Stereochemical Characterization of the Diastereomers of the Phenobarbital N-β-D-Glucose Conjugate Excreted in Human Urine

The absolute configuration of the N--D-glucoside metabolites of phenobarbital was determined by methylation of the diastereomers to make mephobarbital N--D-glucosides, followed by oxidative removal of glucose to give the optical isomers of mephobarbital. Following a single oral dose of phenobarbital to two male subjects, both phenobarbital N--D-glucosides were excreted in the urine. The absolute configuration (C-5 position) of the major phenobarbital N--D-glucoside excreted in the urine was the S form. A pronounced stereoselective formation and/or urinary excretion occurs for the N-glucoside conjugates of phenobarbital in humans.     

Tumor-Targeted Gene Delivery Using Poly(Ethylene Glycol)-Modified Gelatin Nanoparticles: <Emphasis Type="Italic">In Vitro</Emphasis> and <Emphasis Type="Italic">in Vivo</Emphasis> Studies

Purpose To develop safe and effective systemically administered nonviral gene therapy vectors for solid tumors, DNA-containing poly(ethylene glycol)-modified (PEGylated) gelatin nanoparticles were fabricated and evaluated in vitro and in vivo.Methods Reporter plasmid DNA encoding for -galactosidase (pCMV-) was encapsulated in gelatin and PEGylated gelatin nanoparticles using a water-ethanol solvent displacement method under controlled pH and temperature. Lewis lung carcinoma (LLC) cells in culture were transfected with the pCMV- in the control and nanoparticle formulations. Periodically, the expression of -galactosidase in the cells was measured quantitatively using an enzymatic assay for the conversion of o-nitrophenyl--d-galactopyranoside (ONPG) to o-nitrophenol (ONP). Qualitative expression of -galactosidase in LLC cells was observed by staining with 5-bromo-4-chloro-3-indolyl--d-galactopyranoside (X-gal). Additionally, the plasmid DNA-encapsulated gelatin and PEGylated gelatin nanoparticles were administered intravenously (i.v.) and intratumorally (i.t.) to LLC-bearing female C57BL/6J mice. At various time points postadministration, the animals were sacrificed and transgene expression in the tumor and liver was determined quantitatively by the ONPG to ONP enzymatic conversion assay and qualitatively by X-gal staining.Results Almost 100% of the pCMV- was encapsulated in gelatin and PEGylated gelatin nanoparticles (mean diameter 200 nm) at 0.5% (w/w) concentration. PEGylated gelatin nanoparticles efficiently transfected the LLC cells and the -galactosidase expression, as measured by the ONPG to ONP enzymatic conversion assay at 420 nm absorbance, increased starting from 12 h until 96 h post-transfection. The efficient expression of LLC cells was also evident by the X-gal staining method that shows blue color formation. The in vivo studies showed significant expression of -galactosidase in the tumor following administration of DNA-containing PEGylated gelatin nanoparticles to LLC-bearing mice by both i.v. and i.t. routes. Following i.v. administration of pCMV- in PEGylated gelatin nanoparticles, for instance, the absorbance at 420 nm per gram of tumor increased from 0.60 after 12 h to 0.85 after 96 h of transfection. After i.t. administration, the absorbance values increased from 0.90 after 12 h to almost 1.4 after 96 h.Conclusions The in vitro and in vivo results of this study clearly show that a long-circulating, biocompatible and biodegradable, DNA-encapsulating nanoparticulate system would be highly desirable for systemic delivery of genetic constructs to solid tumors.     

