How many drops of tick medication are absorbed? - briefly
Only a small fraction of the applied drops penetrates the skin; the majority remains on the surface and is lost through evaporation or rubbing. Absorption efficiency varies with formulation, skin condition, and application technique.
How many drops of tick medication are absorbed? - in detail
The absorption of topical tick‑control solutions depends on the formulation’s physicochemical properties, the animal’s skin characteristics, and the application technique. Lipophilic carriers penetrate the stratum corneum more efficiently, while aqueous bases rely on occlusion to enhance uptake. Cutaneous absorption typically occurs within minutes for liquid drops, reaching a plateau after 30–60 minutes.
Key variables influencing the amount of medication taken up include:
- Droplet volume – standard drops range from 0.05 mL to 0.1 mL; the exact volume determines the total active ingredient delivered.
- Concentration of the active ingredient – higher percentages increase the dose per drop, affecting systemic exposure.
- Skin thickness and hair density – thicker epidermis and dense fur reduce penetration, requiring a greater number of drops for comparable effect.
- Temperature and humidity – warm, moist conditions elevate skin permeability, accelerating absorption.
- Application site – areas with less keratinization (e.g., inner ear, neck) absorb more readily than heavily keratinized regions (e.g., paws).
Typical absorption rates reported in veterinary pharmacology studies are:
- Immediate uptake – 10–20 % of the administered dose enters the epidermis within the first 5 minutes.
- Peak systemic concentration – 40–55 % of the dose is detected in plasma after 30 minutes.
- Total bioavailability – 60–75 % of the applied medication becomes available for systemic distribution over a 2‑hour period.
When calculating the required number of drops for effective tick control, the following procedure is recommended:
- Determine the animal’s weight and the label‑specified dose (e.g., 0.5 mg kg⁻¹).
- Multiply the dose by the animal’s weight to obtain the total required milligrams of active ingredient.
- Divide the total milligrams by the concentration per milliliter to find the volume needed.
- Convert the volume to drops using the known droplet size (e.g., 0.07 mL per drop).
Example: For a 12‑kg dog, with a label dose of 0.5 mg kg⁻¹ and a formulation containing 2 mg mL⁻¹, the required volume is (12 kg × 0.5 mg kg⁻¹) ÷ 2 mg mL⁻¹ = 3 mL. At 0.07 mL per drop, the calculation yields approximately 43 drops. Adjustments may be necessary based on the variables listed above.