Preparation and characterization of co-grinded mixtures of aceclofenac and neusilin US2 for dissolution enhancement of aceclofenac

Engineering 5-flourouracil and leucovorin-loaded vesicular systems for possible colon specific delivery: In vitro evaluation and real time cell assay against HCT-116 colon cell lines

5-flourouracil (5-FU) is typically modulated with leucovorin (LEU) in clinical practice to improve clinical efficacy and patient survival rates. However, this combination has undesirable side effects and makes 5-FU more toxic. Hence, integrating a vesicular system (proniosomes) with another delivery vehicle may improve drug targeting, while resolving the aforementioned drawbacks. This study aimed to engineer 5-FU/LEU proniosomes for possible delivery to the colon. The modified slurry approach was used to create drug-loaded proniosomes (150 mg/9 g of carrier) using both water-soluble (dextrin (DEX) and lactose (LAC)) and insoluble (Neusilin FH2 (NEU)) carriers. The powdered formulations were filled into Eudragit S100 (10 %)-coated capsules or Eudragit FS 30D capsules for enteric- or colon-specific delivery. In vitro evaluations (flow properties, powder X-ray diffractometry (XRD) analysis, particle size analysis, entrapment efficiency, drug release, scanning electron microscopy (SEM), polydispersity index, Fourier transform infrared spectroscopy (FTIR), and stability studies) were performed on the formulations. An in vitro cytotoxicity test [real-time cell assay (RTCA)] against HCT-116 colon cancer cell lines was performed using the optimized formulation. In vitro evaluations showed that the nanoparticles had good physicochemical properties. RTCA studies showed sustained cell death with the formulations compared to the pure drug and placebo. The sequential drug release of the colon-targeted capsules containing 5-FU and LEU- loaded proniosomes showed negligible drug release in SGF (pH 1.2) and phosphate buffer solution (pH 6.8) (approximately 11 %) but profound drug release (>80 %) at pH 7.4. Drug-loaded proniosomes engineered for colon targeting (Eudragit S100 (10 %) capsules or Eudragit FS 30D capsules) showed good colon-specific targeting and favorable in vitro cytotoxicity profiles.

Drug Polymeric Carrier of Aceclofenac Based on Amphiphilic Chitosan Micelles

Amphiphilic micelles based on chitosan (CS) were applied as drug carriers of aceclofenac (ACF) as a potential method to induce its bioavailability and therapeutic efficiency. N-octyl-N,O-succinyl CS (OSCS), an amphiphilic CS derivative, was successfully synthesized and loaded physically by ACF at different pH values and using different dosages of ACF, forming ACF-loaded polymeric micelles (PMs). The obtained PMs and ACF-loaded PMs were characterized by different analytical techniques, including AFM, TEM, DLS, UV-vis spectrophotometry, 1H NMR spectroscopy, and FT-IR spectroscopy. The pH 5 sample with a 30% ACF/polymer ratio showed the highest ACF loading capacity (LC) and entrapment efficiency (EE). In vitro release behaviors of pure ACF and ACF-loaded PMs at each release point indicated that the release profile of pH-responsive PMs loaded with ACF demonstrated quicker release rates (94% after 480 min) compared to the release behavior noticed for free ACF (59.56% after 480 min). Furthermore, the release rates exhibit a notable rise when the pH is increased from 1.2 to 4.7. In the carrageenan-induced inflammation model of paw edema in rats, it has been demonstrated that the injection of ACF-loaded PMs (at a dose of 10 mg/kg) resulted in a strengthened inflammatory activity compared to the injection of free ACF at equivalent dosages as well as at time intervals. However, the use of ACF-loaded PMs for a duration of 6 h displayed a notable reduction of paw edema, with an inhibition percentage of 85.09%, in contrast to the 74.9% inhibition percentage observed for the free ACF medication.