Polyvinyl Derivatives as Novel Interactive Polymers for Controlled Gene Delivery to Muscle

Purpose. DNA plasmids (pDNA) can be taken up by and expressed in striated muscle after direct intramuscular injection. We have developed interactive polymeric gene delivery systems that increase pDNA bioavailability to muscle cells by both protecting pDNA from nucleases and controlling the dispersion and retention of pDNA in muscle tissue. Methods. A DNA plasmid, containing a CMV promoter and a -galactosidase reporter gene (CMV--gal), was injected either in saline or formulated in polyvinyl pyrrolidone (PVP) and polyvinyl alcohol (PVA) solutions. Interactions between PVP and pDNA were assessed by dynamic dialysis, Isothermal Titration Calorimetry (ITC), and Fourier-Transformed Infra Red (FT-IR) spectroscopy. Formulations (50 µl) were injected into rat tibialis muscles after surgical exposure. Immuno-histochemistry for -gal was used to visualize the sites of expression in muscle. Results. -gal expression using pDNA in saline reached a plateau while -gal expression using PVP formulations increased linearly in the dose range studied (12.5–150 µg pDNA injected) and resulted in an increase in the number and distribution of cells expressing -gal. The interaction between PVP and pDNA was found to be an endothermic process governed largely by hydrogen-bonding and results in protection of pDNA from extracellular nucleases. Conclusions. Significant enhancement of gene expression using interactive polyvinyl-based delivery systems has been observed. The improved tissue dispersion and cellular uptake of pDNA using polyvinyl-based systems after direct injection into muscle is possibly due to osmotic effects.     

Studies on the chemical constituents from the roots of <Emphasis Type="Italic">Platycodon grandiflorum</Emphasis>

Three known monodesmosidic saponins: 3-O--d-glucopyranosyl-2,3,16,23,24-pentahydroxyolean-12-ene-28-oic acid, 3-O--d-glucopyranosyl polygalacic acid, and 3-O--d-glucopyranosyl-(13)--d-glucopyranosyl polygalacic acid; and two known nonsaponin compounds: a mixed compound of n-tetracosanoic acid (lignoceric acid), n-hexacosanoic acid (cerotic acid), and n-octacosanoic acid, and -monopalmitin; were isolated for the first time from the root of Platycodon grandiflorum A. DC. together with another seven known compounds: platycoside G₁ (3-O--d-glucopyranosyl-(16)--d-glucopyranosyl-(16)--d-glucopyranosyl-2,3,16,23,24-pentahydroxyolean-12-ene-28-oic acid 28-O--d-xylopyranosyl-(14)--l-rhamnopyranosyl-(12)--l-arabinopyranoside), deapio-platycodin D, Polygalacin D, deapio-platycodin D₃, platycoside A, -spinasterol, and -spinasteryl-3-O--d-glucopyranoside. Alkaline hydrolysis of platycoside G₁ afforded a new monodesmosidic prosaponin: 3-O--d-glucopyranosyl-(16)--d-glucopyranosyl-(16)--d-glucopyranosyl-2,3,16,23,24-pentahydroxyolean-12-ene-28-oic acid. Their chemical structures were elucidated on the basis of their spectral data and chemical evidence.     

Isolation and identification of histamine-release inhibitors from Pistacia weinmannifolia J. Pisson ex. Franch

Seven histamine-release inhibitors were isolated from Pistacia weinmannifolia J. Pisson ex. Franch. They were identified as gallic acid, 3-O-galloylquinic acid, methyl gallate, ethyl gallate, penta-O-galloyl--d -glucopyranoside, myricetin 3-O--l-rhamnopyranoside, and myricetin- 3-O-(3-O-galloyl)--l-rhamnopyranoside. These compounds suppressed the compound 48/80-induced histamine release from rat peritoneal mast cells.     

