Posted by admin on Jul 2, 2014 in |
Three simple, rapid, sensitive, specific and economic spectrophotometric methods were developed and validated for simultaneous quantitation of timolol maleate (TM) and brimonidine tartarate (BT) in bulk powder and eye drops. Vierordt’s and bivariate calibration algorithm spectrophotometric methods were developed for the simultaneous estimation of cited drugs in a binary mixture without previous separation. In the simultaneous equation method (Vierordt’s), TM and BT were quantified using their absorptivity values at selected wavelengths 257 nm and 295 nm, respectively. Also bivariate calibration procedure was successfully applied for simultaneous determination of both drugs. Difference spectrophotometric method was also tried and showed high selectivity for BT determination without any interference from TM or eye drops additives. The accuracy and reproducibility of the proposed methods were statistically validated by recovery studies. The calibration curves were found to be rectilinear over the concentration ranges 5-85 μg/mL for TM in all methods. BT calibration curves were rectilinear over the concentration (2–35 μg/mL) in case of D1 and Vierordt’s methods, while (5–35 μg/mL) in case of bivariate...
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Posted by admin on Jul 2, 2014 in |
Eudragit RS100 microcapsules containing Aspirin as a model drug was prepared using solvent evaporation technique. The drug was dispersed in the organic phase and poured into the aqueous phase with stirring until microcapsules formation. The product was collected by filtration and air dried. The particle size analysis of the products was done and normal distribution curve showed for the same size range of different theoretical drug content, microcapsules had different size distribution. The sphericity of the microcapsule was greatly affected by the theoretical drug loaded. The mean microcapsule size decreased upon increasing the percent of theoretical drug content and then increased again. The surface of spherical microcapsule was smooth and no drug crystals attached to the surface. It was noticed drug crystals in the microcapsule structure. The mean actual drug content was markedly higher than the theoretical one. In the same product prepared with the same theoretical drug content, there was a relationship between the actual drug content and the product particle size. These findings were explained according to...
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Posted by admin on Jul 2, 2014 in |
The aim of the present study was to improve commercial twice-a-day Acebrophylline formulation to once-a-day new formulation to improve patient compliances. The double-layered tablet was composed of the fast release layer (Acebrophylline 50 mg) and sustained release layer (Acebrophylline 150 mg). To develop the double-layered tablet, the fast release and sustained release layers were prepared using polymer, wax, excipients and malic acid. The inclusion of malic acid in sustained release layer in double-layered tablet was showed to decrease release rates in pH 1.2 equal to dissolution rate of pH 6.8. The pharmacokinetic parameters such as AUCt and Cmax of double-layered tablet having fast release and sustained release layer were tested on mini pigs. These results showed similar pharmacokinetic parameters of AUCt and Cmax between Surfolase capsule and double-layered tablet. The 90% confidence intervals of the AUCt ratio and the Cmax ratio for double-layered tablet and Surfolase capsule were log 0.9402 ~ log 1.0245 and log 0.9983 ~ log 1.1542, respectively. This mean show that double-layered tablet using malic acid,...
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Posted by admin on Jul 2, 2014 in |
This work investigates the potential of Partial Least Square (PLS) regression using two vibrational spectroscopies as mid infrared (MIR) and near infrared (NIR) spectroscopies for the quantification of molsidomin in tablets. Two very simple, rapid, inexpensive and green strategies were applied for this determination. Powder blends containing molsidomin and excipients were prepared. The excipients correspond to those in Inverter® tablets. Two experimental design approaches were used in generating 9-levels % calibration and validation samples sets. Fourier transforms of mid-infrared (MIR) and near-infrared (NIR) spectra were measured by transmission and diffuse reflection techniques respectively. The calibration models were generated by PLS models without spectral treatment and were used to predict the drug content in the powder blends made for validation models and for commercial tablets. The mean percentages of recoveries for the analysis of molsidomin in generic Inverter® 4 mg tablet are 101.5 and 99.6 % for FT-MIR and FT-NIR...
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Posted by admin on Jul 2, 2014 in |
In the recent years, scientific and technological advancements have been made in the research and development of novel drug delivery systems by overcoming physiological troubles such as short gastric residence times and unpredictable gastric emptying times. Gastric emptying of dosage form is extremely variable process and ability to prolong and control the emptying time. Gastric transit time is valuable asset for dosage forms, which reside in the stomach for a long period of time than conventional dosage form. Several approaches are currently utilized in the prolongation of the gastric residence times, including floating drug delivery systems, swelling and expanding systems, polymeric bioadhesive systems, modified-shape systems, high-density systems and other delayed gastric emptying devices. The purpose of writing this review on floating drug delivery systems (FDDS) was to compile the recent literature with special focus on the principal mechanism of floatation to achieve gastric retention. This review explains briefly about types of floating system, advantages, limitation, floating mechanism, factors affecting floating system, drug candidates suitable for floating, evaluation parameters and...
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