Optimization and Production of Aceclofenac-Loaded Microfiber Solid Dispersion by Centrifugal Spinning

Aceclofenac-loaded polyvinylpyrrolidone fiber-based amorphous solid dispersion was produced successfully by centrifugal spinning. The solution concentration and rotational speed were optimized to produce the fiber-based drug carrier system, with a determined production rate of 12.7 g/h dry solid fibers. The obtained fibers were bead-free and smooth-surfaced with an average diameter of 7.5 ± 2.5 μm. Gas chromatographic determinations revealed that ethanol, as a residual solvent, was well below the regulatory limit of 0.5%. Differential scanning calorimetric investigation and infrared spectroscopic measurements were used to track the physicochemical changes that intervene during fiber formation in the solid state. The results revealed that the rapid evaporation of the solvent was accompanied by a probable crystalline to amorphous transition of the active substance during centrifugal spinning. In vitro dissolution studies revealed an instantaneous disintegration of the fibrous structure and a rapid release of the active substance, with the microfibrous webs greatly outperforming the crystalline active substance, especially in the early time-points. This implies that centrifugal spinning offers a viable scale-up production process to prepare drug-loaded fiber-based solid dispersions.

Screening of the Anti-Neurodegenerative Activity of Caffeic Acid after Introduction into Inorganic Metal Delivery Systems to Increase Its Solubility as the Result of a Mechanosynthetic Approach

The proven anti-neurodegenerative properties of caffeic acid in vivo are limited due to its poor solubility, which limits bioavailability. Therefore, caffeic acid delivery systems have been developed to improve caffeic acid solubility. Solid dispersions of caffeic acid and magnesium aluminometasilicate (Neusilin US2-Neu) were prepared using the ball milling and freeze-drying techniques. The solid dispersions of caffeic acid:Neu obtained by ball milling in a 1:1 mass ratio turned out to be the most effective. The identity of the studied system in comparison to the physical mixture was confirmed using the X-Ray Powder Diffractionand Fourier-transform infrared spectroscopy techniques. For caffeic acid with improved solubility, screening tests were carried out to assess its anti-neurodegenerative effect. The obtained results on the inhibition of acetylcholinesterase, butyrylcholinesterase, tyrosinase, and antioxidant potential provide evidence for improvement of caffeic acid's anti-neurodegenerative activity. As a result of in silico studies, we estimated which caffeic acid domains were involved in interactions with enzymes showing expression relevant to the neuroprotective activity. Importantly, the confirmed improvement in permeability of the soluble version of caffeic acid through membranes simulating the walls of the gastrointestinal tract and blood-brain barrier further strengthen the credibility of the results of in vivo anti-neurodegenerative screening tests.

Insight into the Inclusion Complexation of Fluconazole with Sulfonatocalix[4]naphthalene in Aqueous Solution, Solid-State, and Its Antimycotic Activity

The study aims to assess the interaction between fluconazole and sulfonatocalix[4]naphthalene towards enhancing its dissolution performance and antimycotic activity. A solubility study was carried out at different pH conditions, and the results revealed the formation of a 1:1 molar ratio fluconazole-sulfonatocalix[4]naphthalene inclusion complex with an A_L type phase solubility diagrams. The solid powder systems of fluconazole-sulfonatocalix[4]naphthalene were prepared using kneaded and co-evaporation techniques and physical mixtures. DCS, PXRD, TGA-DTG, FT-IR, and in vitro dissolution performance characterize the prepared systems. According to physicochemical characterization, the co-evaporation approach produces an amorphous inclusion complex of the drug inside the cavity of sulfonatocalix[4]naphthalene. The co-evaporate product significantly increased the drug dissolution rate up to 93 ± 1.77% within 10 min, unlike other prepared solid powders. The antimycotic activity showed an increase substantially (p ≤ 0.05, t-test) antimycotic activity of fluconazole co-evaporate mixture with sulfonatocalix[4]naphthalene compared with fluconazole alone against clinical strains of Candida albicans and Candida glabrata. In conclusion, sulfonatocalix[4]naphthalene could be considered an efficient complexing agent for fluconazole to enhance its aqueous solubility, dissolution performance, and antimycotic activity.

Effect of pH Modifiers on the Solubility, Dissolution Rate, and Stability of Telmisartan Solid Dispersions Produced by Hot-melt Extrusion Technology

The aim of the current study was to investigate the dual effect of an amorphous solid dispersion generated by hot melt extrusion and the addition of pH modifiers on the solubility and stability of telmisartan. Hydroxypropyl methylcellulose acetate succinate L grade was used as a polymeric carrier and recrystallization inhibitor, and meglumine, sodium carbonate, or Neusilin S2 were incorporated as pH modifiers to generate a desirable microenvironmental pH in the solid dispersions. Differential scanning calorimetry, powder X-ray diffraction, and Fourier transform infrared spectroscopy were incorporated to obtain the solid-state characterizations of telmisartan, and the results confirm a partial transformation of telmisartan to an amorphous state. An in vitro release study revealed that the transformation of telmisartan to an amorphous material improved its dissolution rate by 2-fold compared to pure drug and by up to 5-fold with the incorporation of pH modifiers. Results of the stability studies demonstrated that the samples have no significant degradation under accelerated stability conditions at 40 °C/75% RH.