Disparity of in Vitro and in Vivo Oleic Acid-Enhanced β-Estradiol Percutaneous Absorption Across Human Skin

The permeation enhancing property of 5% oleic acid in ethanol on -estradiol was investigated in vitro and in vivo using symmetrical and asymmetrical side-by-side diffusion cells and the human skin sandwich flap, respectively. -Estradiol permeability in vitro and in vivo was similar in 75% ethanol (ETOH). Oleic acid (5%) did not alter -estradiol permeability in vivo but increased permeability sixfold in vitro in symmetrical diffusion cells. -Estradiol permeability in oleic acid was not different from that in ETOH, however, using asymmetrical diffusion cells. Stratum corneum-to-vehicle partition coefficients of -estradiol in the vehicles were similar, yet fourfold more steroid was detected in skin biopsies from the in vitro symmetrical diffusion cells. Thus, oleic acid increased -estradiol permeability in vitro only when skin was equilibrated with fatty acid. Attention to in vitro diffusion cell design and its relevance in vivo is critical to defining the mechanisms of enhanced solute permeation.     

Quantitative determination by HPLC of urinary 6β-hydroxycortisol,an indicator of enzyme induction by rifampicin and antiepileptic drugs

Summary A method for determination of 6-hydroxycortisol in urine by means of high performance liquid chromatography is described. After extraction of 10–30 ml aliquots of urine with ethylacetate, separation is accomplished on a silica gel column (30 cm, Lichrosorb Si 100) with a special two-phase four-component eluent of methylene chloride, n-hexane, ethanol and water. Complete separation of - and-isomers requires 15 to 20 min. For routine determinations precolumn cleaning by backflush permits injections of samples at minimum time intervals. For quantitative determinations, each injection should contain at least 0.05–0.5 µg of 6-hydroxycortisol, depending on the detector employed. The mean excretion rate in healthy male adults (26–40 years) was 273 µg/day (SD=74.5; n=12). In patients on long term mono-therapy with rifampicin, 6-hydroxycortisol excretion had risen fourfold (1166 µg/d; SEM=248; n=7), paralleling the known enzyme-inducing effect of rifampicin. The relatively smaller increase to 498 µg/d observed in patients receiving triple therapy with rifampicin, isoniazid and ethambutol points to possible inhibition by isoniazid. The greatest stimulation of 6-hydroxycortisol excretion (2352 µg/d) was found in patients receiving antiepileptic therapy (phenytoin and/or carbamazepine and other drugs). The HPLC technique for 6-hydroxycortisol proved to be a tool routinely applicable to non-invasive evaluation of drug metabolizing enzyme activity in man.     

Protection Afforded by Maltosyl-β-cyclodextrin Against α-Chymotrypsin-Catalyzed Hydrolysis of a Luteinizing Hormone-Releasing Hormone Agonist, Buserelin Acetate

Purpose. The present study addresses how maltosyl--cyclodextrin (G₂--CyD) impacts upon the -chymotrypsin-catalyzed hydrolysis of buserelin acetate, an agonist of luteinizing hormone-releasing hormone with emphasis upon the direct effect of G₂--CyD on the activity of the protease. Methods. Kinetic and solubility studies were performed in isotonic phosphate buffer (pH 7.4) at 25°C and 37°C. The interaction of -chymotrypsin with G₂--CyD in the buffer solution was examined by differential scanning calorimetry. Results. G₂--CyD decelerated the -chymotrypsin-catalyzed hydrolysis of buserelin acetate to give the 1–3 tripeptide and the 4–9 hexapeptide fragments. This deceleration can be explained solely by a nonproductive encounter between a complex of the substrate with G₂--CyD and the protease at relatively low CyD concentrations, while the direct inhibitory effect of G₂--CyD on the proteolytic activity made a considerable contribution to the overall deceleration of the hydrolysis at higher CyD concentrations. Calorimetric studies indicate the presence of intermediate states in the thermal unfolding of -chymotrypsin, simultaneously accompanied by the autolysis. By contrast, a two-state thermal unfolding of -chymotrypsin was observed in the presence of G₂--CyD, suggesting reduced proteolytic activity upon binding to G₂--CyD. Conclusions. These results suggest that G₂--CyD at higher concentrations inhibits the proteolytic action of -chymotrypsin through direct interaction with the protease, as well as through the formation of a non-productive complex with the substrate.     

