If your pet weighs 4,4lbs you need to buy the appropriate product for its body-weight. If you want to use Frontline on her you need to use the appropriate dose: one pipette of Frontline for dogs up to 22lbs. It is not recommended to use half of a pipette because you can not be sure the quantity is divided exactly in half and you might have the solution for the minimum recommended dose in one treatment and not enough for the next one. On top of that the solution is volatile and it loses its efficacy with time once the applicator is opened. Another reason for not keeping an open pipette inside the house is that the product has serious adverse reactions if ingested, can give rashes if it gets on the skin, is highly toxic to kids.
In conclusion please weigh your pet and buy the correct product indicated by its body-weight and use the correct dose. Please read the information enclosed with the product for safe administration and maximum results.