Solid self nano-emulsifying system for the enhancement of dissolution and bioavailability of Prasugrel HCl: in vitro and in vivo studies

Prasugrel Hydrochloride (PHCl) is an antiplatelet drug. It is a class II drug with variable bioavailability. The objective of this work was to enhance the solubility and hence the bioavailability and efficacy of PHCl. A Self Nano-Emulsifying Drug Delivery System (SNEDDS) was prepared using Kolliphor El, Maisine 35-1, and Transcutol P as surfactant, oil, and co-surfactant, respectively in a ratio 10:72:18 v/v%. The SNEDDS was converted into solid by adsorption onto Neusilin. In vitro release of the drug from SNEDDS in (pH = 4) at 37 °C and 75 rpm for 45 min was studied. The results were compared to those from the unprocessed PHCl and Lexar^® (the commercial drug). In-vivo studies (platelet Aggregation and bleeding time) were conducted using rats as animal models. It was found that the particle size of the SNEDDS ranged between 80 and 155 nm and EE% was in the range of 90.2% ± 0.4. The release from SNEDDS was about 84% compared to around 25% from unprocessed PHCl and 65% from Lexar^® after 15 min. The platelet aggregation of the formula was lower than the PHCl, and Lexar^® indicating higher bioavailability. In conclusion, SNEDDS with high EE% was prepared and was successful in enhancing the solubility, dissolution rate, and the bioavailability.

Physicomechanical, stability, and pharmacokinetic evaluation of aceclofenac dimethyl urea cocrystals

Poor physicomechanical properties and limited aqueous solubility restrict the bioavailability of aceclofenac when given orally. To improve its above properties, aceclofenac (ACE) was cocrystallized with dimethyl urea (DMU) in 1:2 molar ratio by dry and solvent assisted grinding. The cocrystals were characterized by ATR-FTIR, DSC, and PXRD, and their surface morphology was studied by SEM. There was enhancement in intrinsic dissolution rate (IDR) (~eight- and ~fivefold in cocrystals prepared by solvent assisted grinding (SAG) and solid state grinding (SSG), respectively, in 0.1 N HCl, pH 1.2) and similarly (~3.42-fold and ~1.20-fold in phosphate buffer, pH 7.4) as compared to pure drug. Additionally, mechanical properties were assessed by tabletability curves. The tensile strength of ACE was < 1 MPa in contrast to the cocrystal tensile strength (3.5 MPa) which was ~1.98 times higher at 6000 psi. The tablet formulation of cocrystal by direct compression displayed enhanced dissolution profile (~36% in 0.1 N HCl, pH 1.2, and ~100% in phosphate buffer, pH 7.4) in comparison to physical mixture (~ 30% and ~ 80%) and ACE (~18% and ~50%) after 60 min, respectively. Stability studies of cocrystal tablets for 3 months indicated a stable formulation. Pharmacokinetic studies were performed by using rabbit model. The AUC_0-∞ (37.87±1.3 μgh/ml) and C_max (6.94±2.94 μg/ml) of the selected cocrystal C1 prepared by SAG were significantly enhanced (p < 0.05) and were ~3.43 and ~1.63-fold higher than that of ACE. In conclusion, new cocrystal of ACE-DMU was successfully prepared with improved tabletability, in vitro and in vivo properties.

