Fabrication and In-Vivo Evaluation of Polyvinyl pyrrolidone/Poloxamer 188 Hybrid Nanofibers of Deflazacort.

The superior flexibility, efficient drug loading, high surface-to-volume ratio, ease of formulation, and cost-controlled production are considered exceptional advantages of nanofibers (NFs) as a smart delivery system. Deflazacort (DEF) is an anti-inflammatory and immunosuppressant agent. It is categorized as a poorly soluble class II drug. In this study, DEF-loaded polymeric nanofibrous using the electrospinning technique mats, Polyvinyl pyrrolidone (PVP) with or without Poloxamer 188 (PX) were used as mat-forming polymers. Microscopical imaging, drug content (%), and in vitro dissolution studies were conducted for all NFs formulae (F1-F7). All NFs improved the DEF dissolution compared to the unprocessed form, with the superiority of the PVP/PX hybrid. The optimized formula (F7) exhibited an average diameter of 655.46 ± 90.4 nm and % drug content of 84.33 ± 5.58. The dissolution parameters of DEF loaded in PVP/PX NFs (F7) reflected a release of 95.3 % ± 3.1 and 102.6 % ± 1.7 after 5 and 60 min, respectively. NFs (F7) was investigated for drug-polymer compatibility using Fourier-Transform Infrared Spectroscopy (FTIR), Powder X-ray diffraction analysis (PXRD), and Differential Scanning Calorimetry (DSC). In vivo anti-inflammatory study employing male Sprague-Dawley rats showed a significant reduction of rat paw edema for F7 (p < 0.05) compared with unprocessed DEF with a normal epidermal and dermal skin structure comparable to the healthy negative control. Immunohistochemical and morphometric data displayed similarities between the immune reaction of F7 and the negative healthy control. The finding of this work emphasized that DEF loaded in PVP/PX NFs could be considered a useful strategy for enhancing the therapeutic performance of DEF.

Lactosylated Chitosan Nanoparticles Potentiate the Anticancer Effects of Telmisartan In Vitro and in a N-Nitrosodiethylamine-Induced Mice Model of Hepatocellular Carcinoma.

Hepatocellular carcinoma (HCC) is the leading cause of cancer-related mortality worldwide. Telmisartan (TLM), a BSC class II drug, has been reported to have antiproliferative activity in HCC. However, its therapeutic activity is limited by poor bioavailability and unpredictable distribution. This work aimed to enhance TLM's liver uptake for HCC management through passive and active targeting pathways utilizing chitosan nanoparticles decorated with lactose (LCH NPs) as a delivery system. In vitro cell cytotoxicity and cellular uptake studies indicated that TLM-LCH NPs significantly (p < 0.05) enhanced the antiproliferative activity and cellular uptake percentage of TLM. In vivo bioavailability and liver biodistribution studies indicated that TLM-LCH NPs significantly (p < 0.05) enhanced TLM concentrations in plasma and the liver. The relative liver uptake of TLM from TLM-LCH NPs was 2-fold higher than that of unmodified NPs and 5-fold higher than that of plain TLM suspension. In vivo studies of a N-nitrosodiethylamine-induced HCC model revealed that administration of TLM through LCH NPs improved liver histology and resulted in lower serum alpha-fetoprotein (AFP), matrix metalloproteinase 2 (MMP-2), vascular endothelial growth factor (VEGF) levels, and liver weight index compared to plain TLM and TLM-loaded unmodified NPs. These results reflected the high potentiality of LCH NPs as a liver-targeted delivery system for TLM in the treatment of HCC.

Telmisartan-Loaded Lactosylated Chitosan Nanoparticles as a Liver Specific Delivery System: Synthesis, Optimization and Targeting Efficiency.

