjugate capsules of 141 +/- 23 mum diam. had a higher degree of proliferation than those in unmodified agarose capsules. Mitochondrial activity, detected for cell-enclosing conjugate capsules normalized against unit volume of gel, was about double that of unmodified agarose capsules over 28 days. These results demonstrated the feasibility of agarose-gelatin conjugate as a material of cell-enclosing capsules.

Super‐Stable Nonaqueous Foams in Diglycerol Fatty Acid Esters—Non Polar Oil Systems

Abstract: Foamability and foam stability of diglycerol fatty acid esters (designated as Qn‐D, where, n represents the carbon number in the alkyl chain of the amphiphile) were studied in different nonaqueous solvents, namely, liquid paraffin (LP70), squalane, squalene, and glycerol tris (2‐ethylhexanoic) ester (TIO) at 25°C. Five per cent by weight of diglycerol monomyristate (Q14‐D) in LP 70 gave super‐stable foam among all oils; not ruptured for more than 12 hours. Q14‐D/squalene also formed very stable foam, whereas there was no foam in a Q14‐D/squalane system. Diglycerol monolaurate (Q12‐D) in LP 70, squalene and squalane gave foams, which coarsened quickly, leading to the progressive destruction of the foam within few minutes. The above systems are essentially dispersions in which surfactant solid or liquid crystal is finely divided. After phase separation took place or the surfactant was precipitated at the bottom of vial, no foaming was observed from the supernatant phase, which is almost pure solvent. Hence,...

Design and evaluation of diclofenac sodium controlled drug delivery systems

Abstract: Sustained release dosage form of diclofenac sodium containing immediate and controlled release components was designed. Solid dispersion of immediate release component was prepared using polyvinyl pyrrolidone and mannitol carriers by common solvent method. Controlled release component was prepared in form of spherical beads by ionotropic gelation technique. The beads were prepared based on dispersing drug in solutions of ionic polysaccharides such as chitosan and sodium alginate. These dispersions were dropped into solutions of counter ions such as tetrasodium pyrophosphate and calcium chloride, respectively. The beads were also prepared using agar by dropping agar-drug hot solution into a mixture of chilled liquid paraffin and water. Then, diclofenac sodium controlled release drug delivery systems were prepared by combining the immediate release and controlled release components in different ratios. The formulations were found to be effective in providing controlled release of drug for a longer period of time. The beads were characterized by scanning electron microscopy and X-ray diffraction studies.

Thermal analysis for bulk-micromachined electrothermal hydraulic microactuators using a phase change material

Abstract: Paraffin wax has been exploited in microactuators because it exhibits a volumetric expansion of ∼15%, at around its melting point. In order to understand paraffin wax actuation, for the first time, the melting process has been investigated using a combination of analytical modelling (using Stefan's problem and Neumann's solution), finite element method (FEM) simulations and actuation data from measurements of a Braille cell and micropipette. This approach gives information on the location of the melting front (interface) at a given melting time, and on the temperature profiles in the paraffin wax during melting. Using the measured actuation response times of approximately 42 and 10 s for the Braille cell and the micropipette, temperatures for the infinitesimally thin layer of theoretical liquid paraffin wax are calculated at approximately 80 and 110 °C, respectively. These calculated temperatures for the infinitesimally thin layer of liquid paraffin wax are reasonable, when considering the real melting process within the microactuator. Using FEM simulations, the melting process was simulated and the final melting times were found to be almost identical to the analytical results. The results from the analytical method closely resemble the natural behaviour of the real melting process. This analytical modelling of the melting process can provide useful information for designing optimal electrothermal hydraulic microactuators using phase change materials (PCMs) and their operating actuation characteristics.

In vitro response of encapsulated and non-encapsulated somatic embryos of Kinnow mandarin (Citrus nobilis Lour × C. deliciosa Tenora)

Abstract: The aim of present investigation was to study the effect of storage conditions on percentage germination of encapsulated and non-encapsulated somatic embryos of Kinnow mandarin (Citrus nobilis Lour × C. deliciosa Tenora). Different batches of encapsulated and non-encapsulated embryos were preserved at room temperature, 4°C, in liquid nitrogen as such and by embedding in liquid paraffin. In the encapsulated somatic embryos stored at room temperature in sealed Petri plates, percentage of germination was 24.99%, but 5.55% in non-encapsulated embryos after 3 days of storage. Encapsulated embryos stored in vials containing liquid paraffin at room temperature were germinated at 18.05% after 60 days of storage, while it was 13.88% in non-encapsulated embryos after 45 days of storage. Encapsulated somatic embryos stored at 4°C in sealed Petri plates remained viable for up to 75 days with 6.94% germination, whereas non-encapsulated embryos remained viable for up to 45 days with 24.99% germination. Encapsulated embryos stored at 4°C in vials filled with paraffin germinated at 11.11% after 120 days of storage, but 5.55% in non-encapsulated embryos after 90 days of storage. Encapsulated and non-encapsulated embryos stored in liquid nitrogen showed 58.33 and 51.38% survival, respectively, after 7 months of storage. The plantlets developed from these embryos were transplanted after acclimatization and are growing normal.

