Enhanced dissolution of ibuprofen using solid dispersion with poloxamer 407

New Ibuprofen Cystamine Salts With Improved Solubility and Anti-Inflammatory Effect

Two novel ibuprofen cystamine salts (IBU-CYS 1 and IBU-CYS 2) are synthesized by coupling the anion of ibuprofen with cystamine dihydrochloride in 1 : 1 and 2 : 1 ratio to improve the solubility and bioavailability of ibuprofen. The salts are characterized by 1H NMR, FT-IR and UV-Vis spectroscopy, differential scanning calorimetry (DSC), thermogravimetry (TGA, DTA) and X-ray diffraction measurements. IBU-CYS 1 and IBU-CYS 2 show higher solubility (6.11 and 7.81 mg/mL) compared to ibuprofen (0.04 mg/mL) in water. IBU-CYS2 was encapsulated into 2-hydroxyethyl methacrylate: poly (ethylene glycol) acrylate hydrogels for enhanced delivery. The in vitro studies in PBS (pH 7.4) indicate that the salts are effective in relieving inflammatory responses induced by lipopolysaccharide in RAW264.7 macrophage cells (nitrite inhibition percentages of IBU-CYS 1, IBU-CYS 2 and ibuprofen: approximately 34.29, 27.03 and 31.50 respectively) while indicating no cytotoxicity. Therefore, these salts may be promising candidates for the development of effective formulations of this drug.

Thermo-activated in situ rectal gel preparation for Ibuprofen using eutectic mixture

This study aimed to develop a thermosensitive in situ gel formulation for rectal delivery of Ibuprofen as an efficient alternative dosage form. Utilizing poloxamer 188, poloxamer 407, and HPMC via cold technique method, a thermosensitive in situ gel was successfully prepared. The concentration of Ibuprofen in the formulations was 1.2 % (w/w). The prepared gels underwent assessment for clarity, gelation temperature, gelation time, gel strength, spread ability, syringe-ability, pH, viscosity, FTIR, and drug content. The selected formulations exhibited a gelation temperature within the range of 30 °C to 36 °C, with consistent amount of drug soluble in the formulations (93 % - 110 %). Mucoadhesive studies, in vitro release tests, ex vivo modeling of drug release, kinetic studies modeling, and histopathology testing were also conducted. The formulation comprising 18 % poloxamer 407, 12 % poloxamer 188, and 1 % sodium chloride (FS15) demonstrated suitable gelation temperature and desirable drug release rate. In vitro drug release tests indicated completion within one hour for both FS10 (20 % P407 & 10 % P188) and FS15 (18 % P407 & 12 % P188), with consistent and predictable release patterns observed through kinetic modeling analysis. Microscopic histopathology examination confirmed the safety of the selected formula, exhibiting no irritation in the mucosal membrane of the sheep. In conclusion, Ibuprofen thermosensitive in situ gel presents a promising and convenient strategy as a rectal carrier and an alternative dosage form to solid suppositories.

Synthesis of Quarternized Chitosans and Their Potential Applications in the Solubility Enhancement of Indomethacin by Solid Dispersion

This study was designed to synthesize quarternized chitosans (Q-CS) and explore their potential application in aqueous solubility enhancement of indomethacin (IND), a BCS class-II drug. Three different Q-CS; N,N,N-trimethyl chitosan chloride (TMC), N-(4-N'-methylpyridinylmethyl) chitosan chloride (mPyCS), and N-(4-N',N',N'-trimethylaminobenzyl) chitosan chloride (TmBzCS) were synthesized and characterized through various spectroscopic analysis. Q-CS-based solid-dispersion (SD) composites of IND (Q-CS-IND) were prepared using the spray-drying method and characterized through Fourier transform infrared (FTIR), scanning electron microscopy (SEM), differential-scanning calorimetry (DSC), and powder X-ray diffraction (P-XRD). The solubility and dissolution profiles of SD-composites of IND were evaluated and compared with physical mixtures (PM). The IND contents were quantified and validated in the composites using UV-Vis spectrophotometer. FTIR and NMR analysis showed the successful preparation of Q-CS. TMC was found with the highest yield (55.13%) and mPyCS with the highest degree of quaternization (DQ) (63.37%). FT-IR analysis of IND-Q-CS composites demonstrated chemical interaction between carbonyl moieties of IND with functional groups of Q-CS. DSC and PXRD analyses demonstrated the transformation of IND in SD composites from crystalline to an amorphous form. All the IND-Q-CS composites were observed with a significant increase in the solubility and dissolution rate of the drug (1996.0 µg/min) compared to PM (1306.8 µg/min), which is higher than pure IND (791.6 µg/min). The contents of IND in TMC, mPyCS, and TmBzCS composites were 97.69-99.92%, 97.66-100.25%, and 97.18-100.11% respectively. Overall, the findings encourage the applications of Q-CS derivatives for increasing IND water solubility and warrant further in vivo biological profiling of IND composites.