Hepatocellular carcinoma (HCC) has a significant economic impact and a high mortality rate. Telmisartan (TLM) is a potential therapy for HCC, but it has a limited scope in drug delivery due to unpredictable distribution and poor bioavailability. The objective of this study was to prepare, design, and in vitro evaluate lactose-modified chitosan nanoparticles (LCH NPs) as a liver-targeted nanocarrier for TLM with the potential to offer a promising HCC therapy. The combination of chitosan with lactose was successfully attained using the Maillard reaction. TLM-LCH NPs were prepared, characterized, and optimized with the developed 23 full factorial design. The optimized formulation (F1) was in vitro and in vivo characterized. LCH was synthesized with an acceptable yield of 43.8 ± 0.56%, a lactosylation degree of 14.34%, and a significantly higher aqueous solubility (6.28 ± 0.21 g/L) compared to native chitosan (0.25 ± 0.03 g/L). In vitro characterization demonstrated that, F1 had a particle size of 145.46 ± 0.7 nm, an entrapment efficiency of 90.21 ± 0.28%, and a surface charge of + 27.13 ± 0.21 mV. In vitro TLM release from F1 was most consistent with the Higuchi model and demonstrated significantly higher release at pH 5.5. Moreover, a significantly higher ratio of liver to plasma concentration was observed with TLM-LCH NPs compared to plain TLM and unmodified TLM-NPs. The obtained results nominate TLM-LCH NPs as a promising carrier for enhancing liver targeting of TLM in treatment of HCC.

Surfactant vesicles for enhanced antitoxoplasmic effect of norfloxacin: In vitro and in vivo evaluations.

The goal was to scrutinize niosomes as potential carriers for enhanced efficacy of norfloxacin against Toxoplasma gondii RH strain. This was assessed in vitro and in vivo. Standard niosomes of Span 60 and cholesterol were prepared. Gelucire 48/16 or Tween 80 was incorporated as hydrophilic fluidizer. The prepared vesicles were characterized for shape, size, viscosity and norfloxacin release. The in vitro anti-Toxoplasma was assessed by monitoring tachyzoites viability after incubation with niosomes. In vivo efficacy of niosomes encapsulated norfloxacin was evaluated on infected mice. Transmission electron micrographs showed nano-sized spherical vesicles. Norfloxacin release varied with niosomal composition to show faster liberation in presence of fluidizing agent. The half maximum effective concentration of norfloxacin against tachyzoites (EC50) was significantly reduced after niosomal encapsulation compared with simple drug solution with no significant difference between vesicular formulations. Tachyzoite count in the peritoneal fluid of infected mice was reduced by 45.2, 90.8, 88.3 and 84% after treatment with simple drug dispersion, standard niosomes, Gelucire containing and Tween containing vesicles, respectively compared to infected untreated mice. These results correlate with the in vitro data and reflects the efficacy of niosomes. The study introduced surfactant vesicles as a tool for enhanced efficacy of norfloxacin against toxoplasma.

Melting point depression for enhanced dissolution rate of eslicarbazepine acetate.

BACKGROUND: Eslicarbazepine acetate (ESL) is antiepileptic agent which is approved for use as single therapy or in combination with other drugs. However, it suffers from poor oral bioavailability. Modulation of drug crystallinity can be utilized as an approach for enhancing drug dissolution. OBJECTIVE: Accordingly, the aim of this study was to investigate possible eutectic system formation between eslicarbazepine with either tartaric acid or citric acid. METHODOLOGY: Eslicarbazepine acetate was subjected to wet co-grinding with tartaric acid or citric acid at different molar ratios. The prepared formulations were assessed using Fourier-transform infrared (FTIR), X-ray powder diffraction (XRPD), differential scanning calorimetry in addition to dissolution studies. RESULTS: The characterization techniques confirmed eutectic system formation with tartaric and citric acid with the optimum molar ratio for eutexia being 1:1 for both substances. Development of eutectic systems significantly enhanced the dissolution rate of ESL. Increasing the ratio of tartaric acid higher than the optimum ratio for eutexia resulted in additional increase in drug dissolution rate. This suggested the impact of pH modification on drug dissolution rate. The enhanced dissolution rate in case of the formulations containing ESL and citric acid was accredited to combined effect of eutaxia and pH modulation. These explanations were proven from investigating the dissolution rate of the physical mixtures which were inferior in their dissolution rate compared with the prepared formulations. CONCLUSION: co-processing of ESL with either citric acid or tartaric acid resulted in hastened dissolution rate which was accredited to combined effect of eutexia with pH modification.

The Development and Evaluation of Phase Transition Microemulsion for Ocular Delivery of Acetazolamide for Glaucoma Treatment.

