[Study of the polymorph of etoposidum].

Etoposidum: 4'-demethyl-epipodophyllotoxin-beta-D-ethylidene-pyrano-glucoside or VP-16-213 in trade name is a semisynthetic antineoplastic drug. We found that it has two different kinds of crystal form named crystal A and B, they were crystallized from methanol and ethanol respectively. Their structures were identified by NMR and MS. They have similar infrared spectrum but with repeatable small differences. The powder X-ray diffraction pattern of the two kinds of crystals are quite different. The DSC curve of crystal A is rather smooth but that of crystal B shows abnormal positive and negative peaks. On the other hand, they have the same kind of smooth TGA curves. This fact shows that the positive and negative peaks are not the result of chemical reaction. After heating crystal B in DSC oven at 190 degrees C and 250 degrees C, respectively, their IR spectra showed that the pattern of the first one did not change, but the second one changed to the spectrum of crystal A. This reveals that the positive peak is due to the melting of crystal B and the negative peak is the result of the formation of crystal A. The pharmaceutic preparation of VP-16-213 is its glycerine solution, so the crystal form does not influence the efficacy of the drug.

[A new solution of simultaneous equations and its application in assay of compound preparations].

A new solution of simultaneous equations in spectrophotometry is studied. Owing to replacing the absorption coefficients by the absorption ratios, the authors have obtained rather greater accuracy from Vierordt's method than hitherto. A further development of the same formulation has led to a simple theoretical criterion, which enables the analyst to avoid pairs of wavelengths that are unsatisfactory for precision. This new method has been applied to the assay of compound injection of sodium benzoate and caffeine and compound tablet of amidopyrine and caffeine with satisfactory results.

[Studies on synthesis of baogongteng A--a new myotic agent].

Baogongteng A, isolated from Erycibe obtusifolia Benth., is a new tropane alkaloid used for treating glaucoma. Using synthetic 6 beta-acetoxy-tropinone as starting material, racemic Baogongteng A(8) was synthesized. Synthetic Baogongteng A also shows myotic activities in rabbits, but the potency is half of that of the natural product.