Superior performance of engineered mannitol as a carrier in dry powder inhalations containing salbutamol sulphate

The use of freeze drying technique can constitute an important step used in the pharmaceutical industry towards preparing freeze dried carrier particles which could help to solve some problems connected to drug-carrier dry powder aerosol formulations

Effects of various penetration enhancers on percutaneous absorption of piroxicam from emulgels

A suitable emulgel formulation of piroxicam was prepared and its percutaneous permeation was investigated using Wistar rat skin and diffusion cell technique. The concentrations of the drug in receptor phase of diffusion cells were measured using HPLC method. The effect of three types of penetration enhancers (Myrj 52, cineol and Transcutol P) with different concentrations on transdermal permeation of the drug was also evaluated. Flux, Kp and enhancement ratios (ERs) of piroxicam in the presence of enhancers was measured and compared with emulgel base alone and simple commercial gel. The results showed a significant enhancement in the flux from emulgel base compared to hydroalcoholic gel formulation (9.91 folds over simple gel). The highest enhancement ratio (ER=3.11) was observed for Myrj 52 at the concentration of 0.25%. Higher concentrations of Myrj 52did not show any enhancement in the drug flux due to micelle formation and solubilization of the drug by micelles. The increase in solubility, in turn, increases the saturated concentration and reduces the thermodynamic activity of the drug. Transcutol® P with concentrations higher than 0.25% w/w showed burst transportation of the drug through the skin. All concentrations of cineol and Transcutol did not show any enhancing effects over emulgel base alone (ER <1)

Physico-mechanical and dissolution behaviours of ibuprofen crystals crystallized in the presence of various additives

Background and the purpose of the study: The success of any direct-tableting procedure is strongly affected by the quality of the crystals used in the process. Ibuprofen is a poorly compactible drug with a high tendency for capping. In order to use ibuprofen in direct compression formulations, physico-mechanical properties of ibuprofen should be improved considerably. The aim of the present investigation was to employ crystallization techniques in order to improve the physicomechanical properties of ibuprofen for direct compression. Methods: The experimental methods involved the preparation of ibuprofen crystals by solvent change technique. Ibuprofen was dissolved in ethanol and crystallized out with water in the absence or presence of various hydrophilic additives (PEG 6000, 8000, Brij 98P and polyvinyl alcohol 22000, PVA 22000) with different concentrations. The physico-mechanical properties of the ibuprofen crystals were studied in terms of flow, density, tensile strength and dissolution behaviour. Morphology of ibuprofen crystals was studied by scanning electron microscopic (SEM). Solid state of the recrystallized particles was also investigated using differential scanning calorimeter (DSC) and FT-IR. Results: Ibuprofen samples crystallized in the presence of PEG 6000 and 8000 and PVA showed remarkable increase in the tensile strengths of the directly compressed tablets, while some other additives, i.e. Brij 98P did not produce improved ibuprofen crystals. Ibuprofen powders made from particles obtained in the presence of PVA and Brij 98P showed similar dissolution profiles to the commercial ibuprofen particles. DSC and FT-IR results ruled out any significant interaction between ibuprofen and additives except for the samples crystallized in the presence of PEG 8000. Conclusion: The crystal habit of ibuprofen can be altered successfully by the crystallization technique which was developed in this study. The crystals developed in the presence of certain additives can be recommended for direct compression

Utjecaj različitih površinski aktivnih tvari i njihovih koncentracija na kontrolirano oslobađanje kaptoprila iz polimernih matriksa

Various methods are available to formulate water soluble drugs into sustained release dosage forms by retarding the dissolution rate. One of the methods used to control drug release and thereby prolong therapeutic activity is to use hydrophilic and lipophilic polymers. In this study, the effects of various polymers such as hydroxypropyl methylcellulose (HPMC), ethylcellulose (EC) and sodium carboxymethylcellulose (CMC) and surfactants (sodium lauryl sulphate, cetyltrimethylammonium bromide and Arlacel 60) on the release rate of captopril were investigated. The results showed that an increase in the amount of HPMC K15M resulted in reduction of the release rate of captopril from these matrices. When HPMC was partly replaced by NaCMC (the ratio of HPMC/NaCMC was 5:1), the release rate of the drug significantly decreased. However, there was no significant difference in release rate of captopril from matrices produced with ratios of 5:1 and 2:1 of HPMC/NaCMC. The presence of lactose in matrices containing HPMC and NaCMC increased the release rate of captopril. It was interesting to note that although partial replacement of HPMC by EC reduced the release rate of the drug (ratio of HPMC/EC 2:1), the release rate was increased when the ratio of HPMC/EC was reduced to 1:1. The effects of various surfactants on the release rate of captopril from HPMC/EC 1:1 matrices were also investigated. The results showed that the surfactants did not significantly change the release rate of the drug. Release data were examined kinetically and the ideal kinetic models were estimated for the drug release. The kinetic analysis of drug release data from various formulations showed that incorporation of surfactants in HPMC/EC matrices did not produce a zero-order release pattern.Postoje različite metode formuliranja vodotopljivih lijekova u dozirane ljekovite oblike s polaganim oslobađanjem. Jedan od načina postizanja kontroliranog otpuštanja, a prema tome i produljenog učinka je upotreba hidrofilnih i lipofilnih polimera. U ovom radu proučavan je utjecaj različitih polimera poput hidroksipropil metilceluloze (HPMC), etilceluloze (EC) i natrijeve soli karboksimetilceluloze (NaCMC) i površinski aktivnih tvari (natrijevog lauril-sulfata, cetiltrimetilamonijevog bromida i Arlacela 60) na oslobađanje kaptoprila. Rezultati pokazuju da povećanje količine HPMC K15M ima za posljedicu smanjenje oslobađanja kaptoprila iz matriksa. Ako se HPMC djelomično zamijeni s NaCMC (omjer HPMC/NaCMC 5:1), oslobađanje ljekovite tvari značajno se smanjuje. Međutim, nema značajne razlike u oslobađanju kaptoprila iz matriksa s omjerom HPMC/NaCMC 5:1 i 2:1. Prisutnost laktoze u matriksu koji sadrži HPMC i NaCMC povećalo je oslobađanje kaptoprila. Iako djelomična zamjena HPMC s EC smanjuje oslobađanje ljekovite tvari (omjer HPMC/EC 2:1), oslobađanje se povećava uz omjer HPMC/EC 1:1. Nadalje, ispitivan je utjecaj površinski aktivnih tvari na oslobađanje kaptoprila iz matriksa u kojima je omjer HPMC/EC (1:1). Može se zaključiti da površinski aktivne tvari ne utječu značajno na oslobađanje ljekovite tvari. U sklopu istraživanja određen je i kinetički model oslobađanja kaptoprila. Analiza kinetičkih podataka ukazuje da dodatak površinski aktivnih tvari u HPMC/EC matrikse ne slijedi kinetiku nultog reda

