UJI PENETRASI FORMULASI NIOSOM GEL YANG MENGANDUNG MINYAK ATSIRI DAUN SIRIH (Piper betle L.) UNTUK TERAPI ANTI BAKTERI Propionibacterium acnes = THE PENETRATION OF NIOSOM GEL FORMULATION CONTAINING OIL LEAVES AT LEAVES (Piper betle L.) FOR ANTI-BACTERIA THERAPY Propionibacterium acnes