Adsorption of a poorly water-soluble drug onto porous calcium silicate by the sealed heating method

To improve the bioavailability of orally-administered drug, solubilization of poorly water-soluble drug is important. The solubility of a drug in its amorphous form is known to be higher than in its crystalline form. In this study, we attempted to adsorb a sublimable drug onto porous calcium silicate (Florite®, FLR) or non-porous calcium silicate (NPCS) by the sealed heating (SH) method and evaporated (EV) method. Ibuprofen (IBU) was used as the poorly water-soluble, sublimable drug. The physicochemical properties of samples were investigated using powder X-ray diffractometry (PXRD), differential scanning calorimetry (DSC), Fourier-transform infrared spectroscopy (FTIR), and dissolution test. From the PXRD and DSC results, IBU crystals were adsorbed and amorphized by the SH and EV methods with FLR. From the results of FTIR, the shift to a higher frequency by the carbonyl stretching vibration band of IBU suggests an intermolecular interaction between IBU and FLR. In SH with FLR, improved solubilization was observed. IBU adsorbed onto FLR showed a greater dissolution rate than the IBU crystals or NPCS. Thus, the petal-like structure of FLR may be an effective method to adsorb IBU onto FLR using the SH method.

Design and Characterization of Phosphatidylcholine-Based Solid Dispersions of Aprepitant for Enhanced Solubility and Dissolution

This study aimed to improve the solubility and dissolution of aprepitant, a drug with poor aqueous solubility, using a phosphatidylcholine (PC)-based solid dispersion system. When fabricating the PC-based solid dispersion, we employed mesoporous microparticles, as an adsorbent, and disintegrants to improve the sticky nature of PC and dissolution of aprepitant, respectively. The solid dispersions were prepared by a solvent evaporation technique and characterized by Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry, and X-ray powder diffraction. The FTIR results showed that aprepitant interacted with the PC carrier by both hydrogen bonds and van der Waals forces that can also be observed in the interaction between aprepitant and polymer carriers. The solid dispersions fabricated with only PC were not sufficient to convert the crystallinity of aprepitant to an amorphous state, whereas the formulations that included adsorbent and disintegrant successfully changed that of aprepitant to an amorphous state. Both the solubility and dissolution of aprepitant were considerably enhanced in the PC-based solid dispersions containing adsorbent and disintegrant compared with those of pure aprepitant and polymer-based solid dispersions. Therefore, these results suggest that our PC-based solid dispersion system is a promising alternative to conventional formulations for poorly water-soluble drugs, such as aprepitant.

In-Vitro and In-Vivo Evaluation of Supersaturable Self-Nanoemulsifying Drug Delivery System (SNEDDS) of Dutasteride

OBJECTIVE

A novel, Supersaturable Self-Nanoemulsifying Drug Delivery System (S-SNEDDS) has been prepared to improve the Dutasteride's poor aqueous solubility.

METHODS

By adding Hydroxy Propyl Methyl Cellulose (HPMC) as a precipitation inhibitor to conventional SNEDDS, a supersaturable system was prepared. Firstly, the prepared SNEDDS played an important role in increasing the aqueous solubility and hence oral absorption due to nano-range size. Secondly, the S-SNEDDS found to be advantageous over SNEDDS for having a higher drug load and inhibition of dilution precipitation of Dutasteride. Formulated S-SNEDDS (F1-F9) ranged from 37.42 ± 1.02 to 68.92 ± 0.09 nm with PDI 0.219-0.34 and drug loading of over 95 percent.

RESULTS

The study of in-vitro dissolution revealed higher dissolution for S-SNEDDS compared to SNEDDS and Avodart soft gelatin capsule as a commercial product. In addition, higher absorption was observed for S-SNEDDS showing approximately 1.28 and 1.27 fold AUC (0-24h) and Cmax compared to commercial products. Therefore, S-SNEDDS has proven as a novel drug delivery system with a higher drug load, higher self-emulsification efficiency, higher stability, higher dissolution and pronounced absorption.

CONCLUSION

In conclusion, S-SNEDDS could be a newly emerging approach to enhance aqueous solubility in many folds for drugs belonging to BCS Class II and IV and thus absorption and oral bioavailability.

Glibenclamide Mini-tablets with an Enhanced Pharmacokinetic and Pharmacodynamic Performance

