Biomedical subjects

C G Wilson

Publications and source records attributed to C G Wilson.

At least 37 records · Page 2Linked to original sources

PubMed2000

Limited exposure of the healthy distal colon to orally-dosed formulation is further exaggerated in active left-sided ulcerative colitis.

BACKGROUND: Active distal ulcerative colitis is often resistant to topically acting oral formulations. We speculated that the left side of the colon is underexposed to orally-dosed topical agents in patients with active distal colitis. METHODS: Twenty-two healthy volunteers (12 males, aged 22-47 years), and 10 patients (6 males, aged 33-73 years) with active left-sided ulcerative colitis ingested a Eudragit-coated gelatine capsule containing 111In-labelled amberlite resin on four successive days. Regional colonic distribution, transit times and percentage of daily dose resident were calculated from the average of four serial gamma camera images on the 4th day. RESULTS: (mean [95% CI]). When compared to controls, patients with colitis had significantly faster total colon transit (24.3 h [9.5-39.1] vs. 51.7 h [41.1-62.3]) as well as faster proximal colon transit (18.7 h [9.1-28.3] vs. 36.7 [28.5-44.9]), and distal colon transit (3.1 h [-0.5 to 6.8] vs. 15.0 h [10.5-19.5]), respectively (all P < 0.01). Material was asymmetrically distributed in health (proximal colon 69% [63-76] vs. distal colon 31% [24-37]). This asymmetry was more extreme in colitis, with corresponding values of 91% [85-96] vs. 9% [4-15]. As a result colitics had less material in the left-sided colon (9% [4-15] vs. 31% [24-37]), P < 0. 001. Colitics had a significantly lower percentage of the daily dose resident within the left side of the colon compared to controls (13% [-2 to 28] vs. 63% [44-81]), P < 0.01. CONCLUSIONS: Delayed release oral formulation is asymmetrically distributed within the colon in health. This asymmetry is exaggerated in active left-sided ulcerative colitis and, together with faster colonic transit, results in reduced exposure of the distal colon to orally-dosed topical agents.

Administration, Oral↗

PubMed1999

Dry powder dosing in liquid vehicles: ocular tolerance and scintigraphic evaluation of a perfluorocarbon suspension.

The ocular tolerance and precorneal disposition of 99mTc-labelled sterile carbon-perfluorodecalin (PFD) and carbon-aqueous suspensions were examined in a cohort of healthy volunteers. Formulations were prepared in PFD or saline using charcoal particles, radiolabelled with [99mTc]diethylenetriaminepentaacetic acid (DTPA) under GMP conditions. Colloidal silicon dioxide was used as a suspending agent. Ocular tolerance was examined following the instillation of each formulation to the eyes of 12 volunteers. The precorneal distribution of both formulations in man was monitored using gamma scintigraphy. Dynamic and static data acquisitions were taken over a period of 150 min after dosing. Carbon particulates suspended in PFD did not show any irritation to the eye. Administration of PFD formulation in man produced a significant increase in ocular retention over a saline formulation (mean residence time (MRT)=157+/-42 and 0.29+/-0.08 min, respectively, P=0.0001). Distribution of the carbon in man followed the same pattern as in a previous reported study in animals. The carbon deposited uniformly along the lid margin in the case of the PFD vehicle, whereas it agglomerated following dosing in the saline vehicle and was ejected from the eye. The novel non-aqueous vehicle system is able to significantly improve the ocular retention of charcoal particles in man and provides a unique distribution of the particles in the eye, which suggests a potential for the PFD system for the treatment of periocular diseases.

Adult↗

PubMed1999

Esophageal transit of risedronate cellulose-coated tablet and gelatin capsule formulations.

