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Biomedical subjects

A P Launchbury

Publications and source records attributed to A P Launchbury.

8 recordsLinked to original sources
PubMed1992

The influence of particle size on the bioavailability of inhaled temazepam.

1. Temazepam was administered by aerosol using a standard protocol to healthy volunteers. Two studies are reported in which different dosage formulations were used: a) 30 mg of the 5 mu diameter particle (n = 6); b) 10 mg of the 2 mu diameter particle (n = 6). 2. An open crossover design was followed in each study. On one occasion in both studies subjects used a gargling procedure to remove drug which had been deposited in the mouth and oropharynx. 3. Serial venous blood samples were drawn for a period of 24 h. The mean total AUC of the 5 mu preparation was significantly reduced by gargling (3153 ng ml-1 h to 1066 ng ml-1 h) (F = 0.32). Gargling also had a significant effect on the mean AUC(0-1 h). 4. In contrast gargling had no significant effect on the mean AUC associated with the smaller diameter particle preparation (630 ng ml-1 h) vs 397 ng ml-1 h (F = 0.74). 5. These findings also indicate that temazepam deposition in the pulmonary tree is enhanced by the use of a 2 mu rather than a 5 mu diameter particle. However, the plasma drug concentrations achieved are unlikely to produce a sufficiently marked sedative effect for endoscopic investigations such as gastroscopy.

Administration, Inhalation↗
PubMed1991

Comparative pharmacokinetics of temazepam Gelthix and liquid-filled soft gelatin capsules.

An open, randomized, cross-over study involving 24 healthy volunteers, shows that a novel formulation of temazepam (temazepam Gelthix, TG) in soft gelatin capsules designed to resist i.v. abuse has a similar pharmacokinetic (P-K) profile to that of a liquid-filled, reference formulation (TL) when administered as a single oral dose of 20 mg. The relative bioavailability of the two formulations assessed in terms of the area under the time versus plasma concentration profile (AUC), although statistically different (P less than 0.05), is well within the acceptable 80-120% limits for bioequivalence. Although the mean Cmax for TG (616.6 ng/ml) is lower than for TL (707.9 ng/ml) and the median time to reach Cmax (Tmax) is 40 min (TG) vs. 30 min (TL), there is no significant difference between TG and TL either in their absorption constant (Ka) (0.123 vs. 0.138 min-1 respectively) or their distribution (a) (29.5 vs. 32.4 min) and elimination (beta) (6.3 vs. 6.6 h) half-lives (t1/2). Thus the essential P-K characteristics for the use of temazepam as a hypnotic and premedicant, specifically a rapid rise followed by a prompt fall in blood levels, are conserved by the Gelthix formulation.

Administration, Oral↗
PubMed1969

Non-stick ointment.

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Anti-Infective Agents↗