Abstract: A polymer comprising: a polymeric backbone comprising at least one unit having the structure (I), wherein R-R4 comprise groups selected from the group consisting of H, C1-C12 alkyl, C6-C18 aryl, C7-C18 aralkyl, C6-C18 cycloalkyl or any of the group consisting of C1-C12 alkyl, C6-C18 aryl, C7-C18 aralkyl, C6-C18 cycloalkyl substituted, within the carbon chain or appended thereto, with one or more heteroatoms; R and R2 or R and R4 or R and R1 or R2 and R3 may be joined so that with the carbon atom(s) to which they are attached they together form a saturated, partially unsaturated or unsaturated ring system respectively, may have a pendent group which may incorporate a linker unit, (for example a peptide linkage) or a unit having the structure (I); A comprises a proton donating moiety selected from the group consisting of formula (1).

Abstract: A polymer comprising the unit (I) wherein R is selected form the group consisting of hydrogen, C1-C18 alkyl, C1-C18 aralkyl, C1-C18 alkaryl, carboxylic acid, carboxy-C1-6alkyl, or any one of the C1-C18 alkyl, C1-C18 alkenyl, C1-C18 aralkyl, C1-C18 alkaryl substituted with a heteroatom within, or attached to, the carbon backbone; R1 is selected from the group consisting of hydrogen, C1-C6 alkyl groups; X is an acylating agent and wherein the polymer has a polydispersity of less than 1.4, preferably less than 1.2 and a molecular weight (Mw) of less than 100,000, the polymer is preferably made by controlled radical polymerization and is useful in the production of polymer drug conjugates with desirable biological profiles.

Abstract: Diketopiperazines of formula (A): ##STR1## wherein each of R.sub.1 to R.sub.8 is H or an organic radical as described herein and the pharmaceutically acceptable salts thereof have activity as inhibitors of plasminogen activator inhibitor.

Abstract: Diketopiperazines of the formula ##STR1## where one or both of R.sub.1 and R.sub.2, which are different, are chosen from X and a phenyl group substituted by X, C(O)X, OC(O)CH.sub.2 X, OCH.sub.2 CH.sub.2 X, CH.sub.2 X, CONH(CH.sub.2).sub.n X, O(CH.sub.2).sub.n CH(OH)(CH.sub.2).sub.n X ##STR2## and, where appropriate, the other of R.sub.1 and R.sub.2 is a phenyl group optionally substituted by one or more groups selected from halogen, nitro, methoxy, NHC(O)R.sub.12, CO.sub.2 H, O(CH.sub.2).sub.n N(R.sub.12 R.sub.13), C.sub.1 -C.sub.4 alkyl and (CH.sub.2).sub.n C(O)OR.sub.12 ; X is a five- or six-membered heterocyclic ring selected from the group consisting of pyridyl, imidazolyl, furyl, pyrrolyl, pyrrolidinyl, thienyl, piperazinyl, piperidinyl, morpholinyl, quinolyl, isoquinotyl and indolyl, the heteroatom(s) of the said heterocyclic ring, when nitrogen, being optionally substituted by hydrogen, methyl, oxygen, tertiary-butyloxycarbonyl, or SO.sub.

Abstract: Piperazine derivatives of the formula ##STR1## their esters and salts are useful as modulators of multiple drug resistance.

Abstract: Piperazine derivatives of formula (A): ##STR1## wherein .sub.-------- denotes an optional bond, provided that either .sub.----.sup.a.sub.---- and .sub.----.sup.c.sub.---- are both bonds and .sub.----.sup.b.sub.---- and .sub.----.sup.d.sub.---- are not bonds, or .sub.----.sup.b.sub.---- and .sub.----.sup.d.sub.---- are both bonds and .sub.----.sup.a.sub.---- and .sub.----.sup.c.sub.---- are not bonds; each of R.sub.14 and R.sub.15 is independently selected from hydrogen and C.sub.1 -C.sub.6 alkyl which is unsubstituted or substituted by an organic functional group; and each of R.sub.1 to R.sub.10, which may be the same or different, is independently hydrogen or an organic functional group; and the pharmaceutically acceptable salts and esters thereof have utility as modulators of multiple drug resistance (MDR).

Abstract: Diketopiperazines of the formula: ##STR1## where each of R.sub.1 to R.sub.10, which may be the same or different, is independently selected from the group consisting of hydrogen, C.sub.1 -C.sub.6 alkyl unsubstituted or substituted by one or more halogen atoms, C.sub.1 -C.sub.6 alkoxy, C.sub.1 -C.sub.6 alkylthio, halogen, hydroxy, nitro, phenyl, -cyano, --CH.sub.2 OH, --CH.sub.2 COOH, --CO.sub.2 R.sup.11, --NHCOR.sup.11, --NHSO.sub.2 R.sup.13, --SO.sub.2 R.sup.13, --CON(R.sup.11 R.sup.12), --SOR.sup.13, --SO.sub.2 N(R.sup.11 R.sup.12), --N(R.sup.11 R.sup.12), and --O(CH.sub.2).sub.n N(R.sup.11 R.sup.12), --O(CH.sub.2).sub.n CO.sub.2 R.sup.11, --OCOR.sup.11, --CH.sub.2 OCOR.sup.11, --CH.sub.2 NHCOR.sup.11, --CH.sub.2 NHCOOR.sup.13, --CH.sub.2 SR.sup.11, --CH.sub.2 SCOR.sup.11, --CH.sub.2 S(O).sub.m R.sup.13 wherein m is 1 or 2, --CH.sub.2 NHCO(CH.sub.2).sub.n CO.sub.2 R.sup.11, --N(R.sup.11)COR.sup.12, --NHCOCF.sub.3, --NHCO(CH.sub.2).sub.n CO.sub.2 R.sup.11, --NHCO(CH.sub.2).sub.n OCOR.sup.11 and --NHCO(CH.