The release through silicone rubber membranes of benzocaine suspended in carbomer hydrogels containing different concentrations of low molecular weight polysols (ethylene glycol, propylene glycol, glycerol, and sorbitol) was studied to establish general principles and procedures for control of the effects on percutaneous absorption caused by changes in drug solubility and/or diffusivity in the vehicle. The effect of the additives on the release is expressed in terms of the relative released amount, i.e., the ratio, Q/Qw, of the amount of drug released from each additive-containing gel to the amount released at the same time from the additive-free gel. The experimental Q/Qw values are correlated with values calculated by a simple equation involving known or readily measurable parameters such as the drug concentration in the gel, the drug solubility in the pure liquid phase, and the viscosity of this phase. Derivation of such a relationship from a known equation describing the vehicle-controlled relase of suspended drugs was possible because an inverse proportionality was observed between drug diffusivity in the gels and the viscosity of the respective solvents. This relationship is interpreted with respect to current theories on drug diffusion in diluted gels.

Experimental data on release of benzocaine from a series of hydrophilic gels were used for the evaluation of a new method for determining the diffusion coefficient of drugs in semisolid vehicles. The values of D, the drug diffusivity in the vehicle, and of R, the diffusional resistance of the membrane interposed between releasing and receiving phase, resulted from a fit of the experimental release data to theoretical data generated by numerical analysis of a vehicle-membrane controlled diffusional model. Comparison of the computed D (and R) values with values obtained by different routes, or with literature data, showed the method to be conducive to rather accurate estimates of these parameters, in cases where the requirements of the theoretical model were fulfilled by the experimental system. The results are discussed in terms of validity, accuracy and applicability of the proposed method. Results obtained from systems not complying with the diffusional model are also discussed and evaluated. The computations were executed with the aid of an IBM 370/168 computer.

The interaction of four alkyl-p-aminobenzoates with human intact keratin (HIK), human delipidised keratin (HI)K) and animal (wool) keratin (AK) was investigated at 37øC in water and in a saturated high- molecular weight hydrocarbon (pristane). The study had the purpose of assessing on a quantitative basis the skin substantivity of molecules of possible use as sunscreens. In all cases linear sorption isotherms, indicative of a constant partition of the esters between substrates and solution were obtained: the slopes of the isotherms, K, constitute a measure of the relative 'affinity' of a solute for a given substrate. The study of the time-course sorption of ethyl p-aminobenzoate by the three substrates in either solvent evidenced a profound influence on sorption of hydration of HIK. A second parameter characterising the interaction, Sk = K $s (where Ss is the solubility of the interacting substance in the solvent) was also assessed and related to the maximum binding capacity of each substrate for the esters. The influence of solvent, molecular weight and solubility of interacting substance, structure of substrate, etc., on K and Sk are discussed. Possible effects of ad- and absorption by horny layer constituents on skin penetration are also discussed.

The in vitro release of benzocaine, suspended in an aqueous gel, through silicone rubber membranes was studied to test an extension of existing mathematical models. The theoretical treatment proposed is intended for experimental systems involving release, through a non-porous membrane, of a drug whose concentration is a few times (larger than or equal to 3) greater than its solubility in the vehicle. For either micronized (2micrometer) or macrosize (125 micrometer) drug, the Q (amount released) versus t1/2 (time1/2) plots were not linear until substantial time had elapsed. Excellent agreement was found between the experimental points and theoretical plots, generated by a computer fit to experimental data of an equation derived from a reported vehicle-boundary diffusion layer model. The values of the solubility and of the diffusion layer model. The values of the solubility and of the diffusion coefficient of benzocaine in the gel, calculated by the present mathematical treatment from release data, were in agreement with literature data. The particle size of released benzocaine did not influence the release pattern, thus confirming release in the present conditions to be diffusion rather than dissolution controlled. The present method is applicable for determining the solubility and diffusion coefficient of drugs in vehicles in cases not contemplated in current release theories.

The applicability of a permeation rate technique to the determination of drug-macromolecule interactions was tested by measuring the extent of interaction of methylparaben with polyvinylpyrrolidone and polysorbate 80. Results were in agreement with literature data obtained by other techniques. The present method, although restricted to permeant molecules that diffuse readily through nonporous nylon membranes, is of potential value for investigations of drug binding by macromolecules not retained by porous dialysis membranes.

