An automatic injection device (100a - 100i) containing a pre-loaded charge of medicament for automatically self-administering the medicament upon actuation thereof, the device comprising: a housing assembly having an interior chamber, the interior chamber including a wet compartment containing a wet medicament component; a seal structure placed at an orifice of the interior chamber, the seal structure being initially in a sealing condition that maintains the wet component within the interior chamber, the seal structure being converted to a mixing condition as a result of activation of the device; a mixing assembly comprised of at least one microfluidic channel in fluid communication with the interior chamber when the device is activated, and a homogenization zone in fluid communication with the at least one microfluidic channel, and wherein a portion of the mixing assembly contains a dry medicament component provided within the microfluidic channel, the dry medicament configured to mix with the wet medicament component when the seal structure is converted to mixing condition, wherein the mixing assembly is an integrated component of the automatic injection device; a delivery assembly that dispenses a charge of medicament from the housing, the delivery assembly being in fluid communication with the homogenization zone; an activation assembly carried by the housing and including a stored energy source, wherein activation of the activation assembly releases the stored energy from the stored energy source, and wherein the release of the stored energy causes a) the seal structure to be converted from the sealing condition to the mixing condition and thereby permit the wet component to pass there through, b) the wet component to be forced through the at least one microfluidic channel and into the homogenization zone to facilitate mixing and homogenization of the wet and dry components, and c) force the mixed components through the delivery assembly, characterized in that the microfluidic channel of the mixing assembly: includes a plurality of grooves formed therein, wherein said grooves facilitate mixing when a wet component flows by said grooves, or includes a plurality of bends, or includes internal structures, or has a diameter which changes along the length of the microfluidic channel, or is a flexible tube that is able to be repositioned or moved as a wet component flows through the tube. a housing assembly having an interior chamber, the interior chamber including a wet compartment containing a wet medicament component; a seal structure placed at an orifice of the interior chamber, the seal structure being initially in a sealing condition that maintains the wet component within the interior chamber, the seal structure being converted to a mixing condition as a result of activation of the device; a mixing assembly comprised of at least one microfluidic channel in fluid communication with the interior chamber when the device is activated, and a homogenization zone in fluid communication with the at least one microfluidic channel, and wherein a portion of the mixing assembly contains a dry medicament component provided within the microfluidic channel, the dry medicament configured to mix with the wet medicament component when the seal structure is converted to mixing condition, wherein the mixing assembly is an integrated component of the automatic injection device; a delivery assembly that dispenses a charge of medicament from the housing, the delivery assembly being in fluid communication with the homogenization zone; an activation assembly carried by the housing and including a stored energy source, wherein activation of the activation assembly releases the stored energy from the stored energy source, and wherein the release of the stored energy causes a) the seal structure to be converted from the sealing condition to the mixing condition and thereby permit the wet component to pass there through, b) the wet component to be forced through the at least one microfluidic channel and into the homogenization zone to facilitate mixing and homogenization of the wet and dry components, and c) force the mixed components through the delivery assembly, characterized in that the microfluidic channel of the mixing assembly: includes a plurality of grooves formed therein, wherein said grooves facilitate mixing when a wet component flows by said grooves, or includes a plurality of bends, or includes internal structures, or has a diameter which changes along the length of the microfluidic channel, or is a flexible tube that is able to be repositioned or moved as a wet component flows through the tube. includes a plurality of grooves formed therein, wherein said grooves facilitate mixing when a wet component flows by said grooves, or includes a plurality of bends, or includes internal structures, or has a diameter which changes along the length of the microfluidic channel, or is a flexible tube that is able to be repositioned or moved as a wet component flows through the tube.