Determination of the thickness of plastic sheets used in blister packaging by near infrared spectroscopy: development and validation of the method

A near infrared (NIR) quantitative analysis method was developed for determining the thickness of PVC-based plastic sheets used as pharmaceutical packs. Samples that can be analyzed are transparent films made of polyvinyl chloride (PVC), PVC coated with polyvinylidene dichloride (PVDC) or PVC coated with Thermoelast (TE) and PVDC. The method, based on a partial least squares (PLS) algorithm, is used together with a previously developed NIR identification method to acquire simultaneously qualitative and quantitative information about the samples. Validation of the quantitative method was conducted according to the very recent European Agency for the Evaluation of Medicinal Products (EMEA) guidance on the use of NIR spectroscopy. Suggestions were made for a better statistical evaluation of the calibration model prior to validation. Validation consisted of the study of specificity, accuracy (mean recovery from the reference values was 99.56%), precision (repeatability and intermediate precision were <0.6%), linearity, quantification limit (41 microm), and robustness of the method. This demonstration of the applicability of NIR spectroscopy as a validated quality control tool for pharmaceutical packaging films will hopefully facilitate the acceptance of NIR spectroscopy in pharmaceutical laboratories.

Development and validation of a near-infrared method for the quantitation of caffeine in intact single tablets

A near-infrared spectroscopic method was developed and validated for determining the caffeine concentration of single and intact tablets in a Finnish pharmaceutical product containing 58.82% (m/m) caffeine.The spectral region of interest contained a total of 474 data points. The second derivative of Savitsky-Golay, a standard normal variate, and mean centering were used as spectral preprocessing options. The feasibility study showed nonuniformity of caffeine repartition within each tablet. Thus, spectra were recorded from both faces of the tablets, and the analysis result for a single tablet was reported as the average of both face determinations. Precision of the method was validated because the relative standard deviations from repeatability and intermediate precision tests were below 0.75% (m/m). Accuracy validation proved that the NIR results were not significantly different (P = 0.09, n = 12) from the results obtained with the reference HPLC method. The limit of quantification for caffeine was 13.7% (m/m) in the tablets. The method was found to be unaffected by NIR source replacement, but the repeatability of the results was affected if the sample holder was not placed in the correct position in the light beam. Routine NIR analysis of caffeine in tablet form was found to be more flexible and much faster than that performed with the HPLC method.

Simultaneous analysis of alkamides and caffeic acid derivatives for the identification of Echinacea purpurea, Echinacea angustifolia, Echinacea pallida and Parthenium integrifolium roots

A reversed-phase HPLC method was developed using a computer simulation program for the identification of dried roots of Echinacea purpurea, E. angustifolia, E. pallida and Parthenium integrifolium. Hydrophilic and lipophilic compounds were analysed simultaneously leading to a two-fold decrease in analysis time compared to traditional HPLC methods.

Fast identification of Echinacea purpurea dried roots using near-infrared spectroscopy

Near-infrared (NIR) reflectance spectroscopy was used to develop a fast identification method for Echinacea purpurea dried milled roots. Method development was carried out using a PLS (partial least-squares) algorithm and pretreatment options. The aim of this qualitative analysis was to confirm the identity of E. purpurea and to detect the presence of fraud, i.e., samples adulterated or substituted by Echinacea angustifolia, Echinacea pallida, or Parthenium integrifolium. Specificity was demonstrated by testing a validation set against the method. A total of 10% of the E. purpurea batches (true samples) and 0% of the false samples from that validation set were misidentified by the method. The misidentification was due to the difference in particle size distribution of one E. purpurea batch compared to that of the other samples. Adulterated E. purpurea samples can be detected at a minimum of 10% of adulteration. This study demonstrates that NIR spectroscopy is a good tool for the fast identification of E. purpurea roots if the samples are milled using the same procedure as for the calibration samples. The method is robust with respect to the origin of the samples and can be used routinely by the pharmaceutical industry or herbal suppliers to avoid mislabeling errors or adulteration.

Near infrared reflectance spectroscopy for the fast identification of PVC-based films

Near infrared (NIR) reflectance spectroscopy was used to develop a non-destructive and rapid qualitative method for the analysis of plastic films used by the pharmaceutical industry for blistering. Three types of films were investigated: 250 microm PVC [poly(vinyl chloride)] films, 250 microm PVC films coated with 40 g m(-2) of PVDC [poly(vinylidene dichloride)] and 250 microm PVC films coated with 5 g m(-2) of TE (Thermoelast) and 90 g m(-2) of PVDC. Three analyses were carried out using different pre-treatment options and a PLS (partial least squares) algorithm. Each analysis was aimed at identifying one type of film and rejecting all types of false sample (different thickness, colour or layer). True and false samples from four plastics manufacturers were included in the calibration sets in order to obtain robust methods that were suitable regardless of the supplier. Specificity was demonstrated by testing validation sets against the methods. The tests showed 0% of type I (false negative identification) and 1% of type II errors (false positive identification) for the PVC method, 13 and 3%, respectively, for the PVC-PVDC method and no error for the PVC-TE-PVDC method. Type II errors, mostly due to the slight sensitivity of the methods to film thickness, are easily corrected by simple thickness measurements. This study demonstrates that NIR spectroscopy is an excellent tool for the identification of PVC-based films. The three methods can be used by the pharmaceutical industry or plastics manufacturers for the quality control of films used in blister packaging.

Manufacture of polyalkylcyanoacrylate nanoparticles with pilocarpine and timolol by micelle polymerization: factors influencing particle formation

Nanoparticles with pilocarpine and timolol were produced by micelle polymerization. The influence of manufacturing temperature, type of monomer, drug concentration and ethylcyanoacrylate concentration on the particle size were investigated with a Coulter Nano Sizer. The nanoencapsulation succeeded only with the pilocarpine or timolol base, not with the salts of these drugs. Different micelle formation in aqueous medium compared with organic solvents was evidently responsible for this phenomenon. The particle formation was affected both by the manufacturing temperature and the type of monomer. The smallest particles were produced at lower temperatures and with the most lipophilic monomers. The monomer and drug concentration had very little influence on the particle size. The nanoparticles made with pilocarpine were, in general, much bigger than those made with timolol.