The effect of drug concentration on in vitro release of salicylic acid from a series of ointment bases was investigated. The bases were commercially available vehicles containing lanolin and/ or lanolin derivatives and formed stable water-in-oil or oil-in-water emulsions. Release tests were performed both with the anhydrous and with the emulsion forms of the bases, at varying salicylic acid concentrations (0.5–5.0% w/v), and involved the use of silicone rubber membranes. The release of salicylic acid from the bases was in agreement with a reported diffusional model. A linear relationship between release rate, q/√t, and drug concentration in ointments existed when the drug was completely dissolved in the vehicles. The method reported is of potential utility for the determination of drug solubility in ointments and for the evaluation of the optimal drug concentration in topical vehicles. The relationships among type of vehicle, drug concentration, drug solubility, and release rate are discussed.

Chemischer InformationsdienstVolume 4, Issue 9 Isocyclic Compounds ChemInform Abstract: SYNTH. UND PHARMAKOLOGISCHE WIRKUNG EINIGER PHENOXY-ALKYLCARBONSAEUREESTER DES CHLORPHENESINS G. ARMANI, G. ARMANISearch for more papers by this authorF. BOTTARI, F. BOTTARISearch for more papers by this authorM. F. SAETTONE, M. F. SAETTONESearch for more papers by this authorM. F. SERAFINI, M. F. SERAFINISearch for more papers by this author G. ARMANI, G. ARMANISearch for more papers by this authorF. BOTTARI, F. BOTTARISearch for more papers by this authorM. F. SAETTONE, M. F. SAETTONESearch for more papers by this authorM. F. SERAFINI, M. F. SERAFINISearch for more papers by this author First published: February 27, 1973 https://doi.org/10.1002/chin.197309223Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume4, Issue9February 27, 1973 RelatedInformation

AbstractAus den Methylketonen (I) erhält man über eine Bromierung zu (II) und nachfolgende Hydrolyse die Aryl‐hydroxymethyl‐ketone (III), aus denen mit Phosgen und Ammoniak die Carbaminate (IV) entstehen.

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSynthesis and biological activity of some 4-aryl-substituted 4-oxazolin-2-onesFrancesco Bottari, Enrico Nannipieri, Marco F. Saettone, and Maria F. SerafiniCite this: J. Med. Chem. 1972, 15, 1, 39–42Publication Date (Print):January 1, 1972Publication History Published online1 May 2002Published inissue 1 January 1972https://doi.org/10.1021/jm00271a011Request reuse permissions Article Views132Altmetric-Citations6LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (439 KB) Get e-Alertsclose Get e-Alerts

A detailed analysis of the hydrocarbon fractions from the extracts of 21 ferns belonging to 13 families was carried out. n-Alkanes from C24 to C35 and triterpenoid hydrocarbons of the hopane series were identified. The taxonomic value of these results is discussed.

Chemischer InformationsdienstVolume 3, Issue 33 Isocyclic Compounds ChemInform Abstract: DIE THERMISCHE DISSOZIATION VON SULFONYLHARNSTOFFEN 2. MITT. DIE DISSOZIATION VON VIER N- UND N(1)-SUBSTITUIERTEN SULFONYLHARNSTOFFEN IN VERSCHIEDENEN MEDIEN F. BOTTARI, F. BOTTARISearch for more papers by this authorB. GIANNACCINI, B. GIANNACCINISearch for more papers by this authorE. NANNIPIERI, E. NANNIPIERISearch for more papers by this authorM. F. SAETTONE, M. F. SAETTONESearch for more papers by this author F. BOTTARI, F. BOTTARISearch for more papers by this authorB. GIANNACCINI, B. GIANNACCINISearch for more papers by this authorE. NANNIPIERI, E. NANNIPIERISearch for more papers by this authorM. F. SAETTONE, M. F. SAETTONESearch for more papers by this author First published: August 15, 1972 https://doi.org/10.1002/chin.197233255Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume3, Issue33August 15, 1972 RelatedInformation