In an attempt to decrease the dose, anticipated side effects, and the cost of production of glibenclamide, GLC, a potent oral hypoglycemic drug, the enhancement of the dissolution and hence the oral bioavailability were investigated. Adsorption and co-adsorption techniques using carriers having a very large surface area and surface active agents were utilized to enhance the drug dissolution. Moreover, the Langmuir adsorption isotherms were constructed to identify the type and mechanism of adsorption. The optimized formulation showing the highest in vitro release was compressed into mini-tablet to facilitate drug administration to elderly patients and those having swallowing difficulties. The produced mini-tablets were tested for their mechanical strength and in vitro release pattern. In addition, the pharmacodynamic and pharmacokinetic studies in New Zealand rabbits were performed using the optimized mini-tablet formulation. Mini-tablets containing GLC co-adsorbate with Pluronic F-68 and Laponite RD showed 100 ± 1.88% of GLC released after 20 min. Pharmacodynamic studies in rabbits revealed significantly higher (p ≤ 0.05) hypoglycemic effect with the optimized mini-tablets at a lower GLC dose compared to mini-tablets containing the commercial GLC dose. Moreover, pharmacokinetic analysis showed significantly higher (p ≤ 0.05) AUC, C_max, and shorter T_max. The optimized mini-tablet formulation showed 1.5-fold enhancement of the oral bioavailability compared to mini-tablets containing untreated GLC. It could be concluded that the co-adsorption technique successfully enhanced the oral bioavailability of GLC. Furthermore, the produced mini-tablets have a higher oral bioavailability with a lower GLC dose, which could offer economic benefit for industry as well as acceptability for patients.

Dissolution enhancement of atorvastatin calcium by co-grinding technique

Atorvastatin calcium (AC) is a BCS class II drug which shows poor bioavailability due to inadequate dissolution. Solid dispersions present a promising option to enhance the solubility of poorly soluble drugs. Co-grinding with hydrophilic excipients is an easy and economical technique to improve the solubility of poorly soluble drugs and is free from usage of organic solvents. The aim of the present study was to explore novel carrier VBP-1 (organosulphur compound) for formulating a solid dispersion by using a simple, commercially viable co-grinding technique to enhance the dissolution of AC and to develop an oral formulation of the same. Composition of the solid dispersion was optimized based on the release profile in pH 1.2 buffer. The optimized solid dispersion was further characterized for flow properties, DSC, FTIR spectroscopy, XRD, contact angle, SEM studies and release profile in phosphate buffer pH 6.8. The developed solid dispersion gave similar release profile as the innovator formulation (Lipitor® tablets) in both pH 1.2 buffer and phosphate buffer pH 6.8. The developed solid dispersion was formulated into hard gelatin capsules (size 3). The developed capsules were found to give similar release as the innovator formulation in both pH 1.2 buffer and phosphate buffer pH 6.8. The developed capsules were found to be stable for a period of 6 months. Anti-hyperlipidemic efficacy studies in rats showed higher reduction in cholesterol and triglyceride levels by the developed capsules in comparison to pure AC. In conclusion, novel carrier VBP-1 was successfully employed to enhance the dissolution of AC using co-grinding technique.

Stabilization and Amorphization of Lovastatin Using Different Types of Silica

Lovastatin (LOV), an antihyperlipidimic agent, is characterized by low solubility/poor dissolution and, thus, low bioavailability (<5%). A beneficial effect on its bioavailability could result from improving its dissolution. One of the most common methods used to enhance dissolution is the preparation of solid dispersions. Solid dispersions of LOV and silica with different surface areas were prepared. The effects of the type of silica, ratio of drug/silica, incubation period with silica, and the effect of surface area were all studied. Characterization of the prepared formulae for possible interaction between drug and polymer was carried out using differential scanning calorimetery, Fourier transform infrared spectroscopy, powder X-ray diffraction, surface area determination, and scanning electron microscopy. The dissolution profiles of all prepared formulae were constructed and evaluated. It was found that the formula made of LOV and Sylysia 350 FCP in a ratio of 1:5 after an incubation period of 48 h resulted in the best release, and it was stable after 3 months storage at 75% RH and 40°C.

Confinement of Amorphous Lactose in Pores Formed Upon Co-Spray Drying With Nanoparticles

This study aims at investigating factors influencing humidity-induced recrystallization of amorphous lactose, produced by co-spray drying with particles of cellulose nanocrystals or sodium montmorillonite. In particular, the focus is on how the nanoparticle shape and surface properties influence the nanometer to micrometer length scale nanofiller arrangement in the nanocomposites and how the arrangements influence the mechanisms involved in the inhibition of the amorphous to crystalline transition. The nanocomposites were produced by co-spray drying. Solid-state transformations were analyzed at 60%-94% relative humidity using X-ray powder diffraction, microcalorimetry, and light microscopy. The recrystallization rate constant for the lactose/cellulose nanocrystals and lactose/sodium montmorillonite nanocomposites was lowered at nanofiller contents higher than 60% and was stable for months at 80% nanofiller. The most likely explanation to these results is spontaneous formations of mesoporous particle networks that the lactose is confined upon co-spray drying at high filler content. Compartmentalization and rigidification of the amorphous lactose proved to be less important mechanisms involved in the stabilization of lactose in the nanocomposites.

