Antiepileptic dosage form and process for protecting antiepileptic drug

A dosage form for delivering an antiepileptic drug to a gastrointestinal tract includes a compartment containing a drug formulation layer which comprises an antiepileptic drug. The dosage form further includes a semipermeable wall surrounding the compartment. The semipermeable wall has a passageway that allows communication between the compartment and an exterior of the dosage form. An internal lamina is formed on an inner surface of the semipermeable wall. The internal lamina is substantially soluble in water. The internal lamina in a hydrated state forms a gelatinous layer that lubricates the semipermeable wall, thereby preventing crack formation in the semipermeable wall while the dosage form is dispensing the drug.