Upstream elements bestow T-cell and haemopoietic progenitor-specific activity on the granzyme B promoter.

Cytotoxic T cells and early haemopoietic progenitors share the expression of a number of specific genes. Of these, granzyme B has attracted particular interest because of its role in inducing apoptosis during cytotoxic T cell-mediated target cell killing, and its potential role in the mobilisation and homeostasis of haemopoietic stem cells. Studies of granzyme B regulation should therefore yield valuable information concerning the molecular control of these processes, and also identify elements capable of directing gene expression to two cell types of relevance to gene therapy. Here we show that proximal regulatory elements already known to direct promoter activity in T cells are similarly active in haemopoietic progenitors. However, this activity is not strictly specific, since the promoter regions also direct low levels of reporter gene expression in fibroblasts. More importantly, we also report the presence of two previously unidentified clusters of DNaseI hypersensitive sites upstream from the murine granzyme B gene, and show that these regions impart both increased transcriptional activity and the appropriate cell type specificity on the granzyme B promoter. These upstream regulatory regions are therefore likely to play a key role in the coordination of granzyme B expression in vivo.

Comparison of Alora estradiol matrix transdermal delivery system with oral conjugated equine estrogen therapy in relieving menopausal symptoms. Alora Study Group.

OBJECTIVE: To compare the efficacy of two strengths of an estradiol matrix transdermal delivery system with daily oral doses of conjugated equine estrogens in reducing the frequency of moderate-to-severe hot flushes in postmenopausal women. DESIGN: The design of the study provided for the following treatment regimens: an estradiol transdermal delivery system (Alora 0.05 or 0.1 mg/day) administered twice weekly or oral doses of conjugated equine estrogens (CEE 0.625 or 1.25 mg) administered daily were given to 321 highly symptomatic postmenopausal women for 12 weeks following a randomized, parallel-group, double-blind, double-dummy design. RESULTS: Results indicate no statistically significant differences at any time point in mean frequency or mean percentage reduction in frequency of moderate-to-severe hot flushes between patients given Alora 0.1 mg/day and those receiving CEE 1.25 mg/day. Similarly, no significant differences were observed at any time in mean frequency of moderate-to-severe hot flushes between the Alora 0.05 mg/day and CEE 0.625 mg/day groups, although the group receiving CEE 0.625 mg/day exhibited a statistically greater percentage reduction than the Alora 0.05 mg/day group at weeks 3, 4 and 8. By week 12, these two treatments were statistically indistinguishable. There were no serious or unexpected adverse events with the two transdermal systems and local skin tolerability was excellent. Other estrogenic effects such as restoration of vaginal cytology, breast tenderness and unexpected vaginal bleeding were comparable between transdermal and oral administration groups except for a lower incidence of bleeding in those women receiving the lower dose transdermal regimen.

Bioavailability of oestradiol from the Alora (0.1 mg/day) oestradiol matrix transdermal delivery system compared with Estraderm (0.1 mg/day).

This open-label, randomised, two-way crossover study compared the steady-state bioavailability of oestradiol administered by way of a new oestradiol matrix transdermal delivery system (Alora 0.1 mg/day) with that of Estraderm (0.1 mg/day) in 24 subjects. Serum oestradiol, oestrone and oestrone sulphate concentrations were determined by measurement of blood samples. Mean SD pre-dosing, nonadjusted oestradiol levels for Alora (71.9 27.0 pg/ml) were substantially higher than those for Estraderm (26.7 9.7 pg/ml), while peak oestradiol concentrations were comparable. Consequently, fluctuations in steady-state levels were substantially smaller for Alora than for Estraderm; the fluctuation index values (\[C- C ])/ max min C ) were significantly lower for Alora (0.97 0.23) than av for Estraderm (1.68 0.45). Oestradiol levels remained constant over the dosing interval with Alora but decreased significantly after 48 hours with Estraderm. The bioavailability of oestradiol with Alora was 127 56% that of Estraderm. Oestrone and oestrone sulphate data showed the same qualitative and quantitative differences between the two systems. Both systems were well tolerated. In summary, Alora delivered more oestradiol to the systemic circulation with greater consistency and over a longer time than did Estraderm.

