Abstract: This invention provides a process for producing a macrocyclic lactone compound, which comprises cultivating Actinoplanes sp. FERM BP-3832, in the presence of L-proline, L-hydroxyproline or L-nipecotic acid, and then isolating a macrocyclic lactone compound from the fermentation broth. The compounds produced by this process include a compound of formula (I). The present invention also relates to a pharmaceutical composition comprising the same, which is useful as immunosuppressive, antimycotic, antitumor agent or the like.

Abstract: This invention relates to methods of inhibiting sorbitol dehydrogenase, lowering fructose levels, and treating or preventing diabetic complications such as diabetic neuropathy, diabetic retinopathy, diabetic nephropathy, diabetic microangiopathy or diabetic macroangiopathy in a mammal using pyrimidine derivatives of formula (I) wherein R.sup.1, R.sup.2, R.sup.3, R.sup.4 and R.sup.5 are defined as below, and to pharmaceutical compositions containing such derivatives. It also relates to certain novel substituted pyrimidines having the above formula. It also relates to mutual prodrugs of compounds of above formula (I) and aldose reductase inhibiting compounds, and to pharmaceutical compositions comprising a compound of above formula (I) and an aldose reductase inhibitor.