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  • 1
    ISSN: 1573-904X
    Keywords: vaginal delivery ; gamma scintigraphy ; bioadhesion ; pessary ; post-menopausal women
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Purpose. In this paper we report on the first scintigraphic evaluation of vaginal dosage forms in post-menopausal women. To date, almost nothing is known about the in vivo performance of pharmaceutical formulations in the human vagina, which is a major deficiency in the rational design of drug delivery systems for both existing and new indications. Methods. The vaginal spreading and clearance of a radiolabelled pessary formulation and Replens® (polycarbophil) gel, was assessed in six healthy, post-menopausal female volunteers over a six hour period using the technique of gamma scintigraphy. Results. In five out of the six subjects studied, clearance of the two formulations exhibited very little intra-subject variation. However, there was considerable inter-subject variability in clearance; in Subject 5 circa 80% of the products were retained whilst in Subject 2 less than 2% was present at the end of the six hour imaging period. Importantly, there was no evidence to suggest that either of the formulations dispersed material beyond the cervix, into the uterus, in any of the subjects studied. Conclusions. The lack of significant retention of these products in most of the volunteers has obvious implications for the delivery of therapeutic agents. This study shows that gamma scintigraphy is an invaluable technique with which to assess novel formulations aimed at optimising retention in the vagina for topical or systemic drug delivery.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1573-904X
    Keywords: saquinavir ; protease inhibitor ; gastrointestinal tract ; food effects ; pharmacoscintigraphy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Purpose. To evaluate mechanistically the effect of food on the absorption and gastrointestinal transit of the protease inhibitor saquinavir. Methods. Pharmacoscintigraphic investigation in eight healthy volunteers. Results. Gastric emptying occurred rapidly in the fasted state with some capsules leaving the stomach prior to disintegration. Unmeasur-able plasma concentrations were observed in several subjects when dosed under fasted conditions. Following post-prandial administration the radioactive marker became re-distributed within the stomach contents and consequently slower gastric emptying resulted. Plasma concentrations under fed conditions were measurable up to 12 hrs after administration in seven of the eight subjects. Six of the eight plasma profiles showed secondary peaks at c. 4 hours post-dose; two of which coincided with the gastrocolonic response following ingestion of lunch. Conclusions. Bioavailability of saquinavir is significantly improved in the presence of food. Emptying of intact capsules in the fasted state may further reduce bioavailability. In the fed state, capsules disintegrate rapidly and gastric emptying is prolonged which may improve exposure of the drug to target absorption sites. Saquinavir may be absorbed from the colon. Second peaks in the absorption profile can only be attributed to gastrocolonic response following ingestion of a meal in some cases. Increased absorption is more likely to be due to an increase in dissolved drug being available for absorption due to general increased motility and secretion stimulated by ingestion of a meal.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Pharmaceutical research 15 (1998), S. 1026-1030 
    ISSN: 1573-904X
    Keywords: hard gelatin capsule ; cross-linking ; disintegration ; scintigraphy ; gastrointestinal tract
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Purpose. To evaluate if the cross-linking of gelatin affects in vivo capsule disintegration. Methods. Scintigraphic investigation in nine healthy volunteers to provide for a real time visualisation of capsule disintegration. Results. The moderately stressed capsules failed the USP dissolution specification for acetaminophen capsule when tested in water and conventional SGF but passed with the addition of pepsin. Moderately stressed capsules started to disintegrate at 10 ± 6 minutes (range 6 to 24 minutes) compared to 8 ± 2 minutes (range 5 to 11 minutes) for the unstressed capsule. Conclusions. The results of the study clearly demonstrate that with the incisive technique of gamma scintigraphy there are no differences in the in vivodisintegration properties of moderately stressed and unstressed capsules.
    Type of Medium: Electronic Resource
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