bluuebunny/crossref_metadata_2025 huggingface dataset:
Skin Permeation of Testosterone and its Ester Derivatives in Rats
Authors: Kim Mi-Kyeong , Lee Chi-Ho , Kim Dae-Duk
Published: July 2003

To establish the optimum conditions for improving the transdermal delivery of testosterone, we studied the relationship between the lipophilicity of testosterone ester derivatives and the rat skin permeation rate of testosterone. We performed a rat skin permeation study of testosterone and its commercially available ester derivatives, testosterone hemisuccinate, testosterone propionate and testosterone-17β-cypionate, using an ethanol/water co-solvent system.

The aqueous solubility and rat skin permeation rate of each drug, saturated in various compositions of an ethanol/water system, was determined at 37°C. The aqueous solubility of testosterone and its ester derivatives increased exponentially as the volume fraction of ethanol increased up to 100% (v/v). The stability of testosterone propionate in both the skin homogenate and the extract was investigated to observe the enzymatic degradation during the skin permeation process. Testosterone propionate was found to be stable in the isotonic buffer solution and in the epidermis-side extract for 10 h at 37°C. However, in the skin homogenate and the dermis-side extract testosterone propionate rapidly degraded producing testosterone, implying that testosterone propionate rapidly degraded to testosterone during the skin permeation process. The steady-state permeation rates of testosterone in the ethanol/water systems increased exponentially as the volume fraction of ethanol increased, reaching the maximum value (2.69 ± 0.69 μg cm−2 h−1) at 70% (v/v) ethanol in water, and then decreasing with further increases in the ethanol volume fraction. However, in the skin permeation study with testosterone esters saturated in 70% (v/v) ethanol in water system, testosterone esters were hardly detected in the receptor solution, probably due to the rapid degradation to testosterone during the skin permeation process. Moreover, a parabolic relationship was observed between the permeation rate of testosterone and the log P values of ester derivatives. Maximum flux was achieved at a log P value of around 3 which corresponded to that of testosterone (log P = 3.4).

The results showed that the skin permeation rate of testosterone and its ester derivatives was maximized when these compounds were saturated in a 70% ethanolic solution. It was also found that a log P value of around 3 is suitable for the skin permeation of testosterone related compounds.
The Encapsulation of Bleomycin Within Chitosan Based Polymeric Vesicles Does Not Alter its Biodistribution
Authors: Sludden J , Uchegbu I F , Schätzlein A G
Published: July 2003

Polymeric vesicles have recently been developed from an amphiphilic chitosan derivative—palmitoyl glycol chitosan. Their potential as a drug delivery system was evaluated using the anti-cancer compound bleomycin as a model drug.

Palmitoyl glycol chitosan (GCP41) was synthesised by conjugation of palmitoyl groups to glycol chitosan. Bleomycin-containing vesicles (669 nm diameter) were prepared from a mixture of GCP41 and cholesterol by remote loading. The vesicles were imaged by freeze-fracture electron microscopy and their in-vitro stability tested. Incubation of the larger vesicles with plasma in-vitro led to a reduction of mean size by 49%, a reaction not seen with control sorbitan monostearate niosomes (215 nm in size). They also showed a higher initial drug release (1 h), but GCP41 and sorbitan monostearate vesicles retained 62% and 63% of the encapsulated drug after 24 h, respectively. The biodistribution of smaller vesicles (290 nm) prepared by extrusion through a 200-nm filter was also studied in male Balb/c mice. Encapsulation of bleomycin into polymeric vesicles did not significantly alter the pharmacokinetics of biodistribution of bleomycin in male Balb/c mice although plasma and kidney levels were slightly increased.

It is concluded that the extruded GCP41 vesicles break down in plasma in-vivo and hence are unlikely to offer any therapeutic advantage over the free drug.
Enhancement of Ursodeoxycholic Acid Bioavailability by Cross-linked Sodium Carboxymethyl Cellulose
Authors: Scalia Santo , Giunchedi Paolo , Pazzi Paolo , Conte Ubaldo
Published: July 2003

The bioavailability of ursodeoxycholic acid from a new formulation based on drug-loaded cross-linked sodium carboxymethyl cellulose was studied in man. The plasma levels of ursodeoxycholic acid were determined by gas chromatography-mass spectrometry after derivatization and sample purification by solid-phase extraction. Capsules containing the drug/polymer system were prepared and compared with conventional commercial ursodeoxycholic acid capsules after single oral administration using a randomized crossover experimental design.

Although the drug/polymer system improved the in-vitro dissolution rate of ursodeoxycholic acid in simulated intestinal fluid, statistical evaluation of the area under the plasma concentration curves indicated no significant difference in the extent of bioavailability between the two formulations (14.93 ± 4.43 vs 14.95 ± 5.79 μm h; P > 0.2). However, following the administration of the ursodeoxycholic acid/cross-linked sodium carboxymethyl cellulose system with an enteric-coated capsule, the mean area under the plasma concentration curve (27.60 ± 10.11 μm h) was significantly higher than that obtained after treatment with the commercially available ursodeoxycholic acid capsule (16.24 ± 8.38 μm h; P < 0.05).

We concluded that improved intestinal absorption of the drug was obtained with enteric-coated capsules filled with the ursodeoxycholic acid/polymer system. Moreover, the simplicity of the preparation and the non-toxicity of the polymer used as the carrier represented additional advantages of this dosage form.
Chronic Continuous Cocaine Infusion in Rats: Effect on Urine Cocaine, Ecgonine Methylester and Benzoylecgonine Concentrations and Bolus-dose Cocaine Pharmacokinetics
Authors: Mets B , Soo E , Diaz J , Pantuck C , Singh G , Blair I A
Published: July 2003

The aim of this study was to determine the effect of chronic cocaine infusion on urine cocaine, ecgonine methylester and benzoylecgonine concentrations to establish if they varied with dose and duration of cocaine administration.

