A swallowable device for inserting a therapeutic agent preparation (100, 101) into an intestinal wall of a patient's intestinal tract, the device comprising: a swallowable capsule sized to pass through the intestinal tract, the capsule having a capsule wall (20w, 21w), a least a portion of which degrades upon exposure to a selected pH in an intestine while protecting the capsule wall from degradation in the stomach; an expandable member (30, 60, 72) disposed within the capsule, the expandable member having a first and second compartment (34, 35) separated by a releasable valve which releases upon exposure to fluid in the intestinal tract; a reactant contained in one of the compartments; and a liquid contained in the other compartment, wherein when the valve release, the reactant mixes with the liquid to produce a gas which expands the expandable member; a delivery device coupled to the expandable member; at least one tissue penetrating member including a proximal portion detachably coupled to the delivery device, a tissue penetrating distal portion, the tissue penetrating member including a therapeutic agent preparation for delivery into the intestinal wall, wherein the at least one tissue penetrating member is formed at least in part from the therapeutic agent preparation and wherein the tissue penetrating member is configured to be retained in the intestinal wall; and wherein upon expansion of the expandable member, the at least one tissue penetrating member is configured to penetrate the intestinal wall and is advanced into the intestinal wall by the delivery device wherein, the at least one tissue penetrating member is retained in the intestinal wall, and wherein the tissue penetrating member releases the therapeutic agent preparation into the wall of the intestine. a swallowable capsule sized to pass through the intestinal tract, the capsule having a capsule wall (20w, 21w), a least a portion of which degrades upon exposure to a selected pH in an intestine while protecting the capsule wall from degradation in the stomach; an expandable member (30, 60, 72) disposed within the capsule, the expandable member having a first and second compartment (34, 35) separated by a releasable valve which releases upon exposure to fluid in the intestinal tract; a reactant contained in one of the compartments; and a liquid contained in the other compartment, wherein when the valve release, the reactant mixes with the liquid to produce a gas which expands the expandable member; a delivery device coupled to the expandable member; at least one tissue penetrating member including a proximal portion detachably coupled to the delivery device, a tissue penetrating distal portion, the tissue penetrating member including a therapeutic agent preparation for delivery into the intestinal wall, wherein the at least one tissue penetrating member is formed at least in part from the therapeutic agent preparation and wherein the tissue penetrating member is configured to be retained in the intestinal wall; and wherein upon expansion of the expandable member, the at least one tissue penetrating member is configured to penetrate the intestinal wall and is advanced into the intestinal wall by the delivery device wherein, the at least one tissue penetrating member is retained in the intestinal wall, and wherein the tissue penetrating member releases the therapeutic agent preparation into the wall of the intestine.