Things which vitiate fasting
1- Using non-nutritive antibiotic eye drops.
2- Using contact lenses solution (antibacterial and cleansing). Upon wearing contact lenses a drop of the solution usually enters the eyes and travels to the nasal passage and throat.
3- Using skin nourishing moisturizing creams, ointments and hair nourishing oils which are absorbed by the skin and scalp.
4- Using injections (pain killers, antibiotics, etc ...).
5- Using saline solutions, glucose and mannitol (a diuretic used by patients suffering from ocular hypertension).
6- Using moisturizing lip balms.
Questions 1 & 2
Scholars have differed over the ruling for using eye drops during fasting. The dominant opinion of the Hanafis and the apparent position of the Shafi'is is that eye drops do not vitiate fasting. According to them, the reason is because eye drops are not inconsistent with fasting which means abstaining from food and drink. They do not invalidate fasting even if the eye drops can be tasted in the throat because the eyes are not an open body orifice.
Maliki and Hanbali scholars maintained that using eye drops nullifies fasting if the drops reach the throat because, according to them, the eye is an orifice, although not a usual one.
Since the eyes are not considered an open orifice, we opine that anything that enters the eyes, solutions or medicine, does not nullify fasting even if it reaches the throat. The taste of the eye drops in the throat does not mean that the eyes are orifices; rather, they reach the throat through the skin.
Hanafi and Shafi'i scholars as well as Ad-Dardir from among the Malikis have maintained that oils and creams rubbed on the head and abdomen do not invalidate fasting even if they reach an internal body cavity through the pores. This is because they do not reach an internal body cavity through an open orifice and because they are consistent with fasting. According to Al-Mirghani in Al-Hidaya, oils and creams provide a kind of relief and are not among the things that nullify the fast.
The Malikis maintained in their well known opinion, that if a person can taste the oils and creams in his throat, he must make up his fast due to the established principle of their school which states, "Any liquid that reaches the throat, even through other than the mouth, invalidates fasting."
We maintain the opinion of the Shafi'i and Hanafi scholars, that oils and creams do not break the fast, relying on their authentic and strong evidences.
Questions 4 & 5
Injections, saline solution, glucose and mannitol do not invalidate fasting because they do not enter the body through an open orifice but through the skin. They are absorbed by the skin and there is no difference between this and injecting them into the body.
Lip balm takes the same ruling mentioned above for oils and creams. It does not invalidate fasting provided it is absorbed by the lips and is not swallowed.
The above answers the question and Allah Almighty knows best.