The aim of this study was to develop microemulsion (ME) formulation with possible phase transition into liquid crystals upon ocular application to enhance acetazolamide bioavailability. Pseudoternary phase diagrams were constructed using olive oil or castor oil (oily phase), Tween 80 (surfactant), and sodium carbonate solution (aqueous phase). Microemulsion and liquid crystal (LC) formulations were selected from the constructed phase diagrams and were evaluated for rheological properties and in vitro drug release. The efficacy of the developed formulations in reducing intraocular pressure (IOP) was assessed in vivo. In vitro release study showed slower release rate from LC and ME compared with drug solution with the release from LC being the slowest. Ocular application of acetazolamide ME formulations or aqueous solution resulted in significant reduction in IOP from baseline. The recorded Tmax values indicated faster onset of action for acetazolamide aqueous solution (1 h) compared with ME systems (3 h). However, the duration of action was prolonged and the reduction in IOP continued for up to 10 h in case of MEs, while that of aqueous solution was only for 4-5 h. The study suggested ME formulations for ocular delivery of acetazolamide with enhanced efficacy and prolonged duration of action.

Intestinal absorption pathways of lisinopril: Mechanistic investigations.

Lisinopril is an antihypertensive drug with poor intestinal permeability. Enhancement of intestinal absorption depends on a clear understanding of the permeation pathways and absorption mechanisms. Unfortunately, these are not fully elucidated for lisinopril. Accordingly, the aim was to determine lisinopril permeation pathways and obstacles limiting membrane transport with subsequent nomination of appropriate permeation enhancers. This employed an in situ rabbit intestinal perfusion technique, which revealed site-dependent absorptive clearance (PeA/L) from a lisinopril simple solution (5 µg/ml), with paracellular absorption playing a role. Regional drug permeability ranked as colon> duodenum> jejunum> ileum opposing intestinal expression rank of P-glycoprotein (P-gp) efflux transporters. Duodenal and jejunal perfusion of a higher lisinopril concentration (50 µg/ml) reflected saturable absorption, suggesting carrier-mediated transport. The effect of piperine and verapamil as P-gp inhibitors on intestinal absorption of lisinopril was investigated. Coperfusion with either piperine or verapamil significantly enhanced lisinopril absorption, with enhancement being dominant in the ileum segment. This supported the contribution of P-gp transporters to poor lisinopril permeability. On the other hand, coperfusion of lisinopril with zinc acetate dihydrate significantly multiplied lisinopril PeA/L by 2.3- and 6.6-fold in duodenum and ileum segments, respectively, through magnifying intestinal water flux. The study explored the barriers limiting lisinopril intestinal absorption. Moreover, the study exposed clinically relevant lisinopril interactions with common coadministered cargos that should be considered for an appropriate lisinopril regimen. However, this requires further in vivo verification.

Influence of piperine and omeprazole on the regional absorption of Daclatasvir from rabbit intestine.

The study assessed the site dependent intestinal absorption of Daclatasvir and investigated the effects of piperine and omeprazole on such absorption utilizing in situ rabbit intestinal perfusion technique. The intestinal absorption of Daclatasvir was assessed in four segments: duodenum, jejunum, ileum, and colon. The effect of co-perfusion with omeprazole was monitored through the tested anatomical sites. The effect of piperine, a P-glycoprotein (P-gp) inhibitor on Daclatasvir absorption from jejunum and ileum was tested. The results showed that Daclatasvir was incompletely absorbed from the rabbit small and large intestine. The absorptive clearance per unit length (PeA/L) was site dependent and was ranked as colon > duodenum > jejunum > ileum. This rank is the opposite of the rank of P-gp intestinal content suggesting possible influence for P-gp. Co-perfusion with omeprazole increased PeA/L and this was evidenced also with reduced the L95% of Daclatasvir from both small and large intestinal segments. Significant enhancement in Daclatasvir absorption through jejunum and ileum was shown in presence of piperine. Daclatasvir showed site dependent intestinal absorption in a manner suggesting its affection by P-gp efflux. This effect was inhibited by piperine. Co-administration of Daclatasvir with omeprazole can enhance intestinal absorption a phenomenon which requires extension to human pharmacokinetic investigation.

Ocular films versus film-forming liquid systems for enhanced ocular drug delivery.

