How do we prepare best suppositories of Lamictal and what about their resorption? Can rectal administration be considered instead of oral?

PURPOSE: Interruption of oral Drug Administration poses a significant clinical problem for antiepileptic drugs that have no parenteral formulation. If a drug is absorbed rectally, rectal administration can be a useful alternative when the oral route of administration is not possible. The purpose of this study was to compare the single-dose pharmacokinetics of lamotrigine (LTG) compressed tablets after rectal and oral administration in healthy volunteers.
METHODS: A single LTG compressed tablet (100 mg) was administered orally and rectally to 12 volunteers in this single-dose, two-period, crossover study with A 2-week washout between doses. For rectal administration, tablets were crushed and suspended in 10 mL or water. Plasma samples were collected from 0 to 120 hr after each dose and analyzed for LTG by an HPLC method developed for this investigation.
RESULTS: LTG plasma concentrations were lower after rectal administration versus oral administration. The average area under the curve was 28.90 +/-9.5 Microg/mL/hr after rectal administration and 51.71 +/-19.2 Microg/mL/hr after oral administration. The average maximum LTG concentration was 0.53 +/-0.14 Microg/mL after rectal administration and 1.45 +/-0.35 Microg/mL after oral administration. The relative bioavailability for LTG compressed tablets was 0.63 +/-0.33 for rectal administration. There were no drug-related rashes or serious side effects.
CONCLUSIONS: LTG suspension prepared from LTG compressed tablets is absorbed rectally, although not to the same extent or rate as when given orally.

DESIGN: Two-period, crossover study with a 2-week washout between dosing periods.
PATIENTS: Twelve Healthy adult volunteers.
INTERVENTION: One hundred milligrams of a LTG chewable dispersible tablet was administered by oral and rectal routes.
MEASUREMENTS and MAIN RESULTS: Plasma samples were collected before and up to 120 hours after drug Administration. The samples were analyzed for LTG by high-performance liquid chromatography, and the relative bioavailability was determined. Drug concentrations were lower after rectal than after oral administration. The relative bioavailability (F = AUC (rectal)/AUC (oral)) was 0.52 +/-0.23 (SD).
CONCLUSION: Drug prepared from LTG chewable dispersible tablets is absorbed rectally, although not to the same extent as when given orally. Rectal administration of suspension of these tablets can be an acceptable route of administration.