Double-masked, multicenter study of an estradiol matrix transdermal delivery system (Alora) versus placebo in postmenopausal women experiencing menopausal symptoms. Alora Study Group.

This 12-week, double-masked, double-dummy, randomized, parallel-group study compared the efficacy and safety of an estradiol matrix transdermal delivery system (Alora) in two strengths (50-microgram/d estradiol and 100-microgram/d estradiol) with placebo in postmenopausal women who were experiencing at least 60 moderate-to-severe hot flushes per week. In 273 postmenopausal women, the reduction in the frequency of moderate-to-severe hot flushes was significantly better than placebo within 2 weeks of initiating therapy in the 100-microgram/d group and within 3 weeks of initiating therapy in the 50-microgram/d group. The reduction in hot flushes for both active treatment groups remained significantly different from placebo throughout the 12-week trial. Improvement in vaginal cytology profile (maturation index) was observed in both active treatment groups. Serum estradiol concentrations were elevated to early-to mid-follicular levels, in proportion to dose, and the estradiol/estrone ratio remained within the expected premenopausal range. The incidence of estrogen-related side effects was modest but greater in the active treatment groups than in the placebo group: Breast pain was reported in 4.5% of the patients in the 50-microgram/d group, 5.3% of patients in the 100-microgram/d group, and none of the patients in the placebo group. Breakthrough bleeding occurred in 3.4% of women in the 50-microgram/d group, 20.2% of women in the 100-microgram/d group, and 4.4% of women in the placebo group. Only 3 (1.1%) patients terminated treatment because of skin reactions. This study demonstrates that this estradiol matrix transdermal delivery system is effective in the treatment of menopausal symptoms, while providing the skin tolerability desired by patients.

Site-differential gastrointestinal absorption of benazepril hydrochloride in healthy volunteers.

The absorption of benazepril-HCl (BZPH), an orally active angiotensin-converting enzyme (ACE) inhibitor, in various regions of the gastrointestinal (GI) tract was investigated using an intestinal intubation technique. Thirteen subjects completed this single-dose, three-phase sequential crossover study. The drug (20 mg) was administered either as a 4-hr colonic infusion (COLON) or as a small intestinal infusion (SI) in the first two phases and as an oral bolus solution (ORAL) in the third phase, with a 2-week washout between each treatment. Serial plasma and urine samples were collected for up to 4 days after dosing. BZPH and its active metabolite benazeprilat (BZPL) were determined using a gas chromatography/mass spectrometry method. BZPH was absorbed rapidly into the bloodstream (Tmax = 0.5 hr after ORAL). Absorption was also rapid for SI, with a postinfusion half-life (0.57 hr) nearly identical to that for ORAL (0.59 hr). The absorption rate after COLON was much slower (lower Cmax and longer Tmax) compared to that after SI, and the apparent half-life (1.7 hr) was prolonged. SI delivered 90%, whereas COLON delivered 23%, of the drug into the systematic circulation as compared to ORAL. BZPL was rapidly formed upon drug absorption. The metabolite-to-drug AUC ratios were comparable for SI and ORAL (8.9 vs 9.7), indicating that first-pass metabolism of BZPH was neither saturable nor input rate dependent. The metabolite-to-drug AUC ratio was reduced for COLON (5.0), indicating that the mechanism of absorption of BZPH in the colon may be different than that after SI and ORAL. Urinary recovery data were consistent with plasma data.(ABSTRACT TRUNCATED AT 250 WORDS)

Pharmacokinetic characterisation of transdermal delivery systems.