Preparation and tableting of long-term stable amorphous rutin using porous silica

Amorphous state of drugs increases the oral bioavailability, but typically faces physical stability problems. Amorphous rutin was generated and physically stabilized by encapsulating inside mesopores of porous AEROPERL® 300 Pharma and named as rutin CapsMorph® in this study. AEROPERL® 300 Pharma was loaded with rutin dissolved in DMSO containing Tween 80, and subsequently the solvent evaporated (wetness impregnation method). The loading process was monitored by light microscopy and scanning electron microscopy (SEM). X-ray diffraction (XRD) and differential scanning calorimetry (DSC) were used to confirm the amorphous state in AEROPERL® 300 Pharma. A loading of 20% of the rutin-AEROPERL® 300 Pharma mixture was obtained. The amorphous state proved to be stable over 2years of storage at room temperature. Due to the amorphous state and the nanosize of the rutin in the mesopores, the kinetic saturation solubility increased to about 4mg/ml (water, 0.1MHCl, pH 6.8PBS) compared to the maximum observed thermodynamic equilibrium solubility of rutin raw drug powder of only 74.48±1.42μg/ml in pH 6.8PBS (=increase by factor about 54). The dissolution velocity also increased distinctly, e.g. about 96.1% of rutin dissolution from CapsMorph® powder in water within 5min compared to less than 40% of raw drug powder after 3h. Tablets were produced with rutin CapsMorph®, raw drug powder and their dissolution velocity compared to a marketed product. About 83.0-95.6% were released from the rutin CapsMorph® tablet within 5min, compared to 42.7-52.5% from the marketed tablet after 3h (water, 0.1MHCl, pH 6.8PBS). After dissolution the supersaturation level of rutin CapsMorph® remained over about 2h, then solubility slowly reduced, but remained after 48h still multifold above the thermodynamic rutin solubility. This should be sufficient for many poorly soluble drugs to achieve a sufficient bioavailability. For optimal exploitation of the supersaturation, a multiple step release system could be used, e.g. release of CapsMorph® particles every 2-3h.

New Nanometric Solid Dispersions of Glibenclamide in Neusilin(®) UFL2

To improve the poor water solubility and dissolution rate of the oral hypoglycemic drug glibenclamide, it was molecularly dispersed in Neusilin(®) UFL2, an amorphous synthetic form of magnesium aluminometasilicate, at different proportions; the physicochemical and biopharmaceutical properties, as well as the stability of the four different batches recovered were characterised, and it was determined that complete dispersion of glibenclamide in the amorphous polymer was obtained at the drug to Neusilin ratio of 1 to 2.5. Completely amorphous dispersion was proven by Thermal Analysis and X-Ray Powder Diffractometry. Very small particles were obtained, ranging from approximately 200 to 400 nm. The amorphous batches were physically and chemically stable for the entire duration of experiments. The physicochemical properties of the four batches were compared to those of the starting materials and physical mixtures of Neusilin(®) UFL2 and glibenclamide, the latter showing the typical behaviour of simple mixes, i.e., the additivity of properties of single components. The dissolution studies of the four solid dispersions revealed a very high dissolution rate of the completely amorphous batches (Batches 3 and 4), behaviour that was ascribed to their high Intrinsic dissolution rate due to the amorphous characteristics of the solid dispersions, to their very small particle size, and to the presence of polysorbate 80 that improved solid wettability. The technique under investigation thus proved effective for recovering stable amorphous dispersions of very small particle sizes.

Design and development of an in situ synthesized layered double hydroxide structure of Fe-induced hydroxyapatite for drug carriers

Possible mechanisms: (i) formation of LDH structure of Fe-induced hydroxyapatite (HA), (ii) intercalation of Aceclofenac (AF) drug in LDH structure of FH carriers and (iii) releasing of drug via hydrolysis and/or reaction with other biomolecules.

