Preparation of ear drop

Rate this post

Aim- to prepare and submit the ear drop.


Ear drops are categorized under the otic solutions, the primary intended use of these preparations is to remove the wax present in the ear or the treatment of pain, infection, and inflammation in the ear. The preparation including some medication is applied in form of drops. Common classes of drugs used in this preparation are, benzocaine, neomycin, and cortisone for the treatment of pain, infection, and inflammation respectively. These drug molecules can be dissolved in the appropriate solvents/ buffers and dispersants could be used along with them. Moreover, glycerine and propylene glycol can be used for increasing the viscosity of the ear drop. Drug-added viscous solutions allow drugs to remain there for a long time, interestingly, anhydrous glycerine can be useful in reducing the swelling in the ear, due to its hygroscopic nature it removes surrounding moisture, which may result in reduced swelling. These formulations may contain surfactant and viscosity enhancers, which may easily lead to ear wax removal.1

In a patient with a bacterial infection in the ear, antibiotic treatment is necessary and has promising effects in the treatment of infection, however, system antibiotic therapy might increase the bacterial resistance as well as increase the cost of the treatment. The topical antibiotic treatment is the best choice for the treatment of infection, as it reduces the cost as well as it might be highly effective because one can use a high concentration of antibiotics in a topical formulation. Systemic antibiotics go under hepatic metabolism and can show other systemic side effects such as vomiting, diarrhoea, rashes, headache, and serious reactions like Stevens-Johnson syndrome, which could be minimized in topical preparations.2

The ear drop preparation is intended for the treatment of different infections and has been found more effective when dexamethasone is added along with the antibiotics, for instance, the addition of dexamethasone with polymyxin/neomycin sulfate has shown higher efficacy in acute bacterial otitis externa than the antibiotic drug alone.2 Moreover, steroids/antibiotics containing ear drops can reduce otorrhoea. Interestingly, the different drugs shown delayed tympanic membrane healing.3

Furthermore, the pH of the ear drop preparations plays a crucial role in the treatment of various ear problems, usually, the pH of a healthy ear canal skin is acidic in nature, some literature suggests the reacidification of the ear canal may resolve the otitis externa. Many ears drop preparations have a pH in the range of 2.8-7.8, acid is bactericidal to many bacteria as well as the acid can prevent fungal growth also.2,4

Recently, some reports suggest that many of the antibiotics used in ear drops can show ototoxicity (toxicity or ear), some of the components used in the ear drops may reach to the cochlea and vestibule and may cause damage to it. For instance, gentamycin can be toxic to the vestibules and may lead to hearing loss, many reports have been indicating ototoxicity due to gentamycin.2



Beaker, Stirrer/glass rod, Measuring cylinder, Spatula, balance, Storage bottle.


Sodium bicarbonate, Glycerol, Deionized water.

Formulation Table:

Sr.No Ingredients Quantity
1 Sodium Bicarbonate 5 gm
2 Glycerol 30 ml
3 Purified Water 100 ml


For the preparation of ear drops, weigh the required quantity of sodium bicarbonate and add it to the beaker, add some quantity of purified water to the beaker to dissolve the sodium bicarbonate. Add the measured quantity of glycerol to the solution and stir it to mix it well, then transfer the solution to the measuring cylinder and make up the volume up to 100 ml with purified water. Store the prepared ear drop in a storage bottle.3,4

Use: this ear drop is used to remove the wax from the ear.

Label: for external use only


Sodium bicarbonate ear drop is prepared and submitted.

[ps2id id=’references’ target=”/][ps2id id=’1′ target=”/]


  1. Felton L, Remington: Essential of Pharmaceutics, am, J Pharm Educ. 2013.
  2. Pappas, S., et al., Topical antibiotic ear drops: are they safe? International journal of clinical practice. 2006;60(9):1115-9.
  3. Dirain, C.O., B. Kosko, and P.J. Antonelli, Effects of common ear drops on tympanic membrane healing in rats. Otolaryngol Head Neck Surg. 2018;158(5):917-22.
  4. Eng, C.-Y. and A.S. El-Hawrani, The pH of commonly used topical ear drops in the treatment of otitis externa. Ear Nose Throat J. 2011;90(4):160-2.
  5. Mosges, R., et al., Dexamethasone phosphate in antibiotic ear drops for the treatment of acute bacterial otitis externa. Curr Med Res Opin. 2008;24(8):2339-47.
  7. British pharmacopoeia.


  1. Ear drops preparations sterile or non-sterile preparations?

ANS: Ear drops can be both sterile as well as non-sterile, the ear drops used in surgical procedures or in injured ears are sterile preparations

  1. Why the most ear drops have acidic pH?

ANS: External ear canal has an acidic microenvironment; it is considered that the reacidification may resolve the ear infection problems, additionally, acidic pH may cause the prevention of bacterial and fungal growth.


Recent articles: To prepare and submit mouthwash

Labmonk Blogs: Click here to visit.

Labmonk Notice Board: Click here to visit.