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Triesence (Triamcinolone Acetonide Ophthalmic) - Description and Clinical Pharmacology

 
 



DESCRIPTION

TRIESENCE® (triamcinolone acetonide injectable suspension) 40 mg/mL is a synthetic corticosteroid with anti-inflammatory action. Each mL of the sterile, aqueous suspension provides 40 mg of triamcinolone acetonide, with sodium chloride for isotonicity, 0.5% (w/v) carboxymethylcellulose sodium and 0.015% polysorbate 80. It also contains potassium chloride, calcium chloride (dihydrate), magnesium chloride (hexahydrate), sodium acetate (trihydrate), sodium citrate (dihydrate) and water for injection. Sodium hydroxide and hydrochloric acid may be present to adjust pH to a target value 6 - 7.5.

The chemical name for triamcinolone acetonide is 9-Fluro- 11β, 16α, 17,21-tetrahydroxypregna-1,4-diene-3,20-dione cyclic 16,17- acetal with acetone. Its structural formula of C24H31FO6 is:

434.50 MW

Triamcinolone acetonide occurs as a white to cream-colored, crystalline powder having not more than a slight odor and is practically insoluble in water and very soluble in alcohol.

CLINICAL PHARMACOLOGY

Mechanism of Action

Naturally occurring glucocorticoids (hydrocortisone and cortisone), which also have salt-retaining properties, are used as replacement therapy in adrenocortical deficiency states. Their synthetic analogs such as prednisolone and triamcinolone are primarily used for their anti-inflammatory effects in disorders of many organ systems.

Triamcinolone acetonide possesses glucocorticoid activity typical of this class of drug, but with little or no mineralocorticoid activity. For the purposes of comparison, the following is the equivalent milligram dosage of the various glucocorticoids:

Cortisone, 25 Prednisone, 5 Paramethasone, 2
Hydrocortisone, 20 Methylprednisolone, 4 Betamethasone, 0.75
Prednisolone, 5 Triamcinolone, 4 Dexamethasone, 0.75

Corticosteroids have been demonstrated to depress the production of eosinophils and lymphocytes, but erythropoiesis and production of polymorphonuclear leukocytes are stimulated. Inflammatory processes (edema, fibrin deposition, capillary dilatation, migration of leukocytes and phagocytosis) and the later stages of wound healing (capillary proliferation, deposition of collagen, cicatrization) are inhibited.

Pharmacokinetics

Aqueous humor pharmacokinetics of triamcinolone have been assessed in 5 patients following a single intravitreal administration (4 mg) of triamcinolone acetonide. Aqueous humor samples were obtained from 5 patients (5 eyes) via an anterior chamber paracentesis on Days 1, 3, 10, 17 and 31 post injection. Peak aqueous humor concentrations of triamcinolone ranged from 2151 to 7202 ng/mL, half-life 76 to 635 hours, and the area under the concentration-time curve (AUC0-t) from 231 to 1911 ng.h/mL following the single intravitreal administration. The mean elimination half-life was 18.7 ± 5.7 days in 4 nonvitrectomized eyes (4 patients). In a patient who had undergone vitrectomy (1 eye), the elimination half-life of triamcinolone from the vitreous was much faster (3.2 days) relative to patients that had not undergone vitrectomy.

NONCLINICAL TOXICOLOGY

Carcinogenesis, Mutagenesis, Impairment of Fertility

No evidence of mutagenicity was detected from in-vitro tests conducted with triamcinolone acetonide including a reverse mutation test in Salmonella bacteria and a forward mutation test in Chinese hamster ovary cells. With regard to carcinogenicity, in a two-year study in rats, triamcinolone acetonide caused no treatment-related carcinogenicity at oral doses up to 0.001mg/kg and in a two-year study in mice, triamcinolone acetonide caused no treatment-related carcinogenicity at oral doses up to 0.003 mg/kg (less than 1/25th of the recommended human dose). In male and female rats, triamcinolone acetonide caused no change in pregnancy rate at oral doses up to 0.015 mg/kg, but caused increased fetal resorptions and stillbirths and decreases in pup weight and survival at doses of 0.005 mg/kg (less than 1/10th of the recommended human dose).

Animal Toxicology and/or Pharmacology

Studies were conducted with triamcinolone acetonide, including those employing the proposed dosage form, i.e., 4.0% triamcinolone acetonide injectable suspension formulation containing 0.5% carboxymethylcellulose and 0.015% polysorbate-80 in a balanced salt solution.

Triamcinolone acetonide was demonstrated to be non-inflammatory when injected intravitreally in NZW rabbits, non-cytotoxic to mouse L-929 cells in an in-vitro assay and non-sensitizing in a guinea-pig maximization assay. Furthermore, the results of single-dose intravitreal injection studies with triamcinolone acetonide in both rabbits and monkeys demonstrate that the drug is well tolerated for up to one month with only minor findings of slight decrease in body weight gain and slight corneal thinning.

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