Impact of Methods of Preparation on Mechanical Properties, Dissolution Behavior, and Tableting Characteristics of Ibuprofen-Loaded Amorphous Solid Dispersions

This study aims to improve the biopharmaceutical, mechanical, and tableting properties of a poorly soluble drug, ibuprofen (IBP), by preparing amorphous solid dispersion (ASD) followed by a sustained-release tablet formulation. A suitable polymer to develop an ASD system was chosen by utilizing the apparent solubility of IBP in various polymer solutions. ASDs containing various ratios of IBP and selected polymer were prepared by the melt fusion (MF) method. ASD containing optimized drug-polymer ratio prepared by freeze-drying (FD) method was characterized and compared physicochemically. The solubility of IBP in water increased 28-fold and 35-fold when formulated as ASD by MF and FD, respectively. Precise formulations showed amorphization of IBP and increased surface area, improving solubility. The dissolution pattern of optimized ASD-IBP in pH 6.8 phosphate buffer after 60 min in MF and FD was enhanced 3-fold. In addition, direct compression tablets comprising optimized ASD granules from MF and FD were made and assessed using compendial and noncompendial methods. ASD-IBP/MF and ASD-IBP/FD formulations showed a similar drug release profile. In addition, 12 h of sustained IBP release from the ASD-IBP-containing tablets was obtained in a phosphate buffer with a pH of 6.8. From the dissolution kinetics analysis, the Weibull model fitted well. The drug release pattern indicated minimal variations between tablets formed using ASD-IBP prepared by both procedures; however, pre- and postcompression assessment parameters differed. From these findings, the application of ASD and sustained-release polymers in matrix formation might be beneficial in improving the solubility and absorption of poorly soluble drugs such as IBP.

Development and Characterization of Thermosensitive and Bioadhesive Ophthalmic Formulations Containing Flurbiprofen Solid Dispersions

In this study, we aimed to develop thermosensitive and bioadhesive in situ gelling systems containing solid dispersions of flurbiprofen (FB-SDs) using poloxamer 407 (P407) and 188 (P188) for ophthalmic delivery. FB-SDs were prepared with the melt method using P407, characterized by solubility, stability, SEM, DSC, TGA, and XRD analyses. Various formulations of poloxamer mixtures and FB-SDs were prepared using the cold method and P407/P188 (15/26.5%), which gels between 32 and 35 °C, was selected to develop an ophthalmic in situ gelling system. Bioadhesive polymers Carbopol 934P (CP) or carboxymethyl cellulose (CMC) were added in three concentrations (0.2, 0.4, and 0.6% (w/w)). Gelation temperature and time, mechanical properties, flow properties, and viscosity values were determined. The in vitro release rate, release kinetics, and the release mechanism of flurbiprofen (FB) from the ophthalmic formulations were analyzed. The results showed that FB-SDs' solubility in water increased 332-fold compared with FB. The oscillation study results indicated that increasing bioadhesive polymer concentrations decreased gelation temperature and time, and formulations containing CP gel at lower temperatures and in a shorter time. All formulations except F3 and F4 showed Newtonion flow under non-physiological conditions, while all formulations exhibited non-Newtonion pseudoplastic flow under physiological conditions. Viscosity values increased with an increase in bioadhesive polymer concertation at physiological conditions. Texture profile analysis (TPA) showed that CP-containing formulations had higher hardness, compressibility, and adhesiveness, and the gel structure of formulation F4, containing 0.6% CP, exhibited the greatest hardness, compressibility, and adhesiveness. In vitro drug release studies indicated that CP and CMC had no effect below 0.6% concentration. Kinetic evaluation favored first-order and Hixson-Crowell kinetic models. Release mechanism analysis showed that the n values of the formulations were greater than 1 except for formulation F5, suggesting that FB might be released from the ophthalmic formulations by super case II type diffusion. When all the results of this study are evaluated, the in situ gelling formulations prepared with FB-SDs that contained P407/P188 (15/26.5%) and 0.2% CP or 0.2% CMC or 0.4 CMC% (F2, F5, and F6, respectively) could be promising formulations to prolong precorneal residence time and improve ocular bioavailability of FB.

Effect of Drug Loading in Mesoporous Silica on Amorphous Stability and Performance

The encapsulation of drugs within mesoporous silica (MS) has for several years been a subject of research. Previous studies proposed that drug loadings up to the monomolecular loading capacity (MLC) are the optimal choice for maintaining the drug in an amorphous form, whereas filling the pores above the monolayer and up to the pore filling capacity (PFC) may introduce some physical instabilities. The aim of this study was to assess the effect of drug loading in MS-based amorphous formulations on the stability of the amorphous form of the drug as well as the dissolution. In particular, the following drug loadings were investigated: below MLC, at MLC, between MLC and PFC and at PFC. The drug-loaded MS formulations were analyzed directly after preparation and after 18 months of storage under accelerated conditions (40 °C in both dry and humid conditions). The MLC and PFC for the drug celecoxib (CEL) on the MS ParteckSLC500 (SLC) were determined at 33.5 wt.% and 48.4 wt.%, respectively. This study found that SLC can effectively preserve the amorphous form of the drug for 18 months, provided that the loading is below the PFC (<48.4 wt.%) and no humidity is present. On the other hand, drug loading at the PFC showed recrystallization even when stored under dry conditions. Under humid conditions, however, all samples, regardless of drug loading, showed recrystallization upon storage. In terms of dissolution, all freshly prepared formulations showed supersaturation. For drug loadings below PFC, a degree of supersaturation (DS) around 15 was measured before precipitation was observed. For drug loadings at PFC, the DS was found to be lower and only 6-times compared to the crystalline solubility. Lastly, for those samples that remained amorphous during storage for 18 months, the release profiles were found to be the same as the freshly loaded samples, with similar Cmax, Tmax and dissolution rate.

Poloxamer-based nanogels as delivery systems: how structural requirements can drive their biological performance?

Poloxamers or Pluronics®-based nanogels are one of the most used matrices for developing delivery systems. Due to their thermoresponsive and flexible mechanical properties, they allowed the incorporation of several molecules including drugs, biomacromolecules, lipid-derivatives, polymers, and metallic, polymeric, or lipid nanocarriers. The thermogelling mechanism is driven by micelles formation and their self-assembly as phase organizations (lamellar, hexagonal, cubic) in response to microenvironmental conditions such as temperature, osmolarity, and additives incorporated. Then, different biophysical techniques have been used for investigating those structural transitions from the mechanisms to the preferential component's orientation and organization. Since the design of PL-based pharmaceutical formulations is driven by the choice of the polymer type, considering its physico-chemical properties, it is also relevant to highlight that factors inherent to the polymeric matrix can be strongly influenced by the presence of additives and how they are able to determine the nanogels biopharmaceuticals properties such as bioadhesion, drug loading, surface interaction behavior, dissolution, and release rate control. In this review, we discuss the general applicability of three of the main biophysical techniques used to characterize those systems, scattering techniques (small-angle X-ray and neutron scattering), rheology and Fourier transform infrared absorption spectroscopy (FTIR), connecting their supramolecular structure and insights for formulating effective therapeutic delivery systems.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12551-023-01093-2.

