Silk Fibroin as a Novel Alcohol-Resistant Excipient for Sustained-Release Tablet Formulation

Ethanol-induced dose dumping from sodium alginate matrix tablets: Investigation of the effects of medium viscosity and pH

In this work, the swelling and disintegration of drug-free sodium alginate (SA) compacts and the release of metformin HCl from SA matrix tablets were investigated in acidic media of different ethanol concentrations (0, 10, 20, and 40 % v/v), pH (1.2 and 4.5) and HPMC K4M concentrations (0-1 % w/v). The investigated dissolution media represented the consumption of different alcoholic beverages, the pH of fasted and fed states, and a range of viscosity resembling diluted homogenized FDA meal. The dissolution efficiency and the time to 50 % release (t_50%) were selected as release parameters. It was found that both ethanol concentration and medium pH affected drug release from SA matrix tablets and the swelling of SA compacts. Dose dumping occurred at high ethanol concentration (40 %) at both media pH with almost complete drug release within 15-30 min associated with rapid matrix disintegration. HPMC at 0.5-1 % concentrations increased the medium's viscosity, preventing dose dumping at high ethanol concentrations. Erosion and disintegration of SA compacts were decelerated by increasing HPMC concentration in hydroethanolic media in consonance with decreased release rate from matrix tablets. ANOVA tests showed significant effects of pH and concentrations of ethanol and HPMC in the dissolution medium on the release parameters.

Cyclodextrin Complex Formation with Water-Soluble Drugs: Conclusions from Isothermal Titration Calorimetry and Molecular Modeling

Cyclodextrin (CD) complexes are frequently used for enhancing the solubility or absorption of poorly water-soluble drugs. On the contrary, little is known about their complex formation with water-soluble drugs. Here, we have studied the interaction between 2-hydroxypropyl β-CD (HPβCD) and three water-soluble drugs, namely naloxone (NX), oxycodone (OC), and tramadol (TR), by isothermal titration calorimetry (ITC) combined with molecular modeling in view of the potential impact on drug release. The results showed that the complex formation of HPβCD with all three drugs occurs spontaneously. The complexes formed with NX and OC were found to be 2NX:1HPβCD and 3OC:2HPβCD, respectively. TR was found to form 2 complexes with HPβCD; of 1:2 and 1:1 complexation ratios. The binding of HPβCD to NX was greater than to OC due to the higher hydrophobicity of the structure of the former. Moreover, the binding affinity of HPβCD to TR was higher than to OC, which indicated the effect of the higher flexibility of the guest in increasing the binding affinity. In vitro drug release experiments from the various complexes revealed a significant impact of the stoichiometry of the complex on the release profiles. Accordingly, the co-administration of cyclodextrins with water-soluble drugs should be closely monitored, as it may result in unintentional complex formation that can potentially impact the drugs’ gastrointestinal absorption.

A new polymer-excipient for ethanol-resistant, sustained-release oral dosage forms

The use of alcoholic beverages can cause uncontrolled release of drugs from sustained-release solid oral dosage forms and pose severe risks to patient health. The aim of this work was to design a new polymeric excipient with ethanol resistance inherent to the polymer. Polymers were systematically designed, manufactured via emulsion polymerization, and fully characterized. Glass transition temperatures between 10 and 18 °C and minimum film forming temperatures between 10 and 25 °C were chosen because these parameters are ideal for aqueous film-coating processing. Three model drug formulations were made with the new polymer excipients and tested in the presence and absence of ethanol. The concept of an alcohol resistance factor based on Weibull regression analysis was introduced. In vitro results confirmed the hypothesized structure-function relationship between comonomer composition and ethanol resistance. That is, nonionic hydrophilic functional groups interacted more strongly with the ethanolic solvent, as compared with cationic hydrophilic comonomer that interacted more strongly with the surrounding water molecules. The alcohol resistance factor varied between - 44 ± 2% (slower drug release in presence of ethanol) and + 34 ± 0% (faster drug release in presence of ethanol) depending on the comonomer ratio. The main advantages of these new excipients compared with ethanol-resistant excipient blends include ease of use, plasticizers are not necessary, and shorter coating times.