The short residence time, corneal barrier functions, and other effective eye protective mechanisms limited the ocular availability after topical application. Ocular inserts are being developed as polymer films for insertion into the conjunctival sac with the goal of increasing ocular availability. Unfortunately, these devices are not convenient for patients and are associated with many problems. The use of in situ gel/film-forming systems may provide promising alternative with comparable efficacy but this requires verification. Therefore, the current study compared ocular inserts with in situ film-forming liquids containing the same polymer components for ocular delivery of pilocarpine nitrate. Solvent casting technique was employed to prepare the inserts using and polyvinyl alcohol (PVA) as film-forming polymer blended with sodium alginate, as bioadhesive polymer. The effect of addition of either carboxymethycellulose, carbopol, polyvinylpyrrolidone, or methylcellulose was investigated. Solid-state characterization of the inserts indicated compatibility of the drug with film component. All inserts were of acceptable bioadhesive parameters and folding endurance that depended on the film composition. In vitro release studies reflected matrix diffusion kinetics for the film and liquid formulations. This confirms the in situ gelation of liquids. The calculated in vivo miotic pharmacokinetics parameters, using albino rabbits, reflected a better rank for the film but the difference was not statistically different from the in situ gel/film-forming systems. Ocular safety, as reflected by tear volume test, indicated acceptable safety of both liquid and inserts to the eye. The study suggested comparable efficacy of film-forming liquids to that of ocular films. Graphical abstract.

Polymeric nanoencapsulation of zaleplon into PLGA nanoparticles for enhanced pharmacokinetics and pharmacological activity.

Zaleplon (ZP) is a sedative and hypnotic drug used for the treatment of insomnia. Despite its potent anticonvulsant activity, ZP is not commonly used for the treatment of convulsion since ZP is characterized by its low oral bioavailability as a result of poor solubility and extensive liver metabolism. The following study aimed to formulate specifically controlled release nano-vehicles for oral and parenteral delivery of ZP to enhance its oral bioavailability and biological activity. A modified single emulsification-solvent evaporation method of sonication force was adopted to optimize the inclusion of ZP into biodegradable nanoparticles (NPs) using poly (dl-lactic-co-glycolic acid) (PLGA). The impacts of various formulation variables on the physicochemical characteristics of the ZP-PLGA-NPs and drug release profiles were investigated. Pharmacokinetics and pharmacological activity of ZP-PLGA-NPs were studied using experimental animals and were compared with generic ZP tablets. Assessment of gamma-aminobutyric acid (GABA) level in plasma after oral administration was conducted using enzyme-linked immunosorbent assay. The maximal electroshock-induced seizures model evaluated anticonvulsant activity after the parenteral administration of ZP-loaded NPs. The prepared ZP-PLGA NPs were negatively charged spherical particles with an average size of 120-300 nm. Optimized ZP-PLGA NPs showed higher plasma GABA levels, longer sedative, hypnotic effects, and a 3.42-fold augmentation in oral drug bioavailability in comparison to ZP-marketed products. Moreover, parenteral administration of ZP-NPs showed higher anticonvulsant activity compared to free drug. Oral administration of ZP-PLGA NPs achieved a significant improvement in the drug bioavailability, and parenteral administration showed a pronounced anticonvulsant activity.

Co-processing of nateglinide with meglumine for enhanced dissolution rate: in vitro and in vivo evaluation.

OBJECTIVE: The aim of this work was to investigate dry co-grinding of nateglinide with meglumine for enhanced dissolution rate of nateglinide. The study was extended to investigate the effect of this dissolution enhancement on the hypoglycemic effect of the drug in diabetic rats. METHODS: Nateglinide was subjected to dry co-grinding with increasing proportions of meglumine to prepare products containing the drug with meglumine at 1:1, 1:2, and 1:3 molar ratios. These products were evaluated using combined instrumental analysis which employed Fourier transform infrared spectroscopy (FTIR), differential thermal analysis (DTA), and X-ray diffraction (XRD). Drug dissolution was also monitored before and after processing with and without meglumine. The optimum ratio was used to assess the effect of dissolution enhancement on the hypoglycemic effect of nateglinide on diabetic rats. The unprocessed nateglinide was used as control. RESULTS: Co-grinding of nateglinide resulted in changes in the FTIR spectral patterns of nateglinide and meglumine. The changes suggested the formation of amide bond between both compounds at 1:1 molar ratio. The new species was confirmed by DTA and XRD. This species exhibited fast dissolution of nateglinide after incorporation of higher proportions of meglumine. Co-grinding was essential as indicated from slower dissolution from physical mixture containing the highest proportion of meglumine. Enhanced dissolution was reflected in vivo as improved rate and extent of hypoglycemia. CONCLUSION: Dry co-grinding of nateglinide with meglumine developed new species which liberated nateglinide rapidly and enhanced the rate and extent of hypoglycemia of nateglinide.

