Eye drop

As eye drops ( Oculoguttae ) refers to a dosage form of medicines for use in the eye. By dropping this aqueous or oily preparation into the conjunctival sac or on the cornea of the drug contained may act locally. Typical applications for eye drops are the treatment of dryness and irritation of the eye, glaucoma or conjunctivitis (conjunctivitis) and corneal inflammation ( keratitis).

After provision of the European Pharmacopoeia (Ph. Eur ) are to make eye drops always sterile. As a pharmacy- only medicine they may be issued in Germany only in pharmacies. Eye drops are either in single dose ampules or plastic eye dropper bottles made ​​of special glass ( brown glass type I glass) available. In addition to the industrial production of eye drops can also be the recipe usually produced in the pharmacy doctor's prescription.

In order not to irritate the eye, eye drops a physiological pH of 7.4 ( Isohydrie ) and one corresponding to the corneal epithelium osmotic pressure ( isotonic ) should ideally have. However, many drugs are not sufficiently chemically stable under these pH conditions. Therefore, it represents the pH of the eye drops with acids or alkalis so that optimum stability of the active substance is achieved, but the pH is still in physiologically compatible, euhydrischen range ( about pH 7.3 to 9.7 ). After introduction into the eye, the pH is adjusted by the buffer action of the lachrymal fluid on the physiological pH. The eye drops should not be self- buffered in this case, since the buffering capacity present in the tear fluid and bicarbonate Eiweiß-/Phosphat- is very low. However isohydric eye drops can be buffered.

Preservation

Preservatives should get into the bloodstream never possible, so no preservatives may be used in the operated eye or injured. Common preservatives are:

  • Thimerosal 0.002%
  • Organic mercury compounds phenylmercuric
  • 0.002-0.01 % benzalkonium chloride ( quaternary ammonium compounds / quaternary ammonium salts)
  • Chlorhexidine 0.005-0.01 %
  • Benzyl alcohol 0.5-1%

Substances with preservative properties include:

  • Glucose preservative from 70 %
  • Ethanol from 20 %
  • Propylene glycol from 20 %
Active ingredient Osmosis Bicarbonate buffering system
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