QSPR Modeling of Biopharmaceutical Properties of Hydroxypropyl Methylcellulose (Cellulose Ethers) Tablets Based on Its Degree of Polymerization.

Quantitative structure-property relationship (QSPR) approach has been widely used in predicting physicochemical properties of compounds. However, its application in the estimation of formulation properties based on the polymer used in it to achieve desired formulation characteristics is an extremely challenging process. In the present research, predictive QSPR models were developed by correlating the physicochemical properties of varying grades of cellulose ethers (hydroxypropyl methylcellulose, HPMC) with those of nateglinide (NTG) containing tablets (in vitro and in vivo properties). Sustained release tablets of NTG were prepared by using different grades and concentrations of HPMC and subsequently characterized for in vitro as well as in vivo parameters. Further, QSPR models for individual formulation property were developed by correlating the polymeric physicochemical properties with the formulation characteristics. Subsequently, a true external validation method was used to validate the predictability of developed models. The dissolution study indicated Korsmeyer-Peppas as the best fit model following non-Fickian as drug transport mechanism extending the drug release up to 12 h. In vivo studies showed limited absorption of the NTG. Developed QSPR models showed promising validated predictability for formulation characteristics. The applicability of present work in formulation development could significantly reduce the time and cost expenditure on design trials without actually formulating a delivery system.

Quantitative Structure-Property Relationship Approach in Formulation Development: an Overview.

Chemoinformatics is emerging as a new trend to set drug discovery which correlates the relationship between structure and biological functions. The main aim of chemoinformatics refers to analyzing the similarity among molecules, searching the molecules in the structural database, finding potential drug molecule and their property. One of the key fields in chemoinformatics is quantitative structure-property relationship (QSPR), which is an alternative process to predict the various physicochemical and biopharmaceutical properties. This methodology expresses molecules via various numerical values or properties (descriptors), which encodes the structural characteristics of molecules and further used to calculate physicochemical properties of the molecule. The established QSPR model could be used to predict the properties of compounds that have been measured or even have been unknown, which ultimately accelerates the development process of a new molecule or the product. The formulation characteristics (drug release, transportability, bioavailability) can be predicted with the integration of QSPR approach. Therefore, QSPR modeling is an emerging trend to skip conventional drug as well as formulation development process. The current review highlights the overall process involved in the application of the QSPR approach in formulation development.

Novel Cream Containing Microsponges of Anti-Acne Agent: Formulation Development and Evaluation.

The rationale behind present work was to formulate a novel cream containing microsponges of miconazole nitrate to provide prolonged release. By means of quasi-emulsion solvent diffusion method using Eudragit RS-100 with different drug-polymer ratios microsponges were prepared. In the direction of optimizing microsponge formulation, diverse factors that affect microparticles physical properties were also investigated. Microsponges were characterized by SEM, DSC, FT-IR and particle size analysis, and also evaluated for morphology, drug loading and in vitro drug release. The drug polymer ratio reflected notable effect on drug content, encapsulation efficiency and particle size. It has been found that there was no chemical interaction between drug and polymers used as revealed by FT-IR and DSC spectra. SEM micrographs exposed that microsponges were spherical, with porous surface and have had 26.23 µm mean particle size. The microsponges were then incorporated in cream; which showed viscous modulus along with pseudoplastic behavior. In vitro drug release results depicted that microsponge with drug-polymer ratio of 1:2 was more efficient to give extended drug release of 78.28% at the end of 8 h; while conventional formulations get exhausted incredibly earlier by releasing 83.09% drug at the end of 4 h only. Thus the formulated cream containing microsponges of miconazole nitrate would be a promising alternative as compared to conventional therapy for secure and efficient treatment of acne and other topical infections.

Formulation and evaluation of liquisolid compacts of diclofenac sodium.

The technique of liquisolid compacts is a promising method towards enhancing the dissolution of poorly soluble drugs. In the present study, the potential of liquisolid systems to improve the dissolution properties of water-insoluble agents was investigated using diclofenac sodium as the model drug. Several formulations of liquisolid compacts having different drug concentration (30% to 50% w/w) and with varying ratios of carrier to coat (i.e., different R values, ranging from 5 to 50) were prepared. Avicel and Aerosil were used as carrier and coat material, respectively, and propylene glycol was used as a nonvolatile liquid to prepare liquid medication. The effect of added liquid on the flowability and compressibility of the final admixture was studied and the effect of drug concentration on the dissolution pattern of diclofenac sodium was investigated. Liquisolid compacts demonstrated significantly higher drug release rates than the pure drug.

Design of floating bilayer tablets of diltiazem hydrochloride and lovastatin.

The purpose of the study is to design bilayer floating tablets of diltiazem HCI and lovastatin to give immediate release of lovastatin and controlled release of diltiazem HCl and to study the influence of presence of one drug on the release pattern of other drug. The bilayer tablets consist of sodium starch glycolate as superdisintegrant for lovastatin in the immediate release layer and hydroxypropyl methylcellulose (HPMC) K4M and Xanthan gum as release-retarding agents for diltiazem HCl in the controlled release layer. Sodium bicarbonate was used as the gas generating agent. Dicalcium phosphate was used as the channeling agent. The direct compression method was employed for preparation of the bilayer tablets. Various physicochemical parameters were evaluated for the prepared tablets. The physicochemical parameters were found to be within range. There was significant difference in drug release and floating lag time (P < 0.05). All the formulations showed good matrix integrity. All the formulations released lovastatin within 30 min. The diffusion exponent for diltiazem HCl was found to be independent of polymer concentration. The release pattern of diltiazem HCI was fitted to different models based on coefficient of correlation (R). All the formulations followed the Higuchi model, except F1 which followed the Peppas model. HPMC K4M and Xanthan gum retarded the release of diltiazem HCl for 12 h. The release of one drug remained unaffected in presence of the other drug. In conclusion, such kind of combined dosage forms can effectively be formulated to deliver more than one drug so as to have improved patient compliance and better disease management.