Chitosan coated nanostructured lipid carriers for enhanced in vivo efficacy of albendazole against Trichinella spiralis.

The study investigated chitosan coated nanostructured lipid carriers (NLCs) for oral delivery of albendazole in treatment of trichinellosis. NLCs comprised precirol and oleic acid with Tween and Span 80. Dicetylphosphate was used as charging agent to allow chitosan coating. Trichinella spiralis infected mice were used and albendazole suspension, coated or uncoated NLCs were orally administered at different stages of infection. NLCs were spherical with size of 188 and 200 nm for coated and uncoated NLC, respectively. Treatment during intestinal phase reduced worm count with NLCs showing better rank. This was reflected further by reduced larvae count and improved histopathological features. Starting treatment in the migrating phase reduced larval count by 62.9, 99.6 and 89.5 % after administration of suspension, coated and uncoated NLCs, respectively. The same rank was recorded for the encysted phase. NLCs enhanced the efficacy of albendazole against Trichinella spiralis compared with suspension with chitosan coated NLCs being superior.

Preparation of stabilized submicron fenofibrate crystals on niacin as a hydrophilic hydrotropic carrier.

Fenofibrate is antihyperlipidemic which has low and variable oral bioavailability due to erratic dissolution characteristics. Niacin showed a potential atheroprotective effects suggesting possible co-administration with fenofibrate with a potential for development of fixed dose combination. The chemical structure of both drugs highlights the opportunity for interaction upon co-processing due to the existence of complementary hydrogen bonding sites. Accordingly, fenofibrate and niacin were co-processed by wet co-grinding and the resulting product was assessed using scanning electron microscopy, FTIR, thermal analysis and X-ray diffraction in addition to dissolution studies. The instrumental analysis indicated the development of submicron fenofibrate crystals stabilized over the surface of niacin crystals. The developed submicron crystals showed fast dissolution of fenofibrate depending on the relative proportions of fenofibrate to niacin. Co-processing of both drugs at dose ratio which contained higher proportion of niacin resulted in further enhancement in the dissolution rate. This further enhancement was attributed to the hydrotropic effect of niacin which was proved by solubility study in addition to size reduction. This supposition was confirmed from the inferior dissolution of fenofibrate from the physical mixture. The study introduces fenofibrate/niacin as potential fixed dose combination for augmented dissolution rate and pharmacological effects.

Development and evaluation of rapidly dissolving buccal films of naftopidil: in vitro and in vivo evaluation.

Objectives: Development and evaluation of rapidly dissolving film for intra-oral administration of naftopidil. Significance: Formulation of naftopidil in the form of rapidly dissolving buccal film can eliminate the dissolution problem of naftopidil and provide a greater chance for direct absorption into the systemic circulation bypassing the presystemic metabolism. This can improve the oral bioavailability. In addition, this film guarantees patient compliance and is suitable for geriatric patients. Methods: Rapidly dissolving film utilized hydroxypropyl methylcellulose E5 and polyvinylpyrrolidone K30 as the main components. The drug was loaded in pure form or after co-grinding with citric and/or tartaric acid. A solution of naftopidil in plurol oleique, labrasol, and tween 80 self-microemulsifying drug delivery systems (SMEDDS) was also loaded. The interactions of the drug with the excipients were monitored using thermal analysis, Fourier transform infrared spectroscopy, and X-ray diffraction. Naftopidil dissolution was monitored and selected films were used to assess the bioavailability after buccal administration to rabbit. Unprocessed drug suspension was administered orally and used as a reference. Results: Incorporation of naftopidil in the film developed a new crystalline structure. The crystallinity of drug was abolished in the presence of organic acids or SMEDDS. The rapidly dissolving films showed fast liberation of the drug irrespective to the composition. Those films enhanced the bioavailability of naftopidil compared to orally administered suspension with SMEDDS containing film being superior. Conclusion: The study introduced rapidly dissolving buccal film for enhanced dissolution and bioavailability of naftopidil.

Eutexia for enhanced dissolution rate and anti-inflammatory activity of nonsteroidal anti-inflammatory agents: Caffeine as a melting point modulator.