Increasing Cellular Uptake and Permeation of Curcumin Using a Novel Polymer-Surfactant Formulation

Several therapeutically active molecules are poorly water-soluble, thereby creating a challenge for pharmaceutical scientists to develop an active solution for their oral drug delivery. This study aimed to investigate the potential for novel polymer-surfactant-based formulations (designated A and B) to improve the solubility and permeability of curcumin. A solubility study and characterization studies (FTIR, DSC and XRD) were conducted for the various formulations. The cytotoxicity of formulations and commercial comparators was tested via MTT and LDH assays, and their permeability by in vitro drug transport and cellular drug uptake was established using the Caco-2 cell model. The apparent permeability coefficients (Papp) are considered a good indicator of drug permeation. However, it can be argued that the magnitude of Papp, when used to reflect the permeability of the cells to the drug, can be influenced by the initial drug concentration (C₀) in the donor chamber. Therefore, Papp (suspension) and Papp (solution) were calculated based on the different values of C₀. It was clear that Papp (solution) can more accurately reflect drug permeation than Papp (suspension). Formulation A, containing Soluplus^® and vitamin E TPGs, significantly increased the permeation and cellular uptake of curcumin compared to other samples, which is believed to be related to the increased aqueous solubility of the drug in this formulation.

Monoketonic Curcuminoid-Lidocaine Co-Deliver Using Thermosensitive Organogels: From Drug Synthesis to Epidermis Structural Studies

Organogels (ORGs) are remarkable matrices due to their versatile chemical composition and straightforward preparation. This study proposes the development of ORGs as dual drug-carrier systems, considering the application of synthetic monoketonic curcuminoid (m-CUR) and lidocaine (LDC) to treat topical inflammatory lesions. The monoketone curcuminoid (m-CUR) was synthesized by using an innovative method via a NbCl₅–acid catalysis. ORGs were prepared by associating an aqueous phase composed of Pluronic F127 and LDC hydrochloride with an organic phase comprising isopropyl myristate (IPM), soy lecithin (LEC), and the synthesized m-CUR. Physicochemical characterization was performed to evaluate the influence of the organic phase on the ORGs supramolecular organization, permeation profiles, cytotoxicity, and epidermis structural characteristics. The physico-chemical properties of the ORGs were shown to be strongly dependent on the oil phase constitution. Results revealed that the incorporation of LEC and m-CUR shifted the sol-gel transition temperature, and that the addition of LDC enhanced the rheological G′/G″ ratio to higher values compared to original ORGs. Consequently, highly structured gels lead to gradual and controlled LDC permeation profiles from the ORG formulations. Porcine ear skin epidermis was treated with ORGs and evaluated by infrared spectroscopy (FTIR), where the stratum corneum lipids were shown to transition from a hexagonal to a liquid crystal phase. Quantitative optical coherence tomography (OCT) analysis revealed that LEC and m-CUR additives modify skin structuring. Data from this study pointed ORGs as promising formulations for skin-delivery.

Rectal Administration of Ibuprofen: Comparison of Enema and Suppository Form

Ibuprofen is a widely used and well-tolerated analgesic and antipyretic. It is desirable to have a formulation with a rapid rate of absorption because it is required for rapid pain relief and temperature reduction. Previous studies have described the pharmacokinetic profiles of ibuprofen suppository and the mean peak times of ibuprofen suppository were around 1.8 hours, indicating a slower rate of absorption. The aim of this study is to compare the pharmacokinetic parameters of rectal administration of ibuprofen between enema and suppository form in order to provide evidence for the faster absorption rates of ibuprofen enema. This study was a phase-1 clinical study, open-label, randomized and two-way crossover with one-week washout period comparing the absorption profile of equal dose of ibuprofen administered rectally in two treatment phases: ibuprofen suppository and enema. Blood samples were collected post dose for pharmacokinetic analyses. Tmax was analyzed using a Wilcoxon matched paired test. A standard ANOVA model, appropriate for bioequivalence studies was used and ratios of 90% confidence intervals were calculated. This study showed that Tmax for ibuprofen enema was less than half that of ibuprofen suppository (median 40 min vs. 90 min, respectively; p-value=0.0003). Cmax and AUC0-12 for ibuprofen enema were bioequivalent to ibuprofen suppository, as the ratio of test/reference=104.52%, 90% CI 93.41-116.95% and the ratio of test/reference=98.12%, 90%CI 93.34-103.16%, respectively, which fell within 80-125% bioequivalence limit. The overall extent of absorption was similar to the both, which were all well tolerated. In terms of Tmax, Ibuprofen enema was absorbed twice as quickly as from ibuprofen suppository. Therefore it is expected that an ibuprofen enema may provide faster onset of analgesic and antipyretic benefit.

Nanostructured Lipid Carriers for Intranasal Administration of Olanzapine in the Management of Schizophrenia

BACKGROUND

Olanzapine belongs to a new class of dual spectrum antipsychotic agents. It is known to show promise in managing both the positive and negative symptoms of schizophrenia. Drug delivery systems based on nanostructured lipid carriers (NLC) are expected to provide rapid nose-to-brain transport of this drug and improved distribution into and within the brain.