Male rats were continuously infused with cocaine at either 6 or 18 mg kg−1 daily for 13 days. Three urine samples taken over the course of the infusion period showed that cocaine, ecgonine methylester and benzoylecgonine concentrations varied with the dose administered and the duration of administration. Cocaine, ecgonine methylester and benzoylecgonine concentrations were 2–3 times greater in the high-dose group than the low-dose group at each sampling time point. These decreased, respectively, from 7.0 ± 1.1, 26.7 ± 4.5 and 29.5 ± 5.4 μg mL−1 to 2.5 ± 0.5, 10.5 ± 1.8 and 11.8 ± 1.5 μg mL−1 in the high-dose group and from 1.0 ± 0.2, 7.8 ± 1.5 and 6.3 ± 0.1 μg mL−1 to 0.5 ± 0.1, 4.0 ± 0.6 and 3.1 ± 0.4 μg mL−1 in the low-dose group (P < 0.05) over the infusion period. We also studied the pharmacokinetic and metabolic profile of an intravenous bolus dose of 2.5 mg kg−1 cocaine hydrochloride after a similar cocaine infusion in rats. Cocaine pharmacokinetics and the profile of ecgonine methylester, benzoylecgonine and norcocaine were no different from rats chronically infused with saline for the same period. Altered cocaine metabolism could not explain the effect of the duration of cocaine infusion on altered metabolite concentrations in urine. Ecgonine methylester/benzoylecgonine urine concentration ratios did not alter with duration of infusion (1.2 ± 0.2 and 1.1 ± 0.2 in the high-dose group at the first and last time point) and were not affected by the dose of cocaine (1.3 ± 0.6 and 1.2 ± 0.1 at corresponding times in the low-dose group (P > 0.05)).

We conclude that chronic cocaine infusion does not alter cocaine metabolism. This was not reflected by absolute cocaine metabolite urine concentrations, which varied with time, but was represented by urine ecgonine methyl ester/benzoylecgonine concentration ratios.
Effects of Ascorbic Acid on Interactions between Ciprofloxacin and Ferrous Sulphate, Sodium Ferrous Citrate or Ferric Pyrophosphate, in Mice
Authors: Motoya Toshiro , Miyashita Masahide , Kawachi Akio , Yamada Katsushi
Published: July 2003

The absorption of ciprofloxacin has been reported to be impaired by concomitant administration of ferrous sulphate. The effects of sodium ferrous citrate and ferric pyrophosphate, which have been used as extensively as ferrous sulphate, on the absorption of ciprofloxacin were compared with that of ferrous sulphate. The effects of ascorbic acid on the interactions between ciprofloxacin and each iron compound were studied in mice. Mice were treated orally with ciprofloxacin (50 mg kg−1) alone, the iron compound (ferrous sulphate, sodium ferrous citrate or ferric pyrophosphate; 50 mg elemental iron kg−1) alone, ciprofloxacin with each iron compound or ciprofloxacin in combination with each iron compound and ascorbic acid (250 mg kg−1).

The maximum serum concentration of ciprofloxacin was significantly (P < 0.01) reduced from 1.15 ± 0.11 μg mL−1 (ciprofloxacin alone) to 0.17 ± 0.01, 0.27 ± 0.01 or 0.28 ± 0.02 μg mL−1, respectively, when ferrous sulphate, sodium ferrous citrate or ferric pyrophosphate was administered along with ciprofloxacin. The addition of ascorbic acid did not affect the inhibitory effects of each iron compound on the absorption of ciprofloxacin. Ciprofloxacin did not affect the variation of serum iron levels after administration of each iron compound. The addition of ascorbic acid significantly (P < 0.01) enhanced the increase in serum iron concentration after administration of sodium ferrous citrate, showing an increase from 270 ± 6 μg dL−1 to 463 ± 11 μg dL−1 compared with an increase from 248 ± 8 μg dL−1 to 394 ± 18 μg dL−1 after administration of sodium ferrous citrate alone. Ascorbic acid also caused a significant (P < 0.01) increase in serum iron concentration from 261 ± 16 μg dL−1 to 360 ± 12 μg dL−1 after administration of ferric pyrophosphate, although it did not affect the levels after ferrous sulphate administration.

The results suggest that sodium ferrous citrate and ferric pyrophosphate should not be administered with ciprofloxacin (as for ferrous sulphate) and that sodium ferrous citrate is converted to the ferric form more easily than ferrous sulphate. This difference in convertibility might contribute to a clinical difference between sodium ferrous citrate and ferrous sulphate.
Effects of Trimebutine Maleate on Delayed Rectifier K+ Currents in Guinea-pig Ventricular Myocytes
Authors: Morisawa Tsuyoshi , Hasegawa Junichi , Tanabe Katsuyuki , Watanabe Ayako , Kitano Masayuki , Kishimoto Yosuke
Published: July 2003

The effects of trimebutine maleate, a drug commonly used to regulate motility in the gastrointestinal tract, on the delayed rectifier K+ current (IK) were evaluated in guinea-pig ventricular myocytes to determine whether the drug has a proarrhythmic effect through blockade of IK.

