Metronidazole Ointment in Non-healing Pilonidal Sinus Wounds

Inclusion Criteria:

1. Must give written informed consent.
2. Male or female aged ≥18 years.
3. Previous surgery for pilonidal disease and failure of healing for ≥ 6 weeks post-surgical excision of the pilonidal cyst/sinus;
4. Willingness to stop all other concomitant topical preparations at the site of pilonidal sinus wounds.

Exclusion criteria:

The subject will be excluded from the study if any of the following applies:

1. Presence of non-drained abscess (abscess must have been drained ≥ 6 weeks prior to entry).
2. Subjects who are due to undergo surgery related to pilonidal sinus.
3. Previous use (in the last 2 weeks) or current treatment with any antibiotic. To be determined by medical history prior to screening.
4. Previous treatment with topical metronidazole for pilonidal sinus.
5. Known allergic reaction to metronidazole.
6. Known allergic reaction to excipients of IMP and placebo.
7. Subject is taking any prohibited medication (warfarin-type anticoagulants, fluorouracil, glucocorticoids, other topical preparations to the area of the wound, lithium, cyclosporin and disulfiram).
8. Experimental agents must have been discontinued at least 8 weeks prior to screening or for a period equivalent to 5 half-lives of the agent (whichever is longer).
9. History of epilepsy or seizures.
10. Subject has hepatic insufficiency as defined by laboratory values outside the normal ranges.
11. Women of childbearing potential, defined as all women physiologically capable of becoming pregnant, unless surgically sterile must use effective contraception (either combined oestrogen and progestogen containing hormonal contraception associated with inhibition of ovulation \[oral, intravaginal, transdermal\], progestogen only hormonal contraception associated with inhibition of ovulation \[oral, injectable, implantable\], intrauterine device \[IUD\], intrauterine hormone-releasing system \[IUS\], vasectomised partner, sexual abstinence (only considered an acceptable method of contraception when it is in line with the subjects' usual and preferred lifestyle), combination of male condom with either cap, diaphragm or sponge with spermicide \[double barrier methods\]), and willing and able to continue contraception for 1 month after the last administration of IMP. Women using oral contraception must have started using it at least 2 months prior to screening. Women are not considered to be of childbearing potential if they have had 12 months of natural (spontaneous) amenorrhea with an appropriate clinical profile (e.g. age appropriate, history of vasomotor symptoms) or six months of spontaneous amenorrhea with serum FSH levels that have been confirmed to be in the "postmenopausal range". Or have had a surgical bilateral oophorectomy (with or without hysterectomy) or bilateral tubal ligation at least six weeks before the screening visit. In case of oophorectomy alone, the reproductive status of the woman should have been confirmed by follow up hormone level assessment.
12. Women who are pregnant or breastfeeding at baseline.
13. Subjects with concurrent disease considered by the Investigator to be clinically significant in the context of the study.
14. Subjects who have clinically significant abnormalities on their screening blood tests. "Clinically significant" will be determined by the surgeon at the study site.
15. Subjects who will be unavailable for the duration of the trial, deemed unable to comply with the requirements of the study protocol, likely to be noncompliant with the protocol, or who are felt to be unsuitable by the Investigator for any other reason.
16. Subjects who show a 20% reduction in wound size between screening and baseline.