A
polymer double-cavity
prefilled syringe comprises a
barrel with a bypass, the
barrel is provided with a finger
handle and an adapter, a needle seat is arranged on the adapter, a needle body is fixed on the needle seat, and a protective cap is arranged on the outer side of the needle body. A front
plunger, a middle
plunger and a rear
plunger are arranged in the
barrel, and the rear plunger abuts against a plunger rod. The cylinder is formed by integral injection molding of
polymer, a group of ribs which are arranged side by side and protrude towards the interior of the cylinder are arranged on the inner wall of the cylinder, the
axial length of each rib is larger than that of the middle plunger, the bypass is formed by a gap between every two adjacent ribs, and the outer
diameter of the cylinder is larger than that of the adapter; the protective cap is tightly connected with the needle seat, a first anti-falling mechanism is arranged on the joint face of the protective cap and the needle seat, and an inner cavity of the protective cap is communicated with the outside through a
bacteria-blocking, hydrophobic and breathable filter membrane. The bypass is formed in the mode that the protruding edges protrude inwards, demolding is convenient, integrated injection molding
machining can be conducted through polymers, cost is low, damage is not prone to occurring, and the using effect is good. The outer surface of the cylinder is smooth, the heat conduction performance is good, and the vacuum freeze-
drying efficiency is high.