Trimebutine decreased IK in a concentration-dependent manner. To investigate the effects of trimebutine on two components of IK (IKr and IKs; rapidly activated and slowly activated components, respectively), we performed the envelope-of-tails test. Trimebutine-sensitive IK was determined by digital subtraction of IK during exposure to trimebutine from control IK for each duration of the test pulse over the range 50 ms-2 s. The ratio of ΔIK, tail/ΔIK plotted against pulse duration for trimebutine-sensitive IK gradually decreased to a steady-state value as the duration of the test pulse was lengthened. This finding suggested a weak inhibitory effect of trimebutine on both IKr and IKs. The effects of trimebutine on the inward rectifier K+ current (IKl) responsible for the resting potential and final repolarization phase of the action potential were investigated by applying voltage clamp ramps over a broad range of potentials. No significant effects were observed at 10 or 100 μm. We next investigated the effects of the drug on the L-type Ca2+ current (ICa). Significant inhibition of ICa was observed at trimebutine concentrations greater than 10 μm.

These results suggested that trimebutine maleate has weak inhibitory effects on IKr, IKs and ICa at concentrations much higher than those in clinical use.
Endothelium-dependent Sensory Non-adrenergic Non-cholinergic Vasodilatation in Rat Thoracic Aorta: Involvement of ATP and a Role for NO
Authors: Park Jong Il , Shin Chang Yell , Lee Young Wook , Huh In Hoi , Sohn Uy Dong
Published: July 2003

The involvement of non-adrenergic non-cholinergic (NANC) transmitters, such as adenosine 5′-triphosphate (ATP) and nitric oxide (NO), in the neurogenic relaxation of rat thoracic aorta was investigated in vessel segments suspended for isometric tension recording by polygraph.

Responses to electrical field stimulation (EFS) and exogenous vasodilator were investigated in vessels precontracted with 5-hydroxytryptamine. EFS (100 V, 2–16 Hz, for 10 s at 3-min intervals), in the presence of guanethidine (10 μm) and atropine (10 μm) produced frequency-dependent relaxations. Pretreatment with tetrodotoxin (1 μm) markedly reduced the relaxation and desensitization with capsaicin (10 μm) significantly inhibited the relaxation. Exogenously added ATP caused concentration-dependent relaxations. Mechanical removal of the endothelium significantly inhibited EFS- and ATP-induced relaxation by 30 ± 3% and 37 ± 2%, respectively. Pretreatment with a P1-purinoceptor antagonist, 8-phenyltheophylline (10 μm) or P2X-purinoceptor antagonist, Evans blue (10 μm) did not influence the relaxations to EFS and exogenously added ATP. In contrast, the P2Y-purinoceptor antagonist, basilen blue (100 μm) markedly reduced the relaxations to EFS by 52 ± 4% in the endothelium-intact preparations. However, in the endothelium-denuded preparations and capsaicin-pretreated preparations, basilen blue did not change relaxations elicited by EFS. The NO synthase inhibitor, NG-nitro-l-arginine methyl ester (l-NAME, 100 μm) also significantly inhibited the relaxations to EFS and ATP by 40 ± 6% and 30 ± 2%, respectively, in the endothelium-intact preparations but had no effect on the relaxations in the endothelium-denuded preparations or capsaicin-pretreated preparations. In addition, the EFS-induced relaxations were also inhibited 43 ± 7% by pretreatment with 1H-[1,2,4]-oxadiazolo[4,3-α]quinoxalin-1-one (ODQ; 1 μm), soluble guanylate cyclase inhibitor.

This study suggests that the NANC nerve system is present in the thoracic aorta of rat, mediating vasodilatation by sensory nerves. ATP, as a neurotransmitter released from sensory nerves, activates P2Y-purinoceptors located on the endothelium and stimulates the NO/cyclic GMP pathway, resulting in vasodilatation.
Differential Potency of Beclomethasone Esters In-vitro on Human T-lymphocyte Cytokine Production and Osteoblast Activity
Authors: Seeto Celina , Namkung-Matthai Heeja , Jayram Shalini , Foe Kuncoro , Brown Ken F , Hughes J Margaret , Mason Rebecca S , Armour Carol L , Seale J Paul
Published: July 2003

Beclomethasone dipropionate is an inhaled corticosteroid, used for the treatment of asthma. It is metabolised to 17-beclomethasone monopropionate, which has greater affinity for corticosteroid receptors than the parent compound, and to beclomethasone. We investigated the potency of beclomethasone dipropionate, 17-beclomethasone monopropionate and beclomethasone (compared with dexamethasone as a reference steroid) in two different human cell types, peripheral blood mononuclear cells and osteoblasts.

We found that beclomethasone dipropionate, 17-beclomethasone monopropionate (EC50 10−14  m) and beclomethasone (EC50 approx. 10−12  m) were much more potent than dexamethasone (EC50 10−8  m) in inhibiting interleukin-5 production by peripheral blood mononuclear cells. In contrast, beclomethasone dipropionate, 17-beclomethasone monopropionate and beclomethasone were equipotent with dexamethasone (EC50 range 0.3–1.2 times 10−9  m) in affecting several functional assays of osteoblasts (e.g. alkaline phosphatase activity and osteocalcin synthesis).

These results show that the relative bioactivities of corticosteroids vary between different human cell types, and that affinities observed in receptor binding assays are not necessarily predictive of the bioactivity in cell populations, such as peripheral blood mononuclear cells and osteoblasts, which are putatively relevant to efficacy and side effects respectively.
Structure-Activity Relationships of Anthraquinones in the Decrease of Intestinal Motility
Authors: Kuo Daih-Huang , Kuo Sheng-Chu , Cheng Juei-Tang
Published: July 2003

The effects of substituted anthraquinones on intestinal motility were evaluated in-vitro using rabbit small intestinal strips.