OBJECTIVE

The present study deals with the preparation and evaluation of olanzapine loaded NLC via the intranasal route for schizophrenia.

METHODS

Olanzapine-NLC were formulated through the solvent injection method using isopropyl alcohol as the solvent, stearic acid as solid lipid, and oleic acid as liquid lipid, chitosan as a coating agent, and Poloxamer 407 as a surfactant. NLC were characterized for particle size, polydispersity index, entrapment efficiency, pH, viscosity, X-ray diffraction studies, in-vitro mucoadhesion study, in- vitro release and ex-vivo permeation studies. The shape and surface morphology of the prepared NLC was determined through transmission electron microscopy. To detect the interaction of the drug with carriers, compatibility studies were also carried out.

RESULTS

Average size and polydispersity index of developed formulation S6 was 227.0±6.3 nm and 0.460, respectively. The encapsulation efficiency of formulation S6 was found to be 87.25%. The pH, viscosity, in-vitro mucoadhesion study, and in- vitro release of optimized olanzapine loaded NLC were recorded as 5.7 ± 0.05, 78 centipoise, 15±2 min, and 91.96%, respectively. In ex-vivo permeation studies, the percent drug permeated after 210 min was found to be 84.03%.

CONCLUSION

These results reveal the potential application of novel olanzapine-NLC in intranasal drug delivery system for the treatment of Schizophrenia.

Twin-Screw Melt Granulation for Oral Solid Pharmaceutical Products

This article highlights the advantages of pharmaceutical continuous melt granulation by twin-screw extrusion. The different melt granulation process options and excipients are described and compared, and a case is made for expanded use of twin-screw melt granulation since it is a flexible and continuous process. Methods for binder selection are profiled with a focus on rheology and physical stability impacts. For twin-screw melt granulation, the mechanism of granulation and process impact on granule properties are described. Pharmaceutical applications of melt granulation ranging from immediate release of soluble and insoluble APIs, taste-masking, and sustained release formulation are reviewed, demonstrating the range of possibilities afforded by twin-screw melt granulation.

Mutual Effects of Hydrogen Bonding and Polymer Hydrophobicity on Ibuprofen Crystal Inhibition in Solid Dispersions with Poly(N-vinyl pyrrolidone) and Poly(2-oxazolines)

Poly(N-vinyl pyrrolidone) (PVP), poly(2-methyl-2-oxazoline) (PMOZ), poly(2-ethyl-2-oxazoline) (PEOZ), poly(2-n-propyl-2-oxazoline) (PnPOZ), and poly(2-isopropyl-2-oxazoline) (PiPOZ) were used to prepare solid dispersions with ibuprofen (IB), a model poorly-water soluble drug. Dispersions, prepared by solvent evaporation, were investigated using powder X-ray diffractometry, differential scanning calorimetry, and FTIR spectroscopy; hydrogen bonds formed between IB and all polymers in solid dispersions. PMOZ, the most hydrophilic polymer, showed the poorest ability to reduce or inhibit the crystallinity of IB. In contrast, the more hydrophobic polymers PVP, PEOZ, PnPOZ, and PiPOZ provided greater but similar abilities to reduce IB crystallinity, despite the differing polymer hydrophobicity and that PiPOZ is semi-crystalline. These results indicate that crystallinity disruption is predominantly due to hydrogen bonding between the drug molecules and the polymer. However, carrier properties affected drug dissolution, where PnPOZ exhibited lower critical solution temperature that inhibited the release of IB, whereas drug release from other systems was consistent with the degree of ibuprofen crystallinity within the dispersions.

Formulation of solid dispersion to improve dissolution and oral bioavailability of poorly soluble dexibuprofen

Dexibuprofen (DEXI) belongs to BCS class II drug with poor aqueous solubility resulting in poor bioavailability. To enhance solubility and bioavailability of DEXI, DEXI-loaded solid dispersion (SD) was formulated. DEXI-SDs were prepared by melting method and solvent evaporation method. Amphipathic polymer poloxamer 407 (pol 407) was selected based on solubility and dissolution tests. The ratio of DEXI:pol 407 was optimized as 1:2. The physicochemical properties, dissolution, and oral bioavailability of SD3 and SD6 were evaluated to compare preparation methods. The dissolution rate of DEXI from SD formulations was higher at pH 6.8 and pH 7.2 than at pH 1.2. Following oral administration in rats, the C_max and AUC_last of SD3 and SD6 formulations were significantly higher compared with raw DEXI. In addition, the SD6 formulation showed increased C_max and AUC_last by 1.34- and 1.33-fold, compared with those of SD3 formulation, respectively. These results demonstrated that SD formulation has excellent potential as a formulation for poorly soluble drug DEXI.

Docetaxel-loaded solid lipid nanoparticles prevent tumor growth and lung metastasis of 4T1 murine mammary carcinoma cells

BACKGROUND

Metastasis causes the most breast cancer-related deaths in women. Here, we investigated the antitumor effect of solid lipid nanoparticles (SLN-DTX) when used in the treatment of metastatic breast tumors using 4T1-bearing BALB/c mice.

