Transdermal Gel Delivery
Dr. Dawn Merton Boothe
Study Start Date: 03/01/2007
Study End Date: Open
Evidence of Effective Drug Delivery using Transdermal Gel
Delivery Systems in Cats.
number of studies by other investigators have demonstrated poorly predictable drug
concentrations following single doses of transdermal administration. However, drug
delivery may be more predictably effective with multiple dosing, once steady-state
has been achieved and skin permeability has been altered (as has been shown for
methimazole). Because of factors that complicate transdermal drug delivery, efficacy
should be demonstrated for each drug delivered by this method, in the target species.
The simplest way to prove effective delivery of a drug in a patient is by detecting
drug concentrations in patients receiving the gels therapeutically, along with measuring
the drug in the preparation itself (to assure appropriate potency of the compounded
Prospective cohort study, not blinded or randomized.
- Cats currently receiving the following drugs transdermally:
enrofloxacin, metronidazole, prednisolone, fluoxetine, amitriptyline, clomipramine,
buprenorphine, and cyproheptadine and methimazole.
- Owners who will allow the collection of two samples post-dosing.
None. Cats receiving drugs other than those specified above can participate as long
as sufficient information is provided regarding other medications.
Cats receiving the following medications orally: enrofloxacin, metronidazole, prednisolone,
fluoxetine, amitriptyline, clomipramine, buprenorphine, cyproheptadine or methimazole.
- Four total samples will be submitted: the first two at 2 and
12 hrs after the first dose and the second two at 2 and 12 hrs after the 14th (or
thereabouts) dose ( to determine concentration at steady state). For patients receiving
the drug for longer than two weeks, a second and third set of samples are requested
at the end of month two and three. Samples can be plasma or serum (approximately
1 ml), but a serum separator tube should not be used. A very small sample of the
gel being administered will be needed at each sample collection time to confirm
the actual concentration of the preparation administered.
- If you have a patient that is receiving the drug orally, a
matching set of data from a patient (same species) receiving the drug orally will
help with comparisons between gel and oral therapy.
- Second and third choices will be based on what you can send
us. At the very least, one single 2 hr sample after two weeks of therapy.
- For any sample submitted, we MUST have information regarding
the dose, duration, sampling time, and ideally, patient signalment. Whether or not
the animal has responded at the time of sample submission would also be helpful.
All client/patient information will be kept confidential. Materials necessary for
sample collection and submission will be supplied if desired. Serum separator tubes
should not be used.
- A client consent form will need to be completed and can be
obtained from the study investigators.
Laboratory will pay for all shipping and drug analysis. Once collected from the
patient, plasma or serum should be harvested. Samples should be frozen (standard
freezer) until shipped. Batching sample collections such that multiple samples are
shipped simultaneously will help keep costs down. Sample analysis also will be batched
but results will be sent to participating veterinarians as soon as they are available.
Contact Info and Sample Shipping Info:
Please contact the lab to make arrangements for submission materials to be sent
to you, as well as labels to send samples to us:
Clinical Pharmacology Laboratory
142 MacAdory Hall
1500 Wire Road
Auburn, AL 36849
The website for the laboratory is:
PI Contact Info:
Dawn Merton Boothe, DVM, PhD, DACVIM, DACVCP
109 Greene Hall
Auburn, AL 36849
Full Disclosure information:
- The study is funded by a grant from American Association of
- The investigators do not have any conflict of interest.
- The study will be published if results are negative.
- The study will be reported on VIN.
- The authors will acknowledge VIN if the study is published.