Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: KEGG:D03393 (Carbopol 934)
 103 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The electrophoretic mobility of nitrofurantoin (based on the microelectrophoresis method) has been studied in dilute dispersions of the drug. Specifically, the effect of NaCl, CaCl2 and AlCl3, pH, and a thickener, Carbopol 934, was determined. The electrophoretic mobility (mu) increases in absolute terms when the pH is raised between 3 and 9, although mu remains negative in this pH range. The variation of absolute mobility ([mu[) with NaCl concentration shows a pronounced maximum for a concentration of about 10(-4) M. However, when the concentration of CaCl2 in the medium is increased, [mu[ decreases steadily. The effect of AlCl3 concentration on the mobility is markedly influenced by the pH of the dispersing medium although a general trend is observed for mu to become more positive with increasing concentration of the salt. Finally, Carbopol 934 appears to impart an extra negative charge to the nitrofurantoin surface, since higher negative mobilities were measured in the presence of the polymer.
 ...
PMID:Electrophoretic study of nitrofurantoin in aqueous suspensions. Effect of the addition of a polymeric thickener. 197 87

An experimental investigation is described of the electrokinetic properties of nitrofurantoin. The experiments are based on measurements of electrophoretic mobility in suspensions of this drug and the calculation of its zeta potential (zeta) following two different procedures. A simple mechanism is proposed for explaining the sign of the surface charge of nitrofurantoin and its increase with the pH of the medium. The effect on zeta of changes in the concentration of NaCl, CaCl2, or AlCl3 is studied for different pH values of the suspensions. The behavior of zeta in the presence of NaCl shows evidence of Cl- adsorption on the particles, especially at low electrolyte concentrations. The AlCl3 salt was capable of reversing the sign of the surface charge, changing it to positive when a given, pH-dependent concentration was added to the suspension. The effect of this salt on zeta for different pH values was probably due to the hydrolysis of the cation Al3+. A significant increase of the negative surface charge was observed when a small amount (0.1%) of a synthetic polymer, Carbopol 934, was present in NaCl or AlCl3 systems. This appears to indicate that the large polymer molecules adsorb on nitrofurantoin particles as part of their stabilizing mechanism.
 ...
PMID:A study of the electrokinetic and stability properties of nitrofurantoin suspensions. I: Electrokinetics. 231 82

Timolol base was prepared from its maleate salt and checked for purity, pKa (9.03) and n-octanol/phosphate buffer pH 6.6 partition coefficient (1.72). The rate of swelling of sodium carboxymethylcellulose, Carbopol 934 (CP) and hydroxypropylcellulose (HPC) was examined prior to use in bioadhesive compacts with the model drug methylene blue to study their influence on device integrity and drug diffusion. A final compact containing a core of timolol base and Precirol, a bioadhesive layer of CP and HPC, and a cap of magnesium stearate gave sustained release of the drug in simulated saliva pH 6.6. After preliminary evaluation in dogs, the compact was evaluated in a panel of humans in whom it was shown that the flux of drug could be increased from 70 to 127 micrograms mm-2 h-1 by inclusion of the penetration enhancer sodium lauryl-sulphate into the core formulation.
 ...
PMID:Bioadhesive dosage form for peroral administration of timolol base. 278 Jul 57

Localized fluoride delivery to the oral cavity is important in caries prevention. However, no current marketed dosage forms deliver fluoride for an extended period. This work describes the effect of poly (methyl vinyl ether-co-maleic anhydride) mixed calcium/sodium salt (Gantrez MS), sodium carboxymethylcellulose (NaCMC), polyethylene glycol 8000 (PEG8000) and Carbopol 934 (C934) on the in vitro dissolution and ex vivo bioadhesion of sodium fluoride matrix tablets. Dissolution was studied using USP Apparatus 2 and a low volume (3.1 ml), low flow (0.5 ml/min) dissolution apparatus. In both apparatus, the percent drug dissolved at 2, 4 and 8 h was found to be statistically dependent on the fractions of Gantrez MS and NaCMC. The interaction term was significant at 2 and 4 h (probability > (t) of less than 0.05). Ex vivo bioadhesion was studied using excised bovine gingiva and a TA.XT2i Texture Analyzer. Peak bioadhesive force and work of bioadhesion were found to be statistically dependent on the fractions of Gantrez MS and NaCMC with no interaction (probability > (t) of less than 0.01). Results indicate that bioadhesive matrix fluoride tablets of these mixtures can be designed to exhibit both bioadhesive and extended release properties.
 ...
PMID:Development and evaluation of extended release bioadhesive sodium fluoride tablets. 1560 63

Studies on the effect of polymers on physicochemical properties hydrogels for topical use. Rheological parameters were tested and pharmaceutical availability of hydrocortisone from gels. Formulation of hydrogels with 1% hydrocortisone content produced on the basis of methylcellulose, carboxymethlcellulose sodium salt and Carbopol 934 P.
 ...
PMID:[Influence of polymers on hydrogels with hydrocortisone properties]. 2186 96