Risedronate sodium is an orally active antiresorptive agent and a member of the pyridinyl class of bisphosphonates. It has been approved for the treatment of Paget's disease of the bone and is under development as a chronic therapy for the treatment and prevention of osteoporosis. A novel cellulose film-coated tablet formulation was developed to optimize esophageal transit of this bisphosphonate. The aim of the present study was to compare the esophageal transit of the film-coated tablet formulation of risedronate with its original gelatin capsule dose form. A total of 25 elderly, healthy volunteers (mean 66 years), who were dysphagia-free, participated in this randomized cross-over study. On separate occasions, volunteers swallowed radiolabeled placebo formulations with 50 ml water. Dynamic images with participants in a sitting position were recorded for 10 min using a gamma camera. Scintigraphic imaging showed a delay in esophageal transit (greater than 15 s) in 28% of patients in the capsule group but in none of the tablet group (P<0.05). The mean transit times of the capsules and tablets were 23.8 and 3.3 s, respectively. Esophageal transit of film-coated tablets was faster than gelatin capsules, suggesting that film-coated tablets would be the appropriate formulation for all pivotal trials with risedronate and for subsequent commercialization.

Aged↗

PubMed1999

Temporal dependence of ectopeptidase expression in alveolar epithelial cell culture: implications for study of peptide absorption.

There is little data available regarding the extent of peptide metabolism encountered following inhalation to the lung. We have studied the activity of five ectopeptidases in primary rat alveolar epithelial cells, A549 cells and pulmonary macrophages. Peptidase activity was assayed in the plasma membrane fractions (PMF) of primary type II alveolar epithelial cells (ATII cells) after 2 days in culture and after 7 days in culture when they had formed monolayers of type I-like cells (ATI-like cells). Dipeptidyl peptidase IV (DPP) activity fell from 36.65 mU/mg protein to 16.29 mU/mg protein between day 2 and day 7 in culture, aminopeptidase N (AMN) activity increased from 16.16 mU/mg protein to 23.99 mU/mg protein, angiotensin-converting enzyme (ACE) activity was lost (4.29 mU/mg protein at day 2, not detected at day 7), and carboxypeptidase M (CPM) activity was acquired (not detected at day 2, 5.20 mU/mg protein at day 7). The profile of exopeptidase expression in A549 cells was similar to that of primary rat alveolar cells at day 7 in culture (DPP 24.24 mU/mg protein, AMN 47.74 mU/mg protein, CPM 4.28 mU/mg protein, ACE not detected). Macrophages expressed high levels of aminopeptidases (DPP 46.85 mU/mg protein, AMN 28.28 mU/mg protein) but carboxypeptidase activity was not detected. Low neutral endopeptidase 24.11 (NEP) activity was found in all cell types studied (0.96-2.41 mU/mg protein). The qualitative and quantitative changes in the peptidase activity of primary cultured rat alveolar cells between day 2 and day 7 in culture has implications for the use of alveolar cell monolayers as drug absorption models to investigate peptide absorption from the lung. Ectopeptidase activity in cultured alveolar cells can be used to infer the peptide-metabolising capacity of the surface of the alveolar epithelium. The aminopeptidase activity in particular, if representative of enzyme activity in vivo, would offer a significant metabolic barrier to systemic delivery of peptides via the lung.

Absorption↗

PubMed1999

Stool water content and colonic drug absorption: contrasting effects of lactulose and codeine.