Poboljšanje fizičko-mehaničkih svojstava karbamazepina prekristalizacijom pri različitim pH

The morphology of crystals has an appreciable impact on the physicochemical properties of drugs. Drug properties such as flowability, dissolution, hardness and bioavailability may be affected by crystallinity behaviors of drugs. The objective of this study was to achieve improved physicomechanical properties of carbamazepine powder through recrystallization from aqueous solutions at different pH values. For this purpose, carbamazapine was recrystallized from aqueous solutions at different pH values (1, 7, 11). The morphology of crystals was investigated using scanning electron microscopy; X-ray powder diffraction (XRPD) was used to identify polymorphism; thermodynamic properties were analyzed using differential scanning calorimetery (DSC). Dissolution was determined using USP dissolution apparatus. Mechanical behavior of recrystallized carbamazepine powders was investigated by making tablets under different compaction pressures and measuring their hardness. SEM studies showed that carbamazepine crystallization in different media affected the morphology and size of carbamazepine crystals. The shape of carbamazepine crystals changed from flaky or thin plate-like to needle-shaped. XRPD and DSC results ruled out any crystallinity changes occurring due to the temperature or pH of crystallization media. The crushing strength of tablets indicated that all the recrystallized carbamazepine samples had better compactibility than the original carbamazepine powder. In vitro dissolution studies of carbamazepine samples showed a higher dissolution rate of carbamazepine crystals obtained from media with pH 11 and 1. Carbamazepine particles recrystallized from aqueous solutions of different pH values (all media) appeared to have superior mechanical properties to those of the original carbamazepine sample.Morfologija kristala ima značajan utjecaj na fizičko-mehanička svojstva lijekova. Kristaliničnost može utjecati na tečnost, oslobađanje, tvrdoću i bioraspoloživost lijekova. Cilj ovog rada bio je poboljšati fizičko-mehanička svojstva praha karbamazepina prekristalizacijom iz vodenih otopina pri različitim pH vrijednostima (1, 7 i 11). Fizičko-mehanička svojstva prekristaliziranog karbamazepina određivana su na sljedeći način: morfologija kristala ispitivana je pretražnom elektronskom mikroskopijom, polimorfi su identificirani rendgenskom difrakcijom praha (XRPD), a termodinamička svojstva analizirana su diferencijalnom pretražnom kalorimetrijom (DSC). Topljivost je određena pomoću aparata prema USP. Mehanička svojstva prekristaliziranog karbamazepina ispitivana su tijekom tabletiranja pri različitim tlakovima i mjerenjem tvrdoće nastalih tableta. SEM ispitivanja pokazala su da kristalizacija karbamazepina iz različitih medija utječe na morfologiju i veličinu kristala. Oblik kristala mijenjao se od pahuljastog ili pločastog do igličastog. Rezultati dobiveni XRPD i DSC metodama isključili su promjene kristaliničnosti zbog temperature ili pH medija. Mjerenjem lomljivosti tableta utvrđeno je da su svi prekristalizirani uzorci karbamazepina bili kompaktniji od polaznog praškastog uzorka. Ispitivanja topljivosti in vitro pokazala su da su kristali dobiveni iz otopine s pH 11 i 1 topljiviji. Uzorci karbamazepina dobiveni prekristalizacijom iz vodenih otopina različite pH vrijednosti imali su bolja mehanička svojstva od originalnog uzorka karbamazepina

Characterization of magnetically triggerable millirobots for on demand drug delivery using a brightfield microscopy metrology system

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