The Interaction of Charged and Uncharged Drugs with Neutral (HP-β-CD) and Anionically Charged (SBE7-β-CD) β-Cyclodextrins

Purpose. The objective of this work was to determine the role that charge might play in the interaction of charged and uncharged drugs with neutral (2-hydroxypropyl--cyclodextrin, HP--CD) and anionically charged (SBE7--CD) modified -cyclodextrins. SBE7--CD is a sulfobutyl ether, sodium salt, derivative variably substituted on the 2-, 3- and the 6-positions of -cyclodextrin. The number seven refers to the average degree of substitution. Methods. The binding of the acidic drugs, indomethacin, naproxen and warfarin and the basic drugs, papaverine, thiabendazole, miconazole and cinnarizine with the two cyclodextrins was determined at 25°C as a function of pH and cyclodextrin concentration by the phase-solubility method. Results. Except for miconazole and cinnarizine (A_P-type diagrams), all other materials studied displayed A_L-type diagrams. By comparing the binding constants of both the charged and uncharged forms of the same drugs to both HP--CD and SBE7--CD, the following conclusions could be drawn. The binding constants for the neutral forms of the drugs were always greater with SBE7--CD than with HP--CD. For the anionic agents, the binding constants between SBE7--CD and HP--CD were similar while the binding constants for the cationic agents with SBE7--CD were superior to those of HP--CD, especially when compared with the neutral form of the same drug. Conclusions. A clear charge effect on complexation, attraction in the case of cationic drugs and perhaps inhibition in the case of anionic drugs, was seen with the SBE7--CD.     

Design and Evaluation of an Osmotic Pump Tablet (OPT) for Chlorpromazine Using (SBE)7m-β-CD

Purpose. The purpose of this study was to develop a controlled-porosity osmotic pump tablet (OPT) which exhibits pH-independent release profiles for a basic drug using a sulfobutyl ether--cyclodextrin, (SBE)_7m--CD, which acts as both a solubilizer and as an osmotic agent. Methods. Chlorpromazine free base (CLP) was chosen as a model drug for this study. The release of CLP from osmotic pump tablets was studied in vitro. In vivo absorption of CLP from the OPT was evaluated in male beagle dogs. Results. The CLP release profile from an OPT prepared from a core tablet composed of a 1:10 molar ratio of CLP to (SBE)_7m--CD was pH-independent, and was controlled by modulating the membrane thickness of the OPT. Another cyclodextrin, hydroxypropyl--cyclodextrin (HP--CD), and a sugar mixture of lactose and fructose resulted in pH-dependent release at the same molar ratio. An in vivo absorption study in dogs with an OPT containing (SBE)_7m--CD correlated very well with the in vitro release profiles using the Japanese Pharmacopoeia dissolution method. Conclusions. In addition to serving as a solubilizer and osmotic agent, (SBE)_7m--CD can also serve as the controlling agent for pH independent release of CLP from OPTs. This system successfully modified the in vivo input rate of CLP without compromising oral bioavailability.     

Differential effects of Bay k 8644, a presumed calcium channel activator,on sinoatrial nodal and ventricular automaticity of the dog heart

Summary In 10 healthy volunteers the effects of acute increases in concentrations of catecholamines in plasma induced by dynamic exercise (on a bicycle for 15 min at 80% of maximum heart rate) on lymphocyte ₂-adrenoceptor density (determined by (±)-¹²⁵iodocyanopindolol binding) and-responsiveness (determined by cyclic AMP responses to 10 mol/l isoprenaline) were investigated. Immediately after exercise plasma catecholamines were increased about 4-fold; concomitantly receptor density and cyclic AMP production increased 55% and 65%, respectively. One hour after exercise -adrenoceptor density and plasma catecholamines had reached values, which were not significantly different from preexercise values, while cyclic AMP production was significantly diminished. It is concluded, that acute increases in concentrations of catecholamines in plasma may increase -adrenoceptor density and — responsiveness in human lymphocytes.     

