The Implications of Bach's Introduction of New Fugal Techniques and Procedures in the Well-Tempered Clavier Book Two

Among the fugues of the WTC II, there are some fugal techniques and procedures that were not explored in the first book. Here, the ‘fugal techniques’ include parallel entries (as used in the fugues in D-sharp minor, G minor and B-flat minor) and double counterpoint at the tenth or twelfth as well as fifteenth (as used in the fugues in G minor and B major). The ‘fugal procedures’, on the other hand, refer to meticulously planned multi-exposition architecture (as seen in the fugues in F-sharp minor exploiting two subsidiary subjects, and B-flat minor exploiting inversion and stretto) and a form in which the appearance of the subsidiary subject is gradually predicted in the fugal discourse (viz. C-sharp minor, G-sharp minor and B major). All these new ideas helped Bach to write more dramatic, more profound fugues for WTC II. The paper will consider how Bach came to acquire the new techniques and to use them in such ways, and what motivated him to adopt these new compositional approaches. Do they offer any clues for our better understanding of why Bach compiled the WTC II?

Book Review: Critical Perspectives on Human Rights and Disability Law

Book Review

Mucoadhesive, syringeable drug delivery systems for controlled application of metronidazole to the periodontal pocket: In vitro release kinetics, syringeability, mechanical and mucoadhesive properties

Novel mucoadhesive formulations containing hydroxyethylcellulose (HEC; 3 and 5%, w/w) or Carbopol (3 and 5%, w/w), polycarbophil (PC; 1 and 3%, w/w) and metronidazole (5%, w/w) at pH 6.8 were designed for the treatment of periodontal diseases. Each formulation was characterised in terms of hardness, compressibility, adhesiveness and cohesiveness (using Texture Profile Analysis), drug release, adhesion to a mucin disc (measured as a detachment force using the texture analyser in tensile mode) and, finally, syringeability (using the texture analyser in compression mode). Drug release from all formulations was non-diffusion controlled. Drug release was significantly decreased as the concentration of each polymeric component was increased, due to both the concomitant increased viscosity of the formulations and, additionally, the swelling kinetics of PC following contact with dissolution fluid. Increasing the concentrations of each polymeric component significantly increased formulation hardness, compressibility, adhesiveness, mucoadhesion and syringeability, yet decreased cohesiveness. Increased product hardness, compressibility and syringeability were due to polymeric effects on formulation viscosity. The effects on cohesiveness may be explained both by increased viscosity and also by the increasing semi-solid nature of products containing 5% HEC or Carbopol and PC (1 or 3%). The observations concerning formulation adhesiveness/mucoadhesion illustrate the adhesive nature of each polymeric component. Greatest adhesion was noted in formulations where neutralisation of PC was maximally suppressed. For the most part, increased time of contact between formulation and mucin significantly increased the required force of detachment, due to the greater extent of mucin polymer hydration and interpenetration with the formulations. Significant statistical interactions were observed between the effects of each polymer on drug release and mechanical/mucoadhesive properties. These interactions may be explained by formulatory effects on the extent of swelling of PC. In conclusion, the formulations described offered a wide range of mechanical and drug release characteristics. Formulations containing HEC exhibited superior physical characteristics for improved drug delivery to the periodontal pocket and are now the subject of long-term clinical investigations. (C) 1997 Elsevier Science B.V.