RESULTS

Solid lipid nanoparticles (SLNs) were produced using the high-energy method. Compritol 888 ATO was selected as the lipid matrix, and Pluronic F127 and Span 80 as the surfactants to stabilize nanoparticle dispersion. The particles had high stability for at least 120 days. The SLNs' dispersion size was 128 nm, their polydispersity index (PDI) was 0.2, and they showed a negative zeta potential. SLNs had high docetaxel (DTX) entrapment efficiency (86%), 2% of drug loading and showed a controlled drug-release profile. The half-maximal inhibitory concentration (IC₅₀) of SLN-DTX against 4T1 cells was more than 100 times lower than that of free DTX after 24 h treatment. In the cellular uptake test, SLN-DTX was taken into the cells significantly more than free DTX. The accumulation in the G2-M phase was significantly higher in cells treated with SLN-DTX (73.7%) than in cells treated with free DTX (23.0%), which induced subsequent apoptosis. TEM analysis revealed that SLN-DTX internalization is mediated by endocytosis, and fluorescence microscopy showed DTX induced microtubule damage. In vivo studies showed that SLN-DTX compared to free docetaxel exhibited higher antitumor efficacy by reducing tumor volume (p < 0.0001) and also prevented spontaneous lung metastasis in 4T1 tumor-bearing mice. Histological studies of lungs confirmed that treatment with SLN-DTX was able to prevent tumor. IL-6 serum levels, ki-67 and BCL-2 expression were analyzed and showed a remarkably strong reduction when used in a combined treatment.

CONCLUSIONS

These results indicate that DTX-loaded SLNs may be a promising carrier to treat breast cancer and in metastasis prevention.

The Effect of Cooling on the Degree of Crystallinity, Solid-State Properties, and Dissolution Rate of Multi-Component Hot-Melt Extruded Solid Dispersions

: The effect of cooling on the degree of crystallinity, solid-state and dissolution properties of multi-component hot-melt extruded solid dispersions [SD] is of great interest for the successful formulation of amorphous SDs and is an area that is unreported, especially in the context of improving the stability of these specific systems. The thermal solid-state properties, degree of crystallinity, drug-polymer interactions, solubility and physical stability over time were investigated. X-ray powder diffraction [XRPD] and hyper differential scanning calorimetry [DSC] confirmed that indomethacin [INM] was converted to the amorphous state; however, the addition of poloxamer 407 [P407] had a significant effect on the degree of crystallinity and the solubility of the SD formulations. Spectroscopy studies identified the mechanism of interaction and solubility studies, showing a higher dissolution rate compared to amorphous and pure INM in pH 1.2 with a kinetic solubility of 20.63 µg/mL and 34.7 µg/mL after 3 and 24 h. XRPD confirmed that INM remained amorphous after 5 months stability testing in solid solutions with Poly(vinylpyrrolidone-co-vinyl acetate) [PVP VA64] and Plasdone S-630 [PL-S630]. Although cooling had a significant effect on the degree of crystallinity and on solubility of INM, the cooling method used did not have any significant effect on the amorphous stability of INM over time.

Advances in Therapeutics and Delayed Drug Release

Reducing the frequency of drug administration in the treatment of exotic pets is advantageous because it may decrease handling frequency and thus potential stress and injury risk for the animal, increase owner compliance with the prescribed treatment, and decrease need for general anesthesia in patients that cannot be handled safely. Increasing efficient drug plasma concentration using sustained-released delivery systems is an appealing solution. Potential candidates that could provide a promising solution have been investigated in exotic pets. In this article, the technologies that are the closest to being integrated in exotic pet medicine are reviewed: osmotic pumps, nanoparticles, and hydrogels.

Development of a Ternary Solid Dispersion Formulation of LW6 to Improve the In Vivo Activity as a BCRP Inhibitor: Preparation and In Vitro/In Vivo Characterization

LW6 (3-[2-(4-adamantan-1-yl-phenoxy)-acetylamino]-4-hydroxy-benzoic acid methyl ester) is a potent inhibitor of drug efflux by the breast cancer resistance protein (BCRP). However, its poor aqueous solubility leads to low bioavailability, which currently limits in vivo applications. Therefore, the present study aimed to develop ternary solid dispersion (SD) formulations in order to enhance the aqueous solubility and dissolution rate of LW6. Various SDs of LW6 were prepared using a solvent evaporation method with different drug/excipient ratios. The solubility and dissolution profiles of LW6 in different SDs were examined, and F8-SD which is composed of LW6, poloxamer 407, and povidone K30 at a weight ratio of 1:5:8 was selected as the optimal SD. The structural characteristics of F8-SD were also examined using Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), X-ray powder diffraction (XRPD), and scanning electron microscopy (SEM). In the acidic to neutral pH range, F8-SD achieved rapid dissolution with a drug release of 76–81% within 20 min, while the dissolution of pure LW6 was negligible. The XRPD patterns indicated that F8-SD probably enhanced the solubility and dissolution of LW6 by changing the drug crystallinity to an amorphous state, in addition to the solubilizing effect of the hydrophilic carriers. Furthermore, F8-SD significantly improved the oral bioavailability of topotecan, which is a BCRP substrate, in rats. The systemic exposure of topotecan was enhanced approximately 10-fold by the concurrent use of F8-SD. In conclusion, the ternary SD formulation of LW6 with povidone K30 and poloxamer 407 appeared to be effective at improving the dissolution and in vivo effects of LW6 as a BCRP inhibitor.

Ex-vivo intestinal absorption study of boswellic acid, cyclodextrin complexes and poloxamer solid dispersions using everted gut sac technique

Acetyl- Keto-β-boswellic acid (AKBA) is a pentacyclic triterpenic acid found in gum resin of Boswellia serrata. Even though it is shown to have anti-inflammatory activity, its bioavailability gets limited due to its poor aqueous solubility and permeability. The present study, hence, deals in enhancement of the intestinal absorption of AKBA from total boswellic acid fraction (TA fraction) using cyclodextrin (CD) and poloxamer solid dispersion (PXM SDs) formulations. Absorption studies were performed using the everted gut sac model prepared from rat jejunum. The glucose uptake assay was performed to show viability of gut sac tissue. The apparent permeability (P_app) value of AKBA from TA fraction was 1.08 ± 0.17 × 10^-6 which was found to be increased by 10-14 fold with CD complex and SD formulations. The intestinal absorption studies showed highest absorption of AKBA from HP-β-CD complex and PXM 407 SD as compared to that from TA fraction. From this study, it can be concluded that HP-β-CD and PXM 407 effectively enhanced intestinal absorption through improved solubility, highlighting their role as efficient drug delivery agents and bioavailability enhancers.