Preparation of Heptakis(2,6-di-O-ethyl)-β-cyclodextrin and Its Nuclear Magnetic Resonance Spectroscopic Characterization

Heptakis(2,6-di-O-ethyl)--cyclodextrin (DE--CyD) was prepared and its ¹H and ¹³C nuclear magnetic resonance (NMR) signals in DMSO-d₆ were unequivocally assigned by two-dimensional COSY and ROESY. The results on ¹H coupling constants indicated that all ethylated glucose units are in a ⁴C₁ chair conformation. The average spin-lattice relaxation times (T ₁) of ring carbons of DE--CyD were only slightly shorter, and their standard deviations from the mean T _l value were larger, than those of -cyclodextrin (-CyD) and heptakis(2,6-di-O-methyl)--cyclodextrin (DM--CyD), suggesting the presence of slightly irregular internal motion in the ethylated glucose units. The temperature dependence of chemical shift of DE--CyD in DMSO-d₆ suggested that the C3 hydroxyl protons may participate as proton donor in the intramolecular hydrogen bond to the C2 ethoxyl groups of neighboring glucose, and the intramolecular hydrogen bond of DE- and DM--CyDs is much stronger than that of -CyD, suggesting the stable macrocyclic ring structure of DE--CyD.     

Effects of deuterium substitution on the chronotropic responses to some sympathomimetic amines in the isolated rat atria

Summary In spontaneously beating rat atria the potencies for the chronotropic effects of the following deuterated phenylethylamine derivatives were higher than the potencies of the corresponding non-substituted (protio-) amines: ,,d₂--phenylethylamine; ,,,-d₄-p-tyramine; ,,,-d₄-m-tyramine; ,,-d₃-p-octopamine. In contrast, ,,-d₃-noradrenaline and ,,-d₃-m-octopamine were equipotent with the corresponding protio-amines. Experiments performed in atria depleted of endogenous noradrenaline by pretreatment with reserpine and in atria exposed to the monoamine oxidase (MAO) inhibitor pargyline indicated: a. p-octopamine had both direct and indirect effects, but the chronotropic responses to p-octopamine in tissues with normal MAO activity depended mostly on the direct action of the amine; deuterium substitution enhanced the indirect component of action of p-octopamine; b. m-octopamine possessed considerable indirect effects while d₃-m-octopamine behaved as an amine of direct action. The substitution of deuterium for hydrogens in the -carbon of the alkyl-side chain of phenylethylamines decreases the rate of deamination by MAO. Therefore, the results obtained with all the amines, except for m-octopamine and ,,p-d₃-m-octopamine, could be interpreted in terms of the direct, indirect or mixed action of those compounds and/or of the influence that MAO activity has on the chronotropic responses to these amines. The results obtained with protio-and deuterio-m-octopamine suggested that deuterium substitution, either at the - or the -carbon, can alter some other mechanisms in addition to the enzymatic deamination.Career Investigator on leave of absence from the Consejo de Investigaciones Cientificas y Técnicas, ININFA, Junín 956, 5°P, RA-1113 Buenos Aires, Argentina Send offprint requests to S. M. Celuch     

Isolation of a Novel Morphinan 3-O-Diglucuronide Metabolite from Dog Urine

Following oral administration of the narcotic antagonist nalmefene [17-(cyclopropyl-methyl)-4,5-epoxy-6-methylenemorphinan-3,14-diol] labeled with ¹⁴C to the dog, approximately 50% of the dose was excreted in the urine as a highly polar water-soluble conjugate. Although this major metabolite could be hydrolyzed with -glucuronidase to yield nalmefene, the intact conjugate was chromatographically more polar on reversed-phase high-performance liquid chromatography (HPLC) than authentic nalmefene 3-O-glucuronide. Milligram quantities of the metabolite were subsequently isolated and subjected to fast atom bombardment (FAB) mass spectral and nuclear magnetic resonance (NMR) analyses. The conjugate was identified as nalmefene 3-O--diglucuronide with a 1,2- linkage between the two glucuronic acids. It is unlikely that this novel form of conjugate is unique to nalmefene and it is probably a metabolite of other morphinans and/or similar drugs in the dog. Nalmefene 3-O-diglucuronide is not a metabolite of nalmefene in man.     

