Formulation and in vitro evaluation of Cyclosporine A emulsion using Experimental Design technique

Postgraduate Thesis uoadl:1319122 311 Read counter

Unit:
Κατεύθυνση Βιομηχανική Φαρμακευτική
Library of the School of Science
Deposit date:
2016-04-19
Year:
2016
Author:
Τζουανάκη Σοφία
Supervisors info:
Παρασκευάς Δάλλας Επίκουρος Καθηγητής
Original Title:
Μορφοποίηση και in vitro Αξιολόγηση Γαλακτωμάτων Κυκλοσπορίνης Α με τη χρήση Πειραματικού Σχεδιασμού
Languages:
Greek
Translated title:
Formulation and in vitro evaluation of Cyclosporine A emulsion using Experimental Design technique
Summary:
The Dry Eye Syndrome (DES) is caused by the alteration of the amount or quality
of the lacrimal fluid resulting in the insufficient lubrication of the front
surface of the cornea. It is accompanied by increased osmolality of the tear
film and inflammation of the ocular surface. Cyclosporine containing
formulations is an option for the treatment of DES, as it acts against
inflammation of the ocular cavity, resulting in the increase of the production
of tears, and the expansion of the conjunctival blood vessels
Due to the extremely low solubility of cyclosporine in aqueous media there have
been many research efforts in order to create a satisfactory ophthalmic
delivery system. Emulsions have many advantages over other formulations as they
are relatively inexpensive and simple to manufacture and sterilize.
Particularly submicron emulsions are sufficiently stable systems. Moreover they
are optically clear or slightly turbid liquids as they contain droplets that
scatter light waves weakly.
The objective of the present study was the formulation and evaluation of a
cyclosporine A formulation suitable for ophthalmic use. For this purpose,
ophthalmic emulsions consisting of approved and safe for the eye excipients
were prepared. The internal oil phase of the emulsions contained dissolved
cyclosporine A with a therapeutic dose of 0.05% w/w. A further desirable
characteristic of these emulsions was the reduction of droplets of the internal
phase in sizes smaller than 100 nm.
The development and the evaluation of the emulsions was performed using Design
of Experiment (DoE) technique. More specifically the type of the Experimental
Design chosen was the Constrained Mixture Design and the factors studied where
the % proportion of Castor Oil and Medium Chain Triglycerides and of the
surfactant Kolliphor HS 15. Preliminary experiments were conducted in order to
determine cyclosporine’s saturation solubility in different oils. Also ternary
phase diagrams were constructed using the titration method proving the area of
microemulsion’s existence. The results of the preliminary experiments were
taken in to consideration for the selection of the DoE factors. The limits of
the factors were selected based on preliminary experiments and the % amounts
appeared
in the literature for the preparation of ophthalmic o/w emulsions. The matrix
of the experimental design consisted of 12 formulations, one of which was a
repetition.
Eleven of the twelve emulsions prepared were macroscopically stable for three
months from the date of manufacture. Furthermore, the hydrodynamic diameter and
the polydispersity index remained unchanged during the one month in which they
were measured. Moreover, all formulations contained cyclosporine within the
limits set by the Pharmacopoeia.
In vitro evaluation of the formulations was performed measuring two responses.
The first was the hydrodynamic diameter of the emulsion’s inner phase droplets
(Dh). The model chosen for the analysis of the data was linear. The factor
which had a statistically significant effect was the % amount of the
surfactant, since the increase of the surfactant resulted in the decrease of
the hydrodynamic diameter.
The second response was the amount of cyclosporine permeated the membrane per
unit area after 6 hours (Q). An in vitro diffusion experiment was performed,
using artificial cellulose membrane for the comparative study of cyclosporine’s
release from the emulsions. The experiment was performed using modified Franz
cells. It was found that the Special Cubic model simulates the relation of Q
and the factors selected. In the release of cyclosporine two factors had equal
significant effect, the oil Castor Oil and the surfactant Kolliphor HS15. By
increasing the amount of the oil the cyclosporine’s release was decreased while
the effect of the surfactant was the opposite.
In conclusion, the increase of cyclosporine’s release is favored by the
reduction in the hydrodynamic diameter of the droplets of the emulsion’s inner
phase, a phenomenon that is probably due to the increase of cyclosporine’s
release surface. So the emulsion with the maximum amount of surfactant and the
minimum amount of oil had the best characteristics, i.e. the smallest Dh and
greater release.
Keywords:
Dry Eye Syndrome, Cyclosporine Α, Microemulsion, Design of Experiment, in vitro release
Index:
Yes
Number of index pages:
119-122
Contains images:
Yes
Number of references:
83
Number of pages:
129
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