PURPOSE: By varying stool water content using lactulose and codeine, we investigated the influence of luminal water content on the absorption of quinine, a transcellular probe, and 51Cr-EDTA, a paracellular probe, from the distal gut. METHODS: Sixteen volunteers entered a three-way cross-over trial in which absorption of probe markers from a timed-release delivery system was determined following treatment with lactulose 20 mls tds (increasing water content), or codeine 30 gms qds (decreasing water content), and compared with control untreated values. Stool water content was assessed by freeze drying stool samples. Site of release was determined by gamma scintigraphy, and absorption was measured by plasma levels and urinary recovery of the marker probes. RESULTS: Lactulose accelerated ascending colon transit (3.7 +/- 0.8 vs 4.5 +/- 1.4 hrs, p < 0.05), increased stool water content (75 +/- 2 vs 71 +/- 2%, p < 0.01), caused greater dispersion of released material (dispersion score 3.4 +/- 0.3 vs 1.8 +/- 0.2, p < 0.01), and enhanced absorption of the transcellular probe quinine (4.66 +/- 0.78 vs 3.02 +/- 0.63%, p < 0.05) compared to control. Conversely codeine slowed ascending colon transit (8.9 +/- 1.8 hrs), reduced stool water content (61 +/- 2 vs 71.2%, p < 0.05), and tended to diminish absorption (2.60 +/- 0.77 vs 3.02 +/- 0.63%, p = 0.20). Within the ascending colon specifically, there was a significant trend for treatments increasing luminal water content to enhance quinine absorption (medians: codeine = 1.2%, [n = 81 < control = 2.3%, [n = 5] < lactulose = 3.2%, [n = 71, p < 0.01). Delivery site also had an important influence on absorption, with more distal release resulting in less absorption in the control arm (medians: small intestine = 4.4% [n = 5] > ascending colon = 2.3% [n = 5] > transverse colon = 1.5% [n = 6], p < 0.005). CONCLUSIONS: Lactulose accelerates transit, increases stool water content, and enhances drug absorption from the distal gut whilst codeine slows transit, decreases stool water content, and tends to diminish absorption, compared to controls. We conclude that water content may be an important determinant in colonic drug absorption.

Adult↗

PubMed1999

Regional differences in quinine absorption from the undisturbed human colon assessed using a timed release delivery system.

PURPOSE: To investigate the regional absorption characteristics of the distal gut using two markers of permeability, quinine (a transcellular probe) and 51CrEDTA (a paracellular probe). METHODS: The permeability markers were delivered to the undisturbed gastrointestinal tract in 39 healthy volunteers using an oral timed-release delivery vehicle which allowed pulsed release within a particular site of the gut. Site of release was identified using gamma scintigraphy. Absorption of quinine and 51CrEDTA was assessed by measuring the percent excretion in the urine using HPLC and gamma counting respectively. Serial plasma samples allowed time-concentration curves for quinine to be plotted. RESULTS: There was a significant trend for diminished absorption with more distal delivery of the transcellular probe, quinine, which was: 6.26 +/- 0.87% (small intestine, n = 10); 4.65 +/- 0.93% (ascending colon, n = 16); and 2.59 +/- 0.52% (transverse colon, n = 10) of the ingested dose excreted respectively (p < 0.001). No such gradient was seen with the paracellular marker, 51CrEDTA. CONCLUSIONS: These results suggest that delayed release formulations should aim for release in the distal small bowel and proximal colon if absorption is to be maximised. Absorption by the transcellular route diminishes in the more distal colon, a fact which has implications for delayed or sustained release formulations.

Adult↗

PubMed1999

Night-time quiescence and morning activation in the human colon: effect on transit of dispersed and large single unit formulations.

OBJECTIVES: Controlling the delivery of drugs to different regions of the colon remains an elusive goal. The aim of this study was to define the diurnal variation in colonic transit and show how this influences the colonic distribution and residence time of different formulations given either in the morning or evening. METHODS: Colonic transit of small particulates and a large capsule was measured during nocturnal sleep and daytime wakefulness. Eighteen healthy volunteers participated in a randomised crossover study. 111In-labelled resin (150-300 microm) and a large 99mTc-labelled non-disintegrating capsule (22 x 8 mm) were swallowed at either 0800h or 1700h. MAIN OUTCOME MEASURES: The geometric centre of isotope (range 1-9) was calculated from serial scintiscans allowing comparison of overnight and daytime transit. RESULTS: Transit of resin was delayed in the overnight compared to daytime 8 h periods (change in geometric centres (GCs), mean +/- SEM, 0.59 +/- 0.14 vs 1.46 +/- 0.39 respectively, P < 0.02). Maximal resin movement occurred immediately after awakening, prior to breakfast, in 9/18 studies (P < 0.05). The capsule was more distal than the resin at the end of the study 15 h after dosing (P < 0.001). There was marked inter-individual variability in distribution of both resin and capsule at 15 h, the range of GCs being 2.8-9 and 2.2-9, respectively. CONCLUSION: Sleep delays colonic transit and large capsules travel faster than dispersed small particles. However, substantial inter-individual variability in transit makes targeting specific regions of the human colon unreliable with either dispersed or single unit formulations.