Dissolution and bioavailability improvement of bioactive apigenin using solid dispersions prepared by different techniques

Apigenin (APG) is a poorly soluble bioactive compound/nutraceutical which shows poor bioavailability upon oral administration. Hence, the objective of this research work was to develop APG solid dispersions (SDs) using different techniques with the expectation to obtain improvement in its in vitro dissolution rate and in vivo bioavailability upon oral administration. Different SDs of APG were prepared by microwave, melted and kneaded technology using pluronic-F127 (PL) as a carrier. Prepared SDs were characterized using "thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), Fourier transform infra-red (FTIR) spectrometer, powder X-ray diffraction (PXRD) and scanning electron microscopy (SEM)". After characterization, prepared SDs of APG were studied for in vitro drug release/dissolution profile and in vivo pharmacokinetic studies. The results of TGA, DSC, FTIR, PXRD and SEM indicated successful formation of APG SDs. In vitro dissolution experiments suggested significant release of APG from all SDs (67.39-84.13%) in comparison with control (32.74%). Optimized SD of APG from each technology was subjected to in vivo pharmacokinetic study in rats. The results indicated significant improvement in oral absorption of APG from SD prepared using microwave and melted technology in comparison with pure drug and commercial capsule. The enhancement in oral bioavailability of APG from microwave SD (319.19%) was 3.19 fold as compared with marketed capsule (100.00%). Significant enhancement in the dissolution rate and oral absorption of APG from SD suggested that developed SD systems can be successfully used for oral drug delivery system of APG.

Early formulation development of CKD-519, a new CETP inhibitor, for phase 1 clinical study based on in vitro and in vivo evaluation

CKD-519, a potent cholesteryl ester transfer protein (CETP) inhibitor, is a clinical candidate being developed for the treatment of dyslipidemia. It is considered a Biopharmaceutical Classification System II compound with low solubility and high permeability. The objective of this study was to develop early formulations focusing on the dissolution rate of the compound to achieve dose-dependent exposure. High performance formulation strategies including solid dispersion (SD) and a self-microemulsifying drug delivery system (SMEDDS) were investigated and their in vivo and in vitro correlations were also evaluated in monkeys along with dose optimization in human volunteers. The SD granules were prepared in a fluid bed granulator using microcrystalline cellulose and mannitol as carriers. Poloxamer 407 and Eudragit E PO were each found to be a suitable solubilizing agent and polymer for the improvement of the CKD-519 dissolution rate. Pharmacokinetic studies in monkeys showed that the SD tablets exhibited better absorption than the SMEDDS in a dose-dependent manner from 1.5 mg to 100 mg. The mannitol-based SD tablet formulations were bioequivalent. However, pharmacokinetics studies in humans showed that the dose was saturable above 100 mg of CKD-519. This study was performed to determine how to develop early formulations for clinical studies and to identify rational formulation development strategies for CKD-519 to establish the pharmaceutical proof-of-concept in humans.

Preparation of Ibuprofen Microparticles by Antisolvent Precipitation Crystallization Technique: Characterization, Formulation, and In Vitro Performance

This study demonstrates the preparation and characterization of ibuprofen (IBP) microparticles with some excipients by a controlled crystallization technique with improved dissolution performance. Using the optimum concentrations pluronic F127, hydroxypropyl methyl cellulose, D-mannitol, and l-leucine in aqueous ethanol, the IBP microparticles were prepared. The dissolution tests were performed in phosphate buffer saline using a United States Pharmacopoeia dissolution tester at 37°C. The Raman spectroscopy was used to investigate the interactions and distribution of the IBP with the additives in the microcrystals. The prepared IBP microparticles showed higher dissolution compared to that of the smaller sized original IBP particles. The Raman data revealed that the excipients with a large number of hydroxyl groups distributed around the IBP particle in the crystal enhanced the dissolution of the drug by increasing the drug-solvent interaction presumably through hydrogen bonding. The Raman mapping technique gave an insight into the enhanced dissolution behavior of the prepared IBP microparticles, and such information will be useful for developing pharmaceutical formulations of hydrophobic drugs. The controlled crystallization was a useful technique to prepare complex crystals of IBP microparticles along with other additives to achieve the enhanced dissolution profile.

Investigation of Ethylene Oxide-co-propylene Oxide for Dissolution Enhancement of Hot-Melt Extruded Solid Dispersions

The optimal design of amorphous solid dispersion formulations requires the use of excipients to maintain supersaturation and improve physical stability to ensure shelf-life stability and better absorption during intestinal transit, respectively. Blends of excipients (surfactants and polymers) are often used within pharmaceutical products to improve the oral delivery of Biopharmaceutical Classification System class II drugs. Therefore, in this study, a dissolution enhancer, poloxamer 407 (P407), was investigated to determine its effect on the dissolution properties and on the amorphous nature of the active pharmaceutical ingredient contained in the formulation. Phase solubility studies of indomethacin (INM) in aqueous solutions of P407 and poly(vinylpyrrolidone-vinyl acetate copolymer) showed an increase in the kinetic solubility of INM compared with the pure drug at 37°C with a K_a value of 0.041 μg/mL. The solid dispersions showed a higher dissolution rate when compared to pure and amorphous drugs when performed in pH buffer 1.2 with a kinetic solubility of 21 μg/mL. The stability data showed that the amorphous drug in solid solutions with poly(vinylpyrrolidone-vinyl acetate copolymer) and P407 remained amorphous, and the %P407 loading had no effect on the amorphous stability of INM. This study concluded that the amorphous solid dispersion contributed to the increased solubility of INM.

