Aiman A. Obaidat

Controlled release of tramadol hydrochloride from matrices prepared using glyceryl behenate

An inert matrix to control the release of tramadol HCl was prepared using glyceryl behenate as a matrix-forming agent. The matrices were prepared by either direct compression of a physical mixture of the drug and the matrix-forming agent or by compression of granules prepared by hot fusion of the drug and the matrix-forming agent. The hot fusion method was found to be more effective than compression of physical mixtures in retarding the release of the drug from the matrix. Drug release was adjusted by using release enhancers, such as microcrystalline cellulose and lactose, and the results showed that higher release rates were obtained using lactose. However, the release of the drug was independent of the compression force and the pH of the dissolution medium. This study showed that glyceryl behenate is an appropriate waxy material that can be used as a matrix-forming agent to control the release of a water-soluble drug such as tramadol HCl.

Preparation of mucoadhesive oral patches containing tetracycline hydrochloride and carvacrol for treatment of local mouth bacterial infections and candidiasis.

The specific aim of this work was to prepare mucoadhesive patches containing tetracycline hydrochloride and carvacrol in an attempt to develop a novel oral drug delivery system for the treatment of mouth infections. The bilayered patches were prepared using ethyl cellulose as a backing layer and carbopol 934 as a matrix mucoadhesive layer. Patches were prepared with different loading amounts of tetracycline hydrochloride and carvacrol. The antimicrobial activity was assessed for the prepared patches using the disc-diffusion method against the yeast Candida albicans and five bacterial strains, including Pseudomonas aeruginosa, Escherichia coli, Bacillus cereus, Staphylococcus aureus, and Bacillus bronchispti. In this work, we highlighted the possibility of occurrence of a synergistic action between carvacrol and tetracycline. The best formulation was selected based on microbiological tests, drug release, ex-vivo mucoadhesive performance, and swelling index. Physical characteristics of the selected formulations were determined. These included pH, patch thickness, weight uniformity, content uniformity, folding endurance, and patch stability.

A new controlled-release liquid delivery system based on diclofenac potassium and low molecular weight chitosan complex solubilized in polysorbates

A complex of low molecular weight chitosan (LMWC) with oleic acid and diclofenac potassium (DP) was prepared and dispersed in high concentrations of polysorbate 20, 60 and 80 in water to form a solution which releases its components slowly. The formed complex was characterized using different analytical methods. The size of the resulted nanoparticles and the effect of tweens on size were followed using dynamic light scattering (DLS). The release of DP from this delivery system was monitored by altering the molecular weight of chitosan and the type and concentration of the polysorbates used. The most suitable preparation consisted of DP, LMWC 13 kDa, and oleic acid. This was dispersed in 5% Tween 80 and the release was followed by the adaptation of USP II apparatus using a cellophane bag. This preparation offers a release of up to 24 h.

Development and evaluation of fast-dissolving tablets of meloxicam-β-cyclodextrin complex prepared by direct compression.

Development and evaluation of fast-dissolving tablets of meloxicam-β-cyclodextrin complex prepared by direct compression The aim of this study was to prepare fast-dissolving tablets of meloxicam after its complexation with β-cyclodextrin (β-CD) and to investigate the effect of using different superdisintegrants on the disintegration and release of meloxicam from the tablets. A complex of meloxicam with β-CD was prepared by spray drying and then compressed in the form of tablets utilizing the direct compression technique. Three superdisintegrants were employed at various levels - sodium starch glycolate, croscarmellose sodium, and crospovidone. Co-spray dried micro-crystalline cellulose and mannitol (Avicel HFE-102) were used as diluents in the tablets. Prior to compression, the pre-compression parameters showed satisfactory flow properties. Post-compression parameters showed that all tablet formulations had acceptable mechanical properties. Wetting and disintegration times were prolonged by increasing the level of sodium starch glycolate in the tablets. This was attributed to the formation of a viscous gel layer around the tablets by sodium starch glycolate whereas this effect was not observed with croscarmellose sodium and crospovidone. Dissolution studies showed fast release of meloxicam except in tablets containing a high level of sodium starch glycolate. Complexation of meloxicam with β-CD significantly improved the solubility of the drug and improved the mechanical properties of tablets produced by direct compression. Razvoj i vrednovanje lako topljivih tableta kompleksa meloksikama s β-ciklodekstrinom pripravljenih izravnom kompresijom Cilj rada bio je priprava lako topljivih tableta kompleksa meloksikama s β-ciklodekstrinom (β-CD) te ispitati utjecaj različitih superdezintegratora na raspadljivost tableta i oslobađanje meloksikama. Kompleks meloksikama s β-CD pripravljen je metodom sušenja sprejem, a komprimiran je u tablete metodom izravne kompresije. U pripravi tableta korištene su tri različite količine triju superdezintegratora: natrijev škrobni glikolat, natrijeva sol kroskarmeloze i krospovidon, dok su mikrokristalinična celuloza i manitol (Avicel HFE-102) upotrijebljeni kao punila. Predkompresijski parametri ukazivali su na zadovoljavajuću tečnost. Postkompresijski parametri pokazali su da sve tablete imaju prihvatljiva mehanička svojstva. Vlaženje i vrijeme raspadanja bilo je produljeno kada se povećao udio natrijevog škrobnog glikolata u tabletama. To je pripisano stvaranju viskoznog sloja gela oko tableta, što nije primijećeno u pripravi tableta s natrijevom soli kroskarmeloze i krospovidonom. Oslobađanje meloksikama bilo je brzo iz svih tableta, osim iz tableta s visokim udjelom natrijeve soli škrobnog glikolata. Kompleksiranje meloksikama s β-CD značajno je povećalo topljivost lijeka i poboljšalo mehanička svojstva tableta.

The hydrolysis kinetics of monobasic and dibasic aminoalkyl esters of ketorolac

Six aminoethyl and aminobutyl esters of ketorolac containing 1-methylpiperazine (MPE and MPB), N-acetylpiperazine (APE and APB) or morpholine (ME and MB), were synthesized and their hydrolysis kinetics were studied. The hydrolysis was studied at pH 1 to 9 (for MPE, APE and ME) and pH 1 to 8 (for MPB, APB and MB) in aqueous phosphate buffer (0.16 M) with ionic strength (0.5 M) at 37°C. Calculation of kobs, construction of the pH-rate profiles and determination of the rate equations were performed using KaleidaGraph® 4.1. The hydrolysis displays pseudo-first order kinetics and the pH-rate profiles shows that the aminobutyl esters, MPE, APB and MB, are the most stable. The hydrolysis of the ethyl esters MPE, APE and ME, depending on the pH, is either fast and catalyzed by the hydroxide anion or slow and uncatalyzed for the diprotonated, monoprotonated and nonprotonated forms. The hydrolysis of the butyl esters showed a similar profile, albeit it was also catalyzed by hydronium cation. In addition, the hydroxide anion is 105 more effective in catalyzing the hydrolysis than the hydronium cation. The hydrolysis pattern of the aminoethyl esters is affected by the number and pKa of its basic nitrogen atoms. The monobasic APE and ME, show a similar hydrolysis pattern that is different than the dibasic MPE. The length of the side chain and the pKa of the basic nitrogen atoms in the aminoethyl moiety affect the mechanism of hydrolysis as the extent of protonation at a given pH is directly related to the pKa.