This structure-activity relationship study revealed the critical requirement of a hydroxy group at R2 position. The intestinal motility was inhibited 50% (IC50) by emodine (8 μM), 2-hydroxy anthraquinone (20 μM), 2,6-dihydroxy anthraquinone (25 μM), 2,7-dihydroxy anthraquinone (10 μM), 1,2,4-trihydroxy anthraquinone (80 μM) and 1,2,5,8-tetra-hydroxy-anthraquinone (9 μM). The presence of other polar groups at R2 position such as an amino, aldehyde and carboxylic acid group significantly reduced the activity (IC50 360–400 μM). The presence of a methyl group and esterification of the carboxylic acid at R2 position was found to abolish the activity.

These data are useful for the future development of anthraquinones as laxative agents.
The Effect of Progesterone on Spontaneous and Agonist-Evoked Contractions of the Rat Aorta and Portal Vein
Authors: Mukerji Mark S , Leathard Helen L , Huddart Henry
Published: July 2003

The mechanisms underlying the suppression of vasocontractility caused by progesterone were investigated by studying changes in the contractile force of rat isolated aorta and portal vein, induced by altering extracellular concentrations of noradrenaline (NA) potassium ions (K+) and calcium ions (Ca2+).

In the aorta, progesterone (10 μM) had a general suppressive effect on NA-, Ca2+- and K+-induced contractions. In contrast, in the portal vein a more selective suppression of contractions was observed. Both tonic and phasic components of contractions induced by cumulative addition of Ca2+ to tissues equilibrated in Ca2+-free saline were suppressed. The phasic but not tonic components of contractions induced by NA addition were suppressed. There was no significant effect on tonic contractions induced by elevated (40–120 mM) K+, but a concentration-dependent suppression of the phasic component of contractions was observed during depolarisation with smaller elevations of K+ concentrations (5–20 mM).

These results suggest that on the portal vein the suppressive effect of progesterone is due to a potassium channel opening action, whilst on the aorta a different or additional mechanism of suppression exists.
Effects of the Oral Administration of a β3-Adrenergic Agonist on Lipid Metabolism in Alloxan-Diabetic Rats
Authors: Milagro Fermín I , Martínez J Alfredo
Published: July 2003

Previous studies have reported that β3-adrenergic agonists regulate plasma glucose, triglycerides and free fatty acids in situations of hyperglycaemia and dyslipidaemia in rodents. In this study Trecadrine, a novel compound with affinity for β3-adrenergic receptors, has been tested in an alloxan-induced model of hyperglycaemia in rats.

Alloxan-induced hyperglycaemic rats were orally treated with Trecadrine (1 mg/kg/day for 4 days), resulting in an improvement of hyperglycaemia (from 16.6 to 8.3 mmol L−1, P < 0.001). This effect was not associated with statistical differences in plasma insulin levels, which may be explained by changes in insulin resistance and carbohydrate oxidation in peripheral tissues. Furthermore, a reduction in internal white fat weight (-39%), which was not statistically significant, as well as in plasma triglycerides (from 1.89 to 0.33 mmol L−1, P < 0.001) and free fatty acids (from 0.70 to 0.39 mmol L−1, P < 0.001), was found after Trecadrine administration. Trecadrine apparently induced lipolytic activity in adipocytes, as suggested by the increase of oxygen consumption in white adipose tissue (+282%, P < 0.001), while free fatty acids decreased apparently through their utilisation in other tissues. Furthermore, the increase in brown adipose tissue oxygen consumption (+50%, P < 0.01) and in rectal temperature (P < 0.05) suggests that both glucose and fatty acid oxidation may be enhanced in this tissue.

These results give support to the possible therapeutic use of β3-adrenergic compounds in situations of hyperglycaemia, particularly when this is accompanied by hypertriglyceridaemia.
Inhibition of Vascular Smooth Muscle Tone by the H+, K+-ATPase Inhibitor SCH 28080
Authors: Rhoden Kerry J
Published: July 2003

Vascular smooth muscle is thought to possess an H+-K+ ATPase that contributes to the regulation of intracellular K+ concentration and pH. We have examined the effect of the H+, K+-ATPase inhibitor SCH 28080 on vascular smooth muscle tone in guinea-pig and human isolated arteries, and on 86Rb+ uptake in cultured guinea-pig aortic smooth muscle cells.

SCH 28080 (0.1–300 μM) produced relaxation of isolated guinea-pig aorta, guinea-pig pulmonary artery and human pulmonary artery. Relaxation occurred in tissues pre-contracted with phenylephrine, histamine or the thromboxane mimetic U44069. Relaxation was reversible, and was not affected by tetrodotoxin, indomethacin, nordihydroguiaretic acid (NDGA), 1-aminobenzotriazole (1-ABT), NG-nitro-L-arginine methyl ester (L-NAME), removal of the endothelium or removal of extracellular K+. SCH 28080 had no effect on 86Rb+ uptake in cultured guinea-pig aortic smooth muscle cells.

In conclusion, SCH 28080 relaxes vascular smooth muscle at concentrations known to inhibit the H+-K+ ATPase. The persistence of relaxation in a K+-free medium and the failure of SCH 28080 to inhibit 86Rb+ uptake suggest that relaxation may be unrelated to H+, K+-ATPase inhibition, and indicate that this agent may not be considered as a selective H+, K+-ATPase inhibitor in vascular preparations.
Effect of Iron(III) Chitosan Intake on the Reduction of Serum Phosphorus in Rats
Authors: Baxter Joseph , Shimizu Fuki , Takiguchi Yasuyuki , Wada Masahiro , Yamaguchi Tatsuaki
Published: July 2003

Because of the widespread use of aluminium- and calcium-containing phosphate binders for the control of hyperphosphataemia in patients with end-stage renal failure, an iron(III) chitosan complex was synthesised and fed to rats to measure its effect on serum phosphorus and calcium, intestinal phosphate binding and phosphate absorption.

