A validated stability indicating DAD–HPLC method for determination of pentoxifylline in presence of its pharmacopeial related substances

A validated, simple and sensitive stability-indicating HPLC method was introduced for the analysis of Pentoxifylline in the presence of its pharmacopeial related substances, Caffeine anhydrous and Theophylline anhydrous, in the presence of its forced degradation products. This was achieved using a gradient DAD–HPLC method in order to achieve a good separation between the related substance peaks, complying with the pharmacopeial requirement, and an adequate retention time for the Pentoxifylline peak. The method was validated according to the ICH guidelines and different HPLC parameters were optimized for the determination of Pentoxifylline in its dosage form (sustained release tablets). Furthermore, the study of forced degradation of Pentoxifylline was done under various conditions including; hydrolysis (acid, alkaline and neutral), oxidation, dry heat and photo-decomposition. The proposed method could separate Pentoxifylline peak from those of the different forced degradation product peaks and the purity of the Pentoxifylline peak was confirmed using the photo-diode array detector

Adsorption behavior of some metal ions on nanoparticles used in pharmaceutical matrices: Application to laboratory made drug formulation

The adsorption behavior of some metal ions (Pb, Mn, Mg, Zn and Ca) was studied on silicon dioxide nanoparticles, SiO2 NP, alone and its mixture with microcrystalline cellulose, MCC, powder (1:1) as drug carriers in pharmaceutical preparations. The effect of different conditions as temperature and pH on adsorption was investigated. It was found that upon increasing the temperature, the ability of the adsorbent material increases. The pH of the metal solution has the same effect as temperature till pH 8. However, above pH 8 the adsorbent material began to lose its adsorption efficiency. Although, the use of SiO2 NP mixture with MCC powder can improve the excipient functionality, it is important to take into consideration their metal adsorption behavior. The study was applied on laboratory made drug formulation contains different drug carriers. The study points at the importance of adjusting the permissible level of metals in different active and inactive ingredients used in pharmaceutical preparations containing nanoparticles as drug carriers. The type of nanoparticles used and the pH of these preparations are important factors affecting the metal adsorption behavior. At the maximum temperature of adsorption, the calculated metal adsorption capacity of a mixture of MCC and SiO2 NP (1:1) compared to SiO2 NP alone was found to be 0.2043 and 0.1169 for Pb, 0.1948 and 0.1041 for Zn, 0.2114 and 0.1207 for Mg, 0.2220 and 0.1222 for Ca and 0.2068 and 0.1054 for Mn, respectively. Flame atomic spectrometry was used for determining metal remained concentration after adsorption

Spectrophotometric analysis of two eye preparations, vial and drops, containing ketorolac tromethamine and phenylephrine hydrochloride binary mixture and their ternary mixture with chlorphenirmaine maleate

Ketorolac tromethamine, KTC and phenylephrine hydrochloride, PHE binary mixture is co-formulated as eye vial, while their ternary mixture with chlorpheniramine maleate is co-formulated as eye drops. The existing work utilizes different spectrophotometric methods which are considered to be simple and rapid for the determination of both mixtures. These methods include: zero-order (D0), first derivative (D1), derivative (DR) or difference ratio (R.D), delta absorbance (ΔA) and finally convolution of derivative data using discrete Fourier functions (FFD). In the binary mixture, KTC is assayed using D0, D1 and ΔA methods with no interference from PHE, while PHE needed some spectroscopic treatments for its analysis due to the spectral overlap of KTC with its maximum wavelength (λmax) at 273 nm. Such treatments involve D1 R.D, D2R, FFD2 and ΔA methods. In the ternary mixture, KTC is assayed using D0 and D1 with no interference from both PHE and CPM, while R.D, D1R and FFD2 are used to assay both PHE and CPM to resolve the overlap in their spectra. Linear regression lines were obtained over the concentration ranges 1–18 and 6–48 μg.mL−1 for KTC and PHE (binary mixture), respectively and 2–9, 1–18 and 2–9 μg.mL−1 for CPM, KTC and PHE (ternary mixture), respectively yielding high correlation coefficients values (higher than 0.999). The lowest LOQ value for KTC (0.46 μg.mL−1) was obtained upon using the D1 method in the binary mixture while the R.D method yielded the lowest LOQ values for both PHE (0.34 μg.mL−1) and CPM (0.97 μg.mL−1) in the ternary mixture