CN102608057A - Method for measuring contents of lamivudine and zidovudine in mixture - Google Patents

Abstract

The invention discloses a method for measuring contents of lamivudine and zidovudine in a mixture. Firstly, a prediction model of a relation between concentration and optical parameters of a standard sample is established through a method which is as follows: mixing the lamivudine and the zidovudine uniformly, and preparing into standard samples with different concentrations; collecting terahertz spectroscopies corresponding to the standard samples with different concentrations, wherein the scanning range of the spectroscopy is 0.1-3.0THz; converting the collected terahertz spectroscopies into the optical parameters of the standard samples; establishing the prediction model of the standard samples according to the concentrations of the standard samples and corresponding optical parameters of the standard samples; and collecting a terahertz spectroscopy of an unknown sample, extracting corresponding optical parameters, inputting the optical parameters into the prediction model, and determining the content of each component in the unknown sample. The method for measuring contents of the lamivudine and the zidovudine in the mixture has the advantages of simple measuring method, quickness and convenience in measurement, and the like.

Description

A kind of method of measuring Lamivudine and Zidovudine content in the potpourri

Technical field

The present invention relates to a kind of method of measuring Lamivudine and Zidovudine content in the potpourri, especially a kind of method of utilizing THz wave spectral technology quick nondestructive to measure Lamivudine and Zidovudine content in the potpourri.

Background technology

Lamivudine (lamivudine) and Zidovudine (zidovudine) are two kinds of nucleotide reverse transcriptase inhibitors, are used to treat human immunodeficiency virus (HIV) and infect, and the treatment works well for the two drug combination of clinical proof.

The method of Lamivudine and Zidovudine content mainly is ultraviolet (UV) spectral technique, high performance liquid chromatography (HPLC) and capillary electrophoresis in the mensuration potpourri at present.But Lamivudine and Zidovudine all do not have tangible fingerprint absorption peak or overlapped being difficult to of both absorption peaks to distinguish at ultraviolet band, and ultraviolet photon energy height may produce ionization destruction to sample; The specimen preparation of HPLC method is complicated, the test duration is long, can not accomplish quick measurement; In addition, though Capillary Electrophoresis can be measured the content of Lamivudine and Zidovudine in the biological fluid respectively, can not measure in the medicine both content simultaneously.Therefore need a kind ofly can to can't harm, the means of Lamivudine and Zidovudine content in the fast detecting potpourri.

Summary of the invention

The present invention is intended to overcome the deficiency of traditional detection method, and a kind of method of measuring Lamivudine and Zidovudine content in the potpourri is provided.

The method of Lamivudine and Zidovudine content is following in the mensuration potpourri provided by the present invention:

---set up the forecast model that concerns about between the concentration of standard model and the optical parametric through following method:

Lamivudine and Zidovudine are mixed, process the standard model that concentration does not wait; Gather the pairing Terahertz wave spectrum of said standard model of each concentration, its wave spectrum sweep limit is 0.1～3.0THz; The Terahertz wave spectrum of being gathered is converted into the optical parametric of said standard model; Set up the forecast model of standard model according to the optical parametric of the concentration of each standard model and corresponding standard model;

---gather the Terahertz wave spectrum of unknown sample, extract its corresponding optical parametric, and this optical parametric is input in the said forecast model, confirm each components contents in the unknown sample.

Further, optical parametric according to the invention is absorption coefficient or transmitance.

Further, when the present invention set up said forecast model, the optical parametric characteristic of correspondence absorption bands of said each standard model was 0.2～1.2THz.

Further, during the Terahertz wave spectrum of collected specimens of the present invention, used method is: each sample is repeatedly scanned, the terahertz signal that measures is got arithmetic mean.

Further, the concentration of standard model according to the invention is Lamivudine or mass percent concentration, volumetric molar concentration, N or the quality-volumetric concentration of Zidovudine in potpourri.

Further, the present invention adopts transmission or reflection mode to gather the Terahertz wave spectrum of said sample.

The present invention can can't harm, detect simply, quickly and accurately the content of Lamivudine and Zidovudine in the potpourri.More particularly, advantage is following:

(1) fingerprint peaks

The energy of transition is roughly suitable between the vibration of the photon energy of THz wave and most of organic molecule and molecular group and the rotational energy level; Therefore the THz of material spectrum has comprised abundant physics and chemical information, and Lamivudine and Zidovudine all exist fingerprint peaks at terahertz wave band.