Thirty-six Wistar rats were randomly selected and distributed into a baseline group (n = 6), a control group (n = 8 (days 0–15), n = 8 (days 16–30)) and a treatment group (n = 8 (days 0–15), n = 8 (days 16–30)). The control groups ingested AIN-76 diet mix with a 1% w/w fibre content; however, the treatment groups had the fibre content completely substituted with iron(III) chitosan. The mean weights of the treated rats were slightly lower from 15 days (not significant); but overall, rat growth was not stunted in the treatment groups. The serum phosphorus levels of the treated group (n = 8) were significantly reduced after 15 days (P = 0.004; control: 5.7 ± 0.9 mg dL−1; treatment: 4.4±0.5 mg dL−1; 95% CI of difference: 0.5–2.2) and 30 days (P = 0.002; control: 5.5 ± 0.9 mg dL−1; treatment = 4.1 ± 0.6 mg dL−1; 95% CI of difference: 0.6–2.3) as compared with the respective control group. The serum calcium-phosphorus product was 62.0 ± 12.1 mg2 dL−2 for the control and 45.1 ± 6.6 mg2 dL−2 for the treatment group after 30 days (P = 0.004). The serum iron concentration of the treatment group did not differ from the baseline value after 15 and 30 days, but the treatment group was significantly higher than the control group (P < 0.05) after 30 days. The faeces phosphorus levels (mg day−1) were higher (P < 0.01) and its iron content was much higher (P < 0.01) for the treated group. The urine phosphorus (mg kg−1) was not significantly reduced for the treated group, but the mean was consistently less. The kidney and liver weights of both groups were similar, but the phosphorus content of the kidney (mg (g kidney)−1) was higher for the treated group after 30 days (P = 0.041; control, 4.2 ± 1.2 mg g−1 vs treatment, 5.6 ± 1.4 mg g−1. Because iron(III) chitosan had a high phosphorus-binding capacity of 308 (mg P) per gram of Fe3+ for both the in-vitro (pH 7.5) and in-vivo studies, which is greater than nearly all commonly used phosphate binders, and a small net phosphorus absorption difference of 3.7 mg day−1, it is an efficient phosphate binder for lowering serum phosphate levels without increasing serum calcium levels.
The Ethanol-soluble Part of a Hot-water Extract from Artemisia iwayomogi Inhibits Liver Fibrosis Induced by Carbon Tetrachloride in Rats
Authors: Park Eun-Jeon , Nan Ji-Xing , Kim Ji-Young , Kang Hee-Chul , Choi Jung Hwan , Lee So Jung , Lee Bo Hye , Kim Sun Jin , Lee Jae Hyun , Kim Yoon Chul , Sohn Dong Hwan
Published: July 2003

This study was carried out to investigate the protective effects of the hot-water extract from Artemisia iwayomogi (Compositae) on carbon tetrachloride-induced liver fibrosis in rats.

Liver injury was induced by oral administration of carbon tetrachloride (1 mL kg−1) twice a week during 4 weeks of A. iwayomogi treatment. Extracts from A. iwayomogi were prepared and administered to rats orally (2 g kg−1 as A. iwayomogi for 4 weeks) as follows: group 1, hot-water extract; group 2, ethanol-soluble part of hot-water extract; group 3, ethanol-insoluble part of hot-water extract; and group 4, methanol extract.

In rats treated with the ethanol-soluble part of the hot-water extract, liver hydroxyproline content was reduced to 74% that of carbon tetrachloride control rats (P < 0.05). Protein expression of alpha smooth muscle cell like actin was also decreased in rats treated with the ethanol-soluble part of the hot-water extract, which indicates inhibition of hepatic stellate cell activation. Liver malondialdehyde levels were significantly lowered in rats treated with the ethanol-soluble part of hot-water extract (P < 0.05). Serum cholesterol levels in rats treated with hot-water extract, ethanol-soluble or -insoluble parts of hot-water extract or methanol extract were significantly reduced when compared with those of carbon tetrachloride control rats (P < 0.05).

The ethanol-soluble part of the hot-water extract from A. iwayomogi inhibited fibrosis and lipid peroxidation in rats with liver fibrosis induced by carbon tetrachloride. Both hot-water extract (either ethanol-soluble or -insoluble) and methanol extract of A. iwayomogi also lowered serum cholesterol levels in fibrotic rats.
Antitumour Activity and Side Effects of Combined Treatment with Chitosan and Cisplatin in Sarcoma 180-Bearing Mice
Authors: Kimura Yoshiyuki , Onoyama Mitsuko , Sera Toshiki , Okuda Hiromichi
Published: July 2003

We examined the possible modulation by chitosan of the antitumour effects and side effects of cisplatin (cis-diaminedichloroplatinum, CDDP). The study showed that CDDP had potent antitumour activity when administered orally as well as intraperitoneally. We also compared the antitumour activity and side effects of orally administered CDDP plus orally administered chitosan versus intraperitoneally administered CDDP plus orally administered chitosan in sarcoma 180-bearing mice.

When CDDP (1.25 mg kg−1 × 2 day−1) was intraperitoneally administered to sarcoma 180-bearing mice, myelotoxicity (the reduction of leucocyte and platelet numbers), nephrotoxicity (the increase of blood nitrogen urea level), immunotoxicity (the reduction of spleen and thymus weight) and a reduction in body weight resulted. These intraperitoneally administered CDDP-induced side effects were not prevented by oral administration of chitosan (150 mg kg−1 × 2 day−1 and 750 mg kg−1 × 2 day−1) for 14 consecutive days. On the other hand, the side effects such as the reductions of body and spleen weights induced by orally administered CDDP (1.25 mg kg−1 × 2 day−1) were prevented by the oral administration of chitosan (150 mg kg−1 × 2 day−1 and 750 mg kg−1 × 2 day−1).

