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parameters B and C. Thus, after the recognition of A, B, and C an optimal dissolution profile for that product can be generated. For a hypothetical drug, whose physicochemical properties warrant that T = 10 h and A = 0, the desired optimal dissolution profile is generated. The scientist can then work diligently with the available resources to achieve a formulation that performs accordingly. The data generated can be regressed with the optimal profile to determine the coefficient of correlation and determination and respective p value. Thus the effort will be more directed, less time consuming, and will save resources. |
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2. If formulation work for a drug is in progress wherein critical variables such as drug load, polymer:drug ratio, etc. are carefully being evaluated for their influence on dissolution performance, then these models can be employed for predicting the influence of the variables studied on the performance of the product. Let us assume the influence of drug:polymer ratio on dissolution performance of drug is being evaluated. A few series of drug:polymer ratios are processed to formulate the dosage form. The dissolution data respective to each formulation will yield T and A values and B and C values can be calculated/computed. The respective B and C values generated can be graphed as a function of drug:polymer ratio. The profile will provide valuable insight as to whether the intended objectivesuch as whether there is a proportional increase/decrease in duration of release with respect to various drug:polymer ratiosis being met. This can lead to valuable time-saving and resource-saving judgments. |
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d. Practical Experiences with the Makoid-Banakar Function While these equations might be useful in evaluation of dissolution and absorption profiles, the point regarding the utility of less complex equations may be made using one or two of the equations to evaluate data from the literature. |
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Comparison of Data Sets. Evaluation and reanalysis of data by Chau et al. (1980) fit to the Hill equation is shown in Fig. 18. Similar analyses can be done using any of the above equations. Some will fit better than others. However, all will fit the data to a relatively high degree. Using the Hill function, for example, the time lag, the time for 50% absorption, gamma-shape fixer, and the maximum percent of the drug absorbed can be obtained. These parameters can be easily compared between data sets just as the parameters of the Makoid-Banakar function will be compared subsequently. |
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We recently presented a paper in which the dissolution profiles of two sustained release theophylline products were evaluated. The products were from two different manufacturers (Key and Searle) and at three different strengths, under three different dissolution conditions. Using statistical analysis, it was determined if the fractions released at a given time, for a given product, strength, and condition pair were or were not significantly different. That, however, is |
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