Characterization of an Anti-Dermatophyte Cream from Zataria multiflora Boiss.

Abstract: Throughout the world, there has been an increasing incidence of fungal infections, and because of drug resistance and toxicity associated with long-term treatment with antifungal drugs search for new drugs to treat fungal infections is ongoing. The aim of this study was to evaluate the physicochemical properties and stability of creams containing different concentrations of Zataria multiflora extract as anti-dermatophyte preparations. First, the minimum inhibitory concentration (MIC) of methanolic extract of aerial parts of Z. multiflora was assayed against various dermatophytes by in vitro tube dilution technique (MIC=0.5%). To select the best cream formulation, one general formula of cleansing cream was considered and then corrected. The best base formula was chosen according to its monotonousness, straightness and external attractiveness. Formulations containing 1, 2 or 3% of the plant extracts were prepared. Finally, a cream containing 10% bees wax, 58.8% liquid paraffin, 1.2% hard paraffin, 5% spermaceti, 1% borax, 1.4% tween 80, 0.15% methyl paraben, 0.15% lactic acid, 0.05% propyl paraben, 2% Zataria extract and water was chosen as the best formulation. The final product was a W/O cream with suitable appearance and desirable physicochemical stability.

A randomised trial of liquid paraffin versus lactulose in the treatment of chronic functional constipation in children

Abstract: Liquid paraffin has been suggested as a good laxative comparing to lactulose as a treatment option in pediatric constipation. This study was performed to compare liquid paraffin with lactulose in pediatric constipation. A total of 247 patients (127 males and 120 females) aged 2-12 years (mean 4.1 ± 2.7 years) with chronic functional constipation were included in an 8 week, randomized, controlled trial. After faecal disimpaction, patients received oral liquid paraffin (1-2 cc/kg/day) or lactulose (1-2 cc/kg/day). Primary outcome measures were: defecation and encopresis frequency per week and successful treatment after 8 weeks. Success was defined as a defecation frequency ≥ 3 per week and encopresis ≤ 1 every two weeks. Secondary outcome measures were side effects during 8 weeks of treatment. A significant increase in defecation frequency, liquid paraffin group, 3 pre, versus, 12 post treatment per week and lactulose group: 3 pre, versus 8 post, per week was found. A significant decrease in encopresis frequency, liquid paraffin: 10 pre, versus 1 post per week; lactulose: 9 pre, versus 3 post per week, was found in both groups. However success was significantly higher in the liquid paraffin group (85%) compared with the lactulose group (29%). Liquid paraffin patients reported less abdominal pain, straining and pain at defecation than children using lactulose. Liquid paraffin is more effective than lactulose in the treatment of chronic functional constipation of childhood. It provided a higher success rate with fewer side effects. Liquid paraffin should be the laxative of first choice in childhood functional constipation.

Development of a microfluidic biosensor for detection of environmental mycobacteria

Abstract: In this paper, we describe the development of a microfluidic culture-based biosensor for detecting mycobacteria in environmental samples. The biochips rely upon the unique paraffinophilic (i.e., wax-loving) nature of mycobacteria to rapidly and selectively differentiate them from non-target microorganisms. A new method of depositing and patterning paraffin was developed to fabricate the prototype biosensors using Opticlear™ as solvent to generate liquid paraffin and pattering with positive photoresist lift-off. The prototype biochips were experimentally tested to demonstrate the concept of rapid and selective detection of mycobacteria using pure cultures and epifluorescence microscopy to visualize microorganisms on the surface. Our successful demonstration of the culture-based biochip technology presents an alternative approach for developing new technology to track microorganisms in complex environmental samples. A microfluidic chip to selectively culture mycolic acid containing actinomycetes from environmental samples will improve screening for mycobacteria to protect public health as well as screening for mycobacteria to reduce the costs associated with treating nocardiafoam at sewage treatment plants.