From these results, we conclude that the orally administered chitosan plus CDDP might be useful for the prevention of body weight reduction and immunotoxicity (the reduction of spleen weight) induced by the orally administered CDDP without diminishing antitumour activity.
Effect of Luffa echinata on Lipid Peroxidation and Free Radical Scavenging Activity
Authors: Kumar V Prashanth , Shashidhara S , Kumar M M , Sridhara B Y
Published: July 2003

The dried alcoholic (50%) extract of the plant Luffa echinata was investigated for inhibition of lipid peroxidation, for hydroxyl radical scavenging activity and interaction with 1,1-diphenyl-2-picrylhydrazyl stable free radical (DPPH).

It was found that the test extract exhibited a considerable inhibition of lipid peroxidation and possessed hydroxyl radical scavenging activity. Evaluation of antiradical scavenging activity showed significant interaction with DPPH.

These properties could be considered as a useful and exploitable combination for justifying the reported activity.
In-vitro Inhibition of Human Erythrocyte Acetylcholinesterase by Salvia lavandulaefolia Essential Oil and Constituent Terpenes
Authors: Perry Nicolette S L , Houghton Peter J , Theobald Anthony , Jenner Peter , Perry Elaine K
Published: July 2003

Sage (Salvia spp) is reputed in European herbal encyclopaedias to enhance memory, and current memory-enhancing/anti-dementia drugs are based on enhancing cholinergic activity by inhibiting cholinesterase. In this study the effects of Salvia lavandulaefolia Vahl. (Spanish sage) essential oil and some of its constituent terpenes on human erythrocyte acetylcholinesterase were examined in-vitro. The main constituents in the essential oil batch used for analysis of cholinesterase inhibition were camphor (27%), 1,8-cineole (13%), α- and β-pinene (10–15%) and bornyl acetate (10%) with other minor constituents (1% or less) including geraniol, limonene, linalool, terpineol and γ-terpinene.

Using the Ellman spectrophotometric method, kinetic analysis was conducted on the interaction of the essential oil and the main monoterpenoids, camphor, 1,8-cineole and α-pinene. IC50 values were obtained for the essential oil, 1,8-cineole and α-pinene and were 0.03 μg mL−1, 0.67 mM and 0.63 mM, respectively. Camphor and other compounds tested (geraniol, linalool and γ-terpinene) were less potent (camphor IC50: >10 mM). The essential oil, α-pinene, 1,8-cineole and camphor were found to be uncompetitive reversible inhibitors.

These findings suggest that if the inhibitory activity of the essential oil is primarily due to the main inhibitory terpenoid constituents identified, there is a major synergistic effect among the constituents. Since no single constituent tested was particularly potent, it remains to be determined whether these in-vitro cholinesterase inhibitory activities are relevant to in-vivo effects of the ingestion of S. lavandulaefolia essential oil on brain acetylcholinesterase activity.
Apolipoprotein A-I, Cyclodextrins and Liposomes as Potential Drugs for the Reversal of Atherosclerosis. A Review
Authors: Dass Crispin R , Jessup Wendy
Published: July 2003

Several studies have revealed that high-density lipoprotein (HDL) is the most reliable predictor for susceptibility to cardiovascular disease. Since apolipoprotein A-I (apoA-I) is the major protein of HDL, it is worthwhile evaluating the potential of this protein to reduce the lipid burden of lesions observed in the clinic. Indeed, apoA-I is used extensively in cell culture to induce cholesterol efflux. However, while there is a large body of data emanating from in-vitro and cell-culture studies with apoA-I, little animal data and scant clinical trials examining the potential of this apolipoprotein to induce cholesterol (and other lipid) efflux exists. Importantly, the effects of oxysterols, such as 7-ketocholesterol (7KC), on cholesterol and other lipid efflux by apoA-I needs to be investigated in any attempt to utilise apoA-I as an agent to stimulate efflux of lipids.

Lessons may be learnt from studies with other lipid acceptors such as cyclodextrins and phospholipid vesicles (PLVs, liposomes), by combination with other effluxing agents, by remodelling the protein structure of the apolipoprotein, or by altering the composition of the lipoprotein intended for administration in-vivo. Akin to any other drug, the usage of this apolipoprotein in a therapeutic context has to follow the traditional sequence of events, namely an evaluation of the biodistribution, safety and dose-response of the protein in animal trials in advance of clinical trials. Mass production of the apolipoprotein is now a simple process due to the advent of recombinant DNA technology.

This review also considers the potential of cyclodextrins and PLVs for use in inducing reverse cholesterol transport in-vivo. Finally, the potential of cyclodextrins as delivery agents for nucleic acid-based constructs such as oligonucleotides and plasmids is discussed.
Body Distribution of Poly-DL-lactide-poly(ethylene glycol) Microspheres with Entrapped Leptospira interrogans Antigens Following Intravenous and Oral Administration to Guinea-pigs
Authors: Li Xiaohong , Zhang Yanhua , Yan Ronghua , Zhang Min , Yuan Minglong , Deng Xianmo , Huang Zhitang
Published: July 2003

Poly-DL-lactide-poly(ethylene glycol) (PELA) microspheres with entrapped antigens were administered intravenously and orally into guinea-pigs to quantitatively determine the in-vivo distribution and release profiles.