Fast dissolution of nonsteroidal anti-inflammatory drugs (NSAIDs) is a prerequisite from patient perspective. However, most NSAIDs are slowly dissolving acidic compounds. Caffeine, a commonly used analgesic adjuvant with NSAIDs showed high potential as eutectic co-former for acidic compounds. The study investigated eutectic forming potential of caffeine with meloxicam, aceclofenac and flurbiprofen. Each drug was co-ground with caffeine in various ratios and the products were characterized by thermal analysis to determine the optimum eutectic composition from phase diagram and Tamman's triangle. The optimum systems were subjected to X-ray powder diffraction (XRPD), Fourier-transform infrared (FTIR) and dissolution studies. Co-ground systems at dose ratio were also assessed for drug dissolution and anti-inflammatory effect using carrageenan induced rat paw edema method. Eutexia was confirmed by thermal analysis with the optimum composition being 1:1, 1:1 and 1:2 (NSAID: caffeine) for aceclofenac, flurbiprofen and meloxicam, respectively. Eutexia did not alter FTIR spectra with minor changes being recorded in XRPD patterns. The eutectic systems underwent fast liberation of drugs with fast dissolution being retained even at dose ratios. Dissolution enhancement was associated with enhanced anti-inflammatory response. The study introduced caffeine as eutectic forming analgesic for fixed dose combination with NSAIDs to enhance drug dissolution and anti-inflammatory effect.

Co-crystallization for enhanced dissolution rate of bicalutamide: preparation and evaluation of rapidly disintegrating tablets.

Objectives: Enhance the dissolution rate of bicalutamide via co-crystallization with sucralose (sweetener), with the aim to develop rapidly disintegrating tablets with subsequent prompt dissolution. Significance: Bicalutamide is antiandrogenic agent for the treatment of prostate cancer but has low and variable oral bioavailability, mainly attributed to poor dissolution. Co-crystallization with benign excipients is promising for dissolution enhancement with the additive serving dual functions. The benefit will become greater if dissolution enhancement is associated with the development of orodispersible tablets which is suitable for elderly patients who are the most vulnerable for prostate cancer. Methods: Bicalutamide was dissolved in acetone in the presence of increasing molar ratios of sucralose. The solvent was evaporated while mixing to deposit crystals that were subjected to wet co-grinding until drying. The developed solids were characterized using Fourier transform infrared spectroscopy, differential thermal analysis and X-ray diffraction in addition to monitoring bicalutamide dissolution. Results: Instrumental analysis provided evidences for co-crystallization which was initiated at 1:1 molar ratio of bicalutamide to sucralose with complete co-crystallization at 1:4 molar ratio. The co-crystals provided faster bicalutamide dissolution compared with the unprocessed drug and that recrystalized from acetone in the absence of sucralose. The formulation containing bicalutamide with sucralose at 1:4 molar ratio was selected for tablet formulation into which superdisintegrants were included. The developed tablets exhibited flash disintegration with subsequent fast dissolution of bicalutamide. Conclusions: The study introduced co-crystallization of bicalutamide with sucralose as an efficient tool to enhance the dissolution rate and to develop rapidly dissolving tablets for intraoral administration.

Essential oils in niosomes for enhanced transdermal delivery of felodipine.

The fluidity of vesicular membrane affects vesicular transdermal drug delivery. Essential oils can be located in vesicular membrane imparting flexibility and influencing transdermal delivery. Accordingly, the objective was to investigate the effect of incorporation of essential oils in niosomes on felodipine transdermal delivery. Rigid niosomes comprising Span 60 with cholesterol (2:1, w/w) were used with clove, eucalyptus or lemon oils being incorporated in the vesicles at increasing concentrations. The vesicle size and shape was monitored using scanning electron microscopy. Thermal analysis was used to monitor the thermal behavior. Drug entrapment efficiency, release and skin permeation were monitored. Niosomes were spherical with size ranging from 279 to 345 nm. The drug entrapment ranged from 97.9 to 98.8%. Thermal analysis confirmed the existence of oils within vesicular membrane and highlighted the membrane fluidizing effect. Drug release depended on the oil with clove oil or eucalyptus oil showing a trend of increased drug release compared with plain niosomes. In contrast, lemon oil reduced drug release rate. Skin permeation study reflected the superiority of oil containing niosomes. The results correlated with the fluidizing and penetration enhancing effects of oils. The study introduced essential oils as potential niosomes fluidizing agents for enhanced transdermal drug delivery.

Inhibition of Co-Crystallization of Olmesartan Medoxomil and Hydrochlorothiazide for Enhanced Dissolution Rate in Their Fixed Dose Combination.

