Lacidipine encapsulated gastroretentive microspheres prepared by chemical denaturation for Pylorospasm

Enhanced Solubility and Dissolution Rate of Lacidipine Nanosuspension: Formulation Via Antisolvent Sonoprecipitation Technique and Optimization Using Box-Behnken Design

Lacidipine (LCDP) is a highly lipophilic calcium channel blocker of poor aqueous solubility leading to poor oral absorption. This study aims to prepare and optimize LCDP nanosuspensions using antisolvent sonoprecipitation technique to enhance the solubility and dissolution of LCDP. A three-factor, three-level Box-Behnken design was employed to optimize the formulation variables to obtain LCDP nanosuspension of small and uniform particle size. Formulation variables were as follows: stabilizer to drug ratio (A), sodium deoxycholate percentage (B), and sonication time (C). LCDP nanosuspensions were assessed for particle size, zeta potential, and polydispersity index. The formula with the highest desirability (0.969) was chosen as the optimized formula. The values of the formulation variables (A, B, and C) in the optimized nanosuspension were 1.5, 100%, and 8 min, respectively. Optimal LCDP nanosuspension had particle size (PS) of 273.21 nm, zeta potential (ZP) of -32.68 mV and polydispersity index (PDI) of 0.098. LCDP nanosuspension was characterized using x-ray powder diffraction, differential scanning calorimetry, and transmission electron microscopy. LCDP nanosuspension showed saturation solubility 70 times that of raw LCDP in addition to significantly enhanced dissolution rate due to particle size reduction and decreased crystallinity. These results suggest that the optimized LCDP nanosuspension could be promising to improve oral absorption of LCDP.

Design, formulation and optimization of valsartan transdermal gel containing iso-eucalyptol as novel permeation enhancer: preclinical assessment of pharmacokinetics in Wistar albino rats

OBJECTIVE

The aim of this study was to develop and optimize a transdermal gel formulation of valsartan using Box-Behnken design and to evaluate it for pharmacokinetic study.

METHODS

The independent variables were Carbopol 940 (X1), PEG 400 (X2) and ethanol (X3) while valsartan flux (Y1), Tlag (Y2) and gel viscosity (Y3) were the dependent variables. Iso-eucalyptol was added in all gel formulations as permeation enhancer except for control gel.

RESULTS

It was observed that the permeation rate of valsartan significantly increased in direct proportion to the ethanol concentration, but significantly decreased in direct proportion to polymer concentration. Lag time and viscosity decreased in reverse proportion to ethanol concentration. The optimized valsartan gel formulation (VGF-OPT) yielded flux of 143.27 ± 7.11 µg/cm(2)/h and 27.55 ± 2.51 µg/cm(2)/h across rat and human cadaver skin, respectively. In vivo pharmacokinetic study of VGF-OPT-transdermal therapeutic system containing iso-eucalyptol showed a significant increase in the bioavailability (2.52 times) compared with oral formulation of valsartan by virtue of better permeation through Wistar rat skin.

CONCLUSION

It was concluded that the developed transdermal gel accentuates the flux of valsartan and could be used as an antihypertensive dosage form for effective transdermal delivery of valsartan.

Removal of xylenol orange from its aqueous solution using SDS self-microemulsifying systems: optimization by Box-Behnken statistical design

The aim of present study was to develop and evaluate sodium dodecyl sulfate (SDS) self-microemulsifying systems (SMES) for the removal of an anionic dye xylenol orange (XO) from its bulk aqueous media via liquid-liquid adsorption. The composition of SDS SMES was optimized by Box-Behnken statistical design for the maximum removal of XO from its aqueous solution. Various SDS formulations were prepared by spontaneous emulsification method and characterized for thermodynamic stability, self-microemulsification efficiency, droplet size, and viscosity. Adsorption studies were conducted at 8, 16, and 24 h by mixing small amounts of SDS formulations with relatively large amounts of bulk aqueous solution of XO. Droplet size and viscosity of SDS formulations were significantly influenced by oil phase concentration (triacetin), while surfactant concentration had little impact on droplet size and viscosity. However, the percentage of removal of XO was influenced by triacetin concentration, surfactant concentration, and adsorption time. Based on lowest droplet size (35.97 nm), lowest viscosity (29.62 cp), and highest percentage of removal efficiency (89.77 %), formulation F14, containing 2 % w/w of triacetin and 40 % w/w of surfactant mixture (20 % w/w of SDS and 20 % w/w of polyethylene glycol 400), was selected as an optimized formulation for the removal of XO from its bulk aqueous media after 16 h. These results indicated that SDS SMES could be suitable alternates of solid-liquid adsorption for the removal of toxic dyes such as XO from its aqueous solution through liquid-liquid adsorption.