PELA microspheres containing 125I-labelled outer-membrane protein Leptospira interrogans antigens (125I-OMP) were prepared by double-emulsion solvent extraction procedure, and characterized with respect to size, morphology and in-vitro release profiles. The fractured sections of liver and spleen were inspected by scanning electron microscopy, which indicated that microspheres had successfully been entrapped within the above tissues after intravenous injection and oral administration. At predetermined intervals, the blood and such tissues as the liver, spleen, kidney, thyroid, small intestine and mesentery were collected, and the radioactivity was measured by gamma scintillation counting. Following intravenous administration, 56.7% of administered microspheres were accumulated in immunization-related tissues, and 40.1% of microspheres were located in the liver and spleen. However, there was limited uptake efficiency (8.33%) following oral administration, and 49.5% of the absorbed microspheres were located in the intestinal mucosa. Compared with in-vitro release, the in-vivo release profiles of 125I-OMP from PELA microspheres, determined from the decreasing radioactivity in the above tissues, were much faster and the burst effect was higher.

Antigen-loaded PELA microspheres were efficiently entrapped within immunization-related tissues after intravenous administration, but orally administered PELA microspheres showed limited uptake efficiency. Further investigation is needed to improve intestinal absorption.
A Human Oral-throat Cast Integrated with a Twin-stage Impinger for Evaluation of Dry Powder Inhalers
Authors: Srichana T , Martin G P , Marriott C
Published: July 2003

The aim of this study was to investigate the applicability of replacing the glass throat from a twin-stage impinger (TSI) with a human oral-throat cast. Monodisperse aerosols were used to calibrate the human oral cast-TSI at 60 L min−1 and cut-off in particle size was compared with that of the TSI described in the British Pharmacopoeia which employs a glass throat. The amount of salbutamol sulphate (and lactose) delivered by the Cyclohaler depositing on various elements of the in-vitro model were determined.

The calibration of the model containing a human oral-throat cast at 60 L min−1 gave a particle size cut-off of 5.2 μm which was less than that of the TSI (6.3 μm). The oral-throat cast trapped more drug than the glass throat model with a formulation that employed the larger carrier (63–90 μm; P<0.05) while it trapped a lesser amount of drug with those filled with the lower size carrier (Lactochem, micronised lactose). The greater amount of lactose in the formulation that employed the larger-sized carrier (63–90 μm) was deposited closer to the inlet of the oral-throat cast than to the inlet of the glass throat model.

Replacement of the glass throat in the TSI by the human oral-throat cast, leads to a change in deposition efficiency, with the cast having a higher filter efficiency and hence more aerosol particles being captured before their entry into the TSI. This should be investigated further to determine whether such a model might provide a more realistic assessment of the in-vivo characteristics of an aerosol in comparison with the TSI currently being employed, which utilises the glass throat as the portal of entry.
Cytotoxicity and Teratogenicity of Chlorhexidine Diacetate Released from Hollow Nylon Fibres
Authors: Ostad S Nasser , Gard Paul R
Published: July 2003

Intra-uterine contraceptive devices are associated with an increased incidence of pelvic infections, possible due to the introduction of vaginal bacteria into the uterus at insertion. One potential means to overcome this problem is the use of a device which releases the antimicrobial agent chlorhexidine although such an approach carries with it the risk of adverse effects on the endometrium and, possibly, teratogenic effects.

Cultured monolayers of endometrial cells were used to assess the cytotoxicity of both chlorhexidine and chlorhexidine-releasing devices. The results indicated that the agent is toxic at concentrations of 1 μg mL−1 and that the devices potentiated the toxicity. When the devices were tested in a guinea-pig model, endometrial damage was seen only at the high dose of chlorhexidine, suggesting that there is greater distribution of chlorhexidine in-vivo. Assessment of the teratogenic effects of chlorhexidine in rat embryonic limb bud tissue cells in-vitro showed that the foetal cells were highly susceptible to the toxic effects of chlorhexidine, but that there was no evidence of teratogenicity.

Overall, the findings suggest that chlorhexidine-releasing devices may be a safe means of reducing infections related to intra-uterine devices, but that the chlorhexidine may have a toxic effect on foetal cells.
Investigations of the In-vitro Metabolism of Three Opioid Tetrapeptides by Pancreatic and Intestinal Enzymes
Authors: Krondahl Eva , Von Euler-Chelpin Hans , Orzechowski Achim , Ekström Gunilla , Lennernäs Hans
Published: July 2003

The metabolism of three opioid tetrapeptides, Tyr-D-Arg-Phe-Nva-NH2, Tyr-D-Arg-Phe-Phe-NH2 and Tyr-D-Ala-Phe-Phe-NH2, was investigated in the presence of pure pancreatic enzymes (trypsin, chymotrypsin, elastase, carboxypeptidase A and carboxypeptidase B), as well as in the presence of pure carboxylesterase and aminopeptidase N. The cleavage patterns of the pure pancreatic enzymes were then compared with those found in rat and human jejunal fluid. Metabolism was also studied in homogenates from different intestinal regions (duodenum, jejunum, ileum and colon) and in enterocyte cytosol from rats. The effect of various protease inhibitors was investigated in the jejunal homogenate. The parent peptides were assayed by high-performance liquid chromatography and metabolites were identified by means of liquid chromatography-mass spectrometry.

Of the pure enzymes, the quickest hydrolysis of the peptides was observed for the pancreatic enzymes chymotrypsin, trypsin and carboxypeptidase A. In most cases they formed the corresponding deamidated tetrapeptides (chymotrypsin and trypsin) or tripeptides with a missing C-terminal amino acid (carboxypeptidase A). Regional differences in intestinal metabolism rates were found for all three peptides (P < 0.001), with the highest rates observed in jejunal and/or colonic homogenates. The deamidated tetrapeptides were formed both in rat intestinal homogenates and in enterocyte cytosol. Metabolism in the jejunal homogenate was markedly inhibited by some serine and combined serine and cysteine protease inhibitors.