(2) harmless

The photon energy of THz ripple very little (having only milli electron-volt magnitude) can be avoided in the test process sample being caused harmful ionization, carries out Non-Destructive Testing.

(3) quick

The THz wave detection technique is a kind of of spectrum detection technique, has short advantage of spectral detection time.

(4) multicomponent is measured simultaneously

Lamivudine and Zidovudine be at the fingerprint peaks obvious difference of terahertz wave band, can utilize fingerprint peaks to measure the content of Lamivudine and Zidovudine in the potpourri simultaneously.

(5) the present invention provides technical foundation for the online in real time detection of Lamivudine in the potpourri and Zidovudine content.

With reference to the following description of advantages example property embodiment, each characteristic of the present invention will become more clear.

Description of drawings

The THz wave absorption spectra of Fig. 1 Lamivudine;

The THz wave absorption spectra of Fig. 2 Zidovudine;

The standard model absorption spectra that the transmission of Fig. 3 THz-TDS system records;

The unknown sample absorption spectra that the transmission of Fig. 4 THz-TDS system records;

Fig. 5 uses predicted value and the comparison diagram of actual value of the Lamivudine mass percent concentration of absorption coefficient;

Fig. 6 uses predicted value and the comparison diagram of actual value of the Zidovudine mass percent concentration of absorption coefficient;

The standard model transmitance that the transmission of Fig. 7 THz-TDS system records;

The unknown sample transmitance that the transmission of Fig. 8 THz-TDS system records;

Fig. 9 uses predicted value and the comparison diagram of actual value of the Lamivudine mass percent concentration of transmitance;

Figure 10 uses predicted value and the comparison diagram of actual value of the Zidovudine mass percent concentration of transmitance.

Embodiment

A kind of method of measuring Lamivudine and Zidovudine content in the potpourri, step is following:

(1), sets up forecast model

Adopt mathematical method set up sample concentration with the forecast model of sample optical parametric.The mathematical method that adopts can comprise PLS, linear regression, multiple linear regression, artificial neural network.Common similar sample was verified during preferable mathematical model utilization was produced, and obtained after optimizing repeatedly according to the error requirements in the actual production.

Described forecast model is set up through following method:

A configuration standard sample

Lamivudine and Zidovudine are mixed, process the standard model that concentration does not wait;

B gathers the standard model wave spectrum

Gather the corresponding Terahertz wave spectrum of each concentration standard sample, said wave spectrum sweep limit is generally: 0.1～3.0THz.Test environment is generally dry nitrogen environment, and temperature is generally room temperature.

The pre-service of c wave spectrum

Convert the standard model Terahertz wave spectrum of gathering into optical parametric, said optical parametric is absorption coefficient or transmitance.

D sets up forecast model

Concentration and the optical parametric corresponding with this sample according to each standard model are set up forecast model; And the optical parametric matrix of each standard model imported said forecast model; Utilize each components contents in each standard model of forecast model prediction, with the quality of evaluation model.

For example, adopt offset minimum binary (PLS) Return Law to set up the forecast model of sample concentration and sample optical parametric.Pattern function is: Y=XB+E, and wherein X is the optical parametric matrix of all standard models under the special frequency, and as input matrix, Y is all standard model concentration matrixes, and as output matrix, B is the regression coefficient matrix, and E is a residual matrix.

Introduce parameter correlation coefficient (R), root-mean-square error (RMSE), absolute deviation (E _Ab), the quality of valuation prediction models, expression formula is following:

$R=\frac{\underset{i=1}{\overset{N}{\mathrm{\Σ}}}(y_r^i-\stackrel{\‾}{y_r})(y_p^i-\stackrel{\‾}{y_p})}{\sqrt{\underset{i=1}{\overset{N}{\mathrm{\Σ}}}{(y_r^i-\stackrel{\‾}{y_r})}^2\underset{i=1}{\overset{N}{\mathrm{\Σ}}}{(y_p^i-\stackrel{\‾}{y_p})}^2}}$

$\mathrm{RMSE}=\sqrt{\frac{1}{N}\·\underset{i=1}{\overset{N}{\mathrm{\Σ}}}{(y_p^i-y_r^i)}^2}$

$E_{\mathrm{ab}}=\max \left|(y_p^i-y_r^i)\right|,$ i＝1，2，3...，N.

