This semisynthetic penicillin, analogous to penicillin V, was introduced in the early 1960s. Although it is better absorbed from the gastrointestinal tract, overall it is inferior to phenoxymethylpenicillin and phenoxyethylpenicillin because of its lower antibacterial activity [1].

Experiments were designed to test the antibiotic (1-phenoxypropyl)penicillin (propicillin) against a complex microflora of periodontal bacteria [2]. Peptostreptococcus species, Prevotella intermedia, Lactobacillus catenaforme, and Streptococcus species were dominant members of the enrichment culture. None of the strains isolated from the enrichment culture exhibited detectable b-lactamase activity. MICs of propicillin for the organisms ranged from 0.1 to 1.2 mg/ml. Propicillin was added to the cultures in single doses that were repeated once or twice at 24-h intervals, that is, after 2.4 volume changes of the culture vessel. Analyses done 24 h after the last addition of propicillin revealed that total cell counts of the culture were hardly affected by 1 mg of propicillin per liter, although some changes in the microbial composition occurred. The relative insusceptibility of the culture might be explained by the low growth rate. Higher concentrations (5, 10, and 50 mg/ml) of the antibiotic caused 10- to 20-fold drops in total cell counts. In these cultures P. intermnedia was selectively suppressed to below the detection level, whereas other organisms that were equally susceptible to propicillin were less affected.

 Therapeutic use


Dosage and Administration





Protein binding  
Cmax (mg/ml)  
tmax (hrs)  
Distribution volume Vd (l/kg)  






Mechanism of Action

By binding to specific penicillin-binding proteins (PBPs) located inside the bacterial cell wall, penicillin V inhibits the third and last stage of bacterial cell wall synthesis. Cell lysis is then mediated by bacterial cell wall autolytic enzymes such as autolysins.

Other pharmacological effects


Medicinal Chemistry

CAS number:  551-27-9  EINECS:

Molecular Formula: C18H22N2O5S

Average mass: 378.442688 Da

Monoisotopic mass: 378.124939 Da

Systematic name: (2S,5R,6R)-3,3-Dimethyl-7-oxo-6-[(2-phenoxybutanoyl)amino]-4-thia-1-azabicyclo[3.2.0]heptane-2-carboxylic acid

SMILES: CCC(C(=O)N[C@H]1[C@@H]2N(C1=O)[C@H](C(S2)(C)C)C(=O)O)OC3=CC=CC=C3

Std. InChI: 1S/C18H22N2O5S/c1-4-11(25-10-8-6-5-7-9-10)14(21)19-12-15(22)20-13(17(23)24)18(2,3)26-16(12)20/h5-9,11-13,16H,4H2,1-3H3,(H,19,21)(H,23,24)/t11?,12-,13+,16-/m1/s1

ACD/LogP: 2.750.26 # of Rule of 5 Violations: 0
ACD/LogD (pH 5.5): -0.22 ACD/LogD (pH 7.4): -0.97
ACD/BCF (pH 5.5): 1.00 ACD/BCF (pH 7.4): 1.00
ACD/KOC (pH 5.5): 1.00 ACD/KOC (pH 7.4): 1.00
#H bond acceptors: 7 #H bond donors: 2
#Freely Rotating Bonds: 6 Polar Surface Area: 121.24 2
Index of Refraction: 1.628 Molar Refractivity: 97.30.4 cm3
Molar Volume: 274.25.0 cm3 Polarizability: 38.60.5 10-24cm3
Surface Tension: 63.35.0 dyne/cm Density: 1.40.1 g/cm3
Flash Point: 362.331.5 C Enthalpy of Vaporization: 104.23.0 kJ/mol
Boiling Point: 675.555.0 C at 760 mmHg Vapour Pressure: 0.02.2 mmHg at 25C


Major Impurities:


Melting point:

Optical rotation:

Solubility: 22.7 mg/L

logP: 2.65




1. Bond J.M., Lightbown J.W., Barber M., Waterworth P.M. "A comparison of four phenoxypenicillins". Br. Med. J. 2: 956, (1963).

2. Van der Hoeven  J. S. and Van den Kieboom C. W. "Effects of propicillin on mixed continuous cultures of periodontal bacteria". Antimicrob. Agents Chemother. 35(9): 17171720, (1991).




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