The key aspects of the pharmacokinetics of transdermal delivery systems including time lag, steady-state plasma levels and decline phase are illustrated in this review. The 7 currently marketed transdermal systems [nitroglycerin (glyceryl trinitrate), estradiol, clonidine, fentanyl, nicotine, scopolamine (hyoscine) and estradiol/norethisterone acetate] are discussed, as are systems in development. Single-dose absolute bioavailability studies characterise the period of onset, the steady-state plateau and the declining phase, and typify transdermal delivery. More complex temporal profiles result from interactions with enhancers or removal of the system before steady-state conditions are achieved. Clinically these systems are used to achieve multiple peak serum estradiol concentrations after application of transdermal estradiol, and an initial peak systemic concentration of testosterone after application of transdermal testosterone. Multiple-dose, dose proportionality and skin site bioequivalence studies are needed for the full pharmacokinetic characterisation of a transdermal delivery system. The relationship of system design to variability is discussed. Although the data are limited, population factors, cutaneous metabolism and tolerance all appear to influence the disposition of drugs administered transdermally. For example, the route of delivery influences which nitroglycerin metabolite predominates. Furthermore, as a result of tolerance to nitrates, a transdermal delivery system must be removed for 8 to 12 hours for optimal effect. Therefore, transdermal delivery systems, designed on the basis of pharmacokinetic principles and concentration-effect relationships, have the potential to provide optimal therapy for the treatment of some conditions.

Effect of food on the relative bioavailability of a hypolipidemic agent (CGP 43371) in healthy subjects.

The relative bioavailability of a capsule formulation and the effects of food on the pharmacokinetics of a hypolipidemic agent (CGP 43371) in 12 healthy subjects were examined. Each subject randomly received a single dose of 800 mg of CGP 43371, either as a dispersion formulation under fasting conditions or as a capsule formulation under fasting and fed conditions in a three-way crossover design with a washout period of 2 weeks between each treatment. Serial blood samples were collected at frequent intervals up to 96 h after each treatment. The concentrations of CGP 43371 in plasma were determined by a normal-phase HPLC method. Similar mean pharmacokinetic data (peak plasma drug concentration, 0.16 versus 0.18 micrograms/mL; area under the plasma drug concentration-time curve from time zero to infinity, 4.56 versus 4.22 micrograms.h/mL; time to the peak plasma drug concentration, 10.3 versus 10.2 h; lag time, 3.7 versus 3.8 h; and terminal elimination half-life, 17.8 versus 15.0 h) for the dispersion and capsule formulations under fasting conditions indicated that both formulations were bioequivalent with respect to the rate and extent of absorption. In contrast, the mean peak plasma drug concentration (2.01 micrograms/mL) and area under the curve from time zero to infinity (57.35 micrograms.h/mL) for the capsule formulation with food were enhanced approximately 11- and 14-fold, respectively, when compared with that without food. The corresponding mean lag time (2.1 h) was decreased approximately 50%. These differences in pharmacokinetic parameters were statistically significant, on the basis of an analysis of variance.(ABSTRACT TRUNCATED AT 250 WORDS)

Pharmacokinetic interaction study between benazepril and amlodipine in healthy subjects.

Pharmacokinetic interaction between benazepril (ACE inhibitor) and amlodipine (calcium channel blocker) was studied in 12 healthy subjects. Single doses of benazepril hydrochloride (10-mg tablet) and amlodipine besylate (tablet equivalent to 5 mg amlodipine) were administered alone or in combination according to a three-way, Latin-Square, randomized cross-over design. Serial blood samples were collected following each administration for the determination of benazepril and its active metabolite benazeprilat and amlodipine. The mean values of AUC (0-4 h), Cmax and Tmax for benazepril given as combination versus given alone were 161 vs 140 ng.h.ml-1, 168 vs 149 ng.ml-1, and 0.5 vs 0.6 h. The mean values of AUC (0-24 h), Cmax and Tmax for benazeprilat after benazepril given as combination versus given alone were 1470 vs 1410 ng.h.ml-1, 292 vs 257 ng.ml-1, and 1.7 vs 1.5 h. The mean values of AUC (0-144 h), Cmax and Tmax for amlodipine given as combination versus given alone were 118 vs 114 ng.h.ml-1, 2.5 vs 2.3 ng.ml-1, and 8.3 vs 9.0 h. The differences in these pharmacokinetic parameters between the combination and monotherapy treatments were not statistically significant based on ANOVA. The results of this study indicate that no pharmacokinetic interaction existed between the two drugs.

Hypoglycemic and insulin response to a continuous intravenous infusion of CGP-35126 recombinant human insulin-like growth factor-I (rhIGF-I) in healthy males.