Y wherein _r ⁱAnd y _p ⁱRepresent the concentration input value and the predicted value of i sample,

With

Be the mean value of sample concentration input value and the mean value of predicted value, N is the total sample number amount.

(2), detect unknown sample

The optical parametric matrix of unknown sample is imported said forecast model, confirm each components contents in the unknown sample.

In order to improve the precision of measuring the result; The characteristic absorption wave band of setting up forecast model accepted standard sample is 0.2～1.2THz; With repeatedly scanning the disposal route of getting arithmetic mean, the concentration of standard model and unknown sample generally can adopt Lamivudine or Zidovudine mass percent concentration, volumetric molar concentration, N, the quality-volumetric concentration in potpourri when gathering the Terahertz wave spectrum.

During the Terahertz wave spectrum of collected specimens, can adopt transmission or reflection measurement.

Top description only is used to realize embodiment of the present invention, in any modification or the local replacement that do not break away from the scope of the invention, all should belong to the scope of claim of the present invention.

Embodiment

Pass through example in detail the present invention below, but the present invention is not limited to this.

Embodiment 1

(1) sets up forecast model

Adopt mathematical method to set up the forecast model of sample concentration and sample optical parametric, concrete method for building up is following:

A, preparation standard model

According to different mass ratio weighing Lamivudine and Zidovudines, after fully mixing, weigh out the potpourri about 200mg, with the pressure of 4Mpa, being pressed into diameter is that 13mm, thickness are the standard model about 1mm, sample structure is even, both ends of the surface are parallel.

16 samples have been prepared; Wherein the mass percent concentration of the Lamivudine in the sample is 11 samples of 0%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90% and 100% are used for model as standard model (calibration set) foundation; Content is 5%; 5 samples of 15%, 22%, 25% and 35% are used for the check of model as unknown sample (checking collection).

B, collection standard model wave spectrum

(terahertz time-domain spectroscopy, THz-TDS) transmissive system is measured standard model, obtains the Terahertz wave spectrum of sample in 0.1～3.0THz scope to adopt terahertz time-domain spectroscopic technology.Wherein, the terahertz signal that measures with not through sample the time is a reference signal, and the terahertz signal that measures with through sample the time is a sample signal.Measurement environment is dry nitrogen environment, and temperature is a room temperature.

C, wave spectrum pre-service

Handle the Terahertz wave spectrum of standard model; Obtain the absorption coefficient of sample; Computing formula is:

wherein α (ω) be the absorption coefficient of sample; N (ω) is the refractive index real part of sample; Be called for short refractive index; D is a thickness of sample; ω is a frequency, and φ (ω) and ρ (ω) are respectively the phase differential and the quotient of amplitudes of sample and reference signal, and c is the light velocity in the vacuum.

Fig. 1 and Fig. 2 are respectively Lamivudine and the Zidovudine sample is composed at the absorption coefficient of 0.2～1.2THz wave band, and visible by Fig. 1 and Fig. 2, there are absorption peak in Lamivudine and Zidovudine at 0.66THz and 0.85THz place respectively, and differ greatly.Fig. 3 is the absorption coefficient spectrum of standard model at 0.2～1.2THz wave band; Can clearly tell all standard models from Fig. 3 and all simultaneously have characteristic absorption peak at 0.66THz and 0.85THz; And among Fig. 3 along with the increase of Lamivudine content; The absorption coefficient of standard model at the 0.66THz place is and increases progressively trend; The trend and the absorption coefficient at the 0.85THz place tapers off, all there is approximate linear in the mass percent concentration of standard model Lamivudine in the absorption coefficient at 0.66THz and 0.85THz place and sample.

D, set up forecast model

The absorption coefficient of the mass percent concentration of Lamivudine and counter sample is set up forecast model in the according to standard sample.