Development of a binary carrier system consisting polyethylene glycol 4000 - ethyl cellulose for ibuprofen solid dispersion

Background and Objective

One of the established strategies to improve solubility and dissolution rate of poorly water-soluble drugs is solid dispersion (SD). Polyethylene glycol (PEG) is used as common carrier despite its stability problem which may be overcome by the addition of hydrophobic polymer. The present research aimed to develop an SD formulation with ibuprofen, a poor water-soluble BCS Class II drug as active pharmaceutical ingredient (API) and PEG 4000-ethyl cellulose (EC) as binary carrier.

Methods

Melt mixing SD method was employed using a ratio of API: binary carrier (1:3.5 w/w) (SD_PE). Another SD was prepared using only PEG (SD_P) as a carrier for comparative study. The developed formulation was evaluated using optical microscopy, scanning electron microscopy (SEM), determination of moisture content, differential scanning calorimetry (DSC), in vitro dissolution test, attenuated total reflection-Fourier transform infrared spectroscopy (ATR-FTIR) and flow properties.

Results

SEM and DSC indicated the conversion of crystalline ibuprofen to fine partly amorphous solid dispersion, which was responsible for the increase in dissolution rate of SD than a physical mixture. The release characteristics within 1 h from the higher to the lower value were the SD_PE> SD_P> physical mixture. Flow property evaluation using the angle of repose showed no difference between SD and PM. However, by Carr index and Hausner ratio, the flow properties of SD_PE was excellent.

Conclusion

The SD formulation with the PEG 4000-EC carrier can be effective to enhance in vitro dissolution of ibuprofen immediate release dosage form.

Characterization, Molecular Docking, and In Vitro Dissolution Studies of Solid Dispersions of 20(S)-Protopanaxadiol

In this study, we prepared solid dispersions (SDs) of 20(S)-protopanaxadiol (PPD) using a melting-solvent method with different polymers, in order to improve the solubility and dissolution performance of drugs with poor water solubility. The SDs were characterized via differential scanning calorimetry (DSC), powder X-ray diffraction (PXRD), Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance (NMR), and molecular docking and dynamics study. DSC and PXRD results indicated that PPD crystallinity in SDs was significantly reduced, and that the majority of PPD is amorphous. No interaction was observed between PPD and polymers on FTIR and NMR spectra. Molecular docking and dynamic calculations indicated that the PPD molecule localized to the interpolated charged surface, rather than within the amorphous polymer chain network, which might help prevent PPD crystallization, consequently enhancing the PPD dispersion in polymers. An in vitro dissolution study revealed that the SDs considerably improved the PPD dissolution performance in distilled water containing 0.35% Tween-80 (T-80). Furthermore, among three PPD-SDs formulations, Poloxamer188 (F68) was the most effective in improving the PPD solubility and was even superior to the mixed polymers. Therefore, the SD prepared with F68 as a hydrophilic polymer carrier might be a promising strategy for improving solubility and in vitro dissolution performance. F68-based SD, containing PPD with a melting-solvent preparation method, can be used as a promising, nontoxic, quick-release, and effective intermediate for other pharmaceutical formulations, in order to achieve a more effective drug delivery.

Poloxamer-based thermoresponsive ketorolac tromethamine in situ gel preparations: Design, characterisation, toxicity and transcorneal permeation studies

This study was aimed at preparing, characterising and evaluating in situ gel formulations based on a blend of two hydrophilic polymers i.e. poloxamer 407 (P407) and poloxamer 188 (P188) for a sustained ocular delivery of ketorolac tromethamine (KT). Drug-polymer interaction studies were performed using DSC and FT-IR. The gelation temperature (T_sol-gel), gelation time, rheological behaviour, mucoadhesive characteristics of these gels, transcorneal permeation and ocular irritation as well as toxicity was investigated. DSC and FT-IR studies revealed that there may be electrostatic interactions between the drug and the polymers used. P188 modified the T_sol/gel of P407 bringing it close to eye temperature (35°C) compared with the formulation containing P407 alone. Moreover, gels that comprised P407 and P188 exhibited a pseudoplastic behaviour at different concentrations. Furthermore, mucoadhesion study using mucin discs showed that in situ gel formulations have good mucoadhesive characteristics upon increasing the concentration of P407. When comparing formulations PP11 and PP12, the work of adhesion decreased significantly (P<0.001) from 377.9±7.79mNmm to 272.3±6.11mNmm. In vitro release and ex vivo permeation experiments indicated that the in situ gels were able to prolong and control KT release as only 48% of the KT released within 12h. In addition, the HET-CAM and BCOP tests confirmed the non-irritancy of KT loaded in situ gels, and HET-CAM test demonstrated the ability of ocular protection against strongly irritant substances. MTT assay on primary corneal epithelial cells revealed that in situ gel formulations loaded with KT showed reasonable and acceptable percent cell viability compared with control samples.

Ultrasound influence on the solubility of solid dispersions prepared for a poorly soluble drug

Solid dispersions have been successfully used to enhance the solubility of several poorly water soluble drugs. Solid dispersions are produced by melting hydrophilic carriers and mixing in the poorly water soluble drug. Supersaturation is obtained by quickly cooling the mixture until it solidifies, thereby entrapping the drug. The effects of using ultrasound to homogenize the molten carrier and drug mixture were studied. In particular, the increase in drug solubility for the resulting solid dispersions was analyzed. Piroxicam, which has very low water solubility, was used as a model drug. A full factorial design was used to analyze how sonication parameters affected the solubility and in vitro release of the drug. The results show that the use of ultrasound can significantly increase the solubility and dissolution rate of the piroxicam solid dispersion. Pure piroxicam presented a solubility of 13.3 μg/mL. A maximum fourfold increase in solubility, reaching 53.8 μg/mL, was observed for a solid dispersion sonicated at 19 kHz for 10 min and 475 W. The in vitro dissolution rate test showed the sonicated solid dispersion reached a maximum rate of 18%/min, a sixfold increase over the piroxicam rate of 2.9%/min. Further solid state characterization by thermal, X-ray diffraction and Fourier transform infrared analyses also showed that the sonication process, in the described conditions, did not adversely alter the drug or significantly change its polymorphic form. Ultrasound is therefore an interesting technique to homogenize drug/carrier mixtures with the objective of increasing the solubility of drugs with poor water solubility.