Administration, Rectal↗

PubMed1998

Mebeverine decreases mass movements and stool frequency in lactulose-induced diarrhoea.

BACKGROUND: In spite of its frequent use in the treatment of irritable bowel disease little is known about mebeverine's mode of action in man. AIM: To examine mebeverine's effect on transit though the gut during lactulose-induced diarrhoea. METHODS: Nine healthy volunteers undertook a two-way randomized crossover study. Diarrhoea was induced using lactulose pre-treatment (20 m t.d.s., 4 days) and subjects received either mebeverine (135 mg t.d.s.) or no treatment. Transit of two enteric-coated capsules containing radiolabelled 8.4 mm tablets and 180-250 microM ion exchange resin were followed using gamma scintigraphy. Stool frequency and symptoms were assessed by diary cards. RESULTS: Mebeverine reduced mean daily stool frequency associated with lactulose ingestion from a median of 2.25 (interquartile range (IQR) 1.75-2.75) to 1.5 (IQR 1.25-2.25) movements. Mebeverine significantly reduced the number of mass movements observed in the colon during the 11 h of the study from 2 (2-2) to 1 (1-2), and the number of retrograde movements from 1 (0-2) to 0 (0-0) (P < 0.05). Mebeverine did not significantly alter the gastric emptying rate of the intact capsule (2.9 (1.9-3.2) to 2.8 (2.6-4.0) h) however it induced a small but significant acceleration in small intestinal transit of the capsule (1.6 (0.8-2.0) h to 1.0 (0.52-1.32) h, P=0.02). CONCLUSION: Mebeverine reduces the diarrhoeal effect of lactulose by decreasing the mass movements induced in the ascending colon. This effect may contribute to its clinical effect in irritable bowel syndrome.

Adolescent↗

PubMed1998

In-vivo monitoring of dosage forms.

The use of imaging techniques including gamma scintigraphy to follow the behaviour of drug formulations has revolutionized our knowledge of absorption and distribution in drug delivery. The development of gamma camera techniques as physiological tools to explore organ function became routine by the mid-seventies. Several research groups started to explore the applications of technique in drug delivery. Within 5 years, the utility of the technique became obvious and scintigraphy is now widely accepted as an important investigation tool in formulation research. Gamma scintigraphy is especially useful in exploring sources of inter-subject variation, especially in examining food effects in pharmacokinetic estimations and establishing windows of absorption for oral delivery. As a tool to examine drug delivery to the lung and to the eye, scintigraphy is the method of choice. Magnetic Resonance Imaging (MRI) became more generally employed in medicine two decades after the gamma camera. The superior soft-tissue contrast and resolution compared to computed X-ray tomography rapidly established MRI in clinical investigation. Recent applications in oral drug research has allowed the pharmaceutical scientist to explore new facets of delivery and ultimately combine MRI and scintigraphy in human clinical trials.

Dosage Forms↗

PubMed1998

Ocular contact time of a carbomer gel (GelTears) in humans.