Recombinant human insulin-like growth factor-I (rhIGF-I) produced by expression in a yeast vector was evaluated in seven normal men to determine effects on plasma glucose and insulin levels. Each subject received an initial intravenous infusion of normal saline and on the following day, rhIGF-I at a rate of 21.4 micrograms/kg/hour. Each infusion lasted for 7 hours. The subjects' fasting baseline glucose and insulin levels were not statistically different (P > .05) from their pre-dose levels. Compared with the saline (control) infusion, serum glucose levels were statistically lower (P < .05) 2 hours into the rhIGF-I infusion. These lower glucose levels were maintained until the subjects consumed a standard lunch (4 hours into the infusion). Insulin levels demonstrated a similar response to rhIGF-I, but decreases in insulin levels occurred after the rhIGF-I hypoglycemic effect. This observation suggests that suppression of insulin levels may be due to secondary hypoglycemia rather than to a direct rhIGF-I effect. This study demonstrated the desired rhIGF-I effect of lowering subjects' glucose levels without clinically significant hypoglycemia. This finding suggests that rhIGF-I may have potential clinical utility in hyperglycemic states.

Relationship between systemic drug absorption and gastrointestinal transit after the simultaneous oral administration of carbamazepine as a controlled-release system and as a suspension of 15N-labelled drug to healthy volunteers.

1. Plasma drug concentrations after a single oral administration of a suspension of carbamazepine (CBZ) and a 20/200 CBZ Oros osmotic pump system were measured in eight healthy male volunteers. The oral suspension contained 100 mg CBZ labelled with the stable isotope nitrogen-15, whilst the Oros contained 200 mg unlabelled CBZ. Plasma concentrations of [15N]-CBZ and CBZ were measured simultaneously by gas chromatography-mass spectrometry. 2. The position of the CBZ Oros (labelled with indium-111) in the gastrointestinal tract was followed by gamma scintigraphy. Plasma drug concentrations after the two treatments were used to relate pharmacokinetic with transit data. 3. The Oros was taken after breakfast and gastric emptying occurred between 1.1- greater than h post-dosing (median, 5.3 h). Small intestinal transit times ranged from 1.5- greater than 3.6 h, with a median of 2.2 h. There were wide individual variations in colonic transit, and the total transit time ranged from 10-60 h (median, 22 h). 4. Relative systemic bioavailability of CBZ from the Oros was reduced compared with that from the suspension (mean dose normalised AUC ratio = 0.69 +/- 0.17; mean dose-normalised AUC ratio = 0.85 +/- 0.13, allowing for actual release from the Oros system). 5. The in vivo absorption of drug into the systemic circulation from the Oros was estimated using the Wagner-Nelson method. This showed that absorption of CBZ was rapid when the Oros was present in the stomach and small intestine, the rate being determined by the release of drug from the system.(ABSTRACT TRUNCATED AT 250 WORDS)

Pharmacokinetics of multiple daily transdermal doses of nicotine in healthy smokers.

The plasma concentration-time profiles and pharmacokinetics were characterized for nicotine and its major metabolite, cotinine, after multiple daily application of a nicotine user-activated transdermal therapeutic system (UATTS) to nine healthy smokers. The volunteers abstained from smoking 24 hr prior to and during the course of the study. A 10-cm2 system (designed to deliver 75 micrograms/cm2/hr) was applied every 24 hr for 5 days, with serial blood samples taken on Days 1 and 5 and after system removal on Day 5. Generally, the nicotine UATTS was well tolerated. Predose nicotine concentrations on Days 3 to 5 indicated that steady state was reached by Day 3. The nicotine pharmacokinetic parameters for Day 1 and Day 5 were similar: the mean (SD) AUC(0-24) values for Days 1 and 5 were 271.7 (50.7) and 311.7 (55.0) ng.hr/ml, the mean (SD) Cmax values were 16.3 (2.6) and 16.8 (2.9) ng/ml, and the median (range) Tmax values on Days 1 and 5 were 12 (9-24) hr and 12 (0-24) hr, respectively. There was only slight or no accumulation of nicotine after multiple dosing as indicated by the Day 5 to Day 1 AUC and Cmax ratios of 1.15 (0.09) and 0.98 (0.06), respectively. Overall, the UATTS system maintained relatively constant plasma nicotine concentrations and is suitable for once-daily application.

