Electronic pills are electronically controlled ingestible capsules which can be used to provide therapeutic treatment during traversal of the alimentary tract. An electronic pill generally comprises a medicine reservoir, a dispensing opening, and a pump for transporting the medicine from the reservoir to the dispensing opening. Generally, the electronic pill also comprises control means to activate the dispensing pump at the desired moment, e.g. responsive to a signal from a sensor, such as a pH sensor which can be an integral part of the pill. After swallowing the pill is moved along the alimentary tract by the peristaltic movement of the muscles along the alimentary tract. During its travel through the intestines the pill drifts from the pylorus to the ileocaecal valve at about 1 m/hour. Due to the peristalsis of the small intestines superposed on the drift velocity, large velocity variations occur pushing the pill back and forth through the intestines. This way medication released from the pill is mixed thoroughly before it will be taken up through the wall of the intestines or becomes locally effective.
An example of an electronic pill is disclosed in WO 2006077529. One of the embodiments of the electronic pill disclosed in this publication comprises different reservoirs for delivering more than one medicament. Associated closure members are independently controlled for dispensing medicament.
Being capable of dispensing a medical fluid is useful for medicines which are in liquid form, or aqueous solution or suspension. However, a majority of drugs are in solid state and have poor solubility in a biocompatible solvent and often their solutions have a much shorter shelf life (typically factor 1000 shorter than solid) as compared with solid. Powder or granule is a common elemental or intermediate form of in the production of a drug. It is therefore very desirable to have an electronic capsule capable of dispensing medication powders or granules.
Powder dispensers have been used widely in various industries, such as the pharmaceutical industry where they are used as in-line dosing, handling, or transport equipment. When these powder dispensers are in operation, they are in a fixed orientation, may use a gravity feed, and are continuously fed with powder supply. Further, they always dispense powders in air. A powder dispenser to be used in an electronic capsule must release powder in a wet environment, even under a fluid, and can not assume a dominant orientation. Because of these unconventional conditions, existing powder dispensers are not suitable for an electronic capsule to release medication powders. The wet environment presents another problem for some moisture-absorbing powders, which may crystallize or cluster quickly after absorbing moisture. Another limitation is presented by large particle size distribution, which makes precise dosing difficult with a miniaturized powder dispenser based on continuous feeding. For both research and therapy, it is desirable to delivery drugs as powder in given doses to multiple targeted locations of the gastro-intestinal tract autonomously.