Development of duloxetine hydrochloride loaded mesoporous silica nanoparticles: characterizations and in vitro evaluation

This study investigated the potential use of mesoporous silica nanoparticles (MSNs) as a carrier for duloxetine hydrochloride (DX), which is prone to acid degradation. Sol-gel and solvothermal methods were used to synthesize the MSNs, which, after calcination and drug loading, were then characterized using X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) technique, thermogravimetric analysis (TGA), Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM), differential scanning calorimetry (DSC), and diffuse reflectance ultraviolet-visible (DRS-UV-Vis) spectroscopy. Releases of DX from the MSNs were good in pH 7.4 (90%) phosphate buffer but poor in acidic pH (40%). In a comparative release study between the MSNs in phosphate buffer, TW60-3DX showed sustained release for 140 h, which was higher than the other nanoparticles. The mechanism of DX release from the MSNs was studied using Peppas kinetics model. The "n" value of all three MSNs ranged from 0.45 to 1 with a correlation coefficient (r (2)) >0.9, which indicated that the release of the drug from the system follows the anomalous transport or non-Fickian diffusion. The results supported the efficacy of mesoporous silica nanoparticles synthesized here as a promising carrier for duloxetine hydrochloride with higher drug loading and greater pH-sensitive release.

Azad M, Islam Aovi F, Ahmeda Sultana N. Effect of Poloxamer on release of poorly water soluble drug Loratadine from solid dispersion: Kneading method

The main objective of the current study was to enhance the solubility and dissolution of poorly water soluble drug Loratadine (LOR) through formulation of solid dispersion systems (SDs) using hydrophilic polymers. SDs were prepared by kneading method using different drug-to-polymer ratios (1:3 and 1:5) with poloxomer 188 (samples DS1, DS2) and poloxomer 407 (samples DS3, DS4) as hydrophilic polymers. In vitro drug release studies were performed on prepared SDs (DS1-DS4) and compared to pure drug (LOR only, sample DS0). Prepared SDs showed significant improvement in the release profile compared to LOR.

Coating solid dispersions on microneedles via a molten dip-coating method: development and in vitro evaluation for transdermal delivery of a water-insoluble drug

This study demonstrates for the first time the ability to coat solid dispersions on microneedles as a means to deliver water-insoluble drugs through the skin. Polyethylene glycol (PEG) was selected as the hydrophilic matrix, and lidocaine base was selected as the model hydrophobic drug to create the solid dispersion. First, thermal characterization and viscosity measurements of the PEG-lidocaine mixture at different mass fractions were performed. The results show that lidocaine can remain stable at temperatures up to ∼130°C and that viscosity of the PEG-lidocaine molten solution increases as the mass fraction of lidocaine decreases. Differential scanning calorimetry demonstrated that at lidocaine mass fraction less than or equal to 50%, lidocaine is well dispersed in the PEG-lidocaine mixture. Uniform coatings were obtained on microneedle surfaces. In vitro dissolution studies in porcine skin showed that microneedles coated with PEG-lidocaine dispersions resulted in significantly higher delivery of lidocaine in just 3 min compared with 1 h topical application of 0.15 g EMLA®, a commercial lidocaine-prilocaine cream. In conclusion, the molten coating process we introduce here offers a practical approach to coat water-insoluble drugs on microneedles for transdermal delivery.

Physical stabilization of low-molecular-weight amorphous drugs in the solid state: a material science approach

Use of the amorphous state is considered to be one of the most effective approaches for improving the dissolution and subsequent oral bioavailability of poorly water-soluble drugs. However as the amorphous state has much higher physical instability in comparison with its crystalline counterpart, stabilization of amorphous drugs in a solid-dosage form presents a major challenge to formulators. The currently used approaches for stabilizing amorphous drug are discussed in this article with respect to their preparation, mechanism of stabilization and limitations. In order to realize the potential of amorphous formulations, significant efforts are required to enable the prediction of formulation performance. This will facilitate the development of computational tools that can inform a rapid and rational formulation development process for amorphous drugs.

Formulation of immediate release pellets containing famotidine solid dispersions

Famotidine (FM) is a potent H2-receptor antagonist used for the treatment of peptic ulcer. It has a low and variable bioavailability which is attributed to its low water solubility. In this study, the dissolution of the drug was enhanced by a preparation of solid dispersion using two hydrophilic carriers, namely Gelucire 50/13 and Pluronic F-127. The prepared solid dispersions were characterized by differential scanning calorimetry (DSC), which indicated that there were no signs of interaction of the drug with the carriers used in the case of solid dispersions containing higher polymeric contents (1:3 and 1:5). FM solid dispersions in the matrices of Gelucire 50/13 and Pluronic F-127 (1:3) were used to prepare pellets. The scanning electron microscope (SEM) images of pellets showed that the pellets have spherical shape and their size depends on the carrier used. The dissolution of the drug from either solid dispersion or pellets was performed. The dissolution study depicted that, the presence of the drug in solid dispersion enhanced its dissolution in comparison with the drug itself. Also, the drug release from the manufactured pellets was found to be improved in the case of solid dispersions (drug:carrier 1:3). A complete drug release occurred after 30 min from pellets containing solid dispersions, while only about 30% of the loaded FM was released from pellets containing untreated drug after 2 h.