BACKGROUND/AIMS: Carbomers are widely used in products for the treatment of dry eye; however, the polymer gel thins on addition of probes (for example, fluorescein salt) confounding the comparison of products by objective clinical tests such as spectrophotofluorimetry or scintigraphy. A novel method of radiolabelling carbomer gels, with minimum change to their rheology, has permitted the non-invasive evaluation of precorneal residence of the gel in volunteers using gamma scintigraphy. The technique was used to evaluate the precorneal clearance of the liquid phase and of a suspended particulate in GelTears. METHODS: Low sodium technetium-99m labelled diethylenetriaminepentacetic acid (99mTc-DTPA) was used to label carbomer 940 gel, either adsorbed onto sterile charcoal to model an entrapped drug, or added directly to the gel to a final activity of 1 MBq per 25 microliters dose. The clearance of the labelled gels was then compared with 99mTc-DTPA labelled saline in 12 volunteers. RESULTS: The addition of the low sodium radiopharmaceutical produced insignificant rheological changes in the gel compared with conventional 99mTc-DTPA labelling. The residence times on the eye of the gel formulations were significantly greater than that of the saline control. At 8 minutes postdosing, the label levels retained (mean (SD)) on the ocular surface were: saline, 7% (7%); 99mTc-DTPA gel, 42% (27%); and 99mTc-carbon gel, 42% (20%) of administered dose. There was no difference observed in the precorneal distribution between 99mTc-DTPA solution and particulate markers. CONCLUSIONS: These data demonstrate that carbomer based gels significantly extend contact of solutes or suspended solids with the corneal surface. The method of labelling does not significantly change the initial viscosity and is superior to previous methods which have used sodium salts (for example, sodium fluorescein) and therefore underestimate contact time.

Acrylic Resins↗

PubMed1998

[The effect of pretreatment with ranitidine on the pharmacokinetics and gastrointestinal transit of a sustained-release theophylline preparation].

A scintigraphic and pharmacokinetic study of the behavior of Bronchoretard forte (theophylline, CAS 58-55-9) was carried out in 8 healthy male volunteers to evaluate the sensitivity of the preparation to changes in gastric pH. The volunteers were pretreated with ranitidine (CAS 66357-35-5) (150 mg b.i.d.) or placebo for three days prior to and on the study day to reduce gastric acidity. The effect of the pretreatment with ranitidine on gastric pH was measured on the day before study begin and the mean pH was significantly increased compared to the placebo (ranitidine pH 2.2 +/- 2.4; placebo pH 1.6 +/- 2.0, p < 0.01 Wilcoxon Signed Rank test). All subjects were pretreated with theophylline for 3 days (500 mg b.i.d.) to achieve steady state. On the study day, the volunteers swallowed two theophylline sustained release capsules, radiolabelled by inclusion of indium-111 micronised Amberlite resin, and the gastrointestinal transit was followed continuously for 14 h using gamma scintigraphy with a further image at 24 h. Blood samples were taken from each subject throughout the study to determine the pharmacokinetic profile of theophylline in the sustained release formulation. No significant differences were found in the gastrointestinal transit of the labelled microparticulates between the data obtained from the group treated with ranitidine and that from the placebo group. Plasma theophylline concentration profiles were identical for the two treatments. These data indicate that the theophylline sustained release formulation is not sensitive to the effects of major changes in gastric H+ concentration.

Adult↗

PubMed1997

Effect of cardiopulmonary C fibre activation on the firing activity of ventral respiratory group neurones in the rat.

1. Cardiopulmonary C fibre receptor stimulation elicits apnoea and rapid shallow breathing, but the effects on the firing activity of central respiratory neurones are not well understood. This study examined the responses of ventral respiratory group neurones: decrementing expiratory (Edec), augmenting expiratory (Eaug), and inspiratory (I) neurones during cardiopulmonary C fibre receptor-evoked apnoea and rapid shallow breathing. 2. Extracellular neuronal activity, phrenic nerve activity and arterial pressure were recorded in urethane-anaesthetized rats. Cardiopulmonary C fibre receptors were stimulated by right atrial injections of phenylbiguanide. Neurones were tested for antidromic activation from the contra- and ipsilateral ventral respiratory group (VRG), spinal cord and cervical vagus nerve. 3. Edec neurones discharged tonically during cardiopulmonary C fibre-evoked apnoea and rapid shallow breathing, displaying increased burst durations, number of impulses per burst, and mean impulse frequencies. Edec neurones recovered either with the phrenic nerve activity (25 s) or much later (3 min). 4. By contrast, the firing activity of Eaug and most I neurones was decreased, featuring decreased burst durations and number of impulses per burst and increased interburst intervals. Eaug activity recovered in approximately 3 min and inspiratory activity in approximately 1 min. 5. The results indicate that cardiopulmonary C fibre receptor stimulation causes tonic firing of Edec neurones and decreases in Eaug and I neuronal activity coincident with apnoea or rapid shallow breathing.

