Synthesis, pharmacokinetics, efficacy, and rat retinal toxicity of a novel mitomycin C-triamcinolone acetonide conjugate.

A novel conjugate of mitomycin C (MMC) and triamcinolone acetonide (TA) was synthesized using glutaric acid as a linker molecule. To determine the rate of hydrolysis, the conjugate was dissolved in aqueous solution and the rate of appearance of free MMC and TA was determined by high-performance liquid chromatography analysis. Antiproliferative activity of the MMC-TA conjugate and parent compounds was assessed using an NIH 3T3 fibroblast cell line. Cell growth was quantified using the MTT assay. Kinetic analysis of the hydrolysis rate demonstrated that the conjugate had a half-life of 23.6 h in aqueous solutions. The antiproliferative activities of the MMC-TA conjugate and MMC were both concentration dependent, with similar IC(50) values of 2.4 and 1.7 microM, respectively. However, individual responses at concentrations above 3 microM showed that the conjugate was less active than MMC alone. TA alone showed only limited inhibition of cell growth. Studies evaluating intravitreal injection of the conjugate demonstrate that this agent produced no measurable toxicity. Our data provide evidence that the MMC-TA conjugate could be used as a slow-release drug delivery system. This could in turn be used to modulate a posttreatment wound healing process or to treat various proliferative diseases.

Triamcinolone acetonide 21-oic acid methyl ester: a potent local antiinflammatory steroid without detectable systemic effects.

There have been many previous attempts to prepare glucocorticoid analogs that would have high antiinflammatory activity at the site of application but minimal systemic side effects. In principle, esters of cortoic acids could fulfill these criteria, if they had sufficient affinity for the glucocorticoid receptors but were rapidly hydrolyzed to the inactive acids in the circulation. With this rationale, we have synthesized esters of the 21-oic acid of triamcinolone acetonide (TA, 9 alpha-fluoro-11 beta, 16 alpha, 17 alpha, 21-tetrahydroxy-pregna-1, 4-diene-3,20-dione 16,17-acetonide), a potent synthetic glucocorticoid, in both tritiated and unlabeled forms. The synthesis involves 1) oxidation to the 21-dehydro compound with methanolic cupric acetate, 2) further oxidation to the acid with methylene blue in the presence of KCN at pH 6.5, 3) esterification with diazomethane in the presence of methanol or ethanol, to produce the methyl ester of TA (TAme) or ethyl ester, respectively, and 4) purification of the products by TLC and HPLC. The molecular weights and structures of the esters were established by mass spectrometry and nuclear magnetic resonance. The binding of [3H]TAme to steroid receptors or serum steroid-binding proteins and the in vitro hydrolysis of the ester were evaluated simultaneously, by chromatography on Sephadex LH-20 columns in aqueous buffer. [3H]TAme is bound with high affinity by receptors from human leukemic cells and rat liver. The pattern of competition for this binding is characteristic of glucocorticoid receptors: TA approximately equal to TAme greater than R5020 (a synthetic progestin) approximately equal to aldosterone greater than 5 alpha-dihydrotestosterone. [3H]TAme is not bound detectably by serum steroid-binding proteins and is rapidly hydrolyzed during incubation with serum at 37 C. The acidic product has a very low affinity for the glucocorticoid receptor. Complexes of [3H]TAme with human and rat receptors have sedimentation coefficients of 9-10S in hypotonic buffer containing 20 mM Na2MoO4 and approximately 4S in hypertonic, molybdate-free buffer. These values of s20,w are similar to those of the oligomeric and monomeric forms, respectively, of the same receptors labeled with [3H]TA, and of mammalian steroid receptors, in general. The antiinflammatory activity of TAme in rats is comparable to that of prednisolone, but the ester is devoid of the side effects associated with prednisolone treatment (suppression of thymic weight and of serum corticosterone concentration). These bioassay data and the high affinity of the ester for human glucocorticoid receptors suggest that TAme may eventually be useful clinically, as a loc

Chemical modification of triamcinolone acetonide to improve liposomal encapsulation.

The 21-palmitate of triamcinolone acetonide was synthesized to aid in the liposomal encapsulation of the drug. Encapsulation efficiency of triamcinolone acetonide-21-palmitate was 85%, compared with 5% for the parent drug.

3-Chloro-1,3,5-pregnatriene derivatives with glucocorticoid activity.

Novel synthetic glucocorticoid analogues were tested for receptor binding and glucocorticoid activity. They were of unusual structure, insofar as they had a 3-chloro rather than a 3-oxo function. 3-Chloro analogues of fluorinated glucocorticoids formed extremely stable complexes with the rat liver glucocorticoid receptor. 3-Chloro derivative of fluocinolone acetonide also had in vivo glucocorticoid activity. It induced tyrosine aminotransferase in the liver and repressed thymidine kinase in the thymus very effectively. It is concluded that 3-chloro analogues may retain glucocorticoid activity as well as the ability to bind to the glucocorticoid receptor protein.

[New esters of prednisolone and triamcinolone acetonide and their anti-inflammatory activity]. / Nuovi esteri del prednisolone e del triamcinolone acetonide e loro attività antiinfiammatoria

Seventeen acids with diphenylyl and cyclohexylphenyl groups were esterified with the hydroxyl group at position 21 of prednisolone and triamcinolone acetonide. Some of these esters showed marked activity against carrageenin edema and Selye spots in the rat, especially on local application.