Formulation and evaluation of sustained release dextromethorphan resinate syrup

Aiming to decrease the dosing frequency of the antitussive dextromethorphan, different coated drug resinates were prepared and formulated in syrup form. Polystyrene divinylbenzene sulfonic acid ion exchanger [Amberlite IRP 69, H+ form] was used to prepare the resinates, which were further coated with different concentrations of carnauba wax, Eudragit RL 100, or ethyl cellulose. The in vitro release performance of the coated and uncoated resinates was determined in simulated gastric and intestinal fluids. Selected systems were formulated in syrup form and evaluated for their physicochemical and release performance when fresh and on storage. Dextromethorphan resinates showed relatively rapid release pattern, where 74.2% of the drug released through two hours in acid medium. The release pattern decreased from coated resinates on increasing polymer coat depending on the type of coating polymer. Coated dextromethorphan resinate syrups acquired mixed zero- and first-order release pattern with optimum release rates and suitable first flush values. The dextromethorphan flush in the first five minutes ranged between 9.1 and 12.3% with first-order release rate constants of 0.0048-0.0097 min-1

Bio-pharmaceutical evaluation of tenoxicam suppositories

With the object of reducing hepatic first-pass elimination of tenoxicam, the drug was formulated in suppository form using different suppository bases. The bases used include Witepsols, Suppocires, Novatas in addition to PEGs an cacao butter. The effect of different additives, surfactants and gels, on drug suppository formulation in Witepsol H15 was also investigated. Suppositories containing tenoxicam solid dispersions were also evaluated, using PEG 4000 and 6000, PVP K25, the hydrotropes sodium benzoate and sodium salicylate, urea, lactose, sorbitol, mannitol, and the electrolytes sodium chloride, magnesium carbonate and aluminum hydroxide. The suppositories prepared were evaluated for in vitro drug release, when fresh and on storage. Selected formulae were also evaluated through tenoxicam relative bioavailability and its anti-inflammatory activity compared to indomethacin as reference drug

Formulation and evaluation of tenoxicam capsules

With the aim of preparing tenoxicam capsules, different additives commonly used in capsule formulation were used for the preparation of tenoxicam capsules. Twenty-four different capsule formulae were prepared and were subjected to an in vitro dissolution study using the USP dissolution tester. The anti-inflammatory activity was determined using the rat paw edema technique taking indomethacin as a standard for comparison. The study revealed that there was a significant difference between indomethacin and tenoxicam from its capsule formulations indicating the superior anti-inflammatory activity of tenoxicam. The bioavailability of tenoxicam was determined using an HPLC assay, where the pharmacokinetic parameters were determined using rabbits plasma. A good correlation was found between the percentage inhibition in edema activity and the peak plasma concentration as a measure of drug absorption where the correlation coefficient was found to be 0.928