In conclusion, the C-terminal amide of these tetrapeptides did not fully stabilise them against intestinal deamidase and carboxypeptidase activities. The significant hydrolysis of the peptides by pure chymotrypsin, trypsin and carboxypeptidase A showed that lumenal pancreatic proteases might be a clear metabolic obstacle in oral delivery even for small peptides such as these tetrapeptides.
Recombinant Factor VIII SQ—Stability of VIII: C in Homogenates from Porcine, Monkey and Human Subcutaneous Tissue
Authors: Fatouros Angelica , Lidén Ylva , Sjöström Brita
Published: July 2003

The aim of this paper was to investigate whether a formulation-based approach to understanding and addressing stability could generate a subcutaneous factor VIII preparation for patients as an alternative to the existing intravenous products. The low bioavailability of subcutaneously administered factor VIII could have several causes: proteolytic degradation of the protein in the interstitium; adsorption to tissue, in particular to acidic phospholipids such as L-α phosphatidyl-L-serine (phosphatidylserine); the absence of free von Willebrand factor in the interstitum; phagocytosis by macrophages in the interstitium or in the lymph nodes; and coagulation could be initiated upon injection. This study was undertaken to investigate the first three factors in-vitro (i.e., proteolytic degradation, adsorption to tissue and the protective effect of von Willebrand factor). The influence of some other macromolecular stabilisers and protease inhibitors was also investigated. The stability of factor VIII activity (VIII: C) was investigated in homogenates from porcine, monkey and human subcutaneous tissue. Possible coagulation was prevented in these studies by the presence of both citrate and antithrombin. An exploratory in-vivo study was performed in the pig; plasma samples were assayed with a factor VIII: Ag (90 kDa) ELISA.

The decrease in VIII:C appeared to be more pronounced in homogenates from monkey and human tissues than in porcine homogenate. The results from human tissue homogenate resembled the degradation profile seen in monkey homogenate. Both the von Willebrand factor and phosphatidylserine/phosphatidylcholine (PS/PC) liposomes showed a significant stabilising effect on VIII:C in the tissue homogenates. The qualitative pattern was similar in porcine, monkey and human tissue. A combination of several protease inhibitors seemed to have a protective effect on the stability of VIII:C albeit at high concentrations of inhibitors and the effect was less than that of PS/PC. An exploratory in-vivo study was performed in the pig with phosphatidylserine in two formulations; either in the form of PS/PC liposomes or together with Polysorbate 80 in the form of mixed micelles (phosphatidylserine/P80). Including phosphatidylserine in the formulations appeared to increase the availability of subcutaneously administered r-VIII SQ in the pig. However, further studies are necessary, preferably in the monkey where in-vitro studies indicate a closer resemblance to the human.

In conclusion, a proposed inactivation mechanism for r-VIII SQ in subcutaneous tissue could be adsorption to phospholipid surfaces followed by proteolytic degradation. However, additional studies are required due to the multitude of factors influencing the subcutaneous absorption route. A combination of protease inhibitor(s) together with phosphatidylserine-containing liposomes are suggested for further investigation, preferably in a monkey animal model.
Intravenous Formulations of the Enantiomers of Thalidomide: Pharmacokinetic and Initial Pharmacodynamic Characterization in Man
Authors: Eriksson Tommy , Björkman Sven , Roth Bodil , Höglund Peter
Published: July 2003

Thalidomide, a racemate, is coming into clinical use as an immunomodulating and antiinflammatory drug. These effects may chiefly be exerted by S-thalidomide, but the enantiomers are interconverted in-vivo. Thalidomide is given orally, although parenteral administration would be desirable in some clinical situations. The aim of this study was to prepare solutions of the enantiomers of thalidomide for intravenous administration and to investigate their pharmacokinetics and sedative effects following infusion in man.

Solubility and stability of the enantiomers in 5% glucose solution was investigated. After a dose-determination experiment in one subject, six healthy male volunteers received R- and S-thalidomide separately by 1-h infusions in a randomized double-blind crossover study. Blood was sampled over 22 h and sedative effects were recorded. Blood concentrations of the enantiomers were determined by stereospecific HPLC. A four-compartment model consisting of a two-compartment model for each enantiomer, with elimination from both compartments, connected by rate constants for chiral inversion was fitted to the concentration data, while the sedative effects were correlated with the blood concentrations of R- and S-thalidomide by means of logistic regression. The enantiomers of thalidomide were chemically stable in solution for at least a week at room temperature. The infusions were well tolerated. Sedation, which was the only observed effect, was related to the blood concentration of R-thalidomide. Inter-individual variation in the disposition of the enantiomers was modest (e.g. terminal half-lives ranged between 3.9 and 5.3 h). Pharmacokinetic modelling predicted that varying the infusion time of a fixed dose of S-thalidomide between 10 min and 6 h would have little influence on the maximal blood concentration of formed R-thalidomide.

To our knowledge this is the first time that thalidomide has been administered intravenously.
Isolation and Identification of Three Potential Impurities of Pholcodine Bulk Drug Substance
Authors: Denk Oliver M , Gray Alexander I , Skellern Graham G , Watson David G
Published: July 2003

Three previously unreported manufacturing impurities were isolated from a pholcodine mother liquor using preparative reversed-phase HPLC.

The liquor was the residue remaining after recrystallisation of a production batch of pholcodine. The impurities, which are structurally related to pholcodine, were initially detected by thin-layer chromatography (TLC). Their structures were determined after separation by preparative HPLC (Econo-Prep 5 μm C18 column, 30 cm × 21.2 mm i.d.). Structure elucidation was carried out using nuclear magnetic resonance (NMR) spectroscopy, mass spectroscopy (MS) and ultra violet (UV) spectroscopy.

The impurities were identified as alkylated derivatives of pholcodine possessing second 2-morpholinoethyl substituents at various positions.