Determination of abacavir, lamivudine and zidovudine in pharmaceutical tablets, human serum and in drug dissolution studies by HPLC

A simple, accurate, precise and fully automated method for the simultaneous determination of abacavir, lamivudine and zidovudine in pharmaceutical tablets, human serum samples and drug dissolution studies has been developed. Separation was performed on a 5 μm Zorba

Effect of polymer type on characteristics of buccal tablets using factorial design

A two factor three level factorial design was used to investigate the effects of carbopol and cationic hydrophilic polymers which have a common use in buccal drug formulations. Statistical models with interaction terms were derived to evaluate influence of carbopol (X1) and chitosan (X2) on tablet disintegration (Y1) and dissolution (Y2), mechanical properties (Y3), swelling (Y4). Tablet disintegration studies were carried out using two different pH environments within buccal region pH limits and also two different commonly used dissolution methods for buccal tablets were also investigated to compare the effect of polymer type on dissolution. Polymer type and ratio affect the characteristics of the buccal tablets due to their different physicochemical behavior at buccal pH. Also significant variances between dissolution profiles for buccal tablets, using either USP Paddle or flow through cell methods were found. These results indicate that both polymer type and ratio as well as combination of them effects the drug behavior in different ways. Keywords: Buccal tablet, Hydrophilic matrix, Effect of polymer, Carbopol, Chitosa

Determination of valacyclovir hydrochloride in tablets and spiked plasma samples by spectrofluorimetry

A novel, simple and rapid stability-indicating spectrofluorimetric method has been developed for the determination of valacyclovir hydrochloride in tablets and spiked plasma samples. Method based on the reaction between valacyclovir and fluorescamine in borate buffer solution of pH 9.0 to give highly fluorescent derivatives that were measured at 475 nm using an excitation wavelength of 390 nm. The method has linear relation with fluorescence intensity in the concentration range of 0.25-1.25 mu g/mL. The developed spectrofluorimetric method was validated with respect to linearity, precision, sensitivity, accuracy and selectivity. The degradation behavior of the drug was also investigated: the drug solution was subjected to neutral, acid and alkali hydrolysis, oxidation, thermal stress and exposure to the sunlight. The method proved to be selective and useful for the investigation of the stability of valacyclovir. Successful applications of the developed method for the drug determination in tablets and spiked plasma samples were also performed