Optically functional film

Abstract: An optically functional film provided at its outermost surface with an antifouling layer that simultaneously attains imperviousness to fingerprint, imperviousness to marking ink, slipperiness and water repellency The optically functional film is one comprising a substratum, an optically functional layer superimposed on the substratum and an antifouling layer superimposed on the optically functional layer, wherein the antifouling layer exhibits element proportions of 025 to 10 Si/C, meaning a ratio of silicon element (Si) to carbon element (C), and 010 to 10 F/C, meaning a ratio of fluorine element (F) to carbon element (C), and the antifouling layer has the following properties: (a) liquid paraffin contact angle of 65° or greater and liquid paraffin fall angle of 15° or below, (b) black marking ink contact angle of 35° or greater and black marking ink fall angle of 15° or below, and (c) dynamic friction coefficient of below 015

Lightweight calcium carbonate, process for producing the same, and printing paper containing the same

Abstract: The light calcium carbonate in the form of microparticle aggregate of the present invention has a BET specific surface area not smaller than 10 m 2 /g and not larger than 25 m 2 /g, a pore volume of 005 cm 3 /g or larger for pores having a pore diameter of 0 to 1000 Å as determined by the nitrogen adsorption method, and a pore volume ratio of 25% or more for pores having a pore diameter of 250 Å or smaller based on the total pore volume as determined by the nitrogen adsorption method, and shows an oil absorption of 100 cc/100 g or more as determined by using liquid paraffin By using this light calcium carbonate as a filler of printing paper, superior ink absorbing property and opacity (especially opacity after printing) can be imparted to the printing paper

Effect of cyclodextrins on physico-chemical and release properties of Eudragit RS 100 microparticles containing glutathione

Abstract: The objective of this work was to develop a novel microparticulate system based on the mucoadhesive polymer Eudragit-RS 100 and cyclodextrins (CDs), potentially useful for the oral administration of Glutathione (γ–glutamylcysteinylglycine, GSH). For this purpose, an oil-in-oil (O/O) emulsion-solvent evaporation method was used for the preparation of microparticles (MPs) containing GSH alone or together with one of the following CDs: α-, β-, γ-, methyl-β-(Me-β-), hydroxypropyl-β-(HP-β-) or sulfobutylether-β-cyclodextrin (SBE7m-β-CD). MPs were obtained by emulsifying a mixture of Eudragit RS 100, GSH, CD and magnesium stearate in acetone or acetonitrile with a mixture of liquid paraffin and Span 80. Size, encapsulation efficiency, and drug release of the prepared MPs were evaluated. The results clearly indicated that all the examined properties were dependent on the water-miscible solvents and CD used. In particular, MPs prepared by using acetone or acetonitrile showed different size distributions with mean diameters in the ranges 82–350 and 15–22 μm, respectively. Moreover, encapsulation efficiency values were found to be high in all cases (71–99%) and was significantly affected by the CD type. The GSH release rates were evaluated employing dissolution media with different pH values (1.2, 6.8 and 7.4) and the following rank order was obtained for MPs prepared using acetone: MPs incorporating Me-β-CD > MPs without CD > MPs incorporating the remaining CDs. On the other hand, MPs prepared using acetonitrile gave the highest GSH release rate. Finally, stability of GSH encapsulated in MPs containing HP-β-CD to enzymatic attack by pepsin A, α-chymotrypsin, and γ-glutamyltranspeptidase was also investigated.

Preclinical Investigation of the Topical Administration of Phenserine: Transdermal Flux, Cholinesterase Inhibition, and Cognitive Efficacy

Abstract: Phenserine (PS) was designed as a selective acetylcholinesterase (AChE) inhibitor, with a tartrate form (PST) for oral administration in mild to moderate Alzheimer's disease (AD). Recent phase 3 trials of PST in Europe indicate that any clinically relevant activity of PST may be limited by its duration of action. Like many oral drugs, bioavailability and plasma concentrations of PST are regulated by hepatic and gastrointestinal first-pass effects. To minimize the kinetic limitations of first-pass metabolism, transdermal formulations of PS and PST (ointment/patch) were developed and characterized in vitro and in vivo. Initial in vitro kinetic characterization of PS or PST formulations used a diffusion cell chamber and skin samples isolated from hairless mice. Liquid paraffin and fatty alcohol/propylene glycol (FAPG) were found to be suitable vehicles for ointment formulation. Addition of a penetration enhancer, 1-[2-(decylthio)ethyl]-azacyclopentane-2-one (HPE-101), improved stratum corneum permeability. Application of the optimal formulation of PS/HPE-101/FAPG to the shaved back of rats resulted in significantly lowered plasma and brain AChE activities and improved cognitive performance in animals with scopolamine-induced cognitive impairment. These results suggest that the transdermal application of AChE inhibitors may represent an effective therapeutic strategy for AD. Particular benefits over oral therapies might include avoiding first-pass metabolic effects and improved dosing compliance.

Sustained release microspheres of diclofenac sodium using PEGylated rosin derivatives.