Design and Evaluation of an Osmotic Pump Tablet (OPT) for Prednisolone,a Poorly Water Soluble Drug,Using (SBE)7m-β-CD

Purpose. The purpose of this study was to develop a controlled-porosity osmotic pump tablet (OPT) for poorly water soluble drugs using a sulfobutyl ether--cyclodextrin, (SBE)_7m--CD or Captisol, which acted as both a solubilizer and as an osmotic agent. Methods. Prednisolone (PDL) was chosen as a model drug for this study. The release of PDL from osmotic pump devices and tablets was studied. In vivo absorption of PDL from OPT was evaluated in male beagle dogs. Results. PDL release from the osmotic pump tablet with (SBE)_7m--CD was complete. Another cyclodextrin, hydroxypropyl--cyclodextrin (HP--CD), and a sugar mixture of lactose and fructose resulted in incomplete release. Although PDL release from the OPT with (SBE)_7m--CD and the sugar formulation displayed mainly zero-order release characteristics, the tablet utilizing HP--CD showed apparent first-order release characteristics. An in vivo absorption study in dogs correlated very well with the in vitro release profiles using the Japanese Pharmacopoeia dissolution method. Conclusions. The present results confirm that (SBE)_7m--CD can serve as both the solubilizer and the osmotic agent for OPT of PDL, and modify the input rate of PDL without compromising oral bioavailability.     

Comparative invstigations on the duration of action of two synthetic corticotropins

Summary The duration of the adrenocorticotrophic effects of two synthetic ACTH preparations was studied in healthy volunteers. One of the hormones, ^1–24 corticotropin, was adsorbed on zinc; the other, a D-serine¹-norleucine⁴-valinamide²⁵- ^1–25 corticotropin, was thought to be more stable, owing to the replacement of the three most susceptible amino acids in the ACTH molecule. — ^1–24 corticotropin, administered intramuscularly in a dose of 1 mg, showed biological activity lasting for 28 h, an effect equal to that which may be expected of depot preparations of pituitary extracts. D-serine¹-norleucine⁴-valinamide²⁵- ^1–25 corticotropin, administered intra muscularly in a dose of 0.16 mg, had only a weak adreno corticotrophic effect, whereas intravenously the same dose produced a greater effect that persisted for nearly 8 h. After intramuscular injection of both preparations a significant difference was found between the maximum responses shown by men and women.     

Semi-synthetic digoxigenin glycosides

Conclusions Starting with digoxigenin, L-rhamnose, D-glucose, and D-xylose, the monoglycosides digoxigenin-3--L-rhamnopyranoside, 3--D-glycopyranoside, and 3--D-xylopyranoside have been synthesized in approximately 40% yield. The biosides digoxigenin 3,12-di--D-glucopyranoside and 3,12-di--D-xylopyranoside were also obtained in approximately 3% yield. The glycosides obtained possessed high cardiotonic activity.Translated from Khimiko-Farmatsevticheskii Zhurnal, No. 5, pp. 23–27, May, 1969.     

