A1,
A2,
B,
C1,
C2,
D,
E,
F,
G-H,
I-K,
L,
M,
N,
O,
P1,
P2,
Q-R,
S,
T,
U-V,
W-Z
Benzamycin Pharmacology, Pharmacokinetics, Studies, Metabolism - Erythromycin
Benzamycin Pharmacology, Pharmacokinetics, Studies, Metabolism - Erythromycin
CLINICAL PHARMACOLOGY
Pharmacokinetics: Benzoyl peroxide has been shown to be absorbed
by the skin where it is converted to benzoic acid. A single dose pharmacokinetic
study, involving the application of either one or three units of Benzamycin®
Pak, was performed in 16 adult acne patients to determine systemic absorption
of erythromycin. Erythromycin (with a plasma lower limit of quantitation of
2 ng/ml) was not detectable, except in one patient who was in the one unit application
group.
Pharmacodynamics: The exact mechanism by which erythromycin
and benzoyl peroxide reduce lesions of acne vulgaris is not fully known.
CLINICAL STUDIES
In two adequate and well controlled clinical studies 228 patients
used Benzamycin® Pak, 113 patients used the currently marketed Benzamycin®
Topical Gel, and 183 patients used vehicle. Benzamycin® Pak applied twice
daily for 8 weeks was significantly more effective than vehicle and comparable
to Benzamycin® Topical Gel in the treatment of moderate to moderately severe
facial acne vulgaris. Patients entering the study had a minimum of 15 and a
maximum of 80 facial inflammatory lesions (papules and pustules) and a minimum
of 20 and a maximum of 140 facial non-inflammatory lesions (open and closed
comedones). The primary efficacy measures evaluated at week 8 were the lesion
counts and the investigator’s global assessment. Patients were instructed to
wash their face twice daily (morning and evening) with warm water and a mild
cleanser provided by sponsor. No abrasive cloths or sponges, alcoholic toners,
astringents or medicated solutions were used. The medication was to be applied
15 minutes after washing, in a thin film over the entire facial area. A moisturizer
(supplied by the sponsor) or non-medicated make-up could be applied one hour
after application, as needed. All medications were to be kept away from the
eyes. Sun exposure to the face was to be limited.
Outcomes for mean percent reductions in lesion counts and investigators
global weeks of treatment are shown below: assessment after 8
|
Study 1
|
BenzamycinÒ
Pak
|
BenzamycinÒ
Topical Gel
|
BenzamycinÒ
Pak Vehicle
|
BenzamycinÒ
Topical Gel Vehicle
|
|
N = 119
|
N = 113
|
N = 38
|
N = 37
|
|
Mean % Lesion Counts Reduction
|
|
Inflammatory *
|
49%
|
45%
|
17%
|
28%
|
|
Non Inflammatory*
|
46%
|
43%
|
24%
|
20%
|
|
Total *
|
48%
|
44%
|
22%
|
26%
|
|
Investigator’s Global
|
|
Global Success *
|
28%
|
27%
|
3%
|
11%
|
|
* p-value < 0.05 is for the comparison between Benzamycin
Ò Pak and BenzamycinÒ
Pak vehicle
|
|
Study 2
|
Benzamycin Pak
|
Benzamycin Pak Vehicle
|
| |
N = 109
|
N = 108
|
|
Mean % Lesion Counts Reduction
|
|
|
Inflammatory *
|
57%
|
34%
|
|
Non Inflammatory
|
36%
|
30%
|
|
Total *
|
45%
|
31%
|
|
Investigator’s Global
|
|
Global Success *
|
36%
|
12%
|
|
* p-value < 0.05
|
|
|
MICROBIOLOGY
Erythromycin acts by inhibition of protein synthesis in susceptible
organisms by reversibly binding to
50 S ribosomal subunits, thereby inhibiting translocation
of aminoacyl transfer-RNA and inhibiting polypeptide synthesis. Antagonism has
been demonstrated in vitro between erythromycin, lincomycin, chloramphenicol
and clindamycin. Benzoyl peroxide has been shown to be effective in vitro
against Propionibacterium acnes, an anaerobe found in sebaceous follicles
and comedones. Benzoyl peroxide is believed to act by releasing active oxygen.
top
