Police said Ariel Rocabo, 27, one of the security guards detailed at the drugstore branch, sustained a bullet wound in the buttocks after putting up resistance against the suspects.
He is currently recuperating at the Ospital ng Makati.
Investigation showed the suspects entered the drugstore at the corner of Francisco street and Pasig Line in Sta. Ana, Manila at around 7 p.m.
Once inside, two of the suspects disarmed guards Rocalbo and Rod Navarro. The latter was dragged and hogtied inside the store office, while Rocalbo was shot when he resisted.
The suspects ordered seven employees to lie face down on the floor, then started to ransack the store of cash and expensive medicines.
The heist was over in five minutes. The suspects fired successive shots in the air before leaving.
Investigators said the suspects, who were armed with short firearms, stopped a passing taxicab (TWR-855) and ordered the driver to step out before taking the vehicle and speeding off. Two others escaped on board a tricycle.
The taxi was later found abandoned at the corner of Felix and De las Alas streets in Pandacan.
Police said the suspects are remnants of the "Harurot Gang" based in Kahilum street in Pandacan.
The gang laid low for a while after its leader was killed in an encounter with Manila policemen two years ago.