Aspartate138 is required for the high-affinity ligand binding site but not for the low-affinity binding site of the β<Subscript>1</Subscript>-adrenoceptor

The ₁-adrenoceptor two-site ligand binding hypothesis was investigated by comparing the pharmacological activities of the receptor with an Asp to Glu mutation of amino acid 138 after transient transfection into CHO cells. The high-affinity binding of (–)-[³H]-CGP12177 (pK_D=9.4) and binding inhibition by (–)-isoprenaline (pK_i=6.2), observed with Asp138-₁-adrenoceptors, were absent at Glu138-₁-adrenoceptors. (–)-[³H]-CGP12177 bound with a pK_D=7.6 to Glu138-₁-adrenoceptors and (–)-isoprenaline enhanced binding, probably allosterically. Glu138-₁-adrenoceptors compared with Asp138-₁-adrenoceptors showed a 500,000-fold decrease in cyclic AMP-enhancing potency by (–)-isoprenaline and antagonism by (–)-bupranolol (1 M) was abolished. At Glu138-₁-adrenoceptors, the agonist potency of (–)-CGP12177, compared with (–)-isoprenaline was reduced five-fold, but the antagonism by (–)-bupranolol (pK_B=7.1) was not significantly changed, compared with Asp138-₁-adrenoceptor. Thus, Asp138 of the ₁-adrenoceptor is essential for the binding of (–)-isoprenaline, (–)-bupranolol and (–)-CGP12177 to a high-affinity site, but not for the binding of (–)-CGP12177 and (–)-bupranolol to a low-affinity site.     

Enhancement of the Antiinflammatory Effect of Ethyl 4-Biphenylyl Acetate in Ointment by β-Cyclodextrin Derivatives: Increased Absorption and Localized Activation of the Prodrug in Rats

Ethyl 4-biphenylyl acetate (EBA) is a prodrug of the antiinflammatory 4-biphenylyl acetic acid (BPAA). The inclusion complexes of EBA with -cyclodextrin (-CyD), heptakis(2,6-di-O-methyl)--cyclodextrin (DM--CyD), and 2-hydroxypropyl--cyclodextrin (HP--CyD) at a molar ratio of 1:2 (EBA:cyclodextrin) were prepared and used to make hydrophilic antiinflammatory ointments. The in vitro release of EBA from the ointments was enhanced by complexation in the order of -CyD < DM--CyD HP--CyD. The improvement correlated with the improved solubility and not with the decreased diffusibility observed to occur upon the complexation of EBA. In vivo the complexation with cyclodextrin derivatives increased both the release of EBA from the vehicle and its conversion in the underlying tissue to BPAA, but the total of EBA and BPAA in the tissue was decreased. In vitro studies confirmed that the effects of cyclodextrin derivatives on the conversion were exerted indirectly. The combination of the enhanced release and of the enhanced prodrug hydrolysis by esterases in the site where the antiinflammatory action is required resulted in increased therapeutic effects. In the model of carrageenan-induced acute edema in rat paw, the complexation improved the therapeutic effects over those of EBA alone in the order of -CyD < DM--CyD < HP--CyD. HP--CyD may be a particularly useful cyclodextrin derivative since it improves the topical availability and does not irritate tissues.     

Effect of phenytoin,carbamazepine, and valproic acid on caffeine metabolism

Summary Three groups of non-smoking epileptic patients without liver disease receiving antiepileptic monotherapy have been compared with 10 healthy non-smoking volunteers. Group 1 received phenytoin (n=10), Group 2 carbamazepine (n=10) and Group 3 valproic acid (n=6). Cytochrome P-450 activity was monitored by measuring urinary 6--hydroxycortisol output and systemic antipyrine clearance.Both, 6--hydroxycortisol output and antipyrine clearance were significantly enhanced in patients on phenytoin and carbamazepine, but not in those on valproic acid. On the other hand, phenytoin alone increased the clearance of caffeine from 1.5 (controls) to 3.6 ml · min^–1 · kg^–1, and reduced its half life from 4.8 to 2.4 h. Carbamazepine and valproic acid had no effect on caffeine metabolism. The results are in keeping with the well known heterogeneity of the hepatic monooxygenase system, as phenytoin and carbamazepine induce different panels of cytochrome P-450 isoenzymes. Phenytoin treatment may impair the validity of the caffeine liver function test.