Adopt PLS to set up forecast model: Y=XB+E; Absorption coefficient matrix with following 11 standard models of 0.2～1.2THz frequency range is input matrix X; Mass percent concentration matrix with Lamivudine in 11 standard models is output matrix Y; B is the regression coefficient matrix, and E is a residual matrix.Set up after the model, again standard model is taken back forecast model and verify, the related coefficient that obtains model is 0.9994, and root-mean-square error is 1.18%.Fig. 5 is seen in the contrast of the predicted value of Lamivudine mass percent concentration and actual value in the standard model, and Fig. 6 is seen in the contrast of the predicted value of Zidovudine mass percent concentration and actual value in the standard model.The concrete numerical value of Lamivudine predicted value and actual value is seen table 1, and the concrete numerical value of Zidovudine predicted value and actual value is seen table 2.

(2) detect unknown sample

Gather unknown sample Terahertz wave spectrum, extract corresponding absorption coefficient, the result is as shown in Figure 4.The absorption coefficient of 5 unknown samples is imported said forecast model, and the related coefficient that obtains model is 0.9978, and root-mean-square error then is 1.09%.Fig. 5 is seen in the contrast of the predicted value of Lamivudine mass percent concentration and actual value in the unknown sample, and Fig. 6 is seen in the contrast of the predicted value of Zidovudine mass percent concentration and actual value in the unknown sample.The concrete numerical value of Lamivudine predicted value and actual value is seen table 1, and the concrete numerical value of Zidovudine predicted value and actual value is seen table 2.Visible by table 2 and Fig. 5, predicted value and actual value are approaching, and macro-forecast is effective.

The actual value of Lamivudine and predicted value in table 1 sample

The actual value of Zidovudine and predicted value in table 2 sample

The advantage of present embodiment is:

1, all there are fingerprint peaks in Lamivudine and Zidovudine at terahertz wave band.

0.66THz and transition institute energy requirement is roughly suitable between the vibration of the photon energy of 0.85THz difference territory Lamivudine and Zidovudine molecular group and the rotational energy level; Therefore there is fingerprint peaks in they at 0.66THz and 0.85THz place respectively, and are as depicted in figs. 1 and 2 respectively.

2, the precision as a result of quantitative test is high

Absorption coefficient is the build-in attribute of sample, and it is little influenced by extraneous factor, so the root-mean-square error of model is respectively 1.18% and 1.09% when utilizing absorption coefficient prediction standard model and unknown sample, the precision as a result of quantitative test is superior to 1.2%.

Embodiment 2

The method of Lamivudine and Zidovudine content in the mensuration potpourri of present embodiment is following with embodiment 1 difference:

1, the optical parametric of sample is a transmitance.

2, the computing formula of transmitance is: H=E _Sample/ E _RefWherein, H is the transmitance of sample, E _SampleAnd E _RefBe respectively reference signal and sample signal.

3, the transmitance of standard model and unknown sample is seen Fig. 7 and Fig. 8 respectively.

All the transmitance at 0.66THz and 0.85THz is lower can clearly to tell standard model and unknown sample from Fig. 7 and Fig. 8, and this is because the cause of sample fingerprint peaks.Among the figure along with the increase of Lamivudine content; The transmitance of sample at the 0.66THz place trend that tapers off; And the transmitance at the 0.85THz place is and increases progressively trend, and all there is linear approximate relationship in sample in the transmitance at 0.66THz and 0.85THz place and the content of Lamivudine among Fig. 7 and Fig. 8.

4, Fig. 9 is seen in the contrast of the predicted value of Lamivudine content and actual value in the sample; Figure 10 is seen in the contrast of the predicted value of Lamivudine content and actual value in the sample.

Fig. 9 shows the contrast of selecting Lamivudine prediction content and actual content in the sample that 0.2～1.2THz frequency range obtains; Figure 10 shows the contrast of selecting Zidovudine prediction content and actual content in the sample that 0.2～1.2THz frequency range obtains; The result shows that predicted value and actual value are approaching, shows that the precision that changes method is high.

The advantage of present embodiment is: aspect the extraction of optical parametric, the transmitance specific absorptivity extracts more easily.