Olmesartan medoxomil (Olm) and hydrochlorothiazide (HCTZ) are fixed dose combination (FDC) for treatment of hypertension. They have hydrogen bonding sites and may interact during co-processing. The consequences of such interaction are not clear. This study investigated the possibility of this interaction during co-processing. The research was extended to inhibit deleterious interactions. The drugs were co-evaporated from ethanolic solution to maximize the chance of interaction. This was performed in the absence and presence of hydroxypropyl methylcellulose (HPMC) and/or aerosil. The products were characterized using Fourier transform infrared spectroscopy (FTIR), differential thermal analysis, and powder X-ray diffraction (PXRD) in addition to dissolution studies. Co-evaporation of Olm with HCTZ in the absence of excipients produced crystalline material with FTIR spectrum showing intermolecular hydrogen bonding. This material showed thermal pattern of new crystalline species. This was identified as Olm/HCTZ co-crystal by PXRD. This co-crystallization reduced the dissolution rate of both drugs. This co-crystallization was inhibited in the presence of HPMC, but the dissolution rate was not significantly enhanced accordingly. Co-processing in the presence of both HPMC and aerosil eliminated the co-crystallization and minimized the intermolecular drug-drug interaction with subsequent dissolution enhancement. The study introduced a composition for fixed dose combination of Olm and HCTZ with enhanced dissolution.

Controlled precipitation for enhanced dissolution rate of flurbiprofen: development of rapidly disintegrating tablets.

OBJECTIVE: The aim of this work was to investigate the potential of controlled precipitation of flurbiprofen on solid surface, in the presence or absence of hydrophilic polymers, as a tool for enhanced dissolution rate of the drug. The work was extended to develop rapidly disintegrated tablets. SIGNIFICANCE: This strategy provides simple technique for dissolution enhancement of slowly dissolving drugs with high scaling up potential. METHODS: Aerosil was dispersed in ethanolic solution of flurbiprofen in the presence and absence of hydrophilic polymers. Acidified water was added as antisolvent to produce controlled precipitation. The resultant particles were centrifuged and dried at ambient temperature before monitoring the dissolution pattern. The particles were also subjected to FTIR spectroscopic, X-ray diffraction and thermal analyses. RESULTS: The FTIR spectroscopy excluded any interaction between flurbiprofen and excipients. The thermal analysis reflected possible change in the crystalline structure and or crystal size of the drug after controlled precipitation in the presence of hydrophilic polymers. This was further confirmed by X-ray diffraction. The modulation in the crystalline structure and size was associated with a significant enhancement in the dissolution rate of flurbiprofen. Optimum formulations were successfully formulated as rapidly disintegrating tablet with subsequent fast dissolution. CONCLUSIONS: Precipitation on a large solid surface area is a promising strategy for enhanced dissolution rate with the presence of hydrophilic polymers during precipitation process improving the efficiency.

Rapid disintegrating tablets of simvastatin dispersions in polyoxyethylene-polypropylene block copolymer for maximized disintegration and dissolution.

The objective of this research was to improve the dissolution of simvastatin and to incorporate it in rapid disintegrating tablets (RDTs) with an optimized disintegration and dissolution characteristics. Polyoxyethylene-polypropylene block copolymer (poloxamer 188) was employed as a hydrophilic carrier to prepare simvastatin solid dispersions (SDs). Fourier transform infrared spectroscopy, differential scanning calorimetry (DSC) and X-ray diffractometry were employed to understand the interaction between the drug and the carrier in the solid state. The results obtained from Fourier transform infrared spectroscopy showed absence of any chemical interaction between the drug and poloxamer. The results of differential scanning calorimetry and X-ray diffractometry confirmed the conversion of simvastatin to distorted crystalline state. The SD of 1:2 w/w drug to carrier ratio showed the highest dissolution; hence, it was incorporated in RDT formulations using a 32 full factorial design and response surface methodology. The initial assessments of RDTs demonstrated an acceptable flow, hardness, and friability to indicate good mechanical strength. The interaction and Pareto charts indicated that percentage of croscarmellose sodium incorporated was the most important factor affecting the disintegration time and dissolution parameter followed by the hardness value and their interaction effect. Compression force showed a superior influence to increase RDT's porosity and to fasten disintegration rather than swelling action by croscarmellose sodium. On the other hand, croscarmellose sodium was most important for the initial simvastatin release. The results suggest the potential use of poloxamer 188-based SD in RDT for the oral delivery of poor water-soluble antihyperlipidemic drug, simvastatin.