Formulation development and evaluation of alginate microspheres of Ibuprofen.

The present study was designed to investigate the effects of different variables on the release profile of ibuprofen microspheres formulated using modified emulsification method. Eight batches of microspheres (F1-F8) were prepared by applying 2(3) factorial design. The amount of sodium alginate, amount of calcium chloride, and amount of magnesium stearate were selected as formulation variables. All the batches were evaluated in terms of percentage yield, percentage encapsulation efficiency and in vitro release characteristics. The batch F7 was found to be optimum batch and was further characterized via scanning electron microscopy (SEM) and particle size analysis. Multiple linear regression was applied to confirm significant effect of each variable on release characteristics. The model developed in the present study can be effectively utilized to achieve the formulation with desired release characteristics.

Topochemical models for the prediction of permeability through blood-brain barrier.

Relationship between the topochemical indices and permeability of diverse series of compounds through blood-brain barrier has been investigated. Three-topochemical indices, Wiener's topochemical index--a distance-based topochemical descriptor, molecular connectivity topochemical index--an adjacency based topochemical descriptor and eccentric connectivity topochemical index--an adjacency-cum-distance based topochemical descriptor, were used for the present investigation. A data set comprising of 28 compounds with established CNS permeation tendency was selected for present study. The values of all the three-topochemical indices in the original as well as in the normalized form for each of the 28 compounds comprising the data set were computed using an in-house computer program. Resultant data was analyzed and suitable models were developed after identification of the permeable ranges. Subsequently, permeability characteristic was assigned to each compound involved in the data set using these models, which was then compared with the reported permeability through blood-brain barrier. Accuracy of prediction was found to vary from a minimum of 83% to a maximum of approximately 95% using these models.

Simulation of skin permeability in chitosan membranes.

To provide an alternative means of evaluating transdermal drug delivery systems, membranes of chitosan were developed. The membranes were prepared by cast-drying method. The effects of chitosan concentration, sodium tripolyphosphate (NaTPP) concentration and crosslinking (CL) time on flux and lag time were studied using central composite design. It was observed that chitosan membrane at a particular composition simulated the permeation of diclofenac sodium through rat skin The mathematical model developed in the present study can be used to simulate the permeation of drugs through different species of animal skins.