Action Potentials↗

PubMed1996

Non-NMDA receptors transmit cardiopulmonary C fibre input in nucleus tractus solitarii in rats.

1. We sought first to determine whether neurones in caudomedial aspects of commissural nucleus tractus solitarii (NTS) received input from cardiopulmonary C fibre endings supplied by the pulmonary versus systemic circulation. We then examined the role of N-methyl-D-aspartate (NMDA) and non-NMDA receptors in transmitting cardiopulmonary C fibre input to such NTS neurones. 2. Extracellular NTS unit activity, phrenic nerve activity and arterial blood pressure were recorded in urethane-anaesthetized rats. Unit responses to right atrial and left ventricular phenylbiguanide injections were compared in rats with arterial baroreceptors, carotid chemo-receptors and subdiaphragmatic vagal inputs eliminated. Right atrial phenylbiguanide injections produced greater peak responses (27 +/- 11 impulses s-1) than did left ventricular injections (11 +/- 3 impulses s-1) (n = 9). 3. The non-NMDA receptor agonist quisqualic acid (QUIS) and NMDA were ionophoresed onto NTS neurones that were synaptically activated by right atrial phenylbiguanide injection. Responses were compared before and during ionophoresis of the non-NMDA receptor antagonist 2,3-dihydroxy-6-nitro-7-sulphamoylbenzo(f)quinoxaline (NBQX), the NMDA receptor antagonist DL-2-amino-5-phosphovaleric acid (AP5), or the broad spectrum antagonist kynurenic acid (KYN). 4. NBQX, which blocked QUIS-but spared NMDA-evoked responses, significantly attenuated synaptic activation by 65% (n = 9). AP5, which blocked NMDA- but spared QUIS-evoked responses, did not significantly diminish synaptic activation (11%; n = 7). KYN, which blocked QUIS- and NMDA-evoked responses, decreased synaptic activation by 70% (n = 9). 5. The results suggest that input from cardiopulmonary C fibre endings, primarily supplied by the pulmonary circulation, is transmitted to this commissural NTS region largely via non-NMDA receptors.

2-Amino-5-phosphonovalerate↗

PubMed1995

Three-dimensional visualisation of the large bowel: a potential tool for assessing targeted drug delivery and colonic pathology.

A study has been undertaken to assess the feasibility of three-dimensional imaging of the dispersion of a non-absorbable tracer released into the colon of normal subjects. Six healthy volunteers were selected who were participating in a scintigraphic study designed to assess the spreading of 1 MBq indium-111 Amberlite resin delivered from a delayed capsule system targeted to release in the ascending colon. In each case subjects were imaged using a rotating gamma camera over a data collection period of approximately 20 min. Three-dimensional volume rendered images demonstrated good visualisation of the dispersion of the tracer throughout the ascending, transverse and descending colon and provided good anatomical visualisation of the shape of the colon, not previously apparent from the planar views. The present study demonstrates for the first time, the successful three-dimensional imaging of a radiolabelled tracer dispersed throughout the colon and opens up the prospects for more detailed study of quantification of the volume and distribution of tracers contained within the colon.

Adult↗

PubMed1995

Pulmonary venous congestion augments respiratory motoneuronal responses to cigarette smoke in rabbit.

