Dr. Dawn Merton Boothe
Auburn University

Study Start Date: 03/01/2007
Study End Date: Open

Evidence of Effective Drug Delivery using Transdermal Gel Delivery Systems in Cats.

A 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 preparation).

Study Design:
Prospective cohort study, not blinded or randomized.

Sample Size:
Not specified

Inclusion criteria:

1. Cats currently receiving the following drugs transdermally: enrofloxacin, metronidazole, prednisolone, fluoxetine, amitriptyline, clomipramine, buprenorphine, and cyproheptadine and methimazole.
2. Owners who will allow the collection of two samples post-dosing.

Exclusion Criteria:
None. Cats receiving drugs other than those specified above can participate as long as sufficient information is provided regarding other medications.

Study Controls:
Cats receiving the following medications orally: enrofloxacin, metronidazole, prednisolone, fluoxetine, amitriptyline, clomipramine, buprenorphine, cyproheptadine or methimazole.

Samples:

1. 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.
2. 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.
3. 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.
4. 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.
5. A client consent form will need to be completed and can be obtained from the study investigators.

Costs/Reimbursements:
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
finchtm@auburn.edu
334-844-7187 (lab)
The website for the laboratory is: http://www.vetmed.auburn.edu/index.pl/clinpharmlab

PI Contact Info:
Dawn Merton Boothe, DVM, PhD, DACVIM, DACVCP
109 Greene Hall
Auburn, AL 36849
boothdm@vetmed.auburn.edu
334-844-7187

Full Disclosure information:

• The study is funded by a grant from American Association of Feline Practitioners.
• 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.