Directly use formula H=E because extract transmitance _Sample/ E _RefNeed on the basis of transmitance order and extract absorption coefficient

Wherein:

$\mathrm{\ρ}\left(\mathrm{\ω}\right)=\frac{4{[n^2\left(\mathrm{\ω}\right)+k^2\left(\mathrm{\ω}\right)]}^{1/2}}{{[n\left(\mathrm{\ω}\right)+1]}^2+k^2\left(\mathrm{\ω}\right)}{e}^{-k_2\left(\mathrm{\ω}\right)\mathrm{d\ω}/c}$

The computing formula of refractive index, extinction coefficient and the absorption coefficient through the approximate treatment derived sample is generally speaking:

$\left\{\begin{array}{c}n\left(\mathrm{\ω}\right)=\mathrm{\φ}\left(\mathrm{\ω}\right)\frac{c}{\mathrm{\ωd}}+1\\ k\left(\mathrm{\ω}\right)=\ln \left[\frac{4n\left(\mathrm{\ω}\right)}{\mathrm{\ρ}\left(\mathrm{\ω}\right){(n\left(\mathrm{\ω}\right)+1)}^2}\right]\frac{c}{\mathrm{\ωd}}\\ \mathrm{\α}\left(\mathrm{\ω}\right)=\frac{2\mathrm{\ω}}{c}k\left(\mathrm{\ω}\right)=\frac{2}{d}\ln \left[\frac{4n\left(\mathrm{\ω}\right)}{\mathrm{\ρ}\left(\mathrm{\ω}\right){(n\left(\mathrm{\ω}\right)+1)}^2}\right]\end{array}\right.$

Can know that from above analysis the leaching process specific absorptivity of transmitance is simple.

Embodiment 3

The method of Lamivudine and Zidovudine content in the mensuration potpourri of present embodiment is following with the difference of embodiment 1:

1, adopts the Terahertz wave spectrum of THz-TDS reflecting system collected specimens.

Signal with the metallic mirror surface reflection when 2, gathering the Terahertz wave spectrum is a reference signal, and the signal of sample surfaces reflection is a sample signal.

3, the computing formula of absorption coefficient is: $\mathrm{\α}=\frac{2\mathrm{\ω\; k}}{c}=\frac{4\mathrm{\π\; \ν}}{c}\frac{2\left|\mathrm{\γ}\right|\mathrm{Sin}\mathrm{\φ}}{1+{\left|\mathrm{\γ}\right|}^2-2\left|\mathrm{\γ}\right|\mathrm{Cos}\mathrm{\φ}}$

Wherein | γ |=e ^{-i φ}(n-ik-1)/(n+ik+1)

α is the absorption coefficient of sample, and k is an extinction coefficient, and v is a frequency, and c is the light velocity in the vacuum, and γ and φ are respectively the amplitude and the phase places of sample reflection coefficient.

The advantage of present embodiment is: the signal to noise ratio (S/N ratio) of reflection measurement is high, can obtain the spectral range of broad, and it is big or reflect big sample measurement to can be used for absorption coefficient.

Claims (6)

1. method of measuring Lamivudine and Zidovudine content in the potpourri is characterized in that:

---set up the forecast model that concerns about between the concentration of standard model and the optical parametric through following method:

Lamivudine and Zidovudine are mixed, process the standard model that concentration does not wait; Gather the pairing Terahertz wave spectrum of said standard model of each concentration, its wave spectrum sweep limit is 0.1 ~ 3.0THz; The Terahertz wave spectrum of being gathered is converted into the optical parametric of said standard model; Set up the forecast model of standard model according to the optical parametric of the concentration of each standard model and corresponding standard model;

---gather the Terahertz wave spectrum of unknown sample, extract its corresponding optical parametric, and this optical parametric is input in the said forecast model, confirm each components contents in the unknown sample.

2. method according to claim 1 is characterized in that: said optical parametric is absorption coefficient or transmitance.

3. method according to claim 1 is characterized in that: when setting up said forecast model, the optical parametric characteristic of correspondence absorption bands of said each standard model is 0.2 ~ 1.2THz.

4. method according to claim 1 is characterized in that, during the Terahertz wave spectrum of collected specimens, used method is: each sample is repeatedly scanned, the terahertz signal that measures is got arithmetic mean.

5. method according to claim 1 is characterized in that: the concentration of said standard model is Lamivudine or mass percent concentration, volumetric molar concentration, N or the quality-volumetric concentration of Zidovudine in potpourri.

6. according to the arbitrary described method of claim 1 to 5, it is characterized in that: adopt transmission or reflection mode to gather the Terahertz wave spectrum of said sample.

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