We examined the effects of cigarette smoke inhaled during subthreshold pulmonary venous congestion (sPVC) on phrenic nerve (PN) and unit activity in the ventral respiratory group in rabbits. sPVC was achieved by inflating a balloon in the left atrium. Inhalation of low-nicotine cigarette smoke produced initial prolonged bursts in 34 (19 bulbospinal) out of 43 inspiratory (I) cells and in PN. Smoke decreased the activity of 29 out of 36 expiratory (E) cells (27 of 32 early E and 2 of 4 late E). The prolonged PN bursts occasionally progressed to doublets superimposed over regularly occurring PN bursts. sPVC augmented the smoke effects: I cells displayed greater increases in spikes/burst (27 vs. 12%; P = 0.02) and burst duration (42 vs. 20%; P = 0.02) and greater decreases in interburst interval (34 vs. 10%; P < 0.02); PN displayed greater increases in I time (40 vs. 27%; P < 0.05), greater decreases in E time (18 vs. 26%; P < 0.05), and a greater incidence and duration of time of PN doublets (29 +/- 9 vs. 9 +/- 4 s; P < 0.03); E cells displayed greater decreases in spikes/burst (43 vs. 29%; P = 0.01) and burst durations (35 vs. 18%; P < 0.01). Smoke-induced respiratory changes may be exaggerated during sPVC.

Animals↗

PubMed1994

Image shift of intracoronal pins viewed on bite-wing and panoramic radiographs.

Pins were placed into dentin in molars and premolars in a dried mandible. Panoramic and bite-wing radiographs were obtained, and measurements of the images of pins on these radiographs were compared with measurements of the mandible. The bite-wing radiographs showed little distortion of the relative distance between pins. The panoramic radiographs showed magnification and parallax shift of images of pins; the distance between pins placed mesially and distally in a tooth was magnified maximally at the first molar, decreasing to the third molar. For pins related diagonally in a tooth, the image showed magnification and parallax shift so that the apparent distance between pins placed mesiobuccally and distolingually increased from bicuspid to third molar, whereas distobuccally and mesiolingually placed pins showed the reverse trend. Guidelines are given for the evaluation of bite-wing and panoramic radiographs that can give clinically valuable information about the positions of intracoronal features.

Artifacts↗

PubMed1994

The effect of pectin on the gastric emptying rates and blood glucose levels after a test meal.

This study was designed to evaluate the effect of pectin given in a palatable form on the gastric emptying rates of the solid and liquid phases of a test meal and to ascertain whether pectin affected blood glucose levels in ten healthy male and female volunteers. Gastric emptying was measured using dual isotope gamma scintigraphy. Allocation to the treatment group was double-blind and randomized. Sequential blood sampling was used to measure blood glucose levels. The times for the stomach to empty half the radiolabelled meal were similar after both pectin and placebo; however, a significant difference was seen between the AUC values of the meal between the two treatments. This can be attributed to the divergence of the emptying curves after the time point at which 50% of the meal had emptied, as pectin delayed the emptying of the last 20% of the meal. The initial phase of emptying for both pectin and placebo was significantly faster than the meal. No significant difference was found between blood glucose levels when either pectin or placebo was administered.

Blood Glucose↗

PubMed1994

Impaired oesophageal transit of capsule versus tablet formulations in the elderly.

Drug induced oesophageal injury is an important and preventable cause of iatrogenic injury. In most cases the injury is considered to be due to mucosal contact from formulations lodged in the oesophagus. A scintigraphic study was performed comparing the oesophageal transit of enteric coated tablets with similar sized and shaped gelatin capsules, using a population of elderly healthy volunteers similar in age (50-79 years) to the population most likely to be receiving regular treatment. Twenty three volunteers injected the radiolabelled tablet or capsule with 50 ml of water while sitting on two separate occasions according to a randomisation schedule. Oesophageal transit was assessed by gamma scintigraphy. Gastric residence was also assessed in 11 of 23 subjects. While the tablet was readily cleared from the oesophagus, mean transit time 4.3 seconds (range 1.0-14.0), the capsule often showed a comparatively prolonged holdup, mean transit time 20.9 seconds (range 1.5-174.5). Ten of 11 tablets emptied from the stomach intact, while all 11 capsules broke up in the stomach. Gelatin capsules showed a clear tendency to remain within the oesophagus of healthy elderly volunteers, while similar sized enteric coated tablets did not. These studies show the importance of assessing oesophageal transit when designing the formulation of drugs with a potential for oesophageal injury.

Administration, Oral↗