An approach for lacidipine loaded gastroretentive formulation prepared by different methods for gastroparesis in diabetic patients

The present work deals with various attempts to prepare a gastroretentive formulation of lacidipine for treating gastroparesis. High density sucrose beads were modified by coating with certain polymers, but unfortunately sustained release could not be achieved. Granules were prepared by wet granulation technology using different combinations of polymers and a release of the drug was observed. The method failed to release the drug as per desired specifications. Polymeric coating followed by wet granulation was thought to be a better process to sustain the dissolution rate. The release rate can be modified by the incorporation of different polymeric coatings, but the mucoadhesive potential of granules was only 4.23% which might be due to its large size and the presence of other ingredients. Further, the lacidipine loaded microparticles were prepared by different methods such as compression, ionic gelation with TPP, ionic gelation with TPP and glutaraldehyde, spray drying and coacervation techniques. The formulations were evaluated for average particle size, surface morphology, entrapment efficiency, % yield and mucoadhesive potential. The microparticles prepared by compression method using HPMC K4M and SCMC as mucoadhesive polymers and BaSO4 as high density diluent showed poor bioadhesion (8.3%) and poor release characteristics (100% in 120 min). Ionic gelation with tripolyphosphate yielded microspheres with poor mechanical strength. In order to improve its mechanical strength, TPP ionic gelation was combined with step-wise cross-linking with glutaraldehyde. The additional solidification step to improve mechanical strength left this procedure tedious, time consuming and cytotoxic. Spray drying method gave a very low yield with 46.67% bioadhesion. The method using CaCl2 for ionotropic gelation showed the best results with regard to physical characteristics (well formed discrete, spherical surface microcapsule), particle size (88.57 ± 0.51), in vitro bioadhesion (67.33%), yield (>85%) and loading (>70%).

Developing micro-/nanoparticulate drug delivery systems using "design of experiments"

Of late, micro and nanoparticluate drug delivery systems have been gaining immense importance primarily attributed to their improved drug release controlling and targeting efficiencies. Also, the small particle size and desirable surface charge associated with these delivery systems render them suitable for specific applications like lymphatic uptake, pulmonary uptake, tumor targeting, brain targeting, etc. For decades, micro and nanoparticulate systems have been prepared by the conventional "trial and error" approach of changing One Variable at a Time (OVAT). Using this methodology, the solution of a specific problematic formulation characteristic can certainly be achieved, but attainment of the true optimal composition is never guaranteed. Thus, the present manuscript provides an updated account of the systematic approach "Design of Experiments (DoE)" as applicable to formulation development of microparticles and nanostructured systems. Besides providing a bird's eye view of the various experimental designs and optimization techniques employed for DoE optimization of such systems, the present manuscript also presents a copilation of the major micro/nano-structuctred systems optimized through DoE till date. In a nutshell, the article will act both as a ready reckoner of DoE optimization of micro/nano drug delivery systems and a catalyst in providing an impetus to young pharmaceutical "nano & micro" researchers to venture into the rewarding field of systematic DoE optimization.

Gastroretentive microparticles for drug delivery applications

Many strategies have been proposed to explore the possibility of exploiting gastroretention for drug delivery. Such systems would be useful for local delivery, for drugs that are poorly soluble at higher pH or primarily absorbed from the proximal small intestine. Generally, the requirements of such strategies are that the vehicle maintains controlled drug release and exhibits prolonged residence time in the stomach. Despite widespread reporting of technologies, many have an inherent drawback of variability in transit times. Microparticulate systems, capable of distributing widely through the gastrointestinal tract, can potentially minimise this variation. While being retained in the stomach, the drug content is released slowly at a desired rate, resulting in reduced fluctuations in drug levels. This review summarises the promising role of microencapsulation in this field, exploring both floating and mucoadhesive microparticles and their application in the treatment of Helicobacter pylori, highlighting the clinical potential of eradication of this widespread infection.

Formulation and optimization of nanotransfersomes using experimental design technique for accentuated transdermal delivery of valsartan

The purpose of this work was to develop and statistically optimize nanotransfersomes for enhanced transdermal of valsartan vis-à-vis traditional liposomes. Nanotransfersomes bearing valsartan were prepared by conventional rotary evaporation method and characterized for various parameters including entrapment efficiency, vesicles shape, size, size distribution, and skin permeation. In vivo antihypertensive activity conducted on Wistar rats was also taken as a measure of performance of nanotransfersomes and liposomes. Nanotransfersomes proved significantly superior in terms of amount of drug permeated in the skin, with an enhancement ratio of 33.97 ± 1.25 when compared to rigid liposomes. This was further confirmed through a confocal laser scanning microscopy study. Nanotransfersomes showed better antihypertensive activity in comparison to liposomes by virtue of better permeation through Wistar rat skin. Finally, it could be concluded that the nanotransfersomes accentuates the transdermal flux of valsartan and could be used as a carrier for effective transdermal delivery of valsartan.

FROM THE CLINICAL EDITOR

In this paper, the authors discuss the development and optimization of nanotransfersomes for enhanced transdermal of valsartan and demonstrate accentuated transdermal compared to standard preparations.