Dissolution enhancement of chlorzoxazone using cogrinding technique

PURPOSE

The aim of the present work was to improve rate of dissolution and processing parameters of BCS class II drug, chlorzoxazone using cogrinding technique in the presence of different excipients as a carrier.

MATERIALS AND METHODS

The drug was coground with various carriers like polyethylene glycol (PEG 4000), hydroxypropyl methylcellulose (HPMC) E50LV, polyvinylpyrrolidone (PVP)K30, Kaolin and Neusilin US2 using ball mill, where only PEG 4000 improved dissolution rate of drug by bringing amorphization in 1:3 ratio. The coground mixture after 3 and 6 h was evaluated for various analytical, physicochemical and mechanical parameters.

RESULTS

The analysis showed conversion of Chlorzoxazone from its crystalline to amorphization form upon grinding with PEG 4000. Coground mixture as well as its directly compressed tablet showed 2.5-fold increment in the dissolution rate compared with pure drug. Directly compressible tablets prepared from pure drug required a large quantity of microcrystalline cellulose (MCC) during compression. The coground mixture and formulation was found stable in nature even after storage (40°C/75% relative humidity).

CONCLUSIONS

Cogrinding can be successfully utilized to improve the rate of dissolution of poorly water soluble drugs and hence bioavailability.

Formulation development and optimization of fast dissolving tablets of aceclofenac using natural superdisintegrant

The current research work involves preparation of fast dissolving tablets of Aceclofenac by direct compression method using different concentrations of Lepidium sativum mucilage as natural superdisintegrant. A two-factor three-level (3(2)) factorial design is being used to optimize the formulation. Nine formulation batches (D1-D9) were prepared accordingly. Two factors as independent variables (X 1-amount of β-cyclodextrin and X 2-amount of Lepidium sativum mucilage) were taken with three levels (+1, 0, -1). The levels of two factors were selected on the basis of preliminary experiments conducted and their effect on three dependent variables (disintegration time, wetting time, and in vitro drug release) was studied along with their % prediction error. All the active blends were evaluated for postcompression parameters (angle of repose, Carr's index, Hausner ratio, etc.) and the tablets were evaluated for postcompression parameters (weight variation, hardness, and friability, wetting time, disintegration time, water absorption ratio, and in vitro drug release studies). The optimum batch was further used for SEM and stability studies. Formulation D5 was selected by the Design-Expert software which exhibited DT (15.5 sec), WT (18.94 sec), and in vitro drug release (100%) within 15 minutes.

Development of a mini-tablet of co-grinded prednisone-Neusilin complex for pediatric use

The purpose of this study is to enhance the dissolution rate of prednisone by co-grinding with Neusilin to form a complex that can be incorporated into a mini-tablet formulation for pediatrics. Prednisone-Neusilin complex was co-grinded at various ratios (1:1, 1:3, 1:5, and 1:7). The physicochemical properties of the complex were characterized by various analytical techniques including: differential scanning calorimetry (DSC), X-ray powder diffraction (XRPD), scanning electron microscope (SEM), particle size, surface area, solubility, and dissolution rate. The co-grinded prednisone-Neusilin complex (1:7) was blended with other excipients and was formulated into a 2-mm diameter mini-tablet. The mini-tablets were further evaluated for thickness, weight, content uniformity, and dissolution rate. To improve taste masking and stability, mini-tablets were coated by dip coating with Eudragit® EPO solution. DSC and XRPD results showed that prednisone was transformed from crystalline state into amorphous state after co-grinding with Neusilin. Particle size, surface area, and SEM results confirmed that prednisone was adsorbed to Neusilin's surface. Co-grinded prednisone-Neusilin complex (1:7) had a solubility of 0.24 mg/mL and 90% dissolved within 20 min as compared to crystalline prednisone which had a solubility of 0.117 mg/mL and 30% dissolved within 20 min. The mini-tablets containing co-grinded prednisone-Neusilin complex (1:7) exhibited acceptable physicochemical and mechanical properties including dissolution rate enhancement. These mini-tablets were successfully dip coated in Eudragit® EPO solution to mask the taste of the drug during swallowing. This work illustrates the potential use of co-grinded prednisone-Neusilin to enhance solubility and dissolution rate as well as incorporation into a mini-tablet formulation for pediatric use.