Abstract: The PEGylated derivatives of rosin-PD-1 and PD-2 synthesized and characterized earlier () were investigated as potential materials for sustained release microsphere prepared by emulsion solvent evaporation method using diclofenac sodium (DCS) as model drug. All the microspheres exhibited smooth surfaces intercepted by pores; their sizes (d90) ranged between 11–24 μm. The entrapment efficiency (< 80%) of the microspheres increased proportionally with derivative concentration. Presence of solvent like isopropyl alcohol or dichloromethane rendered the microspheres with large sizes but with reduced drug entrapment. Microspheres with small size were obtained at an optimum viscosity of liquid paraffin; any change lead to increase in the particle size. Magnesium stearate was found to be most suitable detackifier in the present system. The drug release was directly related to the particle size—small sized microspheres released drug at a faster rate. The dissolution data complied with Higuchi equation while the me...

Inner wall heat-preservation coating

Abstract: The heat insulating paint for inner wall consists of acrylate emulsion 25-35 wt%, wetting dispersant 2-5 wt%, liquid paraffin 3-5 wt%, hollow bead 10-20 wt%, calcium bentonite 0.5-2.0 wt%, talcum powder 5-10 wt%, titanium white powder 10-20 wt%, buffering agent 0.5-1.5 wt%, thickener 5-20 wt%, hydrotalcite 4-8 wt%, magnesium sulfate 5-10 wt% and water 10- 20 wt%. It features its hydrotalcite and magnesium sulfate components possessing infrared absorbing and blocking performance. The heat insulating paint for inner wall possesses infrared absorbing and blocking performance and high heat insulating effect.

The effect of particle properties on the semisolid spreadability of pharmaceutical pastes

Abstract: The effect of different shapes and size solids and varying solid content added to semisolid base containing Eucerin® and liquid paraffin on the spreadability of obtained pastes were evaluated. Zinc oxide, salicylic acid, acetyl salicylic acid, and sodium chloride) were used as model solids for different shape and size. The samples were tested by extensometer, and the mean values of spread surface for at least three samples were plotted against the exerted weights on the extensometer's upper plate. The results show that, the semisolid spreadability decreased significantly ( P <0.05) as the powder level in the paste increased and decreased by decreasing the particle size of the solids. The results also illustrate that the particle shapes significantly ( P <0.05) affect semisolid spreadability.

Optical functional film

Abstract: An optical functional film having an antifouling layer, at an outermost surface, which simultaneously satisfies the anti-fingerprint property, the anti-magic marker property, slippability and water repellency. The optical functional film has: a substrate, an optical functional layer formed on the substrate, and an antifouling layer formed on the optical functional layer and having a ratio Si/C between a silicon element (Si) and a carbon element (C) of 0.25 to 1.0, a ratio F/C between a fluorine element (F) and a carbon element (C) of 0.10 to 1.0 at a surface, and the following characteristics: a. a contact angle of a liquid paraffin is not less than 65° and a falling angle of the liquid paraffin is not more than 15°; b. a contact angle of a black magic marker is not less than 35° and a falling angle of the black magic marker is not more than 15°; and c. a dynamic friction coefficient is less than 0.15.

Determination of Tetrachloroethylene and Other Volatile Halogenated Organic Compounds in Oil Wastes by Headspace SPME GC–MS

Abstract: Oil wastes and slops are complex mixtures of hydrocarbons, which may contain a variety of contaminants including tetrachloroethylene (perchloroethylene, PCE) and other volatile halogenated organic compounds (VHOCs). The analytical determination of PCE at trace levels in petroleum-derived matrices is difficult to carry out in the presence of large amounts of hydrocarbon matrix components. In the following study, we demonstrate that headspace solid-phase microextraction (HS-SPME) combined with GC–MS analysis can be applied for the rapid measurement of PCE concentration in oil samples. The HS-SPME method was developed using liquid paraffin as matrix matching reference material for external and internal calibration and optimisation of experimental parameters. The limit of quantitation was 0.05 mg kg−1, and linearity was established up to 25 mg kg−1. The HS-SPME method was extended to several VHOCs, including trichloroethylene (TCE) in different matrices and was applied to the quantitative analysis of PCE and TCE in real samples.

Swertia densifolia leaf extract as a dose-dependant attractant or repellent for Apis florea

Abstract: SummaryLeaf extract of an Indian medicinal plant, Chirayata, Swertia densifolia (Griseb.) (Gentianaceae), known to show attractant and repellent properties towards Apis cerana, has been shown to possess similar properties towards Apis florea. Formulations of the extract in liquid paraffin at concentrations of up to 125 mg/ml were repellent and those at higher concentrations were attractant. Beekeepers might be able to develop lures or repellent formulations based on these findings.