Synthesis and Deblocking Investigations of Phenol Blocked Aliphatic Isocyanates and Their Application in the Development of Epoxy-Polyurethane Films

Phenol blocked hexamethylenediisocyanate adducts and polyisocyanates were synthesized and their structure was validated by FTIR, 1H & 13C NMR spectroscopy, TGA, DSC and CO2 evolution techniques were used to evaluate the deblocking temperature of blocked isocyanates. Gel time studies of blocked isocyanates with terathane polyol and solubility study of blocked isocyanates with different polyols were conducted to demonstrate the structure-property correlation. Epoxy-polyurethane films were produced utilizing the blocked isocyanates reported in this work with epoxy resin and their structure was verified by ATR Spectroscopy. TGA, DSC, shore A hardness, tensile strength and flexural strength analysis were used to investigate the thermal and mechanical characteristics of these films. The findings of deblocking temperature and gel time revealed that unsubstituted phenol blocked isocyanates and polyisocyanates deblock at lower temperatures and cure for a shorter time period than substituted phenol blocked isocyanates. Thermal and mechanical characteristics of epoxy-polyurethane films based on blocked polyisocyanates are satisfactory.

Development, Characterization and Evaluation of Ritonavir Nanosuspension Treatment of Antiretroviral Therapy

Oral nanosuspension of ritonavir was prepared by antisolvent precipitation method using various polymers such as Eudragit RS100, Poloxamer 407, SLS and Methanol.The effect of eudragit RS100 and poloxamer 407 used stabilizer and SLS is surfactant was investigated on particle size and distribution, drug content, entrapment efficiency was observed. Ritonavir is having low solubility and low permeability drug belonging to class-IV according to BCS. Drug-excipient compatibility and amorphous nature of ritonavir drug is prepared nanosuspension was confirmed by FTIR, DSC and Motic microscope studies, respectively. The nanosuspension was further evaluated for drug content, saturation solubility study and entrapment efficiency. The average particle size of ritonavir nanaosuspensions formulas was observed from 0.006 µm to 0.017 µm. The studied in the solubility and dissolution rate there are the increase solubility and dissolution rate of ritonavir nanosuspension.

Inclusion Complex of Fexofenadine Hydrochloride with Cyclodextrins

<p>Fexofenadine hydrochloride (FFN), (±)-4-[1-hydroxy-4[4-(hydroxydiphenylmethyl)-1-piperidinyl]-butyl] α,α-dimethylbenzeneacetic acid hydrochloride, is a second-generation antihistamine that is used to treat allergies. The drug is highly hydrophobic and slightly soluble in water. Cyclodextrins are widely used to improve the physicochemical and pharmaceutical properties such as solubility, stability, and bioavailability of poorly soluble drug molecules.Cyclodextrins can molecularly encapsulate various drugs into their hydrophobic cavity without forming any covalent bonds. Cyclodextrin (CDs), especially ß-Cyclodextrin (ß-CD), are widely used in the pharmaceutical field due to its ability to stabilize drug molecules and taste masking purposes.<strong> </strong></p><p>The phase solubility study was performed according to the method of Higuchi and Connors by adding the fexofenadine hydrochloride in excess to different concentrations of cyclodextrin solutions. Phase solubility study records show that the stability constant and complex stoichiometry of FFN-CD complexes increases linearly with CD concentration. Also, an increase in the concentration of β-cyclodextrin leads to an increase in the aqueous solubility of FFN. Complexes were analyzed by UV-VIS spectroscopy using the calibration curve of FFN. Also, UV-VIS spectra indicate a bathochromic shift which proves that complex formation has occurred.</p><p>Solid inclusion complexes of fexofenadine/β-cyclodextrin and its derivatives were prepared at the molar ratios of 1:1 by the physical mixing method. Characterization of the complexes was performed by using infrared spectroscopy. </p>

Critical Aspects in the Preparation of Extemporaneous Flecainide Acetate Oral Solution for Paediatrics

The availability of liquid oral preparations compounded by pharmacists is essential to meet paediatric needs which remain unanswered by the pharmaceutical industry. Unfortunately, compendial monographs are often not available and, in many cases, pre-formulation studies (e.g., compatibility with other excipients and solubility evaluations) are not performed in-depth, leading, in some rare cases, to the inadvertent administration of a toxic dose. In this study, the preparation of an oral liquid formulation for paediatric use, containing flecainide acetate at different strengths, was considered, taking into account the possible effects of conventionally used excipients. First, the optimal vehicle was selected based on a solubility study, evidencing some unexpected formations of precipitates. As a matter of fact, the buffers commonly used for oral solutions significantly reduced flecainide solubility, and the concomitant presence of citrate buffer and methylparaben even caused the formation of non-resuspendable crystals. Then, chemical, physical, and microbiological stability were assessed. Solutions at strengths of 10 and 20 mg/mL flecainide acetate were stable up to 8 weeks when compounded by using a 40% sucrose solution as a vehicle. Microbiological data showed that the use of methylparaben was not necessary over this time period.

Particle Engineering and Spray Drying Process designing for Solubility Enhancement of Lopinavir

To improve the solubility enhancement of solid dispersion of Lopinavir by spray-drying by adding the Soluplus as polymer that is compatible with Lopinavir, was evaluated and the process used for preparation of Spray dried solid dispersion was validated and the 1:3 ratio used for preparation of solid dispersion. Dissolution tests were carried out on several spray dried solid dispersion of Lopinavir and physical mixture. The solid dispersion characterized by DSC, XRD, % Entrapment Efficiency, solubility study, drug content determination, practical yield, dissolution studies. Keyword: Lopinavir, Soluplus, Spray Drying Technique, Dissolution studies

The Preservation and Enantiomeric Selection of Linalool by Nanoencapsulation Using Cyclodextrins

Linalool, a volatile terpene alcohol, is responsible for a characteristic aroma in food, beverages, and cosmetics. However, linalool’s low aqueous solubility and high volatility limit the applications and shelf life of linalool-containing products. Nanoencapsulation using beta-cyclodextrin (BCD), methyl-beta-cyclodextrin (MBCD) and hydroxypropyl-beta-cyclodextrin (HPBCD) was studied to improve the aqueous solubility and stability of linalool. Linalool has two enantiomers with distinct flavors and odors which affect product quality. The enantiomeric selectivity of the cyclodextrins (CDs) toward racemic linalool standard was evaluated. A computational simulation was performed to predict the conformations and interactions of the inclusion complexes. The 1:1 host-guest ratio from the computer simulation was implemented in the experimental study. Phase solubility study shows an improvement in linalool aqueous solubility after being encapsulated by CDs. The encapsulation efficiencies of linalool/BCD, linalool/MBCD, and linalool/HPBCD inclusion complexes are 66.30%, 51.38% and 32.31%, respectively. Nanoencapsulation by CDs can preserve linalool in the form of inclusion complexes compared to its free form. The amount of remaining linalool in linalool/BCD, linalool/MBCD, and linalool/HPBCD inclusion complexes are 89.57%, 87.07%, and 74.86%, respectively which are considerably larger than that of pure linalool (42.30%). CDs also show the enantiomeric selectivity toward (R)-linalool as evident from (R)-linalool percentage of 54.53% in the inclusion complex.