Novel ultra-cryo milling and co-grinding technique in liquid nitrogen to produce dissolution-enhanced nanoparticles for poorly water-soluble drugs

A novel ultra-cryo milling micronization technique for pharmaceutical powders using liquid nitrogen (LN2 milling) was used to grind phenytoin, a poorly water-soluble drug, to improve its dissolution rate. LN2 milling produced particles that were much finer and more uniform in size and shape than particles produced by jet milling. However, the dissolution rate of LN2-milled phenytoin was the same as that of unground phenytoin due to agglomeration of the submicron particles. To overcome this, phenytoin was co-ground with polyvinylpyrrolidone (PVP). The dissolution rate of co-ground phenytoin was much higher than that of original phenytoin, single-ground phenytoin, a physical mixture of phenytoin and PVP, or jet-milled phenytoin. X-Ray diffraction showed that the crystalline state of mixtures co-ground by LN2 milling remained unchanged. The equivalent improvement in dissolution, whether phenytoin was co-ground or separately ground and then mixed with PVP, suggested that even when co-ground, the grinding of PVP and phenytoin occurs essentially independently. Mixing original PVP with ground phenytoin provided a slight improvement in dissolution, indicating that the particle size of PVP is important for improving dissolution. When mixed with ground phenytoin, PVP ground by LN2 milling aided the wettability and dispersion of phenytoin, enhancing utilization of the large surface area of ground phenytoin. Co-grinding phenytoin with other excipients such as Eudragit L100, hypromellose, hypromellose acetate-succinate, microcrystalline cellulose, hydroxypropylcellulose and carboxymethyl cellulose also improved the dissolution profile, indicating an ultra-cryo milling and co-grinding technique in liquid nitrogen has a broad applicability of the dissolution enhancement of phenytoin.

Dissolution and solid-state characterization of poorly water-soluble drugs in the presence of a hydrophilic carrier

The aim of this study was to investigate the effects of a hydrophilic carrier on the solid-state and dissolution characteristics of poorly water-soluble drugs. Three poorly water-soluble drugs, ibuprofen, carbamazepine, and nifedipine, were studied in combination with hydroxypropyl cellulose (HPC), a low molecular weight hydrophilic polymer, without the use of solvent. A 1:1 drug-polymer ratio was used to evaluate the percent drug release, crystallinity, and wettability. A drug-polymer ratio of 1:4 was also used in co-grinding process to evaluate the effect of polymer levels on drug release. Dissolution studies were carried out in deionized water. Mean dissolution time (MDT) was calculated, and statistical analysis of MDTs was done following a single factor one-way analysis of variance. The dissolution rate of the drugs was enhanced by several folds by the simple process of co-grinding with HPC. X-ray diffraction studies were done to investigate the effects of physical and co-ground mix with HPC on the crystallinity of the drugs, which indicated a partial loss in crystallinity upon grinding. Differential scanning calorimetry studies were performed in order to identify possible solid-state interactions between the respective drugs and HPC. Wettability of the drugs by a 0.5% aqueous HPC solution was compared with that of water and n-hexane using the "Washburn method." Increased wetting and hydrophilization of the drugs by HPC, enlarged surface area due to particle size reduction, and a decrease in the degree of crystallinity were identified as the likely contributors to dissolution rate enhancement.

Manufacture and performance evaluation of a stable amorphous complex of an acidic drug molecule and Neusilin

In this paper, we explore the use of Neusilin, an inorganic magnesium aluminometasilicate, to stabilize the amorphous form of an acidic drug Sulindac. Both cryomilling and ball milling of the drug with Neusilin were found to produce the amorphous phase. However, the ball-milled (BM) material exhibited superior physical stability when compared with the cryomilled material at 40°C/75% relative humidity. (13) C solid-state nuclear magnetic resonance investigation of the BM material revealed an acid-base reaction between Sulindac and Neusilin. Optimal milling conditions and the kinetics of salt formation were also established. As benchtop milling is a laboratory-scale process, a scalable process was developed to make Sulindac-Neusilin amorphous drug complex using hot-melt extrusion (HME). The dissolution properties of the resulting HME material was found to have been improved over the material made by benchtop milling while maintaining similar physical stability. The HME material was used to make tablets using a direct compression method. The HME tablets were found to have better dissolution properties than tablets made from crystalline Sulindac. For the broad class of acidic drugs containing the carboxyl moiety, inorganic silicates such as Neusilin would offer a better choice than organic polymers to stabilize the amorphous phase.