Application of radiotelemetric technique in evaluating diclofenac sodium absorption after oral administration of various dosage forms in healthy volunteers.

A radiotelemetric technique with the Heidelberg capsule (HC) was used to improve the quality of data generated in a bioavailability study involving an enteric-coated (EC) formulation. Further, changes in plasma levels of the drug from other dosage forms were related to changes in pH environment as determined by the HC. Eight healthy male subjects received the following treatments, 15 min after a light breakfast, according to a randomized, four-way crossover design: (A) HC and 75 mg of a diclofenac sodium aqueous buffered solution: (B) HC and one 75-mg Voltaren EC tablet; (C) HC and one 100-mg Voltaren slow-release (SR) tablet; and (D) HC alone. Each treatment was separated by a 1-week washout period. Two additional subjects subsequently received Treatment B only. Multiple peaks were observed in the drug plasma level-time profiles for the buffered aqueous solution which, in all cases, occurred before gastric emptying of the HC. The multiple peaks were not observed for the Voltaren SR tablet, but a variable absorption lag time occurred which coincided with the gastric residence time of the SR tablet. For the EC tablet the variability of individual plasma level-time profiles was drastically reduced when the time after dosing was adjusted to coincide with gastric emptying of the HC. Finally, the lag time between gastric emptying of the EC tablet and the onset of drug absorption was consistently at 1 hr for all subjects. This lag time was longer than the in vitro disintegration or dissolution times measured under USP conditions.

The effect of impaired renal function on the pharmacokinetics of metoprolol after single administration of a 14/190 metoprolol OROS system.

Renal function is known to sometimes have a significant effect on the pharmacokinetics of drugs or drug metabolites, which are eliminated in appreciable amounts by the kidneys. For this reason, we conducted a study to compare the plasma concentration profiles of metoprolol and its metabolite, alpha-hydroxymetoprolol (OH-metoprolol), in healthy volunteers and in renally impaired patients. Following a single oral dose of a 14/190 metoprolol OROS (oral osmotic) tablet, plasma metoprolol profiles were shown to be similar for both subject groups. However, in renally impaired patients, renal clearance of OH-metoprolol was reduced and mean plasma levels of OH-metoprolol were increased approximately two- to threefold in comparison with healthy volunteers. The accumulation of OH-metoprolol in plasma, however, is unlikely to contribute to the beta-blocking effect of metoprolol, since OH-metoprolol possesses only one tenth the activity of its parent compound.

Relationship between the rate of appearance of oxprenolol in the systemic circulation and the location of an oxprenolol Oros 16/260 drug delivery system within the gastrointestinal tract as determined by scintigraphy.

1. The position in the gastrointestinal tract of an orally administered oxprenolol Oros drug delivery system labelled with technetium-99m DTPA was followed by gamma scintigraphy, and the corresponding plasma drug concentration-time profiles after oral and i.v. administration were used to relate pharmacokinetic and transit data. 2. Gastric emptying time (0.8 +/- 0.4 h, mean +/- s.d.), and the time to arrival in the colon (3.8 +/- 0.7 h) were reasonably consistent after administration of the Oros system to fasted subjects, as were the calculated small intestine transit times (3.0 +/- 0.7 h). As expected there were wide individual variations in colonic transit, so that recorded values for total transit ranged from 6 to 32 h (median, 24.7 h). 3. Absorption of oxprenolol occurred throughout the GI tract including the colon. Plasma drug concentration-time profiles and input functions (calculated by deconvolution) could be related to transit behaviour and in vitro release. Inflexions in the calculated rate of drug input when the Oros system was located in the colon corresponded with periods of stagnation at the hepatic and splenic flexures in two subjects and the ileocaecal junction in two others. The mechanism of these changes is unclear.

Plasma and synovial fluid concentrations of diclofenac sodium and its hydroxylated metabolites during once-daily administration of a 100 mg slow-release formulation.

