Have you considered improving your medical diagnostic kits with cyclodextrins?
Making SolutionsPowder Mix one part Trappsol CMCyclodextrin powder with 2 parts water by weight, i.e. 1 gram of CMCyclodextrin and 2ml water. Very small quantities can be prepared in this manner using sonication rather than stirring. Large, unwieldy quantities can be solubilized more easily if they can be left sitting overnight. Complete solubilization is highly dependent on completely wetting the powder mass. The final solution will have considerable volume expansion. This increase in volume will cause the weight/weight percentage to differ from the expected weight/weight percentage of 33.3%. This volume expansion varies with concentration and between different cyclodextrin derivatives. Figure 4 shows approximate volume expansion for Trappsol HPB, and is probably a reasonable approximation for other CMCyclodextrin's; the best policy is to allow 1 ml per gram if you are not sure. For example, if your starting volume is 50ml and you add 30.46 grams of THPB, you would anticipate an additional 22ml volume for a final solution volume of 72ml. Two major inferences can be made from this chart. First, small quantities will have a large expansion factor; second, for concentrations above 20% the expansion factor will always be approximately 0.7. Heat will increase the solubility of CMCyclodextrin's in water and may be used when concentrations above 60% of the CMCyclodextrin are desired. Certain anomalous phenomenon occur with some CMCyclodextrin's when their solutions are warmed. For example, dimethyl beta cyclodextrin precipitates when heated above 55°C; this situation reverses as the temperature drops. Most CMCyclodextrin's are sufficiently water soluble so that best results are obtained at room temperature. The viscosity of CMCyclodextrin's can cause some formulation problems. Below 50%, these solutions are easily filtered through a .2µ filter. Above 50%, viscosity increases noticeably. Changes in viscosity vary with each different CMCyclodextrin. Aqueous solutions of all CMCyclodextrin's are probably autoclavable; 50% aqueous solutions of Trappsol HPB have been autoclaved with no change in solution properties. Testing other CMCyclodextrin's for heat stability is recommended. Aqueous solutions of CMCyclodextrin's will support the growth of
some bacteria. Solutions should be refrigerated to retard this growth. |