Plasma and knee joint synovial fluid (SF) concentration of diclofenac sodium and its hydroxylated metabolites were measured after chronic dosing with the 100 mg polymer matrix formulation. Peak concentrations were reached in plasma and SF roughly after administration. Plasma concentrations then fell rapidly, but concentrations in SF were maintained for up to 25 h. The active metabolite was present in both fluids throughout the study period. The slow-release form showed a longer plasma/SF equilibration time than the conventional tablet had in a previous study. Prostaglandin E1 and F2 alpha concentrations were lower in the early post-dose period but did not correlate with drug concentrations.

Baclofen in the elderly stroke patient its side-effects and pharmacokinetics.

A double blind crossover trial of baclofen against placebo in elderly stroke patients was discontinued because the drug produced an unacceptably high level of drowsiness. In a subsequent study baclofen 10 mg was given orally to 12 elderly stroke patients, and drug concentrations measured from a series of plasma samples. A group of healthy subjects given the same dose in a previous study were used as controls. Elderly patients took longer to achieve peak plasma baclofen concentrations, but healthy controls had higher peak values and eliminated the drug more rapidly; areas under the curve were similar in the two groups. Simulations based on mean data suggest that increased drowsiness in the elderly was probably not due to changes in the drug's pharmacokinetic behaviour.

Pharmacokinetics of pirprofen in young volunteers and elderly patients.

Plasma concentrations of pirprofen were measured in 11 elderly arthritic patients and 6 healthy young volunteers at the beginning and end of 8 days treatment with 400 mg doses twice daily. The mean ages of the two groups were 74.5 and 21.8 years, respectively. There were no statistically significant differences in peak concentrations, times to peak, areas under the curve or terminal elimination half-lives between the groups after single dosing. Repeated dosing increased plasma drug concentrations in both groups but the extent was as predicted from the single dose data. Again there were no statistically significant differences between the groups, although pre-dosing plasma concentrations were higher in the elderly compared with the young individuals. The results of this relatively small study suggest that advancing age and arthritic disease appear to have little influence on the pharmacokinetics of pirprofen and no modification in the dosage recommendation in elderly patients without overt renal or hepatic impairment is indicated.

Pharmacokinetic investigation of the absorption of oxprenolol from Oros delivery systems in healthy volunteers: comparison of in vivo and in vitro drug release.

The absorption kinetics of oxprenolol have been investigated in eight healthy volunteers after single dosing with 16/260 Oros drug delivery systems. Oxprenolol disposition kinetics in individual subjects were estimated from intravenous dose data. Loo-Riegelman analysis of the plasma concentration data indicated an extended duration of drug absorption for the Oros system. Initially, the in vivo absorption rate was similar to the in vitro release rate but after 5-6 h it slowed perceptibly. However, at later times similar in vivo and in vitro rates were again observed. The absolute bioavailabilities for prototype and clinical trial systems were shown to be similar, at approximately 42%, and no significant differences in plasma profiles or pharmacokinetic constants were detected between the two Oros forms. A comparison of plasma concentration data in seven subjects who received the prototype system on two occasions in separate studies indicated a consistent level of drug absorption from this preparation. Approximately 10-15% of the administered dose was found in Oros systems recovered from faeces. The quantity of drug remaining was poorly correlated with the observed areas under the plasma concentration-time curve.

Single-dose pharmacokinetic and pharmacodynamic comparison of polymer-matrix (Slow Trasicor) and Oros dosage forms of oxprenolol in healthy volunteers.

Oxprenolol was administered in single doses by mouth to healthy volunteers either in a polymer-matrix slow-release formulation (Slow Trasicor) or in osmotic drug-delivery systems (oxprenolol Oros). Plasma oxprenolol concentrations and heart rates after exercise were measured. Plasma concentrations of the drug were maximal at 3 h but negligible at 24 h after administration of Slow Trasicor. Following ingestion of the Oros systems measurable concentrations were maintained throughout 24 h. Significant reduction of exercise-induced tachycardia persisted for 24 h after administration of oxprenolol Oros. With Slow Trasicor heart rate responses had returned to baseline values by this time. The osmotic drug-delivery systems appear